From c6d5eb1086d5da2a2e7548c5ce3b5efa9ba76f0c Mon Sep 17 00:00:00 2001
From: Michael Vrable <mvrable@cs.ucsd.edu>
Date: Sun, 22 Nov 2009 13:09:54 -0800
Subject: [PATCH] Add reference counting to asynchronous storage operations.

---
 bluesky/bluesky-private.h |  5 +++++
 bluesky/file.c            | 11 ++++++++++-
 bluesky/s3store.c         |  4 ++--
 bluesky/store.c           | 36 ++++++++++++++++++++++++++++++++++++
 4 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/bluesky/bluesky-private.h b/bluesky/bluesky-private.h
index 7f5e646..0dd6446 100644
--- a/bluesky/bluesky-private.h
+++ b/bluesky/bluesky-private.h
@@ -51,6 +51,8 @@ typedef struct {
     GMutex *lock;
     GCond *completion_cond;     /* Used to wait for operation to complete. */
 
+    gint refcount;              /* Reference count for destruction. */
+
     BlueSkyAsyncStatus status;
 
     BlueSkyStoreOp op;
@@ -82,8 +84,11 @@ void bluesky_store_register(const BlueSkyStoreImplementation *impl,
                             const gchar *name);
 
 BlueSkyStoreAsync *bluesky_store_async_new(BlueSkyStore *store);
+void bluesky_store_async_ref(BlueSkyStoreAsync *async);
+void bluesky_store_async_unref(BlueSkyStoreAsync *async);
 void bluesky_store_async_wait(BlueSkyStoreAsync *async);
 void bluesky_store_async_mark_complete(BlueSkyStoreAsync *async);
+void bluesky_store_async_submit(BlueSkyStoreAsync *async);
 
 #ifdef __cplusplus
 }
diff --git a/bluesky/file.c b/bluesky/file.c
index ccb45e4..f9f6444 100644
--- a/bluesky/file.c
+++ b/bluesky/file.c
@@ -194,7 +194,16 @@ void bluesky_block_flush(BlueSkyFS *fs, BlueSkyBlock *block)
     g_checksum_update(csum, data->data, data->len);
     gchar *name = g_strdup(g_checksum_get_string(csum));
 
-    bluesky_store_put(fs->store, name, data);
+    /* Store the file data asynchronously, and don't bother waiting for a
+     * response. */
+    BlueSkyStoreAsync *async = bluesky_store_async_new(fs->store);
+    async->op = STORE_OP_PUT;
+    async->key = g_strdup(name);
+    bluesky_string_ref(data);
+    async->data = data;
+    bluesky_store_async_submit(async);
+    bluesky_store_async_unref(async);
+
     g_free(block->ref);
     block->ref = name;
 
diff --git a/bluesky/s3store.c b/bluesky/s3store.c
index 5ab42e1..bf7c7cd 100644
--- a/bluesky/s3store.c
+++ b/bluesky/s3store.c
@@ -138,10 +138,9 @@ static void s3store_task(gpointer a, gpointer s)
         async->result = 0;
     }
 
-    // TODO: Deallocate resources
-
     g_print("Finish task...\n");
     bluesky_store_async_mark_complete(async);
+    bluesky_store_async_unref(async);
 }
 
 static gpointer s3store_new()
@@ -184,6 +183,7 @@ static void s3store_submit(gpointer s, BlueSkyStoreAsync *async)
     case STORE_OP_GET:
     case STORE_OP_PUT:
         async->status = ASYNC_PENDING;
+        bluesky_store_async_ref(async);
         g_thread_pool_push(store->thread_pool, async, NULL);
         break;
 
diff --git a/bluesky/store.c b/bluesky/store.c
index 13a080f..ec72ec2 100644
--- a/bluesky/store.c
+++ b/bluesky/store.c
@@ -62,6 +62,7 @@ BlueSkyStoreAsync *bluesky_store_async_new(BlueSkyStore *store)
     async->store = store;
     async->lock = g_mutex_new();
     async->completion_cond = g_cond_new();
+    async->refcount = 1;
     async->status = ASYNC_NEW;
     async->op = STORE_OP_NONE;
     async->key = NULL;
@@ -72,6 +73,30 @@ BlueSkyStoreAsync *bluesky_store_async_new(BlueSkyStore *store)
     return async;
 }
 
+void bluesky_store_async_ref(BlueSkyStoreAsync *async)
+{
+    if (async == NULL)
+        return;
+
+    g_atomic_int_inc(&async->refcount);
+}
+
+void bluesky_store_async_unref(BlueSkyStoreAsync *async)
+{
+    if (async == NULL)
+        return;
+
+    if (g_atomic_int_dec_and_test(&async->refcount)) {
+        async->store->impl->cleanup(async->store->handle, async);
+        g_mutex_free(async->lock);
+        g_cond_free(async->completion_cond);
+        g_free(async->key);
+        bluesky_string_unref(async->data);
+        g_free(async);
+        g_print("Freed async\n");
+    }
+}
+
 /* Block until the given operation has completed. */
 void bluesky_store_async_wait(BlueSkyStoreAsync *async)
 {
@@ -87,6 +112,8 @@ void bluesky_store_async_wait(BlueSkyStoreAsync *async)
     while (async->status != ASYNC_COMPLETE) {
         g_cond_wait(async->completion_cond, async->lock);
     }
+
+    g_mutex_unlock(async->lock);
 }
 
 /* Mark an asynchronous operation as complete.  This should only be called by
@@ -98,6 +125,13 @@ void bluesky_store_async_mark_complete(BlueSkyStoreAsync *async)
     g_cond_broadcast(async->completion_cond);
 }
 
+void bluesky_store_async_submit(BlueSkyStoreAsync *async)
+{
+    BlueSkyStore *store = async->store;
+
+    store->impl->submit(store->handle, async);
+}
+
 /* Convenience wrappers that perform a single operation synchronously. */
 BlueSkyRCStr *bluesky_store_get(BlueSkyStore *store, const gchar *key)
 {
@@ -110,6 +144,7 @@ BlueSkyRCStr *bluesky_store_get(BlueSkyStore *store, const gchar *key)
 
     BlueSkyRCStr *data = async->data;
     bluesky_string_ref(data);
+    bluesky_store_async_unref(async);
     return data;
 }
 
@@ -124,6 +159,7 @@ void bluesky_store_put(BlueSkyStore *store,
     store->impl->submit(store->handle, async);
 
     bluesky_store_async_wait(async);
+    bluesky_store_async_unref(async);
 }
 
 #if 0
-- 
2.20.1