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

[Matthew Barnes <mbarnes src gnome org>]

commit 246a3c62d4bd83c322d09f72a3a535796b3b6f3f
Author: Matthew Barnes <mbarnes redhat com>
Date:   Mon Apr 1 08:48:04 2013 -0400

    EBookBackend: Make the "cache-dir" property thread-safe.
    
    New function:
    
        e_book_backend_dup_cache_dir()

 addressbook/libedata-book/e-book-backend.c         |   64 ++++++++++++++++----
 addressbook/libedata-book/e-book-backend.h         |    1 +
 .../libedata-book/libedata-book-sections.txt       |    1 +
 3 files changed, 53 insertions(+), 13 deletions(-)
---
diff --git a/addressbook/libedata-book/e-book-backend.c b/addressbook/libedata-book/e-book-backend.c
index 1f64bf6..a6a4a3d 100644
--- a/addressbook/libedata-book/e-book-backend.c
+++ b/addressbook/libedata-book/e-book-backend.c
@@ -35,12 +35,12 @@ struct _EBookBackendPrivate {
        ESourceRegistry *registry;
        EDataBook *data_book;
 
-       gboolean writable;
-
        GMutex views_mutex;
        GList *views;
 
+       GMutex property_lock;
        gchar *cache_dir;
+       gboolean writable;
 
        GMutex operation_lock;
        GHashTable *operation_ids;
@@ -387,8 +387,8 @@ book_backend_get_property (GObject *object,
 {
        switch (property_id) {
                case PROP_CACHE_DIR:
-                       g_value_set_string (
-                               value, e_book_backend_get_cache_dir (
+                       g_value_take_string (
+                               value, e_book_backend_dup_cache_dir (
                                E_BOOK_BACKEND (object)));
                        return;
 
@@ -442,6 +442,7 @@ book_backend_finalize (GObject *object)
        priv = E_BOOK_BACKEND_GET_PRIVATE (object);
 
        g_mutex_clear (&priv->views_mutex);
+       g_mutex_clear (&priv->property_lock);
 
        g_free (priv->cache_dir);
 
@@ -577,7 +578,7 @@ e_book_backend_init (EBookBackend *backend)
 
        backend->priv->views = NULL;
        g_mutex_init (&backend->priv->views_mutex);
-
+       g_mutex_init (&backend->priv->property_lock);
        g_mutex_init (&backend->priv->operation_lock);
 
        backend->priv->operation_ids = g_hash_table_new_full (
@@ -591,9 +592,9 @@ e_book_backend_init (EBookBackend *backend)
  * e_book_backend_get_cache_dir:
  * @backend: an #EBookBackend
  *
- * 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
  **/
@@ -606,15 +607,46 @@ e_book_backend_get_cache_dir (EBookBackend *backend)
 }
 
 /**
+ * e_book_backend_dup_cache_dir:
+ * @backend: an #EBookBackend
+ *
+ * Thread-safe variation of e_book_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 #EBookBackend:cache-dir
+ *
+ * Since: 3.10
+ **/
+gchar *
+e_book_backend_dup_cache_dir (EBookBackend *backend)
+{
+       const gchar *protected;
+       gchar *duplicate;
+
+       g_return_val_if_fail (E_IS_BOOK_BACKEND (backend), NULL);
+
+       g_mutex_lock (&backend->priv->property_lock);
+
+       protected = e_book_backend_get_cache_dir (backend);
+       duplicate = g_strdup (protected);
+
+       g_mutex_unlock (&backend->priv->property_lock);
+
+       return duplicate;
+}
+
+/**
  * e_book_backend_set_cache_dir:
  * @backend: an #EBookBackend
- * @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 #EBookBackend is initialized with a usable default based on
- * the #ESource given to e_book_backend_open().  Backends should
- * not override the default without good reason.
+ * Note that #EBookBackend 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
  **/
@@ -625,12 +657,18 @@ e_book_backend_set_cache_dir (EBookBackend *backend,
        g_return_if_fail (E_IS_BOOK_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/addressbook/libedata-book/e-book-backend.h b/addressbook/libedata-book/e-book-backend.h
index d6107fc..67cad03 100644
--- a/addressbook/libedata-book/e-book-backend.h
+++ b/addressbook/libedata-book/e-book-backend.h
@@ -173,6 +173,7 @@ struct _EBookBackendClass {
 GType          e_book_backend_get_type         (void) G_GNUC_CONST;
 
 const gchar *  e_book_backend_get_cache_dir    (EBookBackend *backend);
+gchar *                e_book_backend_dup_cache_dir    (EBookBackend *backend);
 void           e_book_backend_set_cache_dir    (EBookBackend *backend,
                                                 const gchar *cache_dir);
 EDataBook *    e_book_backend_ref_data_book    (EBookBackend *backend);
diff --git a/docs/reference/addressbook/libedata-book/libedata-book-sections.txt 
b/docs/reference/addressbook/libedata-book/libedata-book-sections.txt
index 153df5f..276ca45 100644
--- a/docs/reference/addressbook/libedata-book/libedata-book-sections.txt
+++ b/docs/reference/addressbook/libedata-book/libedata-book-sections.txt
@@ -7,6 +7,7 @@ BOOK_BACKEND_PROPERTY_REQUIRED_FIELDS
 BOOK_BACKEND_PROPERTY_SUPPORTED_FIELDS
 BOOK_BACKEND_PROPERTY_REVISION
 e_book_backend_get_cache_dir
+e_book_backend_dup_cache_dir
 e_book_backend_set_cache_dir
 e_book_backend_ref_data_book
 e_book_backend_set_data_book