source: trunk/third/glib2/gobject/gtype.c @ 21369

/* GObject - GLib Type, Object, Parameter and Signal Library
 * Copyright (C) 1998-1999, 2000-2001 Tim Janik and Red Hat, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General
 * Public License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 */
#include        <config.h>
#include        "gtype.h"

/*
 * MT safe
 */

#include        "gtypeplugin.h"
#include        "gvaluecollector.h"
#include        "gbsearcharray.h"
#include        <string.h>


/* NOTE: some functions (some internal variants and exported ones)
 * invalidate data portions of the TypeNodes. if external functions/callbacks
 * are called, pointers to memory maintained by TypeNodes have to be looked up
 * again. this affects most of the struct TypeNode fields, e.g. ->children or
 * CLASSED_NODE_IFACES_ENTRIES() respectively IFACE_NODE_PREREQUISITES() (but
 * not ->supers[]), as all those memory portions can get realloc()ed during
 * callback invocation.
 *
 * TODO:
 * - g_type_from_name() should do an ordered array lookup after fetching the
 *   the quark, instead of a second hashtable lookup.
 *
 * LOCKING:
 * lock handling issues when calling static functions are indicated by
 * uppercase letter postfixes, all static functions have to have
 * one of the below postfixes:
 * - _I:        [Indifferent about locking]
 *   function doesn't care about locks at all
 * - _U:        [Unlocked invocation]
 *   no read or write lock has to be held across function invocation
 *   (locks may be acquired and released during invocation though)
 * - _L:        [Locked invocation]
 *   a write lock or more than 0 read locks have to be held across
 *   function invocation
 * - _W:        [Write-locked invocation]
 *   a write lock has to be held across function invokation
 * - _Wm:       [Write-locked invocation, mutatable]
 *   like _W, but the write lock might be released and reacquired
 *   during invocation, watch your pointers
 */

static GStaticRWLock            type_rw_lock = G_STATIC_RW_LOCK_INIT;
#ifdef LOCK_DEBUG
#define G_READ_LOCK(rw_lock)    do { g_printerr (G_STRLOC ": readL++\n"); g_static_rw_lock_reader_lock (rw_lock); } while (0)
#define G_READ_UNLOCK(rw_lock)  do { g_printerr (G_STRLOC ": readL--\n"); g_static_rw_lock_reader_unlock (rw_lock); } while (0)
#define G_WRITE_LOCK(rw_lock)   do { g_printerr (G_STRLOC ": writeL++\n"); g_static_rw_lock_writer_lock (rw_lock); } while (0)
#define G_WRITE_UNLOCK(rw_lock) do { g_printerr (G_STRLOC ": writeL--\n"); g_static_rw_lock_writer_unlock (rw_lock); } while (0)
#else
#define G_READ_LOCK(rw_lock)    g_static_rw_lock_reader_lock (rw_lock)
#define G_READ_UNLOCK(rw_lock)  g_static_rw_lock_reader_unlock (rw_lock)
#define G_WRITE_LOCK(rw_lock)   g_static_rw_lock_writer_lock (rw_lock)
#define G_WRITE_UNLOCK(rw_lock) g_static_rw_lock_writer_unlock (rw_lock)
#endif
#define INVALID_RECURSION(func, arg, type_name) G_STMT_START{ \
    static const gchar *_action = " invalidly modified type "; \
    gpointer _arg = (gpointer) (arg); const gchar *_tname = (type_name), *_fname = (func); \
    if (_arg) \
      g_error ("%s(%p)%s`%s'", _fname, _arg, _action, _tname); \
    else \
      g_error ("%s()%s`%s'", _fname, _action, _tname); \
}G_STMT_END
#define g_return_val_if_uninitialized(condition, init_function, return_value) G_STMT_START{     \
  if (!(condition))                                                                             \
    {                                                                                           \
      g_log (G_LOG_DOMAIN, G_LOG_LEVEL_CRITICAL,                                                \
             "%s: initialization assertion failed, use %s() prior to this function",            \
             G_STRLOC, G_STRINGIFY (init_function));                                            \
      return (return_value);                                                                    \
    }                                                                                           \
}G_STMT_END

#ifdef  G_ENABLE_DEBUG
#define DEBUG_CODE(debug_type, code_block)  G_STMT_START {    \
    if (_g_type_debug_flags & G_TYPE_DEBUG_ ## debug_type) \
      { code_block; }                                     \
} G_STMT_END
#else /* !G_ENABLE_DEBUG */
#define DEBUG_CODE(debug_type, code_block)  /* code_block */
#endif  /* G_ENABLE_DEBUG */

#define TYPE_FUNDAMENTAL_FLAG_MASK (G_TYPE_FLAG_CLASSED | \
                                    G_TYPE_FLAG_INSTANTIATABLE | \
                                    G_TYPE_FLAG_DERIVABLE | \
                                    G_TYPE_FLAG_DEEP_DERIVABLE)
#define TYPE_FLAG_MASK             (G_TYPE_FLAG_ABSTRACT | G_TYPE_FLAG_VALUE_ABSTRACT)
#define SIZEOF_FUNDAMENTAL_INFO    ((gssize) MAX (MAX (sizeof (GTypeFundamentalInfo), \
                                                       sizeof (gpointer)), \
                                                  sizeof (glong)))

/* The 2*sizeof(size_t) alignment here is borrowed from
 * GNU libc, so it should be good most everywhere.
 * It is more conservative than is needed on some 64-bit
 * platforms, but ia64 does require a 16-byte alignment.
 * The SIMD extensions for x86 and ppc32 would want a
 * larger alignment than this, but we don't need to
 * do better than malloc.
 */
#define STRUCT_ALIGNMENT (2 * sizeof (gsize))
#define ALIGN_STRUCT(offset) \
      ((offset + (STRUCT_ALIGNMENT - 1)) & -STRUCT_ALIGNMENT)


/* --- typedefs --- */
typedef struct _TypeNode        TypeNode;
typedef struct _CommonData      CommonData;
typedef struct _IFaceData       IFaceData;
typedef struct _ClassData       ClassData;
typedef struct _InstanceData    InstanceData;
typedef union  _TypeData        TypeData;
typedef struct _IFaceEntry      IFaceEntry;
typedef struct _IFaceHolder     IFaceHolder;


/* --- prototypes --- */
static inline GTypeFundamentalInfo*     type_node_fundamental_info_I    (TypeNode               *node);
static        void                      type_add_flags_W                (TypeNode               *node,
                                                                         GTypeFlags              flags);
static        void                      type_data_make_W                (TypeNode               *node,
                                                                         const GTypeInfo        *info,
                                                                         const GTypeValueTable  *value_table);
static inline void                      type_data_ref_Wm                (TypeNode               *node);
static inline void                      type_data_unref_Wm              (TypeNode               *node,
                                                                         gboolean                uncached);
static void                             type_data_last_unref_Wm         (GType                   type,
                                                                         gboolean                uncached);
static inline gpointer                  type_get_qdata_L                (TypeNode               *node,
                                                                         GQuark                  quark);
static inline void                      type_set_qdata_W                (TypeNode               *node,
                                                                         GQuark                  quark,
                                                                         gpointer                data);
static IFaceHolder*                     type_iface_peek_holder_L        (TypeNode               *iface,
                                                                         GType                   instance_type);
static gboolean                         type_iface_vtable_base_init_Wm  (TypeNode               *iface,
                                                                         TypeNode               *node);
static void                             type_iface_vtable_iface_init_Wm (TypeNode               *iface,
                                                                         TypeNode               *node);
static gboolean                         type_node_is_a_L                (TypeNode               *node,
                                                                         TypeNode               *iface_node);


/* --- enumeration --- */

/* The InitState enumeration is used to track the progress of initializing
 * both classes and interface vtables. Keeping the state of initialization
 * is necessary to handle new interfaces being added while we are initializing
 * the class or other interfaces.
 */
typedef enum
{
  UNINITIALIZED,
  BASE_CLASS_INIT,
  BASE_IFACE_INIT,
  CLASS_INIT,
  IFACE_INIT,
  INITIALIZED
} InitState;

/* --- structures --- */
struct _TypeNode
{
  GTypePlugin *plugin;
  guint        n_children : 12;
  guint        n_supers : 8;
  guint        _prot_n_ifaces_prerequisites : 9;
  guint        is_classed : 1;
  guint        is_instantiatable : 1;
  guint        mutatable_check_cache : 1;       /* combines some common path checks */
  GType       *children;
  TypeData * volatile data;
  GQuark       qname;
  GData       *global_gdata;
  union {
    IFaceEntry  *iface_entries;         /* for !iface types */
    GType       *prerequisistes;
  } _prot;
  GType        supers[1]; /* flexible array */
};
#define SIZEOF_BASE_TYPE_NODE()                 (G_STRUCT_OFFSET (TypeNode, supers))
#define MAX_N_SUPERS                            (255)
#define MAX_N_CHILDREN                          (4095)
#define MAX_N_IFACES                            (511)
#define MAX_N_PREREQUISITES                     (MAX_N_IFACES)
#define NODE_TYPE(node)                         (node->supers[0])
#define NODE_PARENT_TYPE(node)                  (node->supers[1])
#define NODE_FUNDAMENTAL_TYPE(node)             (node->supers[node->n_supers])
#define NODE_NAME(node)                         (g_quark_to_string (node->qname))
#define NODE_IS_IFACE(node)                     (NODE_FUNDAMENTAL_TYPE (node) == G_TYPE_INTERFACE)
#define CLASSED_NODE_N_IFACES(node)             ((node)->_prot_n_ifaces_prerequisites)
#define CLASSED_NODE_IFACES_ENTRIES(node)       ((node)->_prot.iface_entries)
#define IFACE_NODE_N_PREREQUISITES(node)        ((node)->_prot_n_ifaces_prerequisites)
#define IFACE_NODE_PREREQUISITES(node)          ((node)->_prot.prerequisistes)
#define iface_node_get_holders_L(node)          ((IFaceHolder*) type_get_qdata_L ((node), static_quark_iface_holder))
#define iface_node_set_holders_W(node, holders) (type_set_qdata_W ((node), static_quark_iface_holder, (holders)))
#define iface_node_get_dependants_array_L(n)    ((GType*) type_get_qdata_L ((n), static_quark_dependants_array))
#define iface_node_set_dependants_array_W(n,d)  (type_set_qdata_W ((n), static_quark_dependants_array, (d)))
#define TYPE_ID_MASK                            ((GType) ((1 << G_TYPE_FUNDAMENTAL_SHIFT) - 1))

#define NODE_IS_ANCESTOR(ancestor, node)                                                    \
        ((ancestor)->n_supers <= (node)->n_supers &&                                        \
         (node)->supers[(node)->n_supers - (ancestor)->n_supers] == NODE_TYPE (ancestor))


struct _IFaceHolder
{
  GType           instance_type;
  GInterfaceInfo *info;
  GTypePlugin    *plugin;
  IFaceHolder    *next;
};
struct _IFaceEntry
{
  GType           iface_type;
  GTypeInterface *vtable;
  InitState       init_state;
};
struct _CommonData
{
  guint             ref_count;
  GTypeValueTable  *value_table;
};
struct _IFaceData
{
  CommonData         common;
  guint16            vtable_size;
  GBaseInitFunc      vtable_init_base;
  GBaseFinalizeFunc  vtable_finalize_base;
  GClassInitFunc     dflt_init;
  GClassFinalizeFunc dflt_finalize;
  gconstpointer      dflt_data;
  gpointer           dflt_vtable;
};
struct _ClassData
{
  CommonData         common;
  guint16            class_size;
  guint              init_state : 4;
  GBaseInitFunc      class_init_base;
  GBaseFinalizeFunc  class_finalize_base;
  GClassInitFunc     class_init;
  GClassFinalizeFunc class_finalize;
  gconstpointer      class_data;
  gpointer           class;
};
struct _InstanceData
{
  CommonData         common;
  guint16            class_size;
  guint              init_state : 4;
  GBaseInitFunc      class_init_base;
  GBaseFinalizeFunc  class_finalize_base;
  GClassInitFunc     class_init;
  GClassFinalizeFunc class_finalize;
  gconstpointer      class_data;
  gpointer           class;
  guint16            instance_size;
  guint16            private_size;
  guint16            n_preallocs;
  GInstanceInitFunc  instance_init;
  GMemChunk        *mem_chunk;
};
union _TypeData
{
  CommonData         common;
  IFaceData          iface;
  ClassData          class;
  InstanceData       instance;
};
typedef struct {
  gpointer            cache_data;
  GTypeClassCacheFunc cache_func;
} ClassCacheFunc;
typedef struct {
  gpointer                check_data;
  GTypeInterfaceCheckFunc check_func;
} IFaceCheckFunc;


/* --- variables --- */
static guint           static_n_class_cache_funcs = 0;
static ClassCacheFunc *static_class_cache_funcs = NULL;
static guint           static_n_iface_check_funcs = 0;
static IFaceCheckFunc *static_iface_check_funcs = NULL;
static GQuark          static_quark_type_flags = 0;
static GQuark          static_quark_iface_holder = 0;
static GQuark          static_quark_dependants_array = 0;
GTypeDebugFlags        _g_type_debug_flags = 0;


/* --- type nodes --- */
static GHashTable       *static_type_nodes_ht = NULL;
static TypeNode         *static_fundamental_type_nodes[(G_TYPE_FUNDAMENTAL_MAX >> G_TYPE_FUNDAMENTAL_SHIFT) + 1] = { 0, };
static GType             static_fundamental_next = G_TYPE_RESERVED_USER_FIRST;

static inline TypeNode*
lookup_type_node_I (register GType utype)
{
  if (utype > G_TYPE_FUNDAMENTAL_MAX)
    return (TypeNode*) (utype & ~TYPE_ID_MASK);
  else
    return static_fundamental_type_nodes[utype >> G_TYPE_FUNDAMENTAL_SHIFT];
}

static TypeNode*
type_node_any_new_W (TypeNode             *pnode,
                     GType                 ftype,
                     const gchar          *name,
                     GTypePlugin          *plugin,
                     GTypeFundamentalFlags type_flags)
{
  guint n_supers;
  GType type;
  TypeNode *node;
  guint i, node_size = 0;
  
  n_supers = pnode ? pnode->n_supers + 1 : 0;
  
  if (!pnode)
    node_size += SIZEOF_FUNDAMENTAL_INFO;             /* fundamental type info */
  node_size += SIZEOF_BASE_TYPE_NODE ();              /* TypeNode structure */
  node_size += (sizeof (GType) * (1 + n_supers + 1)); /* self + ancestors + (0) for ->supers[] */
  node = g_malloc0 (node_size);
  if (!pnode)                                         /* offset fundamental types */
    {
      node = G_STRUCT_MEMBER_P (node, SIZEOF_FUNDAMENTAL_INFO);
      static_fundamental_type_nodes[ftype >> G_TYPE_FUNDAMENTAL_SHIFT] = node;
      type = ftype;
    }
  else
    type = (GType) node;
  
  g_assert ((type & TYPE_ID_MASK) == 0);
  
  node->n_supers = n_supers;
  if (!pnode)
    {
      node->supers[0] = type;
      node->supers[1] = 0;
      
      node->is_classed = (type_flags & G_TYPE_FLAG_CLASSED) != 0;
      node->is_instantiatable = (type_flags & G_TYPE_FLAG_INSTANTIATABLE) != 0;
      
      if (NODE_IS_IFACE (node))
        {
          IFACE_NODE_N_PREREQUISITES (node) = 0;
          IFACE_NODE_PREREQUISITES (node) = NULL;
        }
      else
        {
          CLASSED_NODE_N_IFACES (node) = 0;
          CLASSED_NODE_IFACES_ENTRIES (node) = NULL;
        }
    }
  else
    {
      node->supers[0] = type;
      memcpy (node->supers + 1, pnode->supers, sizeof (GType) * (1 + pnode->n_supers + 1));
      
      node->is_classed = pnode->is_classed;
      node->is_instantiatable = pnode->is_instantiatable;
      
      if (NODE_IS_IFACE (node))
        {
          IFACE_NODE_N_PREREQUISITES (node) = 0;
          IFACE_NODE_PREREQUISITES (node) = NULL;
        }
      else
        {
          guint j;
          
