gio/fam/gfamfilemonitor.c

   1 /*
   2  * Copyright © 2015 Canonical Limited
   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 2.1 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
  15  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  16  *
  17  * Author: Ryan Lortie <desrt@desrt.ca>
  18  */
  19
  20 #include "config.h"
  21
  22 #include <gio/glocalfilemonitor.h>
  23 #include <gio/giomodule.h>
  24 #include "glib-private.h"
  25 #include <glib-unix.h>
  26 #include <fam.h>
  27
  28 static GMutex         fam_lock;
  29 static gboolean       fam_initialised;
  30 static FAMConnection  fam_connection;
  31 static GSource       *fam_source;
  32
  33 #define G_TYPE_FAM_FILE_MONITOR      (g_fam_file_monitor_get_type ())
  34 #define G_FAM_FILE_MONITOR(inst)     (G_TYPE_CHECK_INSTANCE_CAST ((inst), \
  35                                       G_TYPE_FAM_FILE_MONITOR, GFamFileMonitor))
  36
  37 typedef GLocalFileMonitorClass GFamFileMonitorClass;
  38
  39 typedef struct
  40 {
  41   GLocalFileMonitor parent_instance;
  42
  43   FAMRequest request;
  44 } GFamFileMonitor;
  45
  46 static GType g_fam_file_monitor_get_type (void);
  47 G_DEFINE_DYNAMIC_TYPE (GFamFileMonitor, g_fam_file_monitor, G_TYPE_LOCAL_FILE_MONITOR)
  48
  49 static gboolean
  50 g_fam_file_monitor_callback (gint         fd,
  51                              GIOCondition condition,
  52                              gpointer     user_data)
  53 {
  54   gint64 now = g_source_get_time (fam_source);
  55
  56   g_mutex_lock (&fam_lock);
  57
  58   while (FAMPending (&fam_connection))
  59     {
  60       const gchar *child;
  61       FAMEvent ev;
  62
  63       if (FAMNextEvent (&fam_connection, &ev) != 1)
  64         {
  65           /* The daemon died.  We're in a really bad situation now
  66            * because we potentially have a bunch of request structures
  67            * outstanding which no longer make any sense to anyone.
  68            *
  69            * The best thing that we can do is do nothing.  Notification
  70            * won't work anymore for this process.
  71            */
  72           g_mutex_unlock (&fam_lock);
  73
  74           g_warning ("Lost connection to FAM (file monitoring) service.  Expect no further file monitor events.");
  75
  76           return FALSE;
  77         }
  78
  79       /* We expect ev.filename to be a relative path for children in a
  80        * monitored directory, and an absolute path for a monitored file
  81        * or the directory itself.
  82        */
  83       if (ev.filename[0] != '/')
  84         child = ev.filename;
  85       else
  86         child = NULL;
  87
  88       switch (ev.code)
  89         {
  90         case FAMAcknowledge:
  91           g_source_unref (ev.userdata);
  92           break;
  93
  94         case FAMChanged:
  95           g_file_monitor_source_handle_event (ev.userdata, G_FILE_MONITOR_EVENT_CHANGED, child, NULL, NULL, now);
  96           break;
  97
  98         case FAMDeleted:
  99           g_file_monitor_source_handle_event (ev.userdata, G_FILE_MONITOR_EVENT_DELETED, child, NULL, NULL, now);
 100           break;
 101
 102         case FAMCreated:
 103           g_file_monitor_source_handle_event (ev.userdata, G_FILE_MONITOR_EVENT_CREATED, child, NULL, NULL, now);
 104           break;
 105
 106         default:
 107           /* unknown type */
 108           break;
 109         }
 110     }
 111
 112   g_mutex_unlock (&fam_lock);
