atk/atkstreamablecontent.c

   1 /* ATK -  Accessibility Toolkit
   2  * Copyright 2001 Sun Microsystems Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 #include "atkstreamablecontent.h"
  21
  22 /**
  23  * SECTION:atkstreamablecontent
  24  * @Short_description: The ATK interface which provides access to
  25  *  streamable content.
  26  * @Title:AtkStreamableContent
  27  *
  28  * An interface whereby an object allows its backing content to be
  29  * streamed to clients.  Typical implementors would be images or
  30  * icons, HTML content, or multimedia display/rendering widgets.
  31  *
  32  * Negotiation of content type is allowed. Clients may examine the
  33  * backing data and transform, convert, or parse the content in order
  34  * to present it in an alternate form to end-users.
  35  *
  36  * The AtkStreamableContent interface is particularly useful for
  37  * saving, printing, or post-processing entire documents, or for
  38  * persisting alternate views of a document. If document content
  39  * itself is being serialized, stored, or converted, then use of the
  40  * AtkStreamableContent interface can help address performance
  41  * issues. Unlike most ATK interfaces, this interface is not strongly
  42  * tied to the current user-agent view of the a particular document,
  43  * but may in some cases give access to the underlying model data.
  44  */
  45
  46 GType
  47 atk_streamable_content_get_type (void)
  48 {
  49   static GType type = 0;
  50
  51   if (!type) {
  52     GTypeInfo tinfo =
  53     {
  54       sizeof (AtkStreamableContentIface),
  55       (GBaseInitFunc) NULL,
  56       (GBaseFinalizeFunc) NULL,
  57
  58     };
  59
  60     type = g_type_register_static (G_TYPE_INTERFACE, "AtkStreamableContent", &tinfo, 0);
  61   }
  62
  63   return type;
  64 }
  65
  66 /**
  67  * atk_streamable_content_get_n_mime_types:
  68  * @streamable: a GObject instance that implements AtkStreamableContentIface
  69  *
  70  * Gets the number of mime types supported by this object.
  71  *
  72  * Returns: a gint which is the number of mime types supported by the object.
  73  **/
  74 gint
  75 atk_streamable_content_get_n_mime_types (AtkStreamableContent *streamable)
  76 {
  77   AtkStreamableContentIface *iface;
  78
  79   g_return_val_if_fail (ATK_IS_STREAMABLE_CONTENT (streamable), 0);
  80
  81   iface = ATK_STREAMABLE_CONTENT_GET_IFACE (streamable);
  82
  83   if (iface->get_n_mime_types)
  84     return (iface->get_n_mime_types) (streamable);
  85   else
  86     return 0;
  87 }
  88
  89 /**
  90  * atk_streamable_content_get_mime_type:
  91  * @streamable: a GObject instance that implements AtkStreamableContent
  92  * @i: a gint representing the position of the mime type starting from 0
  93  *
  94  * Gets the character string of the specified mime type. The first mime
  95  * type is at position 0, the second at position 1, and so on.
  96  *
  97  * Returns: a gchar* representing the specified mime type; the caller
  98  * should not free the character string.
  99  **/
 100 const gchar*
 101 atk_streamable_content_get_mime_type (AtkStreamableContent *streamable,
 102                                       gint                 i)
 103 {
 104   AtkStreamableContentIface *iface;
 105
 106   g_return_val_if_fail (i >= 0, NULL);
 107   g_return_val_if_fail (ATK_IS_STREAMABLE_CONTENT (streamable), NULL);
 108
 109   iface = ATK_STREAMABLE_CONTENT_GET_IFACE (streamable);
 110
 111   if (iface->get_mime_type)
 112     return (iface->get_mime_type) (streamable, i);
 113   else
 114     return NULL;
 115 }
 116
 117 /**
 118  * atk_streamable_content_get_stream:
 119  * @streamable: a GObject instance that implements AtkStreamableContentIface
 120  * @mime_type: a gchar* representing the mime type
 121  *
 122  * Gets the content in the specified mime type.
 123  *
 124  * Returns: (transfer full): A #GIOChannel which contains the content in the
 125  * specified mime type.
 126  **/
 127 GIOChannel*
 128 atk_streamable_content_get_stream (AtkStreamableContent *streamable,
 129                                    const gchar          *mime_type)
 130 {
 131   AtkStreamableContentIface *iface;
 132
 133   g_return_val_if_fail (mime_type != NULL, NULL);
 134   g_return_val_if_fail (ATK_IS_STREAMABLE_CONTENT (streamable), NULL);
 135
 136   iface = ATK_STREAMABLE_CONTENT_GET_IFACE (streamable);
 137
 138   if (iface->get_stream)
 139     return (iface->get_stream) (streamable, mime_type);
 140   else
 141     return NULL;
 142 }
 143
 144 /**
 145  * atk_streamable_content_get_uri:
 146  * @streamable: a GObject instance that implements AtkStreamableContentIface
 147  * @mime_type: a gchar* representing the mime type, or NULL to request a URI
 148  * for the default mime type.
 149  *
 150  * Get a string representing a URI in IETF standard format
 151  * (see http://www.ietf.org/rfc/rfc2396.txt) from which the object's content
 152  * may be streamed in the specified mime-type, if one is available.
 153  * If mime_type is NULL, the URI for the default (and possibly only) mime-type is
 154  * returned.
 155  *
 156  * Note that it is possible for get_uri to return NULL but for
 157  * get_stream to work nonetheless, since not all GIOChannels connect to URIs.
 158  *
 159  * Returns:  Returns a string representing a URI, or NULL if no corresponding URI
 160  * can be constructed.
 161  *
 162  * Since: 1.12
 163  **/
 164 const gchar*
 165 atk_streamable_content_get_uri (AtkStreamableContent *streamable,
 166                                 const gchar          *mime_type)
 167 {
 168   AtkStreamableContentIface *iface;
 169
 170   g_return_val_if_fail (mime_type != NULL, NULL);
 171   g_return_val_if_fail (ATK_IS_STREAMABLE_CONTENT (streamable), NULL);
 172
 173   iface = ATK_STREAMABLE_CONTENT_GET_IFACE (streamable);
 174
 175   if (iface->get_uri)
 176     return (iface->get_uri) (streamable, mime_type);
 177   else
 178     return NULL;
 179 }