          CLASSED_NODE_N_IFACES (node) = CLASSED_NODE_N_IFACES (pnode);
          CLASSED_NODE_IFACES_ENTRIES (node) = g_memdup (CLASSED_NODE_IFACES_ENTRIES (pnode),
                                                         sizeof (CLASSED_NODE_IFACES_ENTRIES (pnode)[0]) *
                                                         CLASSED_NODE_N_IFACES (node));
          for (j = 0; j < CLASSED_NODE_N_IFACES (node); j++)
            {
              CLASSED_NODE_IFACES_ENTRIES (node)[j].vtable = NULL;
              CLASSED_NODE_IFACES_ENTRIES (node)[j].init_state = UNINITIALIZED;
            }
        }
      
      i = pnode->n_children++;
      pnode->children = g_renew (GType, pnode->children, pnode->n_children);
      pnode->children[i] = type;
    }
  
  node->plugin = plugin;
  node->n_children = 0;
  node->children = NULL;
  node->data = NULL;
  node->qname = g_quark_from_string (name);
  node->global_gdata = NULL;
  
  g_hash_table_insert (static_type_nodes_ht,
                       GUINT_TO_POINTER (node->qname),
                       (gpointer) type);
  return node;
}

static inline GTypeFundamentalInfo*
type_node_fundamental_info_I (TypeNode *node)
{
  GType ftype = NODE_FUNDAMENTAL_TYPE (node);
  
  if (ftype != NODE_TYPE (node))
    node = lookup_type_node_I (ftype);
  
  return node ? G_STRUCT_MEMBER_P (node, -SIZEOF_FUNDAMENTAL_INFO) : NULL;
}

static TypeNode*
type_node_fundamental_new_W (GType                 ftype,
                             const gchar          *name,
                             GTypeFundamentalFlags type_flags)
{
  GTypeFundamentalInfo *finfo;
  TypeNode *node;
  
  g_assert ((ftype & TYPE_ID_MASK) == 0);
  g_assert (ftype <= G_TYPE_FUNDAMENTAL_MAX);
  
  if (ftype >> G_TYPE_FUNDAMENTAL_SHIFT == static_fundamental_next)
    static_fundamental_next++;
  
  type_flags &= TYPE_FUNDAMENTAL_FLAG_MASK;
  
  node = type_node_any_new_W (NULL, ftype, name, NULL, type_flags);
  
  finfo = type_node_fundamental_info_I (node);
  finfo->type_flags = type_flags;
  
  return node;
}

static TypeNode*
type_node_new_W (TypeNode    *pnode,
                 const gchar *name,
                 GTypePlugin *plugin)
     
{
  g_assert (pnode);
  g_assert (pnode->n_supers < MAX_N_SUPERS);
  g_assert (pnode->n_children < MAX_N_CHILDREN);
  
  return type_node_any_new_W (pnode, NODE_FUNDAMENTAL_TYPE (pnode), name, plugin, 0);
}

static inline IFaceEntry*
type_lookup_iface_entry_L (TypeNode *node,
                           TypeNode *iface_node)
{
  if (NODE_IS_IFACE (iface_node) && CLASSED_NODE_N_IFACES (node))
    {
      IFaceEntry *ifaces = CLASSED_NODE_IFACES_ENTRIES (node) - 1;
      guint n_ifaces = CLASSED_NODE_N_IFACES (node);
      GType iface_type = NODE_TYPE (iface_node);
      
      do
        {
          guint i;
          IFaceEntry *check;
          
          i = (n_ifaces + 1) >> 1;
          check = ifaces + i;
          if (iface_type == check->iface_type)
            return check;
          else if (iface_type > check->iface_type)
            {
              n_ifaces -= i;
              ifaces = check;
            }
          else /* if (iface_type < check->iface_type) */
            n_ifaces = i - 1;
        }
      while (n_ifaces);
    }
  
  return NULL;
}

static inline gboolean
type_lookup_prerequisite_L (TypeNode *iface,
                            GType     prerequisite_type)
{
  if (NODE_IS_IFACE (iface) && IFACE_NODE_N_PREREQUISITES (iface))
    {
      GType *prerequisites = IFACE_NODE_PREREQUISITES (iface) - 1;
      guint n_prerequisites = IFACE_NODE_N_PREREQUISITES (iface);
      
      do
        {
          guint i;
          GType *check;
          
          i = (n_prerequisites + 1) >> 1;
          check = prerequisites + i;
          if (prerequisite_type == *check)
            return TRUE;
          else if (prerequisite_type > *check)
            {
              n_prerequisites -= i;
              prerequisites = check;
            }
          else /* if (prerequisite_type < *check) */
            n_prerequisites = i - 1;
        }
      while (n_prerequisites);
    }
  return FALSE;
}

static gchar*
type_descriptive_name_I (GType type)
{
  if (type)
    {
      TypeNode *node = lookup_type_node_I (type);
      
      return node ? NODE_NAME (node) : "<unknown>";
    }
  else
    return "<invalid>";
}


/* --- type consistency checks --- */
static gboolean
check_plugin_U (GTypePlugin *plugin,
                gboolean     need_complete_type_info,
                gboolean     need_complete_interface_info,
                const gchar *type_name)
{
  /* G_IS_TYPE_PLUGIN() and G_TYPE_PLUGIN_GET_CLASS() are external calls: _U 
   */
  if (!plugin)
    {
      g_warning ("plugin handle for type `%s' is NULL",
                 type_name);
      return FALSE;
    }
  if (!G_IS_TYPE_PLUGIN (plugin))
    {
      g_warning ("plugin pointer (%p) for type `%s' is invalid",
                 plugin, type_name);
      return FALSE;
    }
  if (need_complete_type_info && !G_TYPE_PLUGIN_GET_CLASS (plugin)->complete_type_info)
    {
      g_warning ("plugin for type `%s' has no complete_type_info() implementation",
                 type_name);
      return FALSE;
    }
  if (need_complete_interface_info && !G_TYPE_PLUGIN_GET_CLASS (plugin)->complete_interface_info)
    {
      g_warning ("plugin for type `%s' has no complete_interface_info() implementation",
                 type_name);
      return FALSE;
    }
  return TRUE;
}

static gboolean
check_type_name_I (const gchar *type_name)
{
  static const gchar *extra_chars = "-_+";
  const gchar *p = type_name;
  gboolean name_valid;
  
  if (!type_name[0] || !type_name[1] || !type_name[2])
    {
      g_warning ("type name `%s' is too short", type_name);
      return FALSE;
    }
  /* check the first letter */
  name_valid = (p[0] >= 'A' && p[0] <= 'Z') || (p[0] >= 'a' && p[0] <= 'z') || p[0] == '_';
  for (p = type_name + 1; *p; p++)
    name_valid &= ((p[0] >= 'A' && p[0] <= 'Z') ||
                   (p[0] >= 'a' && p[0] <= 'z') ||
                   (p[0] >= '0' && p[0] <= '9') ||
                   strchr (extra_chars, p[0]));
  if (!name_valid)
    {
      g_warning ("type name `%s' contains invalid characters", type_name);
      return FALSE;
    }
  if (g_type_from_name (type_name))
    {
      g_warning ("cannot register existing type `%s'", type_name);
      return FALSE;
    }
  
  return TRUE;
}

static gboolean
check_derivation_I (GType        parent_type,
                    const gchar *type_name)
{
  TypeNode *pnode;
  GTypeFundamentalInfo* finfo;
  
  pnode = lookup_type_node_I (parent_type);
  if (!pnode)
    {
      g_warning ("cannot derive type `%s' from invalid parent type `%s'",
                 type_name,
                 type_descriptive_name_I (parent_type));
      return FALSE;
    }
  finfo = type_node_fundamental_info_I (pnode);
  /* ensure flat derivability */
  if (!(finfo->type_flags & G_TYPE_FLAG_DERIVABLE))
    {
      g_warning ("cannot derive `%s' from non-derivable parent type `%s'",
                 type_name,
                 NODE_NAME (pnode));
      return FALSE;
    }
  /* ensure deep derivability */
  if (parent_type != NODE_FUNDAMENTAL_TYPE (pnode) &&
      !(finfo->type_flags & G_TYPE_FLAG_DEEP_DERIVABLE))
    {
      g_warning ("cannot derive `%s' from non-fundamental parent type `%s'",
                 type_name,
                 NODE_NAME (pnode));
      return FALSE;
    }
  
  return TRUE;
}

static gboolean
check_collect_format_I (const gchar *collect_format)
{
  const gchar *p = collect_format;
  gchar valid_format[] = { G_VALUE_COLLECT_INT, G_VALUE_COLLECT_LONG,
                           G_VALUE_COLLECT_INT64, G_VALUE_COLLECT_DOUBLE,
                           G_VALUE_COLLECT_POINTER, 0 };
  
  while (*p)
    if (!strchr (valid_format, *p++))
      return FALSE;
  return p - collect_format <= G_VALUE_COLLECT_FORMAT_MAX_LENGTH;
}

static gboolean
check_value_table_I (const gchar           *type_name,
                     const GTypeValueTable *value_table)
{
  if (!value_table)
    return FALSE;
  else if (value_table->value_init == NULL)
    {
      if (value_table->value_free || value_table->value_copy ||
          value_table->value_peek_pointer ||
          value_table->collect_format || value_table->collect_value ||
          value_table->lcopy_format || value_table->lcopy_value)
        g_warning ("cannot handle uninitializable values of type `%s'",
                   type_name);
      return FALSE;
    }
  else /* value_table->value_init != NULL */
    {
      if (!value_table->value_free)
        {
          /* +++ optional +++
           * g_warning ("missing `value_free()' for type `%s'", type_name);
           * return FALSE;
           */
        }
      if (!value_table->value_copy)
        {
          g_warning ("missing `value_copy()' for type `%s'", type_name);
          return FALSE;
        }
      if ((value_table->collect_format || value_table->collect_value) &&
          (!value_table->collect_format || !value_table->collect_value))
        {
          g_warning ("one of `collect_format' and `collect_value()' is unspecified for type `%s'",
                     type_name);
          return FALSE;
        }
      if (value_table->collect_format && !check_collect_format_I (value_table->collect_format))
        {
          g_warning ("the `%s' specification for type `%s' is too long or invalid",
                     "collect_format",
                     type_name);
          return FALSE;
        }
      if ((value_table->lcopy_format || value_table->lcopy_value) &&
          (!value_table->lcopy_format || !value_table->lcopy_value))
        {
          g_warning ("one of `lcopy_format' and `lcopy_value()' is unspecified for type `%s'",
                     type_name);
          return FALSE;
        }
      if (value_table->lcopy_format && !check_collect_format_I (value_table->lcopy_format))
        {
          g_warning ("the `%s' specification for type `%s' is too long or invalid",
                     "lcopy_format",
                     type_name);
          return FALSE;
        }
    }
  return TRUE;
}

static gboolean
check_type_info_I (TypeNode        *pnode,
                   GType            ftype,
                   const gchar     *type_name,
                   const GTypeInfo *info)
{
  GTypeFundamentalInfo *finfo = type_node_fundamental_info_I (lookup_type_node_I (ftype));
  gboolean is_interface = ftype == G_TYPE_INTERFACE;
  
  g_assert (ftype <= G_TYPE_FUNDAMENTAL_MAX && !(ftype & TYPE_ID_MASK));
  
  /* check instance members */
  if (!(finfo->type_flags & G_TYPE_FLAG_INSTANTIATABLE) &&
      (info->instance_size || info->n_preallocs || info->instance_init))
    {
      if (pnode)
        g_warning ("cannot instantiate `%s', derived from non-instantiatable parent type `%s'",
                   type_name,
                   NODE_NAME (pnode));
      else
        g_warning ("cannot instantiate `%s' as non-instantiatable fundamental",
                   type_name);
      return FALSE;
    }
  /* check class & interface members */
  if (!((finfo->type_flags & G_TYPE_FLAG_CLASSED) || is_interface) &&
      (info->class_init || info->class_finalize || info->class_data ||
       info->class_size || info->base_init || info->base_finalize))
    {
      if (pnode)
        g_warning ("cannot create class for `%s', derived from non-classed parent type `%s'",
                   type_name,
                   NODE_NAME (pnode));
      else
        g_warning ("cannot create class for `%s' as non-classed fundamental",
                   type_name);
      return FALSE;
    }
  /* check interface size */
  if (is_interface && info->class_size < sizeof (GTypeInterface))
    {
      g_warning ("specified interface size for type `%s' is smaller than `GTypeInterface' size",
                 type_name);
      return FALSE;
    }
  /* check class size */
  if (finfo->type_flags & G_TYPE_FLAG_CLASSED)
    {
      if (info->class_size < sizeof (GTypeClass))
        {
          g_warning ("specified class size for type `%s' is smaller than `GTypeClass' size",
                     type_name);
          return FALSE;
        }
      if (pnode && info->class_size < pnode->data->class.class_size)
        {
          g_warning ("specified class size for type `%s' is smaller "
                     "than the parent type's `%s' class size",
                     type_name,
                     NODE_NAME (pnode));
          return FALSE;
        }
    }
  /* check instance size */
  if (finfo->type_flags & G_TYPE_FLAG_INSTANTIATABLE)
    {
      if (info->instance_size < sizeof (GTypeInstance))
        {
          g_warning ("specified instance size for type `%s' is smaller than `GTypeInstance' size",
                     type_name);
          return FALSE;
        }
      if (pnode && info->instance_size < pnode->data->instance.instance_size)
        {
          g_warning ("specified instance size for type `%s' is smaller "
                     "than the parent type's `%s' instance size",
                     type_name,
                     NODE_NAME (pnode));
          return FALSE;
        }
    }
  
  return TRUE;
}

static TypeNode*
find_conforming_child_type_L (TypeNode *pnode,
                              TypeNode *iface)
{
  TypeNode *node = NULL;
  guint i;
  
