1<part id="migrating"> 2 <title>Migrating to GIO</title> 3 4 <chapter> 5 <title>Migrating from POSIX to GIO</title> 6 7 <table id="posix-vs-gio"> 8 <title>Comparison of POSIX and GIO concepts</title> 9 <tgroup cols="2"> 10 <thead> 11 <row><entry>POSIX</entry><entry>GIO</entry></row> 12 </thead> 13 <tbody> 14 <row><entry>char *path</entry><entry>GFile *file</entry></row> 15 <row><entry>struct stat *buf</entry><entry>GFileInfo *info</entry></row> 16 <row><entry>struct statvfs *buf</entry><entry>GFileInfo *info</entry></row> 17 <row><entry morerows="1">int fd</entry><entry>GInputStream *in</entry></row> 18 <row><entry>GOutputStream *out</entry></row> 19 <row><entry>DIR *</entry><entry>GFileEnumerator *enum</entry></row> 20 <row><entry>fstab entry</entry><entry>GUnixMountPoint *mount_point</entry></row> 21 <row><entry>mtab entry</entry><entry>GUnixMountEntry *mount_entry</entry></row> 22 </tbody> 23 </tgroup> 24 </table> 25 26 </chapter> 27 28 <chapter> 29 <title>Migrating from GnomeVFS to GIO</title> 30 31 <table id="gnome-vfs-vs-gio"> 32 <title>Comparison of GnomeVFS and GIO concepts</title> 33 <tgroup cols="2"> 34 <thead> 35 <row><entry>GnomeVFS</entry><entry>GIO</entry></row> 36 </thead> 37 <tbody> 38 <row><entry>GnomeVFSURI</entry><entry>GFile</entry></row> 39 <row><entry>GnomeVFSFileInfo</entry><entry>GFileInfo</entry></row> 40 <row><entry>GnomeVFSResult</entry><entry>GError, with G_IO_ERROR values</entry></row> 41 <row><entry>GnomeVFSHandle & GnomeVFSAsyncHandle</entry><entry>GInputStream or GOutputStream</entry></row> 42 <row><entry>GnomeVFSDirectoryHandle</entry><entry>GFileEnumerator</entry></row> 43 <row><entry>mime type</entry><entry>content type</entry></row> 44 <row><entry>GnomeVFSMonitor</entry><entry>GFileMonitor</entry></row> 45 <row><entry>GnomeVFSVolumeMonitor</entry><entry>GVolumeMonitor</entry></row> 46 <row><entry>GnomeVFSVolume</entry><entry>GMount</entry></row> 47 <row><entry>GnomeVFSDrive</entry><entry>GVolume</entry></row> 48 <row><entry>-</entry><entry>GDrive</entry></row> 49 <row><entry>GnomeVFSContext</entry><entry>GCancellable</entry></row> 50 <row><entry>gnome_vfs_async_cancel</entry><entry>g_cancellable_cancel</entry></row> 51 </tbody> 52 </tgroup> 53 </table> 54 55 <section> 56 <title>Trash handling</title> 57 58 <para> 59 The handling of trashed files has been changed in GIO, compared 60 to gnome-vfs. gnome-vfs has a home-grown trash implementation that 61 predates the freedesktop.org <ulink url="http://www.freedesktop.org/wiki/Specifications/trash-spec">Desktop Trash Can</ulink> specification 62 that is implemented in GIO. The location for storing trashed files 63 has changed from <filename>$HOME/.Trash</filename> to 64 <filename>$HOME/.local/share/Trash</filename> (or more correctly 65 <filename>$XDG_DATA_HOME/Trash</filename>), which means that 66 there is a need for migrating files that have been trashed by 67 gnome-vfs to the new location. 68 </para> 69 <para> 70 In gnome-vfs, the <filename>trash://</filename> scheme offering a 71 merged view of all trash directories was implemented in nautilus, 72 and trash-handling applications had to find and monitor all trash 73 directories themselves. With GIO, the <filename>trash://</filename> 74 implementation has been moved to gvfs and applications can simply 75 monitor that location: 76 </para> 77<informalexample><programlisting> 78static void 79file_changed (GFileMonitor *file_monitor, 80 GFile *child, 81 GFile *other_file, 82 GFileMonitorEvent event_type, 83 gpointer user_data) 84{ 85 switch (event_type) 86 { 87 case G_FILE_MONITOR_EVENT_DELETED: 88 g_print ("'%s' removed from trash\n", g_file_get_basename (child)); 89 break; 90 case G_FILE_MONITOR_EVENT_CREATED: 91 g_print ("'%s' added to trash\n", g_file_get_basename (child)); 92 break; 93 default: ; 94 } 95} 96 97static void 98start_monitoring_trash (void) 99{ 100 GFile *file; 101 GFileMonitor *monitor; 102 103 file = g_file_new_for_uri ("trash://"); 104 monitor = g_file_monitor_directory (file, 0, NULL, NULL); 105 g_object_unref (file); 106 107 g_signal_connect (monitor, "changed", G_CALLBACK (file_changed), NULL); 108 109 /* ... */ 110 111} 112</programlisting></informalexample> 113 <para> 114 GIO exposes some useful metadata about trashed files. There are 115 trash::orig-path and trash::deletion-date attributes. The 116 standard::icon attribute of the <filename>trash://</filename> 117 itself provides a suitable icon for displaying the trash can on 118 the desktop. If you are using this icon, make sure to monitor 119 this attribute for changes, since the icon may be updated to 120 reflect that state of the trash can. 121 </para> 122 <para> 123 Moving a file to the trash is much simpler with GIO. Instead of 124 using gnome_vfs_find_directory() with %GNOME_VFS_DIRECTORY_KIND_TRASH 125 to find out where to move the trashed file, just use the g_file_trash() 126 function. 127 </para> 128 </section> 129 130 <section> 131 <title>Operations on multiple files</title> 132 133 <para> 134 gnome-vfs has the dreaded gnome_vfs_xfer_uri_list() function which 135 has tons of options and offers the equivalent of cp, mv, ln, mkdir 136 and rm at the same time. 137 </para> 138 <para> 139 GIO offers a much simpler I/O scheduler functionality instead, that 140 lets you schedule a function to be called in a separate thread, or 141 if threads are not available, as an idle in the mainloop. 142 See g_io_scheduler_push_job(). 143 </para> 144 145 </section> 146 147 <section> 148 <title>Mime monitoring</title> 149 150 <para> 151 gnome-vfs offered a way to monitor the association between mime types 152 and default handlers for changes, with the #GnomeVFSMIMEMonitor object. 153 GIO does not offer a replacement for this functionality at this time, 154 since we have not found a compelling use case where 155 #GnomeVFSMIMEMonitor was used. If you think you have such a use 156 case, please report it at 157 <ulink url="http://bugzilla.gnome.org">bugzilla.gnome.org</ulink>. 158 </para> 159 </section> 160 </chapter> 161 162</part> 163