From 470bee83fd1039a370745be4eadfaa8f53abb2ac Mon Sep 17 00:00:00 2001
From: Jiwoong Im <jiwoong.im@samsung.com>
Date: Wed, 25 Jan 2017 13:33:56 +0900
Subject: [PATCH] Restore applying cache in vconf library side

- Cache is only used if client uses g_main_loop.

Change-Id: I7096602f921af78e0547b86678e3a1fc962a3d24
Signed-off-by: Jiwoong Im <jiwoong.im@samsung.com>
---
 vconf-compat/vconf.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 119 insertions(+), 2 deletions(-)

diff --git a/vconf-compat/vconf.c b/vconf-compat/vconf.c
index cc793b0..e404c2c 100644
--- a/vconf-compat/vconf.c
+++ b/vconf-compat/vconf.c
@@ -41,6 +41,8 @@
 
 #define LOG_TAG "VCONF"
 
+#define HASH_SIZE 10
+
 static void _restore_noti_cb(gpointer key, gpointer value, gpointer user_data);
 
 static pthread_mutex_t vconf_lock = PTHREAD_MUTEX_INITIALIZER;
@@ -49,6 +51,8 @@ static struct buxton_client *client;
 static struct buxton_layer *system_layer;
 static struct buxton_layer *memory_layer;
 static GHashTable *noti_tbl;
+static GHashTable *cache_tbl;
+static GQueue *victims;
 
 struct noti {
 	char *key;
@@ -62,6 +66,8 @@ struct noti_cb {
 };
 
 static bool last_result;
+static bool cache_enable;
+static bool cache_check_done;
 
 static void free_keynode(struct _keynode_t *keynode)
 {
@@ -201,6 +207,16 @@ static void _close(void)
 	g_hash_table_destroy(noti_tbl);
 	noti_tbl = NULL;
 
+	if (cache_tbl) {
+		g_hash_table_destroy(cache_tbl);
+		cache_tbl = NULL;
+	}
+
+	if (victims) {
+		g_queue_free_full(victims, (GDestroyNotify)free);
+		victims = NULL;
+	}
+
 	buxton_close(client);
 	client = NULL;
 }
@@ -232,6 +248,12 @@ static void _restore_connection(enum buxton_status status,
 	pthread_mutex_unlock(&vconf_lock);
 }
 
+static gboolean _enable_cache(gpointer data)
+{
+	cache_enable = true;
+	return G_SOURCE_REMOVE;
+}
+
 static int _open(void)
 {
 	int r;
@@ -260,6 +282,22 @@ static int _open(void)
 	if (!memory_layer)
 		memory_layer = buxton_create_layer("memory");
 
+	if (!cache_tbl) {
+		cache_tbl = g_hash_table_new_full(g_str_hash, g_str_equal,
+				(GDestroyNotify)free,
+				(GDestroyNotify)buxton_value_free);
+	}
+
+	if (!victims) {
+		victims = g_queue_new();
+		g_queue_init(victims);
+	}
+
+	if (!cache_check_done) {
+		g_idle_add(_enable_cache, NULL);
+		cache_check_done = true;
+	}
+
 	return 0;
 }
 
@@ -638,8 +676,17 @@ static int _vconf_set(const char *key, const struct buxton_value *val)
 	}
 
 	r = buxton_set_value_sync(client, get_layer(key), key, val);
-	if (r == -1)
+	if (r == -1) {
 		LOGE("set value: key '%s' errno %d", key, errno);
+	} else {
+		if (cache_enable) {
+			if (g_hash_table_contains(cache_tbl, key)) {
+				g_hash_table_replace(cache_tbl,
+						strdup(key),
+						buxton_value_duplicate(val));
+			}
+		}
+	}
 
 	_close();
 	pthread_mutex_unlock(&vconf_lock);
@@ -743,22 +790,89 @@ EXPORT int vconf_set_dbl(const char *key, double dblval)
 	return r;
 }
 
+static void _cache_cb(const struct buxton_layer *layer, const char *key,
+		const struct buxton_value *val, void *user_data)
+{
+	if (g_hash_table_contains(cache_tbl, key)) {
+		g_hash_table_replace(cache_tbl,
+				strdup(key), buxton_value_duplicate(val));
+	}
+}
+
+
+static void _reduce_cache()
+{
+	char *key;
+	int r;
+
+	key = (char *)g_queue_pop_tail(victims);
+	if (key == NULL)
+		return;
+
+	r = g_hash_table_remove(cache_tbl, key);
+	if (r == false)
+		return;
+
+	r = buxton_unregister_notification_sync(client, get_layer(key),
+			key, _cache_cb);
+	if (r == -1)
+		return;
+
+	_close();
+
+	free(key);
+}
+
+static void _insert_cache(const char *key, struct buxton_value *val)
+{
+	int r;
+
+	r = _open();
+	if (r == -1)
+		return;
+
+	if (g_hash_table_size(cache_tbl) >= HASH_SIZE)
+		_reduce_cache();
+
+	r = buxton_register_notification_sync(client, get_layer(key), key,
+			_cache_cb, NULL);
+
+	if (r == -1) {
+		_close();
+		return;
+	}
+
+	g_queue_push_head(victims, (char *)strdup(key));
+	r = g_hash_table_insert(cache_tbl, strdup(key),
+			buxton_value_duplicate(val));
+}
+
 static int _vconf_get(const char *key, enum buxton_key_type type,
 		struct buxton_value **val)
 {
 	int r;
-	struct buxton_value *v;
+	struct buxton_value *v = NULL;
 
 	assert(key);
 	assert(val);
 
 	pthread_mutex_lock(&vconf_lock);
+
 	r = _open();
 	if (r == -1) {
 		pthread_mutex_unlock(&vconf_lock);
 		return -1;
 	}
 
+	if (cache_enable)
+		v = g_hash_table_lookup(cache_tbl, key);
+	if (v) {
+		*val = buxton_value_duplicate(v);
+		_close();
+		pthread_mutex_unlock(&vconf_lock);
+		return 0;
+	}
+
 	r = buxton_get_value_sync(client, get_layer(key), key, &v);
 	if (r == -1) {
 		LOGE("get value: key '%s' errno %d", key, errno);
@@ -776,9 +890,12 @@ static int _vconf_get(const char *key, enum buxton_key_type type,
 		} else {
 			*val = v;
 		}
+		if (cache_enable)
+			_insert_cache(key, v);
 	}
 
 	_close();
+
 	pthread_mutex_unlock(&vconf_lock);
 
 	return r;
-- 
2.7.4