[tracker] tracker-extract: Cache TrackerConfig::max-bytes

[Carlos Garnacho <carlosg src gnome org>]

commit e9e7cda6e5b5e83ac9d3b86127e6877b3f9db980
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Feb 28 21:04:12 2017 +0100

    tracker-extract: Cache TrackerConfig::max-bytes
    
    This is the only setting read from extractor modules. It turns out
    that under the right circumstances a g_settings_get_value() call
    can trigger open() calls with readwrite permissions from the caller
    thread. This is forbidden in extractor threads and triggers warnings
    like:
    
    dconf-CRITICAL **: unable to create file '/run/user/1000/dconf/user':
    Permission denied.  dconf will not work properly.
    
    Also, since this setting is meaningless to update during tracker-extract
    lifetime, just drop the g_settings_bind() call, this means the setting
    is only read once on startup.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=779342

 src/tracker-extract/tracker-config.c |    9 +++++++--
 src/tracker-extract/tracker-config.h |    2 +-
 2 files changed, 8 insertions(+), 3 deletions(-)
---
diff --git a/src/tracker-extract/tracker-config.c b/src/tracker-extract/tracker-config.c
index cc30633..7289255 100644
--- a/src/tracker-extract/tracker-config.c
+++ b/src/tracker-extract/tracker-config.c
@@ -226,9 +226,14 @@ config_constructed (GObject *object)
         */
        g_settings_bind (settings, "verbosity", object, "verbosity", G_SETTINGS_BIND_GET | 
G_SETTINGS_BIND_GET_NO_CHANGES);
        g_settings_bind (settings, "sched-idle", object, "sched-idle", G_SETTINGS_BIND_GET);
-       g_settings_bind (settings, "max-bytes", object, "max-bytes", G_SETTINGS_BIND_GET);
        g_settings_bind (settings, "max-media-art-width", object, "max-media-art-width", G_SETTINGS_BIND_GET);
        g_settings_bind (settings, "wait-for-miner-fs", object, "wait-for-miner-fs", G_SETTINGS_BIND_GET);
+
+       /* Cache settings accessed from extractor modules, we don't want
+        * the GSettings object accessed within these as it may trigger
+        * unintended open() calls.
+        */
+       TRACKER_CONFIG (settings)->max_bytes = g_settings_get_int (settings, "max-bytes");
 }
 
 TrackerConfig *
@@ -303,7 +308,7 @@ tracker_config_get_max_bytes (TrackerConfig *config)
 {
        g_return_val_if_fail (TRACKER_IS_CONFIG (config), 0);
 
-       return g_settings_get_int (G_SETTINGS (config), "max-bytes");
+       return config->max_bytes;
 }
 
 gint
diff --git a/src/tracker-extract/tracker-config.h b/src/tracker-extract/tracker-config.h
index daf1574..c8af8ef 100644
--- a/src/tracker-extract/tracker-config.h
+++ b/src/tracker-extract/tracker-config.h
@@ -36,7 +36,7 @@ typedef struct TrackerConfigClass TrackerConfigClass;
 
 struct TrackerConfig {
        GSettings parent;
-       gpointer priv;
+       gint max_bytes;
 };
 
 struct TrackerConfigClass {