gio/inotify/inotify-missing.c

   1 /* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 2; tab-width: 8 -*- */
   2
   3 /* inotify-missing.c - GVFS Monitor based on inotify.
   4
   5    Copyright (C) 2005 John McCutchan
   6
   7    This library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Library General Public
   9    License as published by the Free Software Foundation; either
  10    version 2 of the License, or (at your option) any later version.
  11
  12    This library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Library General Public License for more details.
  16
  17    You should have received a copy of the GNU Library General Public License
  18    along with this library; if not, see <http://www.gnu.org/licenses/>.
  19
  20    Authors:
  21                  John McCutchan <john@johnmccutchan.com>
  22 */
  23
  24 #include "config.h"
  25 #include <glib.h>
  26 #include "inotify-missing.h"
  27 #include "inotify-path.h"
  28 #include "glib-private.h"
  29
  30 #define SCAN_MISSING_TIME 4 /* 1/4 Hz */
  31
  32 static gboolean im_debug_enabled = FALSE;
  33 #define IM_W if (im_debug_enabled) g_warning
  34
  35 /* We put inotify_sub's that are missing on this list */
  36 static GList *missing_sub_list = NULL;
  37 static gboolean im_scan_missing (gpointer user_data);
  38 static gboolean scan_missing_running = FALSE;
  39 static void (*missing_cb)(inotify_sub *sub) = NULL;
  40
  41 G_LOCK_EXTERN (inotify_lock);
  42
  43 /* inotify_lock must be held before calling */
  44 void
  45 _im_startup (void (*callback)(inotify_sub *sub))
  46 {
  47   static gboolean initialized = FALSE;
  48
  49   if (!initialized)
  50     {
  51       missing_cb = callback;
  52       initialized = TRUE;
  53     }
  54 }
  55
  56 /* inotify_lock must be held before calling */
  57 void
  58 _im_add (inotify_sub *sub)
  59 {
  60   if (g_list_find (missing_sub_list, sub))
  61     {
  62       IM_W ("asked to add %s to missing list but it's already on the list!\n", sub->dirname);
  63       return;
  64     }
  65
  66   IM_W ("adding %s to missing list\n", sub->dirname);
  67   missing_sub_list = g_list_prepend (missing_sub_list, sub);
  68
  69   /* If the timeout is turned off, we turn it back on */
  70   if (!scan_missing_running)
  71     {
  72       GSource *source;
  73
  74       scan_missing_running = TRUE;
  75       source = g_timeout_source_new_seconds (SCAN_MISSING_TIME);
  76       g_source_set_callback (source, im_scan_missing, NULL, NULL);
  77       g_source_attach (source, GLIB_PRIVATE_CALL (g_get_worker_context) ());
  78       g_source_unref (source);
  79     }
  80 }
  81
  82 /* inotify_lock must be held before calling */
  83 void
  84 _im_rm (inotify_sub *sub)
  85 {
  86   GList *link;
  87
  88   link = g_list_find (missing_sub_list, sub);
  89
  90   if (!link)
  91     {
  92       IM_W ("asked to remove %s from missing list but it isn't on the list!\n", sub->dirname);
  93       return;
  94     }
  95
  96   IM_W ("removing %s from missing list\n", sub->dirname);
  97
  98   missing_sub_list = g_list_remove_link (missing_sub_list, link);
  99   g_list_free_1 (link);
 100 }
 101
 102 /* Scans the list of missing subscriptions checking if they
 103  * are available yet.
 104  */
 105 static gboolean
 106 im_scan_missing (gpointer user_data)
 107 {
 108   GList *nolonger_missing = NULL;
 109   GList *l;
 110
 111   G_LOCK (inotify_lock);
 112
 113   IM_W ("scanning missing list with %d items\n", g_list_length (missing_sub_list));
 114   for (l = missing_sub_list; l; l = l->next)
 115     {
 116       inotify_sub *sub = l->data;
 117       gboolean not_m = FALSE;
 118
 119       IM_W ("checking %p\n", sub);
 120       g_assert (sub);
 121       g_assert (sub->dirname);
 122       not_m = _ip_start_watching (sub);
 123
 124       if (not_m)
 125         {
 126           missing_cb (sub);
 127           IM_W ("removed %s from missing list\n", sub->dirname);
 128           /* We have to build a list of list nodes to remove from the
 129            * missing_sub_list. We do the removal outside of this loop.
 130            */
 131           nolonger_missing = g_list_prepend (nolonger_missing, l);
 132         }
 133     }
 134
 135   for (l = nolonger_missing; l ; l = l->next)
 136     {
 137       GList *llink = l->data;
 138       missing_sub_list = g_list_remove_link (missing_sub_list, llink);
 139       g_list_free_1 (llink);
 140     }
 141
 142   g_list_free (nolonger_missing);
 143
 144   /* If the missing list is now empty, we disable the timeout */
 145   if (missing_sub_list == NULL)
 146     {
 147       scan_missing_running = FALSE;
 148       G_UNLOCK (inotify_lock);
 149       return FALSE;
 150     }
 151   else
 152     {
 153       G_UNLOCK (inotify_lock);
 154       return TRUE;
 155     }
 156 }