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 "config.h"
  21
  22 #include "atkstreamablecontent.h"
  23
  24 /**
  25  * SECTION:atkstreamablecontent
  26  * @Short_description: The ATK interface which provides access to
  27  *  streamable content.
  28  * @Title:AtkStreamableContent
  29  *
  30  * An interface whereby an object allows its backing content to be
  31  * streamed to clients.  Typical implementors would be images or
  32  * icons, HTML content, or multimedia display/rendering widgets.
  33  *
  34  * Negotiation of content type is allowed. Clients may examine the
  35  * backing data and transform, convert, or parse the content in order
  36  * to present it in an alternate form to end-users.
  37  *
  38  * The AtkStreamableContent interface is particularly useful for
  39  * saving, printing, or post-processing entire documents, or for
  40  * persisting alternate views of a document. If document content
  41  * itself is being serialized, stored, or converted, then use of the
  42  * AtkStreamableContent interface can help address performance
  43  * issues. Unlike most ATK interfaces, this interface is not strongly
  44  * tied to the current user-agent view of the a particular document,
  45  * but may in some cases give access to the underlying model data.
  46  */
  47
  48 GType
  49 atk_streamable_content_get_type (void)
  50 {
  51   static GType type = 0;
  52
  53   if (!type) {
  54     GTypeInfo tinfo =
  55     {
  56       sizeof (AtkStreamableContentIface),
  57       (GBaseInitFunc) NULL,
  58       (GBaseFinalizeFunc) NULL,
  59
  60     };
  61
  62     type = g_type_register_static (G_TYPE_INTERFACE, "AtkStreamableContent", &tinfo, 0);
  63   }
  64
  65   return type;
  66 }
  67
  68 /**
  69  * atk_streamable_content_get_n_mime_types:
  70  * @streamable: a GObject instance that implements AtkStreamableContentIface
  71  *
  72  * Gets the number of mime types supported by this object.
  73  *
  74  * Returns: a gint which is the number of mime types supported by the object.
  75  **/
  76 gint
  77 atk_streamable_content_get_n_mime_types (AtkStreamableContent *streamable)
  78 {
  79   AtkStreamableContentIface *iface;
  80
  81   g_return_val_if_fail (ATK_IS_STREAMABLE_CONTENT (streamable), 0);
  82
  83   iface = ATK_STREAMABLE_CONTENT_GET_IFACE (streamable);
  84
  85   if (iface->get_n_mime_types)
  86     return (iface->get_n_mime_types) (streamable);
  87   else
  88     return 0;
  89 }
  90
  91 /**
  92  * atk_streamable_content_get_mime_type:
  93  * @streamable: a GObject instance that implements AtkStreamableContent
  94  * @i: a gint representing the position of the mime type starting from 0
  95  *
  96  * Gets the character string of the specified mime type. The first mime
  97  * type is at position 0, the second at position 1, and so on.
  98  *
  99  * Returns: a gchar* representing the specified mime type; the caller
 100  * should not free the character string.
 101  **/
 102 const gchar*
 103 atk_streamable_content_get_mime_type (AtkStreamableContent *streamable,
 104                                       gint                 i)
 105 {
 106   AtkStreamableContentIface *iface;
 107
 108   g_return_val_if_fail (i >= 0, NULL);
 109   g_return_val_if_fail (ATK_IS_STREAMABLE_CONTENT (streamable), NULL);
 110
 111   iface = ATK_STREAMABLE_CONTENT_GET_IFACE (streamable);
 112
 113   if (iface->get_mime_type)
 114     return (iface->get_mime_type) (streamable, i);
 115   else
 116     return NULL;
 117 }
 118
 119 /**
 120  * atk_streamable_content_get_stream:
 121  * @streamable: a GObject instance that implements AtkStreamableContentIface
 122  * @mime_type: a gchar* representing the mime type
 123  *
 124  * Gets the content in the specified mime type.
 125  *
 126  * Returns: (transfer full): A #GIOChannel which contains the content in the
 127  * specified mime type.
 128  **/
 129 GIOChannel*
 130 atk_streamable_content_get_stream (AtkStreamableContent *streamable,
 131                                    const gchar          *mime_type)
 132 {
 133   AtkStreamableContentIface *iface;
 134
 135   g_return_val_if_fail (mime_type != NULL, NULL);
 136   g_return_val_if_fail (ATK_IS_STREAMABLE_CONTENT (streamable), NULL);
 137
 138   iface = ATK_STREAMABLE_CONTENT_GET_IFACE (streamable);
 139
 140   if (iface->get_stream)
 141     return (iface->get_stream) (streamable, mime_type);
 142   else
 143     return NULL;
 144 }
 145
 146 /**
 147  * atk_streamable_content_get_uri:
 148  * @streamable: a GObject instance that implements AtkStreamableContentIface
 149  * @mime_type: a gchar* representing the mime type, or NULL to request a URI
 150  * for the default mime type.
 151  *
 152  * Get a string representing a URI in IETF standard format
 153  * (see http://www.ietf.org/rfc/rfc2396.txt) from which the object's content
 154  * may be streamed in the specified mime-type, if one is available.
 155  * If mime_type is NULL, the URI for the default (and possibly only) mime-type is
 156  * returned.
 157  *
 158  * Note that it is possible for get_uri to return NULL but for
 159  * get_stream to work nonetheless, since not all GIOChannels connect to URIs.
 160  *
 161  * Returns: (nullable): Returns a string representing a URI, or %NULL
 162  * if no corresponding URI can be constructed.
 163  *
 164  * Since: 1.12
 165  **/
 166 const gchar*
 167 atk_streamable_content_get_uri (AtkStreamableContent *streamable,
 168                                 const gchar          *mime_type)
 169 {
 170   AtkStreamableContentIface *iface;
 171
 172   g_return_val_if_fail (mime_type != NULL, NULL);
 173   g_return_val_if_fail (ATK_IS_STREAMABLE_CONTENT (streamable), NULL);
 174
 175   iface = ATK_STREAMABLE_CONTENT_GET_IFACE (streamable);
 176
 177   if (iface->get_uri)
 178     return (iface->get_uri) (streamable, mime_type);
 179   else
 180     return NULL;
 181 }