  if (type_lookup_iface_entry_L (pnode, iface))
    return pnode;
  
  for (i = 0; i < pnode->n_children && !node; i++)
    node = find_conforming_child_type_L (lookup_type_node_I (pnode->children[i]), iface);
  
  return node;
}

static gboolean
check_add_interface_L (GType instance_type,
                       GType iface_type)
{
  TypeNode *node = lookup_type_node_I (instance_type);
  TypeNode *iface = lookup_type_node_I (iface_type);
  IFaceEntry *entry;
  TypeNode *tnode;
  GType *prerequisites;
  guint i;

  
  if (!node || !node->is_instantiatable)
    {
      g_warning ("cannot add interfaces to invalid (non-instantiatable) type `%s'",
                 type_descriptive_name_I (instance_type));
      return FALSE;
    }
  if (!iface || !NODE_IS_IFACE (iface))
    {
      g_warning ("cannot add invalid (non-interface) type `%s' to type `%s'",
                 type_descriptive_name_I (iface_type),
                 NODE_NAME (node));
      return FALSE;
    }
  tnode = lookup_type_node_I (NODE_PARENT_TYPE (iface));
  if (NODE_PARENT_TYPE (tnode) && !type_lookup_iface_entry_L (node, tnode))
    {
      /* 2001/7/31:timj: erk, i guess this warning is junk as interface derivation is flat */
      g_warning ("cannot add sub-interface `%s' to type `%s' which does not conform to super-interface `%s'",
                 NODE_NAME (iface),
                 NODE_NAME (node),
                 NODE_NAME (tnode));
      return FALSE;
    }
  /* allow overriding of interface type introduced for parent type */
  entry = type_lookup_iface_entry_L (node, iface);
  if (entry && entry->vtable == NULL && !type_iface_peek_holder_L (iface, NODE_TYPE (node)))
    {
      /* ok, we do conform to this interface already, but the interface vtable was not
       * yet intialized, and we just conform to the interface because it got added to
       * one of our parents. so we allow overriding of holder info here.
       */
      return TRUE;
    }
  /* check whether one of our children already conforms (or whether the interface
   * got added to this node already)
   */
  tnode = find_conforming_child_type_L (node, iface);  /* tnode is_a node */
  if (tnode)
    {
      g_warning ("cannot add interface type `%s' to type `%s', since type `%s' already conforms to interface",
                 NODE_NAME (iface),
                 NODE_NAME (node),
                 NODE_NAME (tnode));
      return FALSE;
    }
  prerequisites = IFACE_NODE_PREREQUISITES (iface);
  for (i = 0; i < IFACE_NODE_N_PREREQUISITES (iface); i++)
    {
      tnode = lookup_type_node_I (prerequisites[i]);
      if (!type_node_is_a_L (node, tnode))
        {
          g_warning ("cannot add interface type `%s' to type `%s' which does not conform to prerequisite `%s'",
                     NODE_NAME (iface),
                     NODE_NAME (node),
                     NODE_NAME (tnode));
          return FALSE;
        }
    }
  return TRUE;
}

static gboolean
check_interface_info_I (TypeNode             *iface,
                        GType                 instance_type,
                        const GInterfaceInfo *info)
{
  if ((info->interface_finalize || info->interface_data) && !info->interface_init)
    {
      g_warning ("interface type `%s' for type `%s' comes without initializer",
                 NODE_NAME (iface),
                 type_descriptive_name_I (instance_type));
      return FALSE;
    }
  
  return TRUE;
}

/* --- type info (type node data) --- */
static void
type_data_make_W (TypeNode              *node,
                  const GTypeInfo       *info,
                  const GTypeValueTable *value_table)
{
  TypeData *data;
  GTypeValueTable *vtable = NULL;
  guint vtable_size = 0;
  
  g_assert (node->data == NULL && info != NULL);
  
  if (!value_table)
    {
      TypeNode *pnode = lookup_type_node_I (NODE_PARENT_TYPE (node));
      
      if (pnode)
        vtable = pnode->data->common.value_table;
      else
        {
          static const GTypeValueTable zero_vtable = { NULL, };
          
          value_table = &zero_vtable;
        }
    }
  if (value_table)
    {
      /* need to setup vtable_size since we have to allocate it with data in one chunk */
      vtable_size = sizeof (GTypeValueTable);
      if (value_table->collect_format)
        vtable_size += strlen (value_table->collect_format);
      if (value_table->lcopy_format)
        vtable_size += strlen (value_table->lcopy_format);
      vtable_size += 2;
    }
   
  if (node->is_instantiatable) /* carefull, is_instantiatable is also is_classed */
    {
      data = g_malloc0 (sizeof (InstanceData) + vtable_size);
      if (vtable_size)
        vtable = G_STRUCT_MEMBER_P (data, sizeof (InstanceData));
      data->instance.class_size = info->class_size;
      data->instance.class_init_base = info->base_init;
      data->instance.class_finalize_base = info->base_finalize;
      data->instance.class_init = info->class_init;
      data->instance.class_finalize = info->class_finalize;
      data->instance.class_data = info->class_data;
      data->instance.class = NULL;
      data->instance.init_state = UNINITIALIZED;
      data->instance.instance_size = info->instance_size;
      /* We'll set the final value for data->instance.private size
       * after the parent class has been initialized
       */
      data->instance.private_size = 0;
#ifdef  DISABLE_MEM_POOLS
      data->instance.n_preallocs = 0;
#else   /* !DISABLE_MEM_POOLS */
      data->instance.n_preallocs = MIN (info->n_preallocs, 1024);
#endif  /* !DISABLE_MEM_POOLS */
      data->instance.instance_init = info->instance_init;
      data->instance.mem_chunk = NULL;
    }
  else if (node->is_classed) /* only classed */
    {
      data = g_malloc0 (sizeof (ClassData) + vtable_size);
      if (vtable_size)
        vtable = G_STRUCT_MEMBER_P (data, sizeof (ClassData));
      data->class.class_size = info->class_size;
      data->class.class_init_base = info->base_init;
      data->class.class_finalize_base = info->base_finalize;
      data->class.class_init = info->class_init;
      data->class.class_finalize = info->class_finalize;
      data->class.class_data = info->class_data;
      data->class.class = NULL;
      data->class.init_state = UNINITIALIZED;
    }
  else if (NODE_IS_IFACE (node))
    {
      data = g_malloc0 (sizeof (IFaceData) + vtable_size);
      if (vtable_size)
        vtable = G_STRUCT_MEMBER_P (data, sizeof (IFaceData));
      data->iface.vtable_size = info->class_size;
      data->iface.vtable_init_base = info->base_init;
      data->iface.vtable_finalize_base = info->base_finalize;
      data->iface.dflt_init = info->class_init;
      data->iface.dflt_finalize = info->class_finalize;
      data->iface.dflt_data = info->class_data;
      data->iface.dflt_vtable = NULL;
    }
  else
    {
      data = g_malloc0 (sizeof (CommonData) + vtable_size);
      if (vtable_size)
        vtable = G_STRUCT_MEMBER_P (data, sizeof (CommonData));
    }
  
  node->data = data;
  node->data->common.ref_count = 1;
  
  if (vtable_size)
    {
      gchar *p;
      
      /* we allocate the vtable and its strings together with the type data, so
       * children can take over their parent's vtable pointer, and we don't
       * need to worry freeing it or not when the child data is destroyed
       */
      *vtable = *value_table;
      p = G_STRUCT_MEMBER_P (vtable, sizeof (*vtable));
      p[0] = 0;
      vtable->collect_format = p;
      if (value_table->collect_format)
        {
          strcat (p, value_table->collect_format);
          p += strlen (value_table->collect_format);
        }
      p++;
      p[0] = 0;
      vtable->lcopy_format = p;
      if (value_table->lcopy_format)
        strcat  (p, value_table->lcopy_format);
    }
  node->data->common.value_table = vtable;
  node->mutatable_check_cache = (node->data->common.value_table->value_init != NULL &&
                                 !((G_TYPE_FLAG_VALUE_ABSTRACT | G_TYPE_FLAG_ABSTRACT) &
                                   GPOINTER_TO_UINT (type_get_qdata_L (node, static_quark_type_flags))));
  
  g_assert (node->data->common.value_table != NULL); /* paranoid */
}

static inline void
type_data_ref_Wm (TypeNode *node)
{
  if (!node->data)
    {
      TypeNode *pnode = lookup_type_node_I (NODE_PARENT_TYPE (node));
      GTypeInfo tmp_info;
      GTypeValueTable tmp_value_table;
      
      g_assert (node->plugin != NULL);
      
      if (pnode)
        {
          type_data_ref_Wm (pnode);
          if (node->data)
            INVALID_RECURSION ("g_type_plugin_*", node->plugin, NODE_NAME (node));
        }
      
      memset (&tmp_info, 0, sizeof (tmp_info));
      memset (&tmp_value_table, 0, sizeof (tmp_value_table));
      
      G_WRITE_UNLOCK (&type_rw_lock);
      g_type_plugin_use (node->plugin);
      g_type_plugin_complete_type_info (node->plugin, NODE_TYPE (node), &tmp_info, &tmp_value_table);
      G_WRITE_LOCK (&type_rw_lock);
      if (node->data)
        INVALID_RECURSION ("g_type_plugin_*", node->plugin, NODE_NAME (node));
      
      check_type_info_I (pnode, NODE_FUNDAMENTAL_TYPE (node), NODE_NAME (node), &tmp_info);
      type_data_make_W (node, &tmp_info,
                        check_value_table_I (NODE_NAME (node),
                                             &tmp_value_table) ? &tmp_value_table : NULL);
    }
  else
    {
      g_assert (node->data->common.ref_count > 0);
      
      node->data->common.ref_count += 1;
    }
}

static inline void
type_data_unref_Wm (TypeNode *node,
                    gboolean  uncached)
{
  g_assert (node->data && node->data->common.ref_count);
  
  if (node->data->common.ref_count > 1)
    node->data->common.ref_count -= 1;
  else
    {
      if (!node->plugin)
        {
          g_warning ("static type `%s' unreferenced too often",
                     NODE_NAME (node));
          return;
        }
      
      type_data_last_unref_Wm (NODE_TYPE (node), uncached);
    }
}

static void
type_node_add_iface_entry_W (TypeNode   *node,
                             GType       iface_type,
                             IFaceEntry *parent_entry)
{
  IFaceEntry *entries;
  guint i;
  
  g_assert (node->is_instantiatable && CLASSED_NODE_N_IFACES (node) < MAX_N_IFACES);
  
  entries = CLASSED_NODE_IFACES_ENTRIES (node);
  for (i = 0; i < CLASSED_NODE_N_IFACES (node); i++)
    if (entries[i].iface_type == iface_type)
      {
        /* this can happen in two cases:
         * - our parent type already conformed to iface_type and node
         *   got it's own holder info. here, our children already have
         *   entries and NULL vtables, since this will only work for
         *   uninitialized classes.
         * - an interface type is added to an ancestor after it was
         *   added to a child type.
         */
        if (!parent_entry)
          g_assert (entries[i].vtable == NULL && entries[i].init_state == UNINITIALIZED);
        else
          {
            /* sick, interface is added to ancestor *after* child type;
             * nothing todo, the entry and our children were already setup correctly
             */
          }
        return;
      }
    else if (entries[i].iface_type > iface_type)
      break;
  CLASSED_NODE_N_IFACES (node) += 1;
  CLASSED_NODE_IFACES_ENTRIES (node) = g_renew (IFaceEntry,
                                                CLASSED_NODE_IFACES_ENTRIES (node),
                                                CLASSED_NODE_N_IFACES (node));
  entries = CLASSED_NODE_IFACES_ENTRIES (node);
  g_memmove (entries + i + 1, entries + i, sizeof (entries[0]) * (CLASSED_NODE_N_IFACES (node) - i - 1));
  entries[i].iface_type = iface_type;
  entries[i].vtable = NULL;
  entries[i].init_state = UNINITIALIZED;

  if (parent_entry)
    {
      if (node->data && node->data->class.init_state >= BASE_IFACE_INIT)
        {
          entries[i].init_state = INITIALIZED;
          entries[i].vtable = parent_entry->vtable;
        }
      for (i = 0; i < node->n_children; i++)
        type_node_add_iface_entry_W (lookup_type_node_I (node->children[i]), iface_type, &entries[i]);
    }
}

static void
type_add_interface_Wm (TypeNode             *node,
                       TypeNode             *iface,
                       const GInterfaceInfo *info,
                       GTypePlugin          *plugin)
{
  IFaceHolder *iholder = g_new0 (IFaceHolder, 1);
  IFaceEntry *entry;
  guint i;
  
  g_assert (node->is_instantiatable && NODE_IS_IFACE (iface) && ((info && !plugin) || (!info && plugin)));
  
  iholder->next = iface_node_get_holders_L (iface);
  iface_node_set_holders_W (iface, iholder);
  iholder->instance_type = NODE_TYPE (node);
  iholder->info = info ? g_memdup (info, sizeof (*info)) : NULL;
  iholder->plugin = plugin;

  /* create an iface entry for this type */
  type_node_add_iface_entry_W (node, NODE_TYPE (iface), NULL);
  
  /* if the class is already (partly) initialized, we may need to base
   * initalize and/or initialize the new interface.
   */
  if (node->data)
    {
      InitState class_state = node->data->class.init_state;
      
      if (class_state >= BASE_IFACE_INIT)
        type_iface_vtable_base_init_Wm (iface, node);
      
      if (class_state >= IFACE_INIT)
        type_iface_vtable_iface_init_Wm (iface, node);
    }
  
  /* create iface entries for children of this type */
  entry = type_lookup_iface_entry_L (node, iface);
  for (i = 0; i < node->n_children; i++)
    type_node_add_iface_entry_W (lookup_type_node_I (node->children[i]), NODE_TYPE (iface), entry);
}

static void
type_iface_add_prerequisite_W (TypeNode *iface,
                               TypeNode *prerequisite_node)
{
  GType prerequisite_type = NODE_TYPE (prerequisite_node);
  GType *prerequisites, *dependants;
  guint n_dependants, i;
  
  g_assert (NODE_IS_IFACE (iface) &&
            IFACE_NODE_N_PREREQUISITES (iface) < MAX_N_PREREQUISITES &&
            (prerequisite_node->is_instantiatable || NODE_IS_IFACE (prerequisite_node)));
  
  prerequisites = IFACE_NODE_PREREQUISITES (iface);
  for (i = 0; i < IFACE_NODE_N_PREREQUISITES (iface); i++)
    if (prerequisites[i] == prerequisite_type)
      return;                   /* we already have that prerequisiste */
    else if (prerequisites[i] > prerequisite_type)
      break;
  IFACE_NODE_N_PREREQUISITES (iface) += 1;
  IFACE_NODE_PREREQUISITES (iface) = g_renew (GType,
                                              IFACE_NODE_PREREQUISITES (iface),
                                              IFACE_NODE_N_PREREQUISITES (iface));
  prerequisites = IFACE_NODE_PREREQUISITES (iface);
  g_memmove (prerequisites + i + 1, prerequisites + i,
             sizeof (prerequisites[0]) * (IFACE_NODE_N_PREREQUISITES (iface) - i - 1));
  prerequisites[i] = prerequisite_type;
  
