source: trunk/third/gnome-vfs/libgnomevfs/gnome-vfs-handle.c @ 15858

/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
/* gnome-vfs-handle.c - Handle object for GNOME VFS files.

   Copyright (C) 1999 Free Software Foundation

   The Gnome Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The Gnome 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the Gnome Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.

   Author: Ettore Perazzoli <ettore@gnu.org>
*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "gnome-vfs.h"
#include "gnome-vfs-private.h"


struct GnomeVFSHandle {
        /* URI of the file being accessed through the handle.  */
        GnomeVFSURI *uri;

        /* Method-specific handle.  */
        GnomeVFSMethodHandle *method_handle;

        /* Open mode.  */
        GnomeVFSOpenMode open_mode;
};

#define CHECK_IF_OPEN(handle)                   \
G_STMT_START{                                   \
        if (handle->uri == NULL)                \
                return GNOME_VFS_ERROR_NOT_OPEN;        \
}G_STMT_END

#define CHECK_IF_SUPPORTED(handle, what)                \
G_STMT_START{                                           \
        if (!VFS_METHOD_HAS_FUNC(handle->uri->method, what))            \
                return GNOME_VFS_ERROR_NOT_SUPPORTED;   \
}G_STMT_END

#define INVOKE(result, handle, what, params)            \
G_STMT_START{                                           \
        CHECK_IF_OPEN (handle);                         \
        CHECK_IF_SUPPORTED (handle, what);              \
        (result) = handle->uri->method->what params;    \
}G_STMT_END

#define INVOKE_AND_RETURN(handle, what, params)         \
G_STMT_START{                                           \
        GnomeVFSResult __result;                        \
                                                        \
        INVOKE (__result, handle, what, params);        \
        return __result;                                \
}G_STMT_END


GnomeVFSHandle *
gnome_vfs_handle_new (GnomeVFSURI *uri,
                      GnomeVFSMethodHandle *method_handle,
                      GnomeVFSOpenMode open_mode)
{
        GnomeVFSHandle *new;

        g_return_val_if_fail (uri != NULL, NULL);
        g_return_val_if_fail (method_handle != NULL, NULL);

        new = g_new (GnomeVFSHandle, 1);

        new->uri = gnome_vfs_uri_ref (uri);
        new->method_handle = method_handle;
        new->open_mode = open_mode;

        if ((open_mode & GNOME_VFS_OPEN_RANDOM) &&
            !VFS_METHOD_HAS_FUNC (uri->method, seek)) {
                GnomeVFSMethodHandle *handle;
                handle = gnome_vfs_seek_emulate (new->uri, method_handle,
                                                 open_mode);
                if (handle) /* Successfully wrapped */
                        new->method_handle = handle;
        }

        return new;
}

void
gnome_vfs_handle_destroy (GnomeVFSHandle *handle)
{
        g_return_if_fail (handle != NULL);

        gnome_vfs_uri_unref (handle->uri);

        g_free (handle);
}


GnomeVFSOpenMode
gnome_vfs_handle_get_open_mode (GnomeVFSHandle *handle)
{
        g_return_val_if_fail (handle != NULL, (GnomeVFSOpenMode) 0);

        return handle->open_mode;
}


/* Actions.  */

GnomeVFSResult
gnome_vfs_handle_do_close (GnomeVFSHandle *handle,
                           GnomeVFSContext *context)
{
        GnomeVFSResult result;

        INVOKE (result, handle, close, (handle->uri->method, handle->method_handle, context));

        /* Even if close has failed, we shut down the handle. */
        gnome_vfs_handle_destroy (handle);

        return result;
}

GnomeVFSResult
gnome_vfs_handle_do_read (GnomeVFSHandle *handle,
                          gpointer buffer,
                          GnomeVFSFileSize num_bytes,
                          GnomeVFSFileSize *bytes_read,
                          GnomeVFSContext *context)
{
        INVOKE_AND_RETURN (handle, read, (handle->uri->method, handle->method_handle,
                                          buffer, num_bytes, bytes_read,
                                          context));
}

GnomeVFSResult
gnome_vfs_handle_do_write (GnomeVFSHandle *handle,
                           gconstpointer buffer,
                           GnomeVFSFileSize num_bytes,
                           GnomeVFSFileSize *bytes_written,
                           GnomeVFSContext *context)
{
        INVOKE_AND_RETURN (handle, write, (handle->uri->method, handle->method_handle,
                                           buffer, num_bytes, bytes_written,
                                           context));
}


GnomeVFSResult
gnome_vfs_handle_do_seek (GnomeVFSHandle *handle,
                          GnomeVFSSeekPosition whence,
                          GnomeVFSFileSize offset,
                          GnomeVFSContext *context)
{
        INVOKE_AND_RETURN (handle, seek, (handle->uri->method, handle->method_handle,
                                          whence, offset, context));
}

GnomeVFSResult
gnome_vfs_handle_do_tell (GnomeVFSHandle *handle,
                          GnomeVFSFileSize *offset_return)
{
        INVOKE_AND_RETURN (handle, tell, (handle->uri->method, handle->method_handle,
                                          offset_return));
}


GnomeVFSResult
gnome_vfs_handle_do_get_file_info (GnomeVFSHandle *handle,
                                   GnomeVFSFileInfo *info,
                                   GnomeVFSFileInfoOptions options,
                                   GnomeVFSContext *context)
{
        INVOKE_AND_RETURN (handle, get_file_info_from_handle,
                           (handle->uri->method, handle->method_handle, info, options,
                            context));
}

GnomeVFSResult gnome_vfs_handle_do_truncate     (GnomeVFSHandle *handle,
                                                 GnomeVFSFileSize length,
                                                 GnomeVFSContext *context)
{
        INVOKE_AND_RETURN (handle, truncate_handle, (handle->uri->method, handle->method_handle, length, context));
}