 113
 114   return TRUE;
 115 }
 116
 117 static gboolean
 118 g_fam_file_monitor_is_supported (void)
 119 {
 120   g_mutex_lock (&fam_lock);
 121
 122   if (!fam_initialised)
 123     {
 124       fam_initialised = FAMOpen2 (&fam_connection, "GLib GIO") == 0;
 125
 126       if (fam_initialised)
 127         {
 128 #ifdef HAVE_FAM_NO_EXISTS
 129           /* This is a gamin extension that avoids sending all the
 130            * Exists event for dir monitors
 131            */
 132           FAMNoExists (&fam_connection);
 133 #endif
 134
 135           fam_source = g_unix_fd_source_new (FAMCONNECTION_GETFD (&fam_connection), G_IO_IN);
 136           g_source_set_callback (fam_source, (GSourceFunc) g_fam_file_monitor_callback, NULL, NULL);
 137           g_source_attach (fam_source, GLIB_PRIVATE_CALL(g_get_worker_context) ());
 138         }
 139     }
 140
 141   g_mutex_unlock (&fam_lock);
 142
 143   return fam_initialised;
 144 }
 145
 146 static gboolean
 147 g_fam_file_monitor_cancel (GFileMonitor *monitor)
 148 {
 149   GFamFileMonitor *gffm = G_FAM_FILE_MONITOR (monitor);
 150
 151   g_mutex_lock (&fam_lock);
 152
 153   g_assert (fam_initialised);
 154
 155   FAMCancelMonitor (&fam_connection, &gffm->request);
 156
 157   g_mutex_unlock (&fam_lock);
 158
 159   return TRUE;
 160 }
 161
 162 static void
 163 g_fam_file_monitor_start (GLocalFileMonitor  *local_monitor,
 164                           const gchar        *dirname,
 165                           const gchar        *basename,
 166                           const gchar        *filename,
 167                           GFileMonitorSource *source)
 168 {
 169   GFamFileMonitor *gffm = G_FAM_FILE_MONITOR (local_monitor);
 170
 171   g_mutex_lock (&fam_lock);
 172
 173   g_assert (fam_initialised);
 174
 175   g_source_ref ((GSource *) source);
 176
 177   if (dirname)
 178     FAMMonitorDirectory (&fam_connection, dirname, &gffm->request, source);
 179   else
 180     FAMMonitorFile (&fam_connection, filename, &gffm->request, source);
 181
 182   g_mutex_unlock (&fam_lock);
 183 }
 184
 185 static void
 186 g_fam_file_monitor_init (GFamFileMonitor* monitor)
 187 {
 188 }
 189
 190 static void
 191 g_fam_file_monitor_class_init (GFamFileMonitorClass *class)
 192 {
 193   GFileMonitorClass *file_monitor_class = G_FILE_MONITOR_CLASS (class);
 194
 195   class->is_supported = g_fam_file_monitor_is_supported;
 196   class->start = g_fam_file_monitor_start;
 197   file_monitor_class->cancel = g_fam_file_monitor_cancel;
 198 }
 199
 200 static void
 201 g_fam_file_monitor_class_finalize (GFamFileMonitorClass *class)
 202 {
 203 }
 204
 205 void
 206 g_io_module_load (GIOModule *module)
 207 {
 208   g_type_module_use (G_TYPE_MODULE (module));
 209
 210   g_fam_file_monitor_register_type (G_TYPE_MODULE (module));
 211
 212   g_io_extension_point_implement (G_LOCAL_FILE_MONITOR_EXTENSION_POINT_NAME,
 213                                  G_TYPE_FAM_FILE_MONITOR, "fam", 10);
 214
 215   g_io_extension_point_implement (G_NFS_FILE_MONITOR_EXTENSION_POINT_NAME,
 216                                  G_TYPE_FAM_FILE_MONITOR, "fam", 10);
 217 }
 218
 219 void
 220 g_io_module_unload (GIOModule *module)
 221 {
 222   g_assert_not_reached ();
 223 }
 224
 225 char **
 226 g_io_module_query (void)
 227 {
 228   char *eps[] = {
 229     G_LOCAL_FILE_MONITOR_EXTENSION_POINT_NAME,
 230     G_NFS_FILE_MONITOR_EXTENSION_POINT_NAME,
 231     NULL
 232   };
 233
 234   return g_strdupv (eps);
 235 }