thunk: add thunk_dispatch_keep() non-freeing variant

In scenarios where a thunk instance must be dispatched multiple
times, the automatic free is a problem.

This commit moves the free out of the dispatch implementations
and into the thunk_dispatch() wrapper.  So the behavior of
thunk_dispatch() is unchanged.

The new thunk_dispatch_keep() is a plain ->dispatch().  This does
implicitly turn 'thunk_t *' being a free() able allocation into
part of the API, which may be a problem later.  But who cares,
this is a .h for vendoring, not a .so w/ABI guarantees.

1 files changed, 15 insertions, 2 deletions

diff --git a/thunk.h b/thunk.h
index 8bcc6d7..4a8060e 100644
--- a/thunk.h
+++ b/thunk.h
@@ -459,7 +459,6 @@ struct thunk_t {
 		assert(env);							\
 										\
 		r = _THUNK_GEN_DISPATCH(_name, env, __VA_ARGS__);		\
-		free(env);							\
 										\
 		return r;							\
 	}									\
@@ -538,7 +537,6 @@ struct thunk_t {
 		assert(env);							\
 										\
 		r = _THUNK_GEN_DISPATCH(_name, env, __VA_ARGS__);		\
-		free(env);							\
 										\
 		return r;							\
 	}									\
@@ -664,6 +662,21 @@ struct thunk_t {
  * including any payload if THUNK_ALLOC() was used.
  */
 static inline int thunk_dispatch(thunk_t *thunk) {
+	int	r;
+
+	r = thunk->dispatch(thunk);
+	free(thunk);
+
+	return r;
+}
+
+/* Same as thunk_dispatch() but without the free.
+ * Callers can trivially free thunk instances w/free(), there's
+ * no fancy destructor stuff or anything.  So when a thunk needs
+ * to be used repeatedly in a loop for instance, use this, then
+ * just free the thunk yourself.
+ */
+static inline int thunk_dispatch_keep(thunk_t *thunk) {
 	return thunk->dispatch(thunk);
 }