  /* we want to get notified when prerequisites get added to prerequisite_node */
  if (NODE_IS_IFACE (prerequisite_node))
    {
      dependants = iface_node_get_dependants_array_L (prerequisite_node);
      n_dependants = dependants ? dependants[0] : 0;
      n_dependants += 1;
      dependants = g_renew (GType, dependants, n_dependants + 1);
      dependants[n_dependants] = NODE_TYPE (iface);
      dependants[0] = n_dependants;
      iface_node_set_dependants_array_W (prerequisite_node, dependants);
    }
  
  /* we need to notify all dependants */
  dependants = iface_node_get_dependants_array_L (iface);
  n_dependants = dependants ? dependants[0] : 0;
  for (i = 1; i <= n_dependants; i++)
    type_iface_add_prerequisite_W (lookup_type_node_I (dependants[i]), prerequisite_node);
}

void
g_type_interface_add_prerequisite (GType interface_type,
                                   GType prerequisite_type)
{
  TypeNode *iface, *prerequisite_node;
  IFaceHolder *holders;
  
  g_return_if_fail (G_TYPE_IS_INTERFACE (interface_type));      /* G_TYPE_IS_INTERFACE() is an external call: _U */
  g_return_if_fail (!g_type_is_a (interface_type, prerequisite_type));
  g_return_if_fail (!g_type_is_a (prerequisite_type, interface_type));
  
  iface = lookup_type_node_I (interface_type);
  prerequisite_node = lookup_type_node_I (prerequisite_type);
  if (!iface || !prerequisite_node || !NODE_IS_IFACE (iface))
    {
      g_warning ("interface type `%s' or prerequisite type `%s' invalid",
                 type_descriptive_name_I (interface_type),
                 type_descriptive_name_I (prerequisite_type));
      return;
    }
  G_WRITE_LOCK (&type_rw_lock);
  holders = iface_node_get_holders_L (iface);
  if (holders)
    {
      G_WRITE_UNLOCK (&type_rw_lock);
      g_warning ("unable to add prerequisite `%s' to interface `%s' which is already in use for `%s'",
                 type_descriptive_name_I (prerequisite_type),
                 type_descriptive_name_I (interface_type),
                 type_descriptive_name_I (holders->instance_type));
      return;
    }
  if (prerequisite_node->is_instantiatable)
    {
      guint i;
      
      /* can have at most one publically installable instantiatable prerequisite */
      for (i = 0; i < IFACE_NODE_N_PREREQUISITES (iface); i++)
        {
          TypeNode *prnode = lookup_type_node_I (IFACE_NODE_PREREQUISITES (iface)[i]);
          
          if (prnode->is_instantiatable)
            {
              G_WRITE_UNLOCK (&type_rw_lock);
              g_warning ("adding prerequisite `%s' to interface `%s' conflicts with existing prerequisite `%s'",
                         type_descriptive_name_I (prerequisite_type),
                         type_descriptive_name_I (interface_type),
                         type_descriptive_name_I (NODE_TYPE (prnode)));
              return;
            }
        }
      
      for (i = 0; i < prerequisite_node->n_supers + 1; i++)
        type_iface_add_prerequisite_W (iface, lookup_type_node_I (prerequisite_node->supers[i]));
      G_WRITE_UNLOCK (&type_rw_lock);
    }
  else if (NODE_IS_IFACE (prerequisite_node))
    {
      GType *prerequisites;
      guint i;
      
      prerequisites = IFACE_NODE_PREREQUISITES (prerequisite_node);
      for (i = 0; i < IFACE_NODE_N_PREREQUISITES (prerequisite_node); i++)
        type_iface_add_prerequisite_W (iface, lookup_type_node_I (prerequisites[i]));
      type_iface_add_prerequisite_W (iface, prerequisite_node);
      G_WRITE_UNLOCK (&type_rw_lock);
    }
  else
    {
      G_WRITE_UNLOCK (&type_rw_lock);
      g_warning ("prerequisite `%s' for interface `%s' is neither instantiatable nor interface",
                 type_descriptive_name_I (prerequisite_type),
                 type_descriptive_name_I (interface_type));
    }
}

GType* /* free result */
g_type_interface_prerequisites (GType  interface_type,
                                guint *n_prerequisites)
{
  TypeNode *iface;
  
  g_return_val_if_fail (G_TYPE_IS_INTERFACE (interface_type), NULL);

  iface = lookup_type_node_I (interface_type);
  if (iface)
    {
      GType *types;
      TypeNode *inode = NULL;
      guint i, n = 0;
      
      G_READ_LOCK (&type_rw_lock);
      types = g_new0 (GType, IFACE_NODE_N_PREREQUISITES (iface) + 1);
      for (i = 0; i < IFACE_NODE_N_PREREQUISITES (iface); i++)
        {
          GType prerequisite = IFACE_NODE_PREREQUISITES (iface)[i];
          TypeNode *node = lookup_type_node_I (prerequisite);
          if (node->is_instantiatable &&
              (!inode || type_node_is_a_L (node, inode)))
            inode = node;
          else
            types[n++] = NODE_TYPE (node);
        }
      if (inode)
        types[n++] = NODE_TYPE (inode);
      
      if (n_prerequisites)
        *n_prerequisites = n;
      G_READ_UNLOCK (&type_rw_lock);
      
      return types;
    }
  else
    {
      if (n_prerequisites)
        *n_prerequisites = 0;
      
      return NULL;
    }
}


static IFaceHolder*
type_iface_peek_holder_L (TypeNode *iface,
                          GType     instance_type)
{
  IFaceHolder *iholder;
  
  g_assert (NODE_IS_IFACE (iface));
  
  iholder = iface_node_get_holders_L (iface);
  while (iholder && iholder->instance_type != instance_type)
    iholder = iholder->next;
  return iholder;
}

static IFaceHolder*
type_iface_retrieve_holder_info_Wm (TypeNode *iface,
                                    GType     instance_type,
                                    gboolean  need_info)
{
  IFaceHolder *iholder = type_iface_peek_holder_L (iface, instance_type);
  
  if (iholder && !iholder->info && need_info)
    {
      GInterfaceInfo tmp_info;
      
      g_assert (iholder->plugin != NULL);
      
      type_data_ref_Wm (iface);
      if (iholder->info)
        INVALID_RECURSION ("g_type_plugin_*", iface->plugin, NODE_NAME (iface));
      
      memset (&tmp_info, 0, sizeof (tmp_info));
      
      G_WRITE_UNLOCK (&type_rw_lock);
      g_type_plugin_use (iholder->plugin);
      g_type_plugin_complete_interface_info (iholder->plugin, instance_type, NODE_TYPE (iface), &tmp_info);
      G_WRITE_LOCK (&type_rw_lock);
      if (iholder->info)
        INVALID_RECURSION ("g_type_plugin_*", iholder->plugin, NODE_NAME (iface));
      
      check_interface_info_I (iface, instance_type, &tmp_info);
      iholder->info = g_memdup (&tmp_info, sizeof (tmp_info));
    }
  
  return iholder;       /* we don't modify write lock upon returning NULL */
}

static void
type_iface_blow_holder_info_Wm (TypeNode *iface,
                                GType     instance_type)
{
  IFaceHolder *iholder = iface_node_get_holders_L (iface);
  
  g_assert (NODE_IS_IFACE (iface));
  
  while (iholder->instance_type != instance_type)
    iholder = iholder->next;
  
  if (iholder->info && iholder->plugin)
    {
      g_free (iholder->info);
      iholder->info = NULL;
      
      G_WRITE_UNLOCK (&type_rw_lock);
      g_type_plugin_unuse (iholder->plugin);
      G_WRITE_LOCK (&type_rw_lock);
      
      type_data_unref_Wm (iface, FALSE);
    }
}

/* Assumes type's class already exists
 */
static inline size_t
type_total_instance_size_I (TypeNode *node)
{
  gsize total_instance_size;

  total_instance_size = node->data->instance.instance_size;
  if (node->data->instance.private_size != 0)
    total_instance_size = ALIGN_STRUCT (total_instance_size) + node->data->instance.private_size;

  return total_instance_size;
}

/* --- type structure creation/destruction --- */
typedef struct {
  gpointer instance;
  gpointer class;
} InstanceRealClass;
static gint
instance_real_class_cmp (gconstpointer p1,
                         gconstpointer p2)
{
  const InstanceRealClass *irc1 = p1;
  const InstanceRealClass *irc2 = p2;
  guint8 *i1 = irc1->instance;
  guint8 *i2 = irc2->instance;
  return G_BSEARCH_ARRAY_CMP (i1, i2);
}
G_LOCK_DEFINE_STATIC (instance_real_class);
static GBSearchArray *instance_real_class_bsa = NULL;
static GBSearchConfig instance_real_class_bconfig = {
  sizeof (InstanceRealClass),
  instance_real_class_cmp,
  0,
};
static inline void
instance_real_class_set (gpointer    instance,
                         GTypeClass *class)
{
  InstanceRealClass key;
  key.instance = instance;
  key.class = class;
  G_LOCK (instance_real_class);
  if (!instance_real_class_bsa)
    instance_real_class_bsa = g_bsearch_array_create (&instance_real_class_bconfig);
  instance_real_class_bsa = g_bsearch_array_replace (instance_real_class_bsa, &instance_real_class_bconfig, &key);
  G_UNLOCK (instance_real_class);
}
static inline void
instance_real_class_remove (gpointer instance)
{
  InstanceRealClass key, *node;
  guint index;
  key.instance = instance;
  G_LOCK (instance_real_class);
  node = g_bsearch_array_lookup (instance_real_class_bsa, &instance_real_class_bconfig, &key);
  index = g_bsearch_array_get_index (instance_real_class_bsa, &instance_real_class_bconfig, node);
  instance_real_class_bsa = g_bsearch_array_remove (instance_real_class_bsa, &instance_real_class_bconfig, index);
  if (!g_bsearch_array_get_n_nodes (instance_real_class_bsa))
    {
      g_bsearch_array_free (instance_real_class_bsa, &instance_real_class_bconfig);
      instance_real_class_bsa = NULL;
    }
  G_UNLOCK (instance_real_class);
}
static inline GTypeClass*
instance_real_class_get (gpointer instance)
{
  InstanceRealClass key, *node;
  key.instance = instance;
  G_LOCK (instance_real_class);
  node = instance_real_class_bsa ? g_bsearch_array_lookup (instance_real_class_bsa, &instance_real_class_bconfig, &key) : NULL;
  G_UNLOCK (instance_real_class);
  return node ? node->class : NULL;
}

GTypeInstance*
g_type_create_instance (GType type)
{
  TypeNode *node;
  GTypeInstance *instance;
  GTypeClass *class;
  guint i;
  gsize total_instance_size;
  
  node = lookup_type_node_I (type);
  if (!node || !node->is_instantiatable)
    {
      g_warning ("cannot create new instance of invalid (non-instantiatable) type `%s'",
                 type_descriptive_name_I (type));
      return NULL;
    }
  /* G_TYPE_IS_ABSTRACT() is an external call: _U */
  if (!node->mutatable_check_cache && G_TYPE_IS_ABSTRACT (type))
    {
      g_warning ("cannot create instance of abstract (non-instantiatable) type `%s'",
                 type_descriptive_name_I (type));
      return NULL;
    }
  
  class = g_type_class_ref (type);

  total_instance_size = type_total_instance_size_I (node);
  
  if (node->data->instance.n_preallocs)
    {
      G_WRITE_LOCK (&type_rw_lock);
      if (!node->data->instance.mem_chunk)
        {
          /* If there isn't private data, the compiler will have already
           * added the necessary padding, but in the private data case, we
           * have to pad ourselves to ensure proper alignment of all the
           * atoms in the slab.
           */
          gsize atom_size = total_instance_size;
          if (node->data->instance.private_size)
            atom_size = ALIGN_STRUCT (atom_size);
          
          node->data->instance.mem_chunk = g_mem_chunk_new (NODE_NAME (node),
                                                            atom_size,
                                                            (atom_size *
                                                             node->data->instance.n_preallocs),
                                                            G_ALLOC_AND_FREE);
        }
      
      instance = g_chunk_new0 (GTypeInstance, node->data->instance.mem_chunk);
      G_WRITE_UNLOCK (&type_rw_lock);
    }
  else
    instance = g_malloc0 (total_instance_size); /* fine without read lock */

  if (node->data->instance.private_size)
    instance_real_class_set (instance, class);
  for (i = node->n_supers; i > 0; i--)
    {
      TypeNode *pnode;
      
      pnode = lookup_type_node_I (node->supers[i]);
      if (pnode->data->instance.instance_init)
        {
          instance->g_class = pnode->data->instance.class;
          pnode->data->instance.instance_init (instance, class);
        }
    }
  if (node->data->instance.private_size)
    instance_real_class_remove (instance);

  instance->g_class = class;
  if (node->data->instance.instance_init)
    node->data->instance.instance_init (instance, class);
  
  return instance;
}

void
g_type_free_instance (GTypeInstance *instance)
{
  TypeNode *node;
  GTypeClass *class;
  
  g_return_if_fail (instance != NULL && instance->g_class != NULL);
  
  class = instance->g_class;
  node = lookup_type_node_I (class->g_type);
  if (!node || !node->is_instantiatable || !node->data || node->data->class.class != (gpointer) class)
    {
      g_warning ("cannot free instance of invalid (non-instantiatable) type `%s'",
                 type_descriptive_name_I (class->g_type));
      return;
    }
  /* G_TYPE_IS_ABSTRACT() is an external call: _U */
  if (!node->mutatable_check_cache && G_TYPE_IS_ABSTRACT (NODE_TYPE (node)))
    {
      g_warning ("cannot free instance of abstract (non-instantiatable) type `%s'",
                 NODE_NAME (node));
      return;
    }
  
  instance->g_class = NULL;
#ifdef G_ENABLE_DEBUG  
  memset (instance, 0xaa, type_total_instance_size_I (node));   /* debugging hack */
#endif  
  if (node->data->instance.n_preallocs)
    {
      G_WRITE_LOCK (&type_rw_lock);
      g_chunk_free (instance, node->data->instance.mem_chunk);
      G_WRITE_UNLOCK (&type_rw_lock);
    }
  else
    g_free (instance);
  
  g_type_class_unref (class);
}

static void
type_iface_ensure_dflt_vtable_Wm (TypeNode *iface)
{
  g_assert (iface->data);

  if (!iface->data->iface.dflt_vtable)
    {
      GTypeInterface *vtable = g_malloc0 (iface->data->iface.vtable_size);
      iface->data->iface.dflt_vtable = vtable;
      vtable->g_type = NODE_TYPE (iface);
      vtable->g_instance_type = 0;
      if (iface->data->iface.vtable_init_base ||
          iface->data->iface.dflt_init)
        {
          G_WRITE_UNLOCK (&type_rw_lock);
          if (iface->data->iface.vtable_init_base)
            iface->data->iface.vtable_init_base (vtable);
          if (iface->data->iface.dflt_init)
            iface->data->iface.dflt_init (vtable, (gpointer) iface->data->iface.dflt_data);
          G_WRITE_LOCK (&type_rw_lock);
        }
    }
}


