通过增加promise_finish函数，实现future的cancel。

1 files changed, 49 insertions, 8 deletions

diff --git a/common/src/tfe_future.cpp b/common/src/tfe_future.cpp
index d0c51f3..19f20f7 100644
--- a/common/src/tfe_future.cpp
+++ b/common/src/tfe_future.cpp
@@ -45,7 +45,9 @@ struct promise
 {
 	struct future f;
 	void * ctx;
-	int has_timeout;
+	char has_timeout;	
+	char ref_cnt;
+	char may_success_many_times;
 	promise_ctx_destroy_cb * cb_ctx_destroy;
 	struct _future_promise_debug debug;
 };
@@ -117,11 +119,34 @@ void future_promise_library_init(const char* profile)
 	g_is_FP_init=1;
 	return;
 }
+static struct promise * __future_to_promise(struct future * f)
+{
+	return (struct promise *) f;
+}
+static void __promise_destroy(struct promise *p)
+{
+	if (p->cb_ctx_destroy != NULL)
+	{
+		p->cb_ctx_destroy(p->ctx);
+	}	
+	if(!g_FP_instance.no_stats)	FS_operate(g_FP_instance.fs_handle,g_FP_instance.fsid_f_num, 0, FS_OP_SUB, 1);
+	memset(p, 0, sizeof(struct promise));
+	free(p);
+	return;
+}
 
 struct promise * future_to_promise(struct future * f)
 {
+	struct promise *p=__future_to_promise(f);
+	p->ref_cnt++;
+	assert(p->ref_cnt==2);
 	return (struct promise *) f;
 }
+void promise_allow_many_successes(struct promise *p)
+{
+	p->may_success_many_times=1;
+	return;
+}
 struct field_get_set_args
 {
 	MESA_htable_handle htable;
@@ -165,6 +190,7 @@ struct future * future_create(const char* symbol, future_success_cb * cb_success
 	p->f.user = user;
 	p->f.cb_success = cb_success;
 	p->f.cb_failed = cb_failed;
+	p->ref_cnt=1;
 	strncpy(p->f.symbol,symbol,sizeof(p->f.symbol));
 	if(!g_FP_instance.no_stats)
 	{
@@ -185,16 +211,23 @@ void future_set_timeout(struct future * f, struct timeval timeout)
 	p->has_timeout=1;
 	return;
 }
+
 void future_destroy(struct future * f)
 {
-	struct promise * p = future_to_promise(f);
-	if (p->cb_ctx_destroy != NULL)
+	struct promise * p = __future_to_promise(f);
+	p->ref_cnt--;
+	if(p->ref_cnt==0)
 	{
-		p->cb_ctx_destroy(p->ctx);
-	}	
-	if(!g_FP_instance.no_stats)	FS_operate(g_FP_instance.fs_handle,g_FP_instance.fsid_f_num, 0, FS_OP_SUB, 1);
-	memset(p, 0, sizeof(struct promise));
-	free(p);
+		__promise_destroy(p);
+	}
+}
+void promise_finish(struct promise * p)
+{
+	p->ref_cnt--;
+	if(p->ref_cnt==0)
+	{
+		__promise_destroy(p);
+	}
 }
 static void fp_stat_latency(struct _future_promise_debug* debug, int is_success)
 {
@@ -220,6 +253,10 @@ void promise_failed(struct promise * p, enum e_future_error error, const char *
 {
 	if(!g_FP_instance.no_stats) fp_stat_latency(&p->debug, 0);
 	p->f.cb_failed(error, what, p->f.user);
+	if(!p->may_success_many_times)
+	{
+		promise_finish(p);
+	}
 	return;
 }
 
@@ -227,6 +264,10 @@ void promise_success(struct promise * p, void * result)
 {
 	if(!g_FP_instance.no_stats) fp_stat_latency(&p->debug, 1);
 	p->f.cb_success(result, p->f.user);
+	if(!p->may_success_many_times)
+	{
+		promise_finish(p);
+	}
 	return;
 }