[tracker/tracker-0.10] libtracker-miner, crawler: Use a cancellable per crawled directory

[JÃrg Billeter <juergbi src gnome org>]

commit 4896092d4c1edfa530da363c4ba5eb7166c150fb
Author: Carlos Garnacho <carlos lanedo com>
Date:   Mon Oct 24 12:54:12 2011 +0200

    libtracker-miner,crawler: Use a cancellable per crawled directory
    
    Reusing the cancellable might bring in issues if tracker_crawler_start()
    (which resets the cancellable) is called shortly after tracker_crawler_stop().
    So pending async tasks that do check for g_cancellable_is_cancelled() might
    run into the wrong state. Possibly fixes NB#287480.
    
    The cancellable might be used to cancel the current operation, but then
    reset and reused for the next one, while the previous operation could
    still be on the way to be cancelled. Instead, create a new cancellable
    to handle any following task.

 src/libtracker-miner/tracker-crawler.c |   28 ++++++++++++++++------------
 1 files changed, 16 insertions(+), 12 deletions(-)
---
diff --git a/src/libtracker-miner/tracker-crawler.c b/src/libtracker-miner/tracker-crawler.c
index d8f3ffc..e9c3dce 100644
--- a/src/libtracker-miner/tracker-crawler.c
+++ b/src/libtracker-miner/tracker-crawler.c
@@ -71,7 +71,7 @@ struct TrackerCrawlerPrivate {
 	/* Directories to crawl */
 	GQueue         *directories;
 
-	GCancellable   *cancellable;
+	GList          *cancellables;
 
 	/* Idle handler for processing found data */
 	guint           idle_id;
@@ -104,6 +104,7 @@ typedef struct {
 	DirectoryRootInfo  *root_info;
 	DirectoryProcessingData *dir_info;
 	GFile *dir_file;
+	GCancellable *cancellable;
 } EnumeratorData;
 
 static void     crawler_finalize        (GObject         *object);
@@ -207,7 +208,6 @@ tracker_crawler_init (TrackerCrawler *object)
 	priv = object->priv;
 
 	priv->directories = g_queue_new ();
-	priv->cancellable = g_cancellable_new ();
 }
 
 static void
@@ -225,7 +225,7 @@ crawler_finalize (GObject *object)
 		g_source_remove (priv->idle_id);
 	}
 
-	g_object_unref (priv->cancellable);
+	g_list_free (priv->cancellables);
 
 	g_queue_foreach (priv->directories, (GFunc) directory_root_info_free, NULL);
 	g_queue_free (priv->directories);
@@ -576,7 +576,10 @@ enumerator_data_new (TrackerCrawler          *crawler,
 	/* Make sure there's always a ref of the GFile while we're
 	 * iterating it */
 	ed->dir_file = g_object_ref (G_FILE (dir_info->node->data));
+	ed->cancellable = g_cancellable_new ();
 
+	crawler->priv->cancellables = g_list_prepend (crawler->priv->cancellables,
+						      ed->cancellable);
 	return ed;
 }
 
@@ -610,8 +613,13 @@ enumerator_data_process (EnumeratorData *ed)
 static void
 enumerator_data_free (EnumeratorData *ed)
 {
+	ed->crawler->priv->cancellables =
+		g_list_remove (ed->crawler->priv->cancellables,
+			       ed->cancellable);
+
 	g_object_unref (ed->dir_file);
 	g_object_unref (ed->crawler);
+	g_object_unref (ed->cancellable);
 	g_slice_free (EnumeratorData, ed);
 }
 
@@ -658,7 +666,7 @@ file_enumerate_next_cb (GObject      *object,
 
 	ed = user_data;
 	crawler = ed->crawler;
-	cancelled = g_cancellable_is_cancelled (crawler->priv->cancellable);
+	cancelled = g_cancellable_is_cancelled (ed->cancellable);
 
 	files = g_file_enumerator_next_files_finish (enumerator,
 	                                             result,
@@ -724,7 +732,7 @@ file_enumerate_next (GFileEnumerator *enumerator,
 	g_file_enumerator_next_files_async (enumerator,
 	                                    FILES_GROUP_SIZE,
 	                                    G_PRIORITY_DEFAULT,
-	                                    ed->crawler->priv->cancellable,
+	                                    ed->cancellable,
 	                                    file_enumerate_next_cb,
 	                                    ed);
 }
@@ -744,7 +752,7 @@ file_enumerate_children_cb (GObject      *file,
 	parent = G_FILE (file);
 	ed = (EnumeratorData*) user_data;
 	crawler = ed->crawler;
-	cancelled = g_cancellable_is_cancelled (crawler->priv->cancellable);
+	cancelled = g_cancellable_is_cancelled (ed->cancellable);
 	enumerator = g_file_enumerate_children_finish (parent, result, &error);
 
 	if (!enumerator) {
@@ -782,7 +790,7 @@ file_enumerate_children (TrackerCrawler          *crawler,
 	                                 FILE_ATTRIBUTES,
 	                                 G_FILE_QUERY_INFO_NOFOLLOW_SYMLINKS,
 	                                 G_PRIORITY_LOW,
-	                                 crawler->priv->cancellable,
+	                                 ed->cancellable,
 	                                 file_enumerate_children_cb,
 	                                 ed);
 }
@@ -804,10 +812,6 @@ tracker_crawler_start (TrackerCrawler *crawler,
 		return FALSE;
 	}
 
-	if (g_cancellable_is_cancelled (priv->cancellable)) {
-		g_cancellable_reset (priv->cancellable);
-	}
-
 	priv->was_started = TRUE;
 	priv->recurse = recurse;
 
@@ -849,7 +853,7 @@ tracker_crawler_stop (TrackerCrawler *crawler)
 	}
 
 	priv->is_running = FALSE;
-	g_cancellable_cancel (priv->cancellable);
+	g_list_foreach (priv->cancellables, (GFunc) g_cancellable_cancel, NULL);
 
 	process_func_stop (crawler);