r12116: got rid of composite_trigger_done() and composite_trigger_error(), and

instead make the normal composite_done() and composite_error()
functions automatically trigger a delayed callback if the caller has
had no opportunity to setup a async callback

this removes one of the common mistakes in writing a composite function
(This used to be commit f9413ce792ded682e05134b66d433eeec293e6f1)

2 files changed, 33 insertions, 34 deletions

diff --git a/source4/libcli/composite/composite.c b/source4/libcli/composite/composite.c
index 3842ddfe9fb..c9cc20e9235 100644
--- a/source4/libcli/composite/composite.c
+++ b/source4/libcli/composite/composite.c
@@ -35,6 +35,8 @@ NTSTATUS composite_wait(struct composite_context *c)
 {
 	if (c == NULL) return NT_STATUS_NO_MEMORY;
 
+	c->used_wait = True;
+
 	while (c->state < COMPOSITE_STATE_DONE) {
 		if (event_loop_once(c->event_ctx) != 0) {
 			return NT_STATUS_UNSUCCESSFUL;
@@ -45,44 +47,10 @@ NTSTATUS composite_wait(struct composite_context *c)
 }
 
 
-/* 
-   callback from composite_trigger_done() and composite_trigger_error()
-*/
-static void composite_trigger(struct event_context *ev, struct timed_event *te,
-			      struct timeval t, void *ptr)
-{
-	struct composite_context *c = talloc_get_type(ptr, struct composite_context);
-	if (c->async.fn) {
-		c->async.fn(c);
-	}
-}
-
-
-/*
-  trigger an immediate 'done' event on a composite context
-  this is used when the composite code works out that the call
-  can be completed without waiting for any external event
-*/
-void composite_trigger_done(struct composite_context *c)
-{
-	c->state = COMPOSITE_STATE_DONE;
-	/* a zero timeout means immediate */
-	event_add_timed(c->event_ctx, c, timeval_zero(), composite_trigger, c);
-}
-
-void composite_trigger_error(struct composite_context *c)
-{
-	c->state = COMPOSITE_STATE_ERROR;
-	/* a zero timeout means immediate */
-	event_add_timed(c->event_ctx, c, timeval_zero(), composite_trigger, c);
-}
-
-
 /*
  * Some composite helpers that are handy if you write larger composite
  * functions.
  */
-
 BOOL composite_is_ok(struct composite_context *ctx)
 {
 	if (NT_STATUS_IS_OK(ctx->status)) {
@@ -95,8 +63,34 @@ BOOL composite_is_ok(struct composite_context *ctx)
 	return False;
 }
 
+/* 
+   callback from composite_done() and composite_error()
+
+   this is used to allow for a composite function to complete without
+   going through any state transitions. When that happens the caller
+   has had no opportunity to fill in the async callback fields
+   (ctx->async.fn and ctx->async.private) which means the usual way of
+   dealing with composite functions doesn't work. To cope with this,
+   we trigger a timer event that will happen then the event loop is
+   re-entered. This gives the caller a chance to setup the callback,
+   and allows the caller to ignore the fact that the composite
+   function completed early
+*/
+static void composite_trigger(struct event_context *ev, struct timed_event *te,
+			      struct timeval t, void *ptr)
+{
+	struct composite_context *c = talloc_get_type(ptr, struct composite_context);
+	if (c->async.fn) {
+		c->async.fn(c);
+	}
+}
+
+
 void composite_error(struct composite_context *ctx, NTSTATUS status)
 {
+	if (!ctx->used_wait && !ctx->async.fn) {
+		event_add_timed(ctx->event_ctx, ctx, timeval_zero(), composite_trigger, ctx);
+	}
 	ctx->status = status;
 	SMB_ASSERT(!composite_is_ok(ctx));
 }
@@ -112,6 +106,9 @@ BOOL composite_nomem(const void *p, struct composite_context *ctx)
 
 void composite_done(struct composite_context *ctx)
 {
+	if (!ctx->used_wait && !ctx->async.fn) {
+		event_add_timed(ctx->event_ctx, ctx, timeval_zero(), composite_trigger, ctx);
+	}
 	ctx->state = COMPOSITE_STATE_DONE;
 	if (ctx->async.fn != NULL) {
 		ctx->async.fn(ctx);
diff --git a/source4/libcli/composite/composite.h b/source4/libcli/composite/composite.h
index 1e6e9f5dc85..26490f1c4a2 100644
--- a/source4/libcli/composite/composite.h
+++ b/source4/libcli/composite/composite.h
@@ -57,4 +57,6 @@ struct composite_context {
 		void (*fn)(struct composite_context *);
 		void *private_data;
 	} async;
+
+	BOOL used_wait;
 };