/* This is called to allocate and do the first part of initializing
 * the interface vtable; type_iface_vtable_iface_init_Wm() does the remainder.
 *
 * A FALSE return indicates that we didn't find an init function for
 * this type/iface pair, so the vtable from the parent type should
 * be used. Note that the write lock is not modified upon a FALSE
 * return.
 */
static gboolean
type_iface_vtable_base_init_Wm (TypeNode *iface,
                                TypeNode *node)
{
  IFaceEntry *entry;
  IFaceHolder *iholder;
  GTypeInterface *vtable = NULL;
  TypeNode *pnode;
  
  /* type_iface_retrieve_holder_info_Wm() doesn't modify write lock for returning NULL */
  iholder = type_iface_retrieve_holder_info_Wm (iface, NODE_TYPE (node), TRUE);
  if (!iholder)
    return FALSE;       /* we don't modify write lock upon FALSE */

  type_iface_ensure_dflt_vtable_Wm (iface);

  entry = type_lookup_iface_entry_L (node, iface);

  g_assert (iface->data && entry && entry->vtable == NULL && iholder && iholder->info);
  
  entry->init_state = IFACE_INIT;

  pnode = lookup_type_node_I (NODE_PARENT_TYPE (node));
  if (pnode)    /* want to copy over parent iface contents */
    {
      IFaceEntry *pentry = type_lookup_iface_entry_L (pnode, iface);
      
      if (pentry)
        vtable = g_memdup (pentry->vtable, iface->data->iface.vtable_size);
    }
  if (!vtable)
    vtable = g_memdup (iface->data->iface.dflt_vtable, iface->data->iface.vtable_size);
  entry->vtable = vtable;
  vtable->g_type = NODE_TYPE (iface);
  vtable->g_instance_type = NODE_TYPE (node);
  
  if (iface->data->iface.vtable_init_base)
    {
      G_WRITE_UNLOCK (&type_rw_lock);
      iface->data->iface.vtable_init_base (vtable);
      G_WRITE_LOCK (&type_rw_lock);
    }
  return TRUE;  /* initialized the vtable */
}

/* Finishes what type_iface_vtable_base_init_Wm started by
 * calling the interface init function.
 * this function may only be called for types with their
 * own interface holder info, i.e. types for which
 * g_type_add_interface*() was called and not children thereof.
 */
static void
type_iface_vtable_iface_init_Wm (TypeNode *iface,
                                 TypeNode *node)
{
  IFaceEntry *entry = type_lookup_iface_entry_L (node, iface);
  IFaceHolder *iholder = type_iface_peek_holder_L (iface, NODE_TYPE (node));
  GTypeInterface *vtable = NULL;
  guint i;
  
  /* iholder->info should have been filled in by type_iface_vtable_base_init_Wm() */
  g_assert (iface->data && entry && iholder && iholder->info);
  g_assert (entry->init_state == IFACE_INIT); /* assert prior base_init() */
  
  entry->init_state = INITIALIZED;
      
  vtable = entry->vtable;

  if (iholder->info->interface_init)
    {
      G_WRITE_UNLOCK (&type_rw_lock);
      if (iholder->info->interface_init)
        iholder->info->interface_init (vtable, iholder->info->interface_data);
      G_WRITE_LOCK (&type_rw_lock);
    }
  
  for (i = 0; i < static_n_iface_check_funcs; i++)
    {
      GTypeInterfaceCheckFunc check_func = static_iface_check_funcs[i].check_func;
      gpointer check_data = static_iface_check_funcs[i].check_data;

      G_WRITE_UNLOCK (&type_rw_lock);
      check_func (check_data, (gpointer)vtable);
      G_WRITE_LOCK (&type_rw_lock);      
    }
}

static gboolean
type_iface_vtable_finalize_Wm (TypeNode       *iface,
                               TypeNode       *node,
                               GTypeInterface *vtable)
{
  IFaceEntry *entry = type_lookup_iface_entry_L (node, iface);
  IFaceHolder *iholder;
  
  /* type_iface_retrieve_holder_info_Wm() doesn't modify write lock for returning NULL */
  iholder = type_iface_retrieve_holder_info_Wm (iface, NODE_TYPE (node), FALSE);
  if (!iholder)
    return FALSE;       /* we don't modify write lock upon FALSE */
  
  g_assert (entry && entry->vtable == vtable && iholder->info);
  
  entry->vtable = NULL;
  entry->init_state = UNINITIALIZED;
  if (iholder->info->interface_finalize || iface->data->iface.vtable_finalize_base)
    {
      G_WRITE_UNLOCK (&type_rw_lock);
      if (iholder->info->interface_finalize)
        iholder->info->interface_finalize (vtable, iholder->info->interface_data);
      if (iface->data->iface.vtable_finalize_base)
        iface->data->iface.vtable_finalize_base (vtable);
      G_WRITE_LOCK (&type_rw_lock);
    }
  vtable->g_type = 0;
  vtable->g_instance_type = 0;
  g_free (vtable);
  
  type_iface_blow_holder_info_Wm (iface, NODE_TYPE (node));
  
  return TRUE;  /* write lock modified */
}

static void
type_class_init_Wm (TypeNode   *node,
                    GTypeClass *pclass)
{
  GSList *slist, *init_slist = NULL;
  GTypeClass *class;
  IFaceEntry *entry;
  TypeNode *bnode, *pnode;
  guint i;
  
  g_assert (node->is_classed && node->data &&
            node->data->class.class_size &&
            !node->data->class.class &&
            node->data->class.init_state == UNINITIALIZED);

  class = g_malloc0 (node->data->class.class_size);
  node->data->class.class = class;
  node->data->class.init_state = BASE_CLASS_INIT;
  
  if (pclass)
    {
      TypeNode *pnode = lookup_type_node_I (pclass->g_type);
      
      memcpy (class, pclass, pnode->data->class.class_size);

      if (node->is_instantiatable)
        {
          /* We need to initialize the private_size here rather than in
           * type_data_make_W() since the class init for the parent
           * class may have changed pnode->data->instance.private_size.
           */
          node->data->instance.private_size = pnode->data->instance.private_size;
        }
    }
  class->g_type = NODE_TYPE (node);
  
  G_WRITE_UNLOCK (&type_rw_lock);
  
  /* stack all base class initialization functions, so we
   * call them in ascending order.
   */
  for (bnode = node; bnode; bnode = lookup_type_node_I (NODE_PARENT_TYPE (bnode)))
    if (bnode->data->class.class_init_base)
      init_slist = g_slist_prepend (init_slist, (gpointer) bnode->data->class.class_init_base);
  for (slist = init_slist; slist; slist = slist->next)
    {
      GBaseInitFunc class_init_base = (GBaseInitFunc) slist->data;
      
      class_init_base (class);
    }
  g_slist_free (init_slist);
  
  G_WRITE_LOCK (&type_rw_lock);

  node->data->class.init_state = BASE_IFACE_INIT;
  
  /* Before we initialize the class, base initialize all interfaces, either
   * from parent, or through our holder info
   */
  pnode = lookup_type_node_I (NODE_PARENT_TYPE (node));

  i = 0;
  while (i < CLASSED_NODE_N_IFACES (node))
    {
      entry = &CLASSED_NODE_IFACES_ENTRIES (node)[i];
      while (i < CLASSED_NODE_N_IFACES (node) &&
             entry->init_state == IFACE_INIT)
        {
          entry++;
          i++;
        }

      if (i == CLASSED_NODE_N_IFACES (node))
        break;

      if (!type_iface_vtable_base_init_Wm (lookup_type_node_I (entry->iface_type), node))
        {
          guint j;
          
          /* need to get this interface from parent, type_iface_vtable_base_init_Wm()
           * doesn't modify write lock upon FALSE, so entry is still valid; 
           */
          g_assert (pnode != NULL);
          
          for (j = 0; j < CLASSED_NODE_N_IFACES (pnode); j++)
            {
              IFaceEntry *pentry = CLASSED_NODE_IFACES_ENTRIES (pnode) + j;
              
              if (pentry->iface_type == entry->iface_type)
                {
                  entry->vtable = pentry->vtable;
                  entry->init_state = INITIALIZED;
                  break;
                }
            }
          g_assert (entry->vtable != NULL);
        }

      /* If the write lock was released, additional interface entries might
       * have been inserted into CLASSED_NODE_IFACES_ENTRIES (node); they'll
       * be base-initialized when inserted, so we don't have to worry that
       * we might miss them. Uninitialized entries can only be moved higher
       * when new ones are inserted.
       */
      i++;
    }
  
  node->data->class.init_state = CLASS_INIT;
  
  G_WRITE_UNLOCK (&type_rw_lock);

  if (node->data->class.class_init)
    node->data->class.class_init (class, (gpointer) node->data->class.class_data);
  
  G_WRITE_LOCK (&type_rw_lock);
  
  node->data->class.init_state = IFACE_INIT;
  
  /* finish initializing the interfaces through our holder info.
   * inherited interfaces are already init_state == INITIALIZED, because
   * they either got setup in the above base_init loop, or during
   * class_init from within type_add_interface_Wm() for this or
   * an anchestor type.
   */
  i = 0;
  while (TRUE)
    {
      entry = &CLASSED_NODE_IFACES_ENTRIES (node)[i];
      while (i < CLASSED_NODE_N_IFACES (node) &&
             entry->init_state == INITIALIZED)
        {
          entry++;
          i++;
        }

      if (i == CLASSED_NODE_N_IFACES (node))
        break;

      type_iface_vtable_iface_init_Wm (lookup_type_node_I (entry->iface_type), node);
      
      /* As in the loop above, additional initialized entries might be inserted
       * if the write lock is released, but that's harmless because the entries
       * we need to initialize only move higher in the list.
       */
      i++;
    }
  
  node->data->class.init_state = INITIALIZED;
}

static void
type_data_finalize_class_ifaces_Wm (TypeNode *node)
{
  guint i;

  g_assert (node->is_instantiatable && node->data && node->data->class.class && node->data->common.ref_count == 0);

 reiterate:
  for (i = 0; i < CLASSED_NODE_N_IFACES (node); i++)
    {
      IFaceEntry *entry = CLASSED_NODE_IFACES_ENTRIES (node) + i;
      if (entry->vtable)
        {
          if (type_iface_vtable_finalize_Wm (lookup_type_node_I (entry->iface_type), node, entry->vtable))
            {
              /* refetch entries, IFACES_ENTRIES might be modified */
              goto reiterate;
            }
          else
            {
              /* type_iface_vtable_finalize_Wm() doesn't modify write lock upon FALSE,
               * iface vtable came from parent
               */
              entry->vtable = NULL;
              entry->init_state = UNINITIALIZED;
            }
        }
    }
}

static void
type_data_finalize_class_U (TypeNode  *node,
                            ClassData *cdata)
{
  GTypeClass *class = cdata->class;
  TypeNode *bnode;
  
  g_assert (cdata->class && cdata->common.ref_count == 0);
  
  if (cdata->class_finalize)
    cdata->class_finalize (class, (gpointer) cdata->class_data);
  
  /* call all base class destruction functions in descending order
   */
  if (cdata->class_finalize_base)
    cdata->class_finalize_base (class);
  for (bnode = lookup_type_node_I (NODE_PARENT_TYPE (node)); bnode; bnode = lookup_type_node_I (NODE_PARENT_TYPE (bnode)))
    if (bnode->data->class.class_finalize_base)
      bnode->data->class.class_finalize_base (class);
  
  g_free (cdata->class);
}

static void
type_data_last_unref_Wm (GType    type,
                         gboolean uncached)
{
  TypeNode *node = lookup_type_node_I (type);
  
  g_return_if_fail (node != NULL && node->plugin != NULL);
  
  if (!node->data || node->data->common.ref_count == 0)
    {
      g_warning ("cannot drop last reference to unreferenced type `%s'",
                 type_descriptive_name_I (type));
      return;
    }

  /* call class cache hooks */
  if (node->is_classed && node->data && node->data->class.class && static_n_class_cache_funcs && !uncached)
    {
      guint i;
      
      G_WRITE_UNLOCK (&type_rw_lock);
      G_READ_LOCK (&type_rw_lock);
      for (i = 0; i < static_n_class_cache_funcs; i++)
        {
          GTypeClassCacheFunc cache_func = static_class_cache_funcs[i].cache_func;
          gpointer cache_data = static_class_cache_funcs[i].cache_data;
          gboolean need_break;
          
          G_READ_UNLOCK (&type_rw_lock);
          need_break = cache_func (cache_data, node->data->class.class);
          G_READ_LOCK (&type_rw_lock);
          if (!node->data || node->data->common.ref_count == 0)
            INVALID_RECURSION ("GType class cache function ", cache_func, NODE_NAME (node));
          if (need_break)
            break;
        }
      G_READ_UNLOCK (&type_rw_lock);
      G_WRITE_LOCK (&type_rw_lock);
    }
  
  if (node->data->common.ref_count > 1) /* may have been re-referenced meanwhile */
    node->data->common.ref_count -= 1;
  else
    {
      GType ptype = NODE_PARENT_TYPE (node);
      TypeData *tdata;
      
      node->data->common.ref_count = 0;
      
      if (node->is_instantiatable && node->data->instance.mem_chunk)
        {
          g_mem_chunk_destroy (node->data->instance.mem_chunk);
          node->data->instance.mem_chunk = NULL;
        }
      
      tdata = node->data;
      if (node->is_classed && tdata->class.class)
        {
          if (CLASSED_NODE_N_IFACES (node))
            type_data_finalize_class_ifaces_Wm (node);
          node->mutatable_check_cache = FALSE;
          node->data = NULL;
          G_WRITE_UNLOCK (&type_rw_lock);
          type_data_finalize_class_U (node, &tdata->class);
          G_WRITE_LOCK (&type_rw_lock);
        }
      else if (NODE_IS_IFACE (node) && tdata->iface.dflt_vtable)
        {
          node->mutatable_check_cache = FALSE;
          node->data = NULL;
          if (tdata->iface.dflt_finalize || tdata->iface.vtable_finalize_base)
            {
              G_WRITE_UNLOCK (&type_rw_lock);
              if (tdata->iface.dflt_finalize)
                tdata->iface.dflt_finalize (tdata->iface.dflt_vtable, (gpointer) tdata->iface.dflt_data);
              if (tdata->iface.vtable_finalize_base)
                tdata->iface.vtable_finalize_base (tdata->iface.dflt_vtable);
              G_WRITE_LOCK (&type_rw_lock);
            }
          g_free (tdata->iface.dflt_vtable);
        }
      else
        {
          node->mutatable_check_cache = FALSE;
          node->data = NULL;
        }

