[evolution-data-server] ECalBackend: Make the "cache-dir" property thread-safe.

[Matthew Barnes <mbarnes src gnome org>]

commit b34eb3dcdeaaca2335937f8b22e0fdf03641c38c
Author: Matthew Barnes <mbarnes redhat com>
Date:   Mon Apr 1 09:03:26 2013 -0400

    ECalBackend: Make the "cache-dir" property thread-safe.
    
    New function:
    
        e_cal_backend_dup_cache_dir()

 calendar/libedata-cal/e-cal-backend.c              |   72 +++++++++++++++-----
 calendar/libedata-cal/e-cal-backend.h              |    1 +
 .../libedata-cal/libedata-cal-sections.txt         |    1 +
 3 files changed, 57 insertions(+), 17 deletions(-)
---
diff --git a/calendar/libedata-cal/e-cal-backend.c b/calendar/libedata-cal/e-cal-backend.c
index 5659493..ea79c80 100644
--- a/calendar/libedata-cal/e-cal-backend.c
+++ b/calendar/libedata-cal/e-cal-backend.c
@@ -42,13 +42,13 @@ struct _ECalBackendPrivate {
        /* The kind of components for this backend */
        icalcomponent_kind kind;
 
-       gboolean writable;
-
-       gchar *cache_dir;
-
        GMutex views_mutex;
        GList *views;
 
+       GMutex property_lock;
+       gchar *cache_dir;
+       gboolean writable;
+
        GHashTable *zone_cache;
        GMutex zone_cache_lock;
 
@@ -498,8 +498,8 @@ cal_backend_get_property (GObject *object,
 {
        switch (property_id) {
                case PROP_CACHE_DIR:
-                       g_value_set_string (
-                               value, e_cal_backend_get_cache_dir (
+                       g_value_take_string (
+                               value, e_cal_backend_dup_cache_dir (
                                E_CAL_BACKEND (object)));
                        return;
 
@@ -555,12 +555,13 @@ cal_backend_finalize (GObject *object)
 
        g_list_free (priv->views);
        g_mutex_clear (&priv->views_mutex);
+       g_mutex_clear (&priv->property_lock);
+
+       g_free (priv->cache_dir);
 
        g_hash_table_destroy (priv->zone_cache);
        g_mutex_clear (&priv->zone_cache_lock);
 
-       g_free (priv->cache_dir);
-
        g_mutex_clear (&priv->operation_lock);
        g_hash_table_destroy (priv->operation_ids);
 
@@ -857,8 +858,8 @@ e_cal_backend_init (ECalBackend *backend)
 
        backend->priv = E_CAL_BACKEND_GET_PRIVATE (backend);
 
-       backend->priv->views = NULL;
        g_mutex_init (&backend->priv->views_mutex);
+       g_mutex_init (&backend->priv->property_lock);
 
        backend->priv->zone_cache = zone_cache;
        g_mutex_init (&backend->priv->zone_cache_lock);
@@ -1054,9 +1055,9 @@ e_cal_backend_is_readonly (ECalBackend *backend)
  * e_cal_backend_get_cache_dir:
  * @backend: an #ECalBackend
  *
- * Returns the cache directory for the given backend.
+ * Returns the cache directory path used by @backend.
  *
- * Returns: the cache directory for the backend
+ * Returns: the cache directory path
  *
  * Since: 2.32
  **/
@@ -1069,15 +1070,46 @@ e_cal_backend_get_cache_dir (ECalBackend *backend)
 }
 
 /**
+ * e_cal_backend_dup_cache_dir:
+ * @backend: an #ECalBackend
+ *
+ * Thread-safe variation of e_cal_backend_get_cache_dir().
+ * Use this function when accessing @backend from multiple threads.
+ *
+ * The returned string should be freed with g_free() when no longer needed.
+ *
+ * Returns: a newly-allocated copy of #ECalBackend:cache-dir
+ *
+ * Since: 3.10
+ **/
+gchar *
+e_cal_backend_dup_cache_dir (ECalBackend *backend)
+{
+       const gchar *protected;
+       gchar *duplicate;
+
+       g_return_val_if_fail (E_IS_CAL_BACKEND (backend), NULL);
+
+       g_mutex_lock (&backend->priv->property_lock);
+
+       protected = e_cal_backend_get_cache_dir (backend);
+       duplicate = g_strdup (protected);
+
+       g_mutex_unlock (&backend->priv->property_lock);
+
+       return duplicate;
+}
+
+/**
  * e_cal_backend_set_cache_dir:
  * @backend: an #ECalBackend
- * @cache_dir: a local cache directory
+ * @cache_dir: a local cache directory path
  *
- * Sets the cache directory for the given backend.
+ * Sets the cache directory path for use by @backend.
  *
- * Note that #ECalBackend is initialized with a usable default based on
- * #ECalBackend:source and #ECalBackend:kind properties.  Backends should
- * not override the default without good reason.
+ * Note that #ECalBackend is initialized with a default cache directory
+ * path which should suffice for most cases.  Backends should not override
+ * the default path without good reason.
  *
  * Since: 2.32
  **/
@@ -1088,12 +1120,18 @@ e_cal_backend_set_cache_dir (ECalBackend *backend,
        g_return_if_fail (E_IS_CAL_BACKEND (backend));
        g_return_if_fail (cache_dir != NULL);
 
-       if (g_strcmp0 (backend->priv->cache_dir, cache_dir) == 0)
+       g_mutex_lock (&backend->priv->property_lock);
+
+       if (g_strcmp0 (backend->priv->cache_dir, cache_dir) == 0) {
+               g_mutex_unlock (&backend->priv->property_lock);
                return;
+       }
 
        g_free (backend->priv->cache_dir);
        backend->priv->cache_dir = g_strdup (cache_dir);
 
+       g_mutex_unlock (&backend->priv->property_lock);
+
        g_object_notify (G_OBJECT (backend), "cache-dir");
 }
 
diff --git a/calendar/libedata-cal/e-cal-backend.h b/calendar/libedata-cal/e-cal-backend.h
index ad21b5c..2d7e0a5 100644
--- a/calendar/libedata-cal/e-cal-backend.h
+++ b/calendar/libedata-cal/e-cal-backend.h
@@ -221,6 +221,7 @@ gboolean    e_cal_backend_is_opened         (ECalBackend *backend);
 gboolean       e_cal_backend_is_readonly       (ECalBackend *backend);
 
 const gchar *  e_cal_backend_get_cache_dir     (ECalBackend *backend);
+gchar *                e_cal_backend_dup_cache_dir     (ECalBackend *backend);
 void           e_cal_backend_set_cache_dir     (ECalBackend *backend,
                                                 const gchar *cache_dir);
 gchar *                e_cal_backend_create_cache_filename
diff --git a/docs/reference/calendar/libedata-cal/libedata-cal-sections.txt 
b/docs/reference/calendar/libedata-cal/libedata-cal-sections.txt
index 0f72f41..9db891e 100644
--- a/docs/reference/calendar/libedata-cal/libedata-cal-sections.txt
+++ b/docs/reference/calendar/libedata-cal/libedata-cal-sections.txt
@@ -16,6 +16,7 @@ e_cal_backend_set_writable
 e_cal_backend_is_opened
 e_cal_backend_is_readonly
 e_cal_backend_get_cache_dir
+e_cal_backend_dup_cache_dir
 e_cal_backend_set_cache_dir
 e_cal_backend_create_cache_filename
 e_cal_backend_add_view