Import Upstream version 2.72.4

gio/kqueue/kqueue-missing.c

@@ -0,0 +1,179 @@
+/*******************************************************************************
+  Copyright (c) 2011, 2012 Dmitry Matveev <me@dmitrymatveev.co.uk>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+  THE SOFTWARE.
+*******************************************************************************/
+
+#include <glib.h>
+#include "glib-private.h"
+
+#include "kqueue-helper.h"
+
+
+#define SCAN_MISSING_TIME 4 /* 1/4 Hz */
+
+static gboolean km_debug_enabled = FALSE;
+#define KM_W if (km_debug_enabled) g_warning
+
+static GSList *missing_subs_list = NULL;
+G_LOCK_DEFINE_STATIC (missing_lock);
+
+static gboolean scan_missing_running = FALSE;  /* must be accessed under @missing_lock */
+
+
+static gboolean
+_km_scan_missing_cb (gpointer user_data)
+{
+  return _km_scan_missing (NULL);
+}
+
+/**
+ * _km_add_missing:
+ * @sub: a #kqueue_sub
+ *
+ * Adds a subscription to the missing files list.
+ **/
+void
+_km_add_missing (kqueue_sub *sub)
+{
+  G_LOCK (missing_lock);
+  if (g_slist_find (missing_subs_list, sub))
+    {
+      KM_W ("asked to add %s to missing list but it's already on the list!\n", sub->filename);
+      G_UNLOCK (missing_lock);
+      return;
+    }
+
+  KM_W ("adding %s to missing list\n", sub->filename);
+  missing_subs_list = g_slist_prepend (missing_subs_list, sub);
+
+  if (!scan_missing_running)
+    {
+      GSource *source;
+      scan_missing_running = TRUE;
+      source = g_timeout_source_new_seconds (SCAN_MISSING_TIME);
+      g_source_set_callback (source, _km_scan_missing_cb, NULL, NULL);
+      g_source_attach (source, GLIB_PRIVATE_CALL (g_get_worker_context) ());
+      g_source_unref (source);
+    }
+
+  G_UNLOCK (missing_lock);
+}
+
+/**
+ * _kh_file_appeared_cb:
+ * @sub: a #kqueue_sub
+ *
+ * A callback function for kqueue-missing subsystem.
+ *
+ * Signals that a missing file has finally appeared in the filesystem.
+ * Emits %G_FILE_MONITOR_EVENT_CREATED.
+ **/
+static void
+_kh_file_appeared_cb (kqueue_sub *sub)
+{
+  gint64 now = g_get_monotonic_time ();
+
+  g_assert (sub != NULL);
+  g_assert (sub->filename);
+
+  if (!g_file_test (sub->filename, G_FILE_TEST_EXISTS))
+    return;
+
+  g_file_monitor_source_handle_event (sub->source, G_FILE_MONITOR_EVENT_CREATED,
+                                      sub->basename, NULL, NULL, now);
+  g_file_monitor_source_handle_event (sub->source, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT,
+                                      sub->basename, NULL, NULL, now);
+}
+
+/**
+ * _km_scan_missing:
+ * @user_data: unused
+ *
+ * The core missing files watching routine.
+ *
+ * Traverses through a list of missing files, tries to start watching each with
+ * kqueue, removes the appropriate entry and invokes a user callback if the file
+ * has appeared.
+ *
+ * Returns: %FALSE if no missing files left, %TRUE otherwise.
+ **/
+gboolean
+_km_scan_missing (kqueue_sub *check_this_sub_only)
+{
+  GSList *head;
+  GSList *not_missing = NULL;
+  gboolean retval = FALSE;
+  
+  G_LOCK (missing_lock);
+
+  if (missing_subs_list)
+    KM_W ("we have a job");
+
+  for (head = missing_subs_list; head; head = head->next)
+    {
+      kqueue_sub *sub = (kqueue_sub *) head->data;
+      g_assert (sub != NULL);
+      g_assert (sub->filename != NULL);
+
+      if (check_this_sub_only != NULL && sub != check_this_sub_only)
+        continue;
+
+      if (_kqsub_start_watching (sub))
+        {
+          KM_W ("file %s now exists, starting watching", sub->filename);
+          if (check_this_sub_only == NULL)
+            _kh_file_appeared_cb (sub);
+          not_missing = g_slist_prepend (not_missing, head);
+        }
+    }
+
+  for (head = not_missing; head; head = head->next)
+    {
+      GSList *link = (GSList *) head->data;
+      missing_subs_list = g_slist_remove_link (missing_subs_list, link);
+    }
+  g_slist_free (not_missing);
+
+  if (missing_subs_list == NULL)
+    {
+      scan_missing_running = FALSE;
+      retval = FALSE;
+    }
+  else
+    retval = TRUE;
+
+  G_UNLOCK (missing_lock);
+  return retval;
+}
+
+
+/**
+ * _km_remove:
+ * @sub: a #kqueue_sub
+ *
+ * Removes a subscription from a list of missing files.
+ **/
+void
+_km_remove (kqueue_sub *sub)
+{
+  G_LOCK (missing_lock);
+  missing_subs_list = g_slist_remove (missing_subs_list, sub);
+  G_UNLOCK (missing_lock);
+}