      /* freeing tdata->common.value_table and its contents is taken care of
       * by allocating it in one chunk with tdata
       */
      g_free (tdata);
      
      G_WRITE_UNLOCK (&type_rw_lock);
      g_type_plugin_unuse (node->plugin);
      G_WRITE_LOCK (&type_rw_lock);
      if (ptype)
        type_data_unref_Wm (lookup_type_node_I (ptype), FALSE);
    }
}

void
g_type_add_class_cache_func (gpointer            cache_data,
                             GTypeClassCacheFunc cache_func)
{
  guint i;
  
  g_return_if_fail (cache_func != NULL);
  
  G_WRITE_LOCK (&type_rw_lock);
  i = static_n_class_cache_funcs++;
  static_class_cache_funcs = g_renew (ClassCacheFunc, static_class_cache_funcs, static_n_class_cache_funcs);
  static_class_cache_funcs[i].cache_data = cache_data;
  static_class_cache_funcs[i].cache_func = cache_func;
  G_WRITE_UNLOCK (&type_rw_lock);
}

void
g_type_remove_class_cache_func (gpointer            cache_data,
                                GTypeClassCacheFunc cache_func)
{
  gboolean found_it = FALSE;
  guint i;
  
  g_return_if_fail (cache_func != NULL);
  
  G_WRITE_LOCK (&type_rw_lock);
  for (i = 0; i < static_n_class_cache_funcs; i++)
    if (static_class_cache_funcs[i].cache_data == cache_data &&
        static_class_cache_funcs[i].cache_func == cache_func)
      {
        static_n_class_cache_funcs--;
        g_memmove (static_class_cache_funcs + i,
                   static_class_cache_funcs + i + 1,
                   sizeof (static_class_cache_funcs[0]) * (static_n_class_cache_funcs - i));
        static_class_cache_funcs = g_renew (ClassCacheFunc, static_class_cache_funcs, static_n_class_cache_funcs);
        found_it = TRUE;
        break;
      }
  G_WRITE_UNLOCK (&type_rw_lock);
  
  if (!found_it)
    g_warning (G_STRLOC ": cannot remove unregistered class cache func %p with data %p",
               cache_func, cache_data);
}


void
g_type_add_interface_check (gpointer                check_data,
                            GTypeInterfaceCheckFunc check_func)
{
  guint i;
  
  g_return_if_fail (check_func != NULL);
  
  G_WRITE_LOCK (&type_rw_lock);
  i = static_n_iface_check_funcs++;
  static_iface_check_funcs = g_renew (IFaceCheckFunc, static_iface_check_funcs, static_n_iface_check_funcs);
  static_iface_check_funcs[i].check_data = check_data;
  static_iface_check_funcs[i].check_func = check_func;
  G_WRITE_UNLOCK (&type_rw_lock);
}

void
g_type_remove_interface_check (gpointer                check_data,
                               GTypeInterfaceCheckFunc check_func)
{
  gboolean found_it = FALSE;
  guint i;
  
  g_return_if_fail (check_func != NULL);
  
  G_WRITE_LOCK (&type_rw_lock);
  for (i = 0; i < static_n_iface_check_funcs; i++)
    if (static_iface_check_funcs[i].check_data == check_data &&
        static_iface_check_funcs[i].check_func == check_func)
      {
        static_n_iface_check_funcs--;
        g_memmove (static_iface_check_funcs + i,
                   static_iface_check_funcs + i + 1,
                   sizeof (static_iface_check_funcs[0]) * (static_n_iface_check_funcs - i));
        static_iface_check_funcs = g_renew (IFaceCheckFunc, static_iface_check_funcs, static_n_iface_check_funcs);
        found_it = TRUE;
        break;
      }
  G_WRITE_UNLOCK (&type_rw_lock);
  
  if (!found_it)
    g_warning (G_STRLOC ": cannot remove unregistered class check func %p with data %p",
               check_func, check_data);
}

/* --- type registration --- */
GType
g_type_register_fundamental (GType                       type_id,
                             const gchar                *type_name,
                             const GTypeInfo            *info,
                             const GTypeFundamentalInfo *finfo,
                             GTypeFlags                  flags)
{
  GTypeFundamentalInfo *node_finfo;
  TypeNode *node;
  
  g_return_val_if_uninitialized (static_quark_type_flags, g_type_init, 0);
  g_return_val_if_fail (type_id > 0, 0);
  g_return_val_if_fail (type_name != NULL, 0);
  g_return_val_if_fail (info != NULL, 0);
  g_return_val_if_fail (finfo != NULL, 0);
  
  if (!check_type_name_I (type_name))
    return 0;
  if ((type_id & TYPE_ID_MASK) ||
      type_id > G_TYPE_FUNDAMENTAL_MAX)
    {
      g_warning ("attempt to register fundamental type `%s' with invalid type id (%lu)",
                 type_name,
                 type_id);
      return 0;
    }
  if ((finfo->type_flags & G_TYPE_FLAG_INSTANTIATABLE) &&
      !(finfo->type_flags & G_TYPE_FLAG_CLASSED))
    {
      g_warning ("cannot register instantiatable fundamental type `%s' as non-classed",
                 type_name);
      return 0;
    }
  if (lookup_type_node_I (type_id))
    {
      g_warning ("cannot register existing fundamental type `%s' (as `%s')",
                 type_descriptive_name_I (type_id),
                 type_name);
      return 0;
    }
  
  G_WRITE_LOCK (&type_rw_lock);
  node = type_node_fundamental_new_W (type_id, type_name, finfo->type_flags);
  node_finfo = type_node_fundamental_info_I (node);
  type_add_flags_W (node, flags);
  
  if (check_type_info_I (NULL, NODE_FUNDAMENTAL_TYPE (node), type_name, info))
    type_data_make_W (node, info,
                      check_value_table_I (type_name, info->value_table) ? info->value_table : NULL);
  G_WRITE_UNLOCK (&type_rw_lock);
  
  return NODE_TYPE (node);
}

GType
g_type_register_static (GType            parent_type,
                        const gchar     *type_name,
                        const GTypeInfo *info,
                        GTypeFlags       flags)
{
  TypeNode *pnode, *node;
  GType type = 0;
  
  g_return_val_if_uninitialized (static_quark_type_flags, g_type_init, 0);
  g_return_val_if_fail (parent_type > 0, 0);
  g_return_val_if_fail (type_name != NULL, 0);
  g_return_val_if_fail (info != NULL, 0);
  
  if (!check_type_name_I (type_name) ||
      !check_derivation_I (parent_type, type_name))
    return 0;
  if (info->class_finalize)
    {
      g_warning ("class finalizer specified for static type `%s'",
                 type_name);
      return 0;
    }
  
  pnode = lookup_type_node_I (parent_type);
  G_WRITE_LOCK (&type_rw_lock);
  type_data_ref_Wm (pnode);
  if (check_type_info_I (pnode, NODE_FUNDAMENTAL_TYPE (pnode), type_name, info))
    {
      node = type_node_new_W (pnode, type_name, NULL);
      type_add_flags_W (node, flags);
      type = NODE_TYPE (node);
      type_data_make_W (node, info,
                        check_value_table_I (type_name, info->value_table) ? info->value_table : NULL);
    }
  G_WRITE_UNLOCK (&type_rw_lock);
  
  return type;
}

GType
g_type_register_dynamic (GType        parent_type,
                         const gchar *type_name,
                         GTypePlugin *plugin,
                         GTypeFlags   flags)
{
  TypeNode *pnode, *node;
  GType type;
  
  g_return_val_if_uninitialized (static_quark_type_flags, g_type_init, 0);
  g_return_val_if_fail (parent_type > 0, 0);
  g_return_val_if_fail (type_name != NULL, 0);
  g_return_val_if_fail (plugin != NULL, 0);
  
  if (!check_type_name_I (type_name) ||
      !check_derivation_I (parent_type, type_name) ||
      !check_plugin_U (plugin, TRUE, FALSE, type_name))
    return 0;
  
  G_WRITE_LOCK (&type_rw_lock);
  pnode = lookup_type_node_I (parent_type);
  node = type_node_new_W (pnode, type_name, plugin);
  type_add_flags_W (node, flags);
  type = NODE_TYPE (node);
  G_WRITE_UNLOCK (&type_rw_lock);
  
  return type;
}

void
g_type_add_interface_static (GType                 instance_type,
                             GType                 interface_type,
                             const GInterfaceInfo *info)
{
  /* G_TYPE_IS_INSTANTIATABLE() is an external call: _U */
  g_return_if_fail (G_TYPE_IS_INSTANTIATABLE (instance_type));
  g_return_if_fail (g_type_parent (interface_type) == G_TYPE_INTERFACE);
  
  G_WRITE_LOCK (&type_rw_lock);
  if (check_add_interface_L (instance_type, interface_type))
    {
      TypeNode *node = lookup_type_node_I (instance_type);
      TypeNode *iface = lookup_type_node_I (interface_type);
      
      if (check_interface_info_I (iface, NODE_TYPE (node), info))
        type_add_interface_Wm (node, iface, info, NULL);
    }
  G_WRITE_UNLOCK (&type_rw_lock);
}

void
g_type_add_interface_dynamic (GType        instance_type,
                              GType        interface_type,
                              GTypePlugin *plugin)
{
  TypeNode *node;
  
  /* G_TYPE_IS_INSTANTIATABLE() is an external call: _U */
  g_return_if_fail (G_TYPE_IS_INSTANTIATABLE (instance_type));
  g_return_if_fail (g_type_parent (interface_type) == G_TYPE_INTERFACE);
  
  node = lookup_type_node_I (instance_type);
  if (!check_plugin_U (plugin, FALSE, TRUE, NODE_NAME (node)))
    return;
  
  G_WRITE_LOCK (&type_rw_lock);
  if (check_add_interface_L (instance_type, interface_type))
    {
      TypeNode *iface = lookup_type_node_I (interface_type);
      
      type_add_interface_Wm (node, iface, NULL, plugin);
    }
  G_WRITE_UNLOCK (&type_rw_lock);
}


/* --- public API functions --- */
gpointer
g_type_class_ref (GType type)
{
  TypeNode *node;
  
  /* optimize for common code path
   */
  G_WRITE_LOCK (&type_rw_lock);
  node = lookup_type_node_I (type);
  if (node && node->is_classed && node->data &&
      node->data->class.class && node->data->common.ref_count > 0)
    {
      type_data_ref_Wm (node);
      G_WRITE_UNLOCK (&type_rw_lock);
      
      return node->data->class.class;
    }
  
  if (!node || !node->is_classed ||
      (node->data && node->data->common.ref_count < 1))
    {
      G_WRITE_UNLOCK (&type_rw_lock);
      g_warning ("cannot retrieve class for invalid (unclassed) type `%s'",
                 type_descriptive_name_I (type));
      return NULL;
    }
  
  type_data_ref_Wm (node);
  
  if (!node->data->class.class)
    {
      GType ptype = NODE_PARENT_TYPE (node);
      GTypeClass *pclass = NULL;
      
      if (ptype)
        {
          G_WRITE_UNLOCK (&type_rw_lock);
          pclass = g_type_class_ref (ptype);
          if (node->data->class.class)
            INVALID_RECURSION ("g_type_plugin_*", node->plugin, NODE_NAME (node));
          G_WRITE_LOCK (&type_rw_lock);
        }
      
      type_class_init_Wm (node, pclass);
    }
  G_WRITE_UNLOCK (&type_rw_lock);
  
  return node->data->class.class;
}

void
g_type_class_unref (gpointer g_class)
{
  TypeNode *node;
  GTypeClass *class = g_class;
  
  g_return_if_fail (g_class != NULL);
  
  node = lookup_type_node_I (class->g_type);
  G_WRITE_LOCK (&type_rw_lock);
  if (node && node->is_classed && node->data &&
      node->data->class.class == class && node->data->common.ref_count > 0)
    type_data_unref_Wm (node, FALSE);
  else
    g_warning ("cannot unreference class of invalid (unclassed) type `%s'",
               type_descriptive_name_I (class->g_type));
  G_WRITE_UNLOCK (&type_rw_lock);
}

void
g_type_class_unref_uncached (gpointer g_class)
{
  TypeNode *node;
  GTypeClass *class = g_class;
  
  g_return_if_fail (g_class != NULL);
  
  G_WRITE_LOCK (&type_rw_lock);
  node = lookup_type_node_I (class->g_type);
  if (node && node->is_classed && node->data &&
      node->data->class.class == class && node->data->common.ref_count > 0)
    type_data_unref_Wm (node, TRUE);
  else
    g_warning ("cannot unreference class of invalid (unclassed) type `%s'",
               type_descriptive_name_I (class->g_type));
  G_WRITE_UNLOCK (&type_rw_lock);
}

gpointer
g_type_class_peek (GType type)
{
  TypeNode *node;
  gpointer class;
  
  node = lookup_type_node_I (type);
  G_READ_LOCK (&type_rw_lock);
  if (node && node->is_classed && node->data && node->data->class.class) /* common.ref_count _may_ be 0 */
    class = node->data->class.class;
  else
    class = NULL;
  G_READ_UNLOCK (&type_rw_lock);
  
  return class;
}

gpointer
g_type_class_peek_static (GType type)
{
  TypeNode *node;
  gpointer class;
  
  node = lookup_type_node_I (type);
  G_READ_LOCK (&type_rw_lock);
  if (node && node->is_classed && node->data &&
      /* peek only static types: */ node->plugin == NULL &&
      node->data->class.class) /* common.ref_count _may_ be 0 */
    class = node->data->class.class;
  else
    class = NULL;
  G_READ_UNLOCK (&type_rw_lock);
  
  return class;
}

gpointer
g_type_class_peek_parent (gpointer g_class)
{
  TypeNode *node;
  gpointer class = NULL;
  
  g_return_val_if_fail (g_class != NULL, NULL);
  
  node = lookup_type_node_I (G_TYPE_FROM_CLASS (g_class));
  /* We used to acquire a read lock here. That is not necessary, since 
   * parent->data->class.class is constant as long as the derived class
   * exists. 
   */
  if (node && node->is_classed && node->data && NODE_PARENT_TYPE (node))
    {
      node = lookup_type_node_I (NODE_PARENT_TYPE (node));
      class = node->data->class.class;
    }
  else if (NODE_PARENT_TYPE (node))
    g_warning (G_STRLOC ": invalid class pointer `%p'", g_class);
  
  return class;
}

gpointer
g_type_interface_peek (gpointer instance_class,
                       GType    iface_type)
{
  TypeNode *node;
  TypeNode *iface;
  gpointer vtable = NULL;
  GTypeClass *class = instance_class;
  
  g_return_val_if_fail (instance_class != NULL, NULL);
  
  node = lookup_type_node_I (class->g_type);
  iface = lookup_type_node_I (iface_type);
  if (node && node->is_instantiatable && iface)
    {
      IFaceEntry *entry;
      
      G_READ_LOCK (&type_rw_lock);
      
      entry = type_lookup_iface_entry_L (node, iface);
      if (entry && entry->vtable)       /* entry is relocatable */
        vtable = entry->vtable;
      
      G_READ_UNLOCK (&type_rw_lock);
    }
  else
    g_warning (G_STRLOC ": invalid class pointer `%p'", class);
  
  return vtable;
}

gpointer
g_type_interface_peek_parent (gpointer g_iface)
{
  TypeNode *node;
  TypeNode *iface;
  gpointer vtable = NULL;
  GTypeInterface *iface_class = g_iface;
  
  g_return_val_if_fail (g_iface != NULL, NULL);
  
  iface = lookup_type_node_I (iface_class->g_type);
  node = lookup_type_node_I (iface_class->g_instance_type);
  if (node)
    node = lookup_type_node_I (NODE_PARENT_TYPE (node));
  if (node && node->is_instantiatable && iface)
    {
      IFaceEntry *entry;
      
      G_READ_LOCK (&type_rw_lock);
      
      entry = type_lookup_iface_entry_L (node, iface);
      if (entry && entry->vtable)       /* entry is relocatable */
        vtable = entry->vtable;
      
      G_READ_UNLOCK (&type_rw_lock);
    }
  else if (node)
    g_warning (G_STRLOC ": invalid interface pointer `%p'", g_iface);
  
  return vtable;
}

gpointer
g_type_default_interface_ref (GType g_type)
{
  TypeNode *node;
  
  G_WRITE_LOCK (&type_rw_lock);
  
  node = lookup_type_node_I (g_type);
  if (!node || !NODE_IS_IFACE (node) ||
      (node->data && node->data->common.ref_count < 1))
    {
      G_WRITE_UNLOCK (&type_rw_lock);
      g_warning ("cannot retrieve default vtable for invalid or non-interface type '%s'",
                 type_descriptive_name_I (g_type));
      return NULL;
    }
  
  type_data_ref_Wm (node);

  type_iface_ensure_dflt_vtable_Wm (node);

  G_WRITE_UNLOCK (&type_rw_lock);
  
  return node->data->iface.dflt_vtable;
}

gpointer
g_type_default_interface_peek (GType g_type)
{
  TypeNode *node;
  gpointer vtable;
  
  node = lookup_type_node_I (g_type);
  G_READ_LOCK (&type_rw_lock);
  if (node && NODE_IS_IFACE (node) && node->data && node->data->iface.dflt_vtable)
    vtable = node->data->iface.dflt_vtable;
  else
    vtable = NULL;
  G_READ_UNLOCK (&type_rw_lock);
  
  return vtable;
}

void
g_type_default_interface_unref (gpointer g_iface)
{
  TypeNode *node;
  GTypeInterface *vtable = g_iface;
  
  g_return_if_fail (g_iface != NULL);
  
  node = lookup_type_node_I (vtable->g_type);
  G_WRITE_LOCK (&type_rw_lock);
  if (node && NODE_IS_IFACE (node) &&
      node->data->iface.dflt_vtable == g_iface &&
      node->data->common.ref_count > 0)
    type_data_unref_Wm (node, FALSE);
  else
    g_warning ("cannot unreference invalid interface default vtable for '%s'",
               type_descriptive_name_I (vtable->g_type));
  G_WRITE_UNLOCK (&type_rw_lock);
}

G_CONST_RETURN gchar*
g_type_name (GType type)
{
  TypeNode *node;
  
  g_return_val_if_uninitialized (static_quark_type_flags, g_type_init, NULL);
  
  node = lookup_type_node_I (type);
  
  return node ? NODE_NAME (node) : NULL;
}

GQuark
g_type_qname (GType type)
{
  TypeNode *node;
  
  node = lookup_type_node_I (type);
  
  return node ? node->qname : 0;
}

GType
g_type_from_name (const gchar *name)
{
  GType type = 0;
  GQuark quark;
  
  g_return_val_if_fail (name != NULL, 0);
  
  quark = g_quark_try_string (name);
  if (quark)
    {
      G_READ_LOCK (&type_rw_lock);
      type = (GType) g_hash_table_lookup (static_type_nodes_ht, GUINT_TO_POINTER (quark));
      G_READ_UNLOCK (&type_rw_lock);
    }
  
  return type;
}

GType
g_type_parent (GType type)
{
  TypeNode *node;
  
  node = lookup_type_node_I (type);
  
  return node ? NODE_PARENT_TYPE (node) : 0;
}

guint
g_type_depth (GType type)
{
  TypeNode *node;
  
  node = lookup_type_node_I (type);
  
  return node ? node->n_supers + 1 : 0;
}

GType
g_type_next_base (GType type,
                  GType base_type)
{
  GType atype = 0;
  TypeNode *node;
  
  node = lookup_type_node_I (type);
  if (node)
    {
      TypeNode *base_node = lookup_type_node_I (base_type);
      
      if (base_node && base_node->n_supers < node->n_supers)
        {
          guint n = node->n_supers - base_node->n_supers;
          
          if (node->supers[n] == base_type)
            atype = node->supers[n - 1];
        }
    }
  
  return atype;
}

static inline gboolean
type_node_check_conformities_UorL (TypeNode *node,
                                   TypeNode *iface_node,
                                   /*        support_inheritance */
                                   gboolean  support_interfaces,
                                   gboolean  support_prerequisites,
                                   gboolean  have_lock)
{
  gboolean match;
  
  if (/* support_inheritance && */
      NODE_IS_ANCESTOR (iface_node, node))
    return TRUE;
  
  support_interfaces = support_interfaces && node->is_instantiatable && NODE_IS_IFACE (iface_node);
  support_prerequisites = support_prerequisites && NODE_IS_IFACE (node);
  match = FALSE;
  if (support_interfaces || support_prerequisites)
    {
      if (!have_lock)
        G_READ_LOCK (&type_rw_lock);
      if (support_interfaces && type_lookup_iface_entry_L (node, iface_node))
        match = TRUE;
      else if (support_prerequisites && type_lookup_prerequisite_L (node, NODE_TYPE (iface_node)))
        match = TRUE;
      if (!have_lock)
        G_READ_UNLOCK (&type_rw_lock);
    }
  return match;
}

static gboolean
type_node_is_a_L (TypeNode *node,
                  TypeNode *iface_node)
{
  return type_node_check_conformities_UorL (node, iface_node, TRUE, TRUE, TRUE);
}

static inline gboolean
type_node_conforms_to_U (TypeNode *node,
                         TypeNode *iface_node,
                         gboolean  support_interfaces,
                         gboolean  support_prerequisites)
{
  return type_node_check_conformities_UorL (node, iface_node, support_interfaces, support_prerequisites, FALSE);
}

gboolean
g_type_is_a (GType type,
             GType iface_type)
{
  TypeNode *node, *iface_node;
  gboolean is_a;
  
  node = lookup_type_node_I (type);
  iface_node = lookup_type_node_I (iface_type);
  is_a = node && iface_node && type_node_conforms_to_U (node, iface_node, TRUE, TRUE);
  
  return is_a;
}

GType* /* free result */
g_type_children (GType  type,
                 guint *n_children)
{
  TypeNode *node;
  
  node = lookup_type_node_I (type);
  if (node)
    {
      GType *children;
      
      G_READ_LOCK (&type_rw_lock);      /* ->children is relocatable */
      children = g_new (GType, node->n_children + 1);
      memcpy (children, node->children, sizeof (GType) * node->n_children);
      children[node->n_children] = 0;
      
      if (n_children)
        *n_children = node->n_children;
      G_READ_UNLOCK (&type_rw_lock);
      
      return children;
    }
  else
    {
      if (n_children)
        *n_children = 0;
      
      return NULL;
    }
}

GType* /* free result */
g_type_interfaces (GType  type,
                   guint *n_interfaces)
{
  TypeNode *node;
  
  node = lookup_type_node_I (type);
  if (node && node->is_instantiatable)
    {
      GType *ifaces;
      guint i;
      
      G_READ_LOCK (&type_rw_lock);
      ifaces = g_new (GType, CLASSED_NODE_N_IFACES (node) + 1);
      for (i = 0; i < CLASSED_NODE_N_IFACES (node); i++)
        ifaces[i] = CLASSED_NODE_IFACES_ENTRIES (node)[i].iface_type;
      ifaces[i] = 0;
      
      if (n_interfaces)
        *n_interfaces = CLASSED_NODE_N_IFACES (node);
      G_READ_UNLOCK (&type_rw_lock);
      
      return ifaces;
    }
  else
    {
      if (n_interfaces)
        *n_interfaces = 0;
      
      return NULL;
    }
}

typedef struct _QData QData;
struct _GData
{
  guint  n_qdatas;
  QData *qdatas;
};
struct _QData
{
  GQuark   quark;
  gpointer data;
};

static inline gpointer
type_get_qdata_L (TypeNode *node,
                  GQuark    quark)
{
  GData *gdata = node->global_gdata;
  
  if (quark && gdata && gdata->n_qdatas)
    {
      QData *qdatas = gdata->qdatas - 1;
      guint n_qdatas = gdata->n_qdatas;
      
      do
        {
          guint i;
          QData *check;
          
          i = (n_qdatas + 1) / 2;
          check = qdatas + i;
          if (quark == check->quark)
            return check->data;
          else if (quark > check->quark)
            {
              n_qdatas -= i;
              qdatas = check;
            }
          else /* if (quark < check->quark) */
            n_qdatas = i - 1;
        }
      while (n_qdatas);
    }
  return NULL;
}

gpointer
g_type_get_qdata (GType  type,
                  GQuark quark)
{
  TypeNode *node;
  gpointer data;
  
  node = lookup_type_node_I (type);
  if (node)
    {
      G_READ_LOCK (&type_rw_lock);
      data = type_get_qdata_L (node, quark);
      G_READ_UNLOCK (&type_rw_lock);
    }
  else
    {
      g_return_val_if_fail (node != NULL, NULL);
      data = NULL;
    }
  return data;
}

static inline void
type_set_qdata_W (TypeNode *node,
                  GQuark    quark,
                  gpointer  data)
{
  GData *gdata;
  QData *qdata;
  guint i;
  
  /* setup qdata list if necessary */
  if (!node->global_gdata)
    node->global_gdata = g_new0 (GData, 1);
  gdata = node->global_gdata;
  
  /* try resetting old data */
  qdata = gdata->qdatas;
  for (i = 0; i < gdata->n_qdatas; i++)
    if (qdata[i].quark == quark)
      {
        qdata[i].data = data;
        return;
      }
  
  /* add new entry */
  gdata->n_qdatas++;
  gdata->qdatas = g_renew (QData, gdata->qdatas, gdata->n_qdatas);
  qdata = gdata->qdatas;
  for (i = 0; i < gdata->n_qdatas - 1; i++)
    if (qdata[i].quark > quark)
      break;
  g_memmove (qdata + i + 1, qdata + i, sizeof (qdata[0]) * (gdata->n_qdatas - i - 1));
  qdata[i].quark = quark;
  qdata[i].data = data;
}

void
g_type_set_qdata (GType    type,
                  GQuark   quark,
                  gpointer data)
{
  TypeNode *node;
  
  g_return_if_fail (quark != 0);
  
  node = lookup_type_node_I (type);
  if (node)
    {
      G_WRITE_LOCK (&type_rw_lock);
      type_set_qdata_W (node, quark, data);
      G_WRITE_UNLOCK (&type_rw_lock);
    }
  else
    g_return_if_fail (node != NULL);
}

static void
type_add_flags_W (TypeNode  *node,
                  GTypeFlags flags)
{
  guint dflags;
  
  g_return_if_fail ((flags & ~TYPE_FLAG_MASK) == 0);
  g_return_if_fail (node != NULL);
  
  if ((flags & TYPE_FLAG_MASK) && node->is_classed && node->data && node->data->class.class)
    g_warning ("tagging type `%s' as abstract after class initialization", NODE_NAME (node));
  dflags = GPOINTER_TO_UINT (type_get_qdata_L (node, static_quark_type_flags));
  dflags |= flags;
  type_set_qdata_W (node, static_quark_type_flags, GUINT_TO_POINTER (dflags));
}

void
g_type_query (GType       type,
              GTypeQuery *query)
{
  TypeNode *node;
  
  g_return_if_fail (query != NULL);
  
  /* if node is not static and classed, we won't allow query */
  query->type = 0;
  node = lookup_type_node_I (type);
  if (node && node->is_classed && !node->plugin)
    {
      /* type is classed and probably even instantiatable */
      G_READ_LOCK (&type_rw_lock);
      if (node->data)   /* type is static or referenced */
        {
          query->type = NODE_TYPE (node);
          query->type_name = NODE_NAME (node);
          query->class_size = node->data->class.class_size;
          query->instance_size = node->is_instantiatable ? node->data->instance.instance_size : 0;
        }
      G_READ_UNLOCK (&type_rw_lock);
    }
}


/* --- implementation details --- */
gboolean
g_type_test_flags (GType type,
                   guint flags)
{
  TypeNode *node;
  gboolean result = FALSE;
  
  node = lookup_type_node_I (type);
  if (node)
    {
      guint fflags = flags & TYPE_FUNDAMENTAL_FLAG_MASK;
      guint tflags = flags & TYPE_FLAG_MASK;
      
      if (fflags)
        {
          GTypeFundamentalInfo *finfo = type_node_fundamental_info_I (node);
          
          fflags = (finfo->type_flags & fflags) == fflags;
        }
      else
        fflags = TRUE;
      
      if (tflags)
        {
          G_READ_LOCK (&type_rw_lock);
          tflags = (tflags & GPOINTER_TO_UINT (type_get_qdata_L (node, static_quark_type_flags))) == tflags;
          G_READ_UNLOCK (&type_rw_lock);
        }
      else
        tflags = TRUE;
      
      result = tflags && fflags;
    }
  
  return result;
}

GTypePlugin*
g_type_get_plugin (GType type)
{
  TypeNode *node;
  
  node = lookup_type_node_I (type);
  
  return node ? node->plugin : NULL;
}

GTypePlugin*
g_type_interface_get_plugin (GType instance_type,
                             GType interface_type)
{
  TypeNode *node;
  TypeNode *iface;
  
  g_return_val_if_fail (G_TYPE_IS_INTERFACE (interface_type), NULL);    /* G_TYPE_IS_INTERFACE() is an external call: _U */
  
  node = lookup_type_node_I (instance_type);  
  iface = lookup_type_node_I (interface_type);
  if (node && iface)
    {
      IFaceHolder *iholder;
      GTypePlugin *plugin;
      
      G_READ_LOCK (&type_rw_lock);
      
      iholder = iface_node_get_holders_L (iface);
      while (iholder && iholder->instance_type != instance_type)
        iholder = iholder->next;
      plugin = iholder ? iholder->plugin : NULL;
      
      G_READ_UNLOCK (&type_rw_lock);
      
      return plugin;
    }
  
  g_return_val_if_fail (node == NULL, NULL);
  g_return_val_if_fail (iface == NULL, NULL);
  
  g_warning (G_STRLOC ": attempt to look up plugin for invalid instance/interface type pair.");
  
  return NULL;
}

GType
g_type_fundamental_next (void)
{
  GType type;
  
  G_READ_LOCK (&type_rw_lock);
  type = static_fundamental_next;
  G_READ_UNLOCK (&type_rw_lock);
  type = G_TYPE_MAKE_FUNDAMENTAL (type);
  return type <= G_TYPE_FUNDAMENTAL_MAX ? type : 0;
}

GType
g_type_fundamental (GType type_id)
{
  TypeNode *node = lookup_type_node_I (type_id);
  
  return node ? NODE_FUNDAMENTAL_TYPE (node) : 0;
}

gboolean
g_type_check_instance_is_a (GTypeInstance *type_instance,
                            GType          iface_type)
{
  TypeNode *node, *iface;
  gboolean check;
  
  if (!type_instance || !type_instance->g_class)
    return FALSE;
  
  node = lookup_type_node_I (type_instance->g_class->g_type);
  iface = lookup_type_node_I (iface_type);
  check = node && node->is_instantiatable && iface && type_node_conforms_to_U (node, iface, TRUE, FALSE);
  
  return check;
}

gboolean
g_type_check_class_is_a (GTypeClass *type_class,
                         GType       is_a_type)
{
  TypeNode *node, *iface;
  gboolean check;
  
  if (!type_class)
    return FALSE;
  
  node = lookup_type_node_I (type_class->g_type);
  iface = lookup_type_node_I (is_a_type);
  check = node && node->is_classed && iface && type_node_conforms_to_U (node, iface, FALSE, FALSE);
  
  return check;
}

GTypeInstance*
g_type_check_instance_cast (GTypeInstance *type_instance,
                            GType          iface_type)
{
  if (type_instance)
    {
      if (type_instance->g_class)
        {
          TypeNode *node, *iface;
          gboolean is_instantiatable, check;
          
          node = lookup_type_node_I (type_instance->g_class->g_type);
          is_instantiatable = node && node->is_instantiatable;
          iface = lookup_type_node_I (iface_type);
          check = is_instantiatable && iface && type_node_conforms_to_U (node, iface, TRUE, FALSE);
          if (check)
            return type_instance;
          
          if (is_instantiatable)
            g_warning ("invalid cast from `%s' to `%s'",
                       type_descriptive_name_I (type_instance->g_class->g_type),
                       type_descriptive_name_I (iface_type));
          else
            g_warning ("invalid uninstantiatable type `%s' in cast to `%s'",
                       type_descriptive_name_I (type_instance->g_class->g_type),
                       type_descriptive_name_I (iface_type));
        }
      else
        g_warning ("invalid unclassed pointer in cast to `%s'",
                   type_descriptive_name_I (iface_type));
    }
  
  return type_instance;
}

GTypeClass*
g_type_check_class_cast (GTypeClass *type_class,
                         GType       is_a_type)
{
  if (type_class)
    {
      TypeNode *node, *iface;
      gboolean is_classed, check;
      
      node = lookup_type_node_I (type_class->g_type);
      is_classed = node && node->is_classed;
      iface = lookup_type_node_I (is_a_type);
      check = is_classed && iface && type_node_conforms_to_U (node, iface, FALSE, FALSE);
      if (check)
        return type_class;
      
      if (is_classed)
        g_warning ("invalid class cast from `%s' to `%s'",
                   type_descriptive_name_I (type_class->g_type),
                   type_descriptive_name_I (is_a_type));
      else
        g_warning ("invalid unclassed type `%s' in class cast to `%s'",
                   type_descriptive_name_I (type_class->g_type),
                   type_descriptive_name_I (is_a_type));
    }
  else
    g_warning ("invalid class cast from (NULL) pointer to `%s'",
               type_descriptive_name_I (is_a_type));
  return type_class;
}

gboolean
g_type_check_instance (GTypeInstance *type_instance)
{
  /* this function is just here to make the signal system
   * conveniently elaborated on instance checks
   */
  if (type_instance)
    {
      if (type_instance->g_class)
        {
          TypeNode *node = lookup_type_node_I (type_instance->g_class->g_type);
          
          if (node && node->is_instantiatable)
            return TRUE;
          
          g_warning ("instance of invalid non-instantiatable type `%s'",
                     type_descriptive_name_I (type_instance->g_class->g_type));
        }
      else
        g_warning ("instance with invalid (NULL) class pointer");
    }
  else
    g_warning ("invalid (NULL) pointer instance");
  
  return FALSE;
}

static inline gboolean
type_check_is_value_type_U (GType type)
{
  GTypeFlags tflags = G_TYPE_FLAG_VALUE_ABSTRACT;
  TypeNode *node;
  
  /* common path speed up */
  node = lookup_type_node_I (type);
  if (node && node->mutatable_check_cache)
    return TRUE;
  
  G_READ_LOCK (&type_rw_lock);
 restart_check:
  if (node)
    {
      if (node->data && node->data->common.ref_count > 0 &&
          node->data->common.value_table->value_init)
        tflags = GPOINTER_TO_UINT (type_get_qdata_L (node, static_quark_type_flags));
      else if (NODE_IS_IFACE (node))
        {
          guint i;
          
          for (i = 0; i < IFACE_NODE_N_PREREQUISITES (node); i++)
            {
              GType prtype = IFACE_NODE_PREREQUISITES (node)[i];
              TypeNode *prnode = lookup_type_node_I (prtype);
              
              if (prnode->is_instantiatable)
                {
                  type = prtype;
                  node = lookup_type_node_I (type);
                  goto restart_check;
                }
            }
        }
    }
  G_READ_UNLOCK (&type_rw_lock);
  
  return !(tflags & G_TYPE_FLAG_VALUE_ABSTRACT);
}

gboolean
g_type_check_is_value_type (GType type)
{
  return type_check_is_value_type_U (type);
}

gboolean
g_type_check_value (GValue *value)
{
  return value && type_check_is_value_type_U (value->g_type);
}

gboolean
g_type_check_value_holds (GValue *value,
                          GType   type)
{
  return value && type_check_is_value_type_U (value->g_type) && g_type_is_a (value->g_type, type);
}

GTypeValueTable*
g_type_value_table_peek (GType type)
{
  GTypeValueTable *vtable = NULL;
  TypeNode *node = lookup_type_node_I (type);
  gboolean has_refed_data, has_table;
  TypeData *data;

  /* speed up common code path, we're not 100% safe here,
   * but we should only get called with referenced types anyway
   */
  data = node ? node->data : NULL;
  if (node && node->mutatable_check_cache)
    return data->common.value_table;

  G_READ_LOCK (&type_rw_lock);
  
 restart_table_peek:
  has_refed_data = node && node->data && node->data->common.ref_count;
  has_table = has_refed_data && node->data->common.value_table->value_init;
  if (has_refed_data)
    {
      if (has_table)
        vtable = node->data->common.value_table;
      else if (NODE_IS_IFACE (node))
        {
          guint i;
          
          for (i = 0; i < IFACE_NODE_N_PREREQUISITES (node); i++)
            {
              GType prtype = IFACE_NODE_PREREQUISITES (node)[i];
              TypeNode *prnode = lookup_type_node_I (prtype);
              
              if (prnode->is_instantiatable)
                {
                  type = prtype;
                  node = lookup_type_node_I (type);
                  goto restart_table_peek;
                }
            }
        }
    }
  
  G_READ_UNLOCK (&type_rw_lock);
  
  if (vtable)
    return vtable;
  
  if (!node)
    g_warning (G_STRLOC ": type id `%lu' is invalid", type);
  if (!has_refed_data)
    g_warning ("can't peek value table for type `%s' which is not currently referenced",
               type_descriptive_name_I (type));
  
  return NULL;
}

G_CONST_RETURN gchar*
g_type_name_from_instance (GTypeInstance *instance)
{
  if (!instance)
    return "<NULL-instance>";
  else
    return g_type_name_from_class (instance->g_class);
}

G_CONST_RETURN gchar*
g_type_name_from_class (GTypeClass *g_class)
{
  if (!g_class)
    return "<NULL-class>";
  else
    return g_type_name (g_class->g_type);
}


/* --- foreign prototypes --- */
extern void     g_value_c_init          (void); /* sync with gvalue.c */
extern void     g_value_types_init      (void); /* sync with gvaluetypes.c */
extern void     g_enum_types_init       (void); /* sync with genums.c */
extern void     g_param_type_init       (void); /* sync with gparam.c */
extern void     g_boxed_type_init       (void); /* sync with gboxed.c */
extern void     g_object_type_init      (void); /* sync with gobject.c */
extern void     g_param_spec_types_init (void); /* sync with gparamspecs.c */
extern void     g_value_transforms_init (void); /* sync with gvaluetransform.c */
extern void     g_signal_init           (void); /* sync with gsignal.c */


/* --- initialization --- */
void
g_type_init_with_debug_flags (GTypeDebugFlags debug_flags)
{
  G_LOCK_DEFINE_STATIC (type_init_lock);
  const gchar *env_string;
  GTypeInfo info;
  TypeNode *node;
  GType type;
  
  G_LOCK (type_init_lock);
  
  G_WRITE_LOCK (&type_rw_lock);
  
  if (static_quark_type_flags)
    {
      G_WRITE_UNLOCK (&type_rw_lock);
      G_UNLOCK (type_init_lock);
      return;
    }
  
  /* setup GObject library wide debugging flags */
  _g_type_debug_flags = debug_flags & G_TYPE_DEBUG_MASK;
  env_string = g_getenv ("GOBJECT_DEBUG");
  if (env_string != NULL)
    {
      static GDebugKey debug_keys[] = {
        { "objects", G_TYPE_DEBUG_OBJECTS },
        { "signals", G_TYPE_DEBUG_SIGNALS },
      };
      
      _g_type_debug_flags |= g_parse_debug_string (env_string,
                                                   debug_keys,
                                                   sizeof (debug_keys) / sizeof (debug_keys[0]));
      env_string = NULL;
    }
  
  /* quarks */
  static_quark_type_flags = g_quark_from_static_string ("-g-type-private--GTypeFlags");
  static_quark_iface_holder = g_quark_from_static_string ("-g-type-private--IFaceHolder");
  static_quark_dependants_array = g_quark_from_static_string ("-g-type-private--dependants-array");
  
  /* type qname hash table */
  static_type_nodes_ht = g_hash_table_new (g_direct_hash, g_direct_equal);
  
  /* invalid type G_TYPE_INVALID (0)
   */
  static_fundamental_type_nodes[0] = NULL;
  
  /* void type G_TYPE_NONE
   */
  node = type_node_fundamental_new_W (G_TYPE_NONE, "void", 0);
  type = NODE_TYPE (node);
  g_assert (type == G_TYPE_NONE);
  
  /* interface fundamental type G_TYPE_INTERFACE (!classed)
   */
  memset (&info, 0, sizeof (info));
  node = type_node_fundamental_new_W (G_TYPE_INTERFACE, "GInterface", G_TYPE_FLAG_DERIVABLE);
  type = NODE_TYPE (node);
  type_data_make_W (node, &info, NULL);
  g_assert (type == G_TYPE_INTERFACE);
  
  G_WRITE_UNLOCK (&type_rw_lock);
  
  g_value_c_init ();

  /* G_TYPE_TYPE_PLUGIN
   */
  g_type_plugin_get_type ();
  
  /* G_TYPE_* value types
   */
  g_value_types_init ();
  
  /* G_TYPE_ENUM & G_TYPE_FLAGS
   */
  g_enum_types_init ();
  
  /* G_TYPE_BOXED
   */
  g_boxed_type_init ();
  
  /* G_TYPE_PARAM
   */
  g_param_type_init ();
  
  /* G_TYPE_OBJECT
   */
  g_object_type_init ();
  
  /* G_TYPE_PARAM_* pspec types
   */
  g_param_spec_types_init ();
  
  /* Value Transformations
   */
  g_value_transforms_init ();
  
  /* Signal system
   */
  g_signal_init ();
  
  G_UNLOCK (type_init_lock);
}

void 
g_type_init (void)
{
  g_type_init_with_debug_flags (0);
}

void
g_type_class_add_private (gpointer g_class,
                          gsize    private_size)
{
  GType instance_type = ((GTypeClass *)g_class)->g_type;
  TypeNode *node = lookup_type_node_I (instance_type);
  gsize offset;

  if (!node || !node->is_instantiatable || !node->data || node->data->class.class != g_class)
    {
      g_warning ("cannot add private field to invalid (non-instantiatable) type '%s'",
                 type_descriptive_name_I (instance_type));
      return;
    }

  if (NODE_PARENT_TYPE (node))
    {
      TypeNode *pnode = lookup_type_node_I (NODE_PARENT_TYPE (node));
      if (node->data->instance.private_size != pnode->data->instance.private_size)
        {
          g_warning ("g_type_add_private() called multiple times for the same type");
          return;
        }
    }
  
  G_WRITE_LOCK (&type_rw_lock);

  offset = ALIGN_STRUCT (node->data->instance.private_size);
  node->data->instance.private_size = offset + private_size;
  
  G_WRITE_UNLOCK (&type_rw_lock);
}

gpointer
g_type_instance_get_private (GTypeInstance *instance,
                             GType          private_type)
{
  TypeNode *instance_node;
  TypeNode *private_node;
  TypeNode *parent_node;
  GTypeClass *class;
  gsize offset;

  g_return_val_if_fail (instance != NULL && instance->g_class != NULL, NULL);

  /* while instances are initialized, their class pointers change,
   * so figure the instances real class first
   */
  class = instance_real_class_get (instance);
  if (!class)
    class = instance->g_class;

  instance_node = lookup_type_node_I (class->g_type);
  if (G_UNLIKELY (!instance_node || !instance_node->is_instantiatable))
    {
      g_warning ("instance of invalid non-instantiatable type `%s'",
                 type_descriptive_name_I (instance->g_class->g_type));
      return NULL;
    }

  private_node = lookup_type_node_I (private_type);
  if (G_UNLIKELY (!private_node || !NODE_IS_ANCESTOR (private_node, instance_node)))
    {
      g_warning ("attempt to retrieve private data for invalid type '%s'",
                 type_descriptive_name_I (private_type));
      return NULL;
    }

  /* Note that we don't need a read lock, since instance existing
   * means that the instance class and all parent classes
   * exist, so the node->data, node->data->instance.instance_size,
   * and node->data->instance.private_size are not going to be changed.
   * for any of the relevant types.
   */

  offset = ALIGN_STRUCT (instance_node->data->instance.instance_size);

  if (NODE_PARENT_TYPE (private_node))
    {
      parent_node = lookup_type_node_I (NODE_PARENT_TYPE (private_node));
      g_assert (parent_node->data && parent_node->data->common.ref_count);

      if (G_UNLIKELY (private_node->data->instance.private_size == parent_node->data->instance.private_size))
        {
          g_warning ("g_type_get_private() requires a prior call to g_type_add_private()");
          return NULL;
        }

      offset += ALIGN_STRUCT (parent_node->data->instance.private_size);
    }

  return G_STRUCT_MEMBER_P (instance, offset);
}