Remove the ability to allow multiple gc prologue and gc epilogue callbacks

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/bigint_operations.h"
@@ skipping 746 matching lines @@
 
   WeakReferenceSet* reference_set = new WeakReferenceSet(keys, num_keys,
                                                          values, num_values);
   state->DelayWeakReferenceSet(reference_set);
   return Api::Success();
 }
 
 
 // --- Garbage Collection Callbacks --
 
 DART_EXPORT Dart_Handle Dart_AddGcPrologueCallback(

[Ivan Posva, 2014/03/12 21:06:41]

We might want to follow the other functions in the API here and use a
Dart_SetGcPrologueCallback() instead of add and remove, where removal is
equivalent to setting a NULL callback. Or since these callback really function
in pairs maybe even just have a single Dart_SetGcCallback()?

To make it easier to roll this change, it is probably OK to have both versions
for a brief period.

[siva, 2014/03/12 22:38:54]

Done, Added Dart_SetGcCallbacks(prologue, epilogue);

The old API is still around until I can remove it's usage from Dartium.

On 2014/03/12 21:06:41, Ivan Posva wrote:

     Dart_GcPrologueCallback callback) {
   Isolate* isolate = Isolate::Current();
   CHECK_ISOLATE(isolate);
-  GcPrologueCallbacks& callbacks = isolate->gc_prologue_callbacks();
-  if (callbacks.Contains(callback)) {
+  if (isolate->gc_prologue_callback() != NULL) {
     return Api::NewError(
-        "%s permits only one instance of 'callback' to be present in the "
-        "prologue callback list.",
+        "%s permits only one gc prologue callback to be registered, please "
+        "remove the existing callback using Dart_RemoveGcPrologueCallback "
+        "and then add this callback",
         CURRENT_FUNC);
   }
-  callbacks.Add(callback);
+  isolate->set_gc_prologue_callback(callback);
   return Api::Success();
 }
 
 
 DART_EXPORT Dart_Handle Dart_RemoveGcPrologueCallback(
     Dart_GcPrologueCallback callback) {
   Isolate* isolate = Isolate::Current();
   CHECK_ISOLATE(isolate);
-  GcPrologueCallbacks& callbacks = isolate->gc_prologue_callbacks();
-  if (!callbacks.Contains(callback)) {
+  if (isolate->gc_prologue_callback() != callback) {
     return Api::NewError(
-        "%s expects 'callback' to be present in the prologue callback list.",
+        "%s expects 'callback' to be the currently registered gc prologue "
+        "callback .",
         CURRENT_FUNC);
   }
-  callbacks.Remove(callback);
+  isolate->set_gc_prologue_callback(NULL);
   return Api::Success();
 }
 
 
 DART_EXPORT Dart_Handle Dart_AddGcEpilogueCallback(
     Dart_GcEpilogueCallback callback) {
   Isolate* isolate = Isolate::Current();
   CHECK_ISOLATE(isolate);
-  GcEpilogueCallbacks& callbacks = isolate->gc_epilogue_callbacks();
-  if (callbacks.Contains(callback)) {
+  if (isolate->gc_epilogue_callback() != NULL) {
     return Api::NewError(
-        "%s permits only one instance of 'callback' to be present in the "
-        "epilogue callback list.",
+        "%s permits only one gc epilogue callback to be registered, please "
+        "remove the existing callback using Dart_RemoveGcEpilogueCallback "
+        "and then add this callback",
         CURRENT_FUNC);
   }
-  callbacks.Add(callback);
+  isolate->set_gc_epilogue_callback(callback);
   return Api::Success();
 }
 
 
 DART_EXPORT Dart_Handle Dart_RemoveGcEpilogueCallback(
     Dart_GcEpilogueCallback callback) {
   Isolate* isolate = Isolate::Current();
   CHECK_ISOLATE(isolate);
-  GcEpilogueCallbacks& callbacks = isolate->gc_epilogue_callbacks();
-  if (!callbacks.Contains(callback)) {
+  if (isolate->gc_epilogue_callback() != callback) {
     return Api::NewError(
         "%s expects 'callback' to be present in the epilogue callback list.",

[Ivan Posva, 2014/03/12 21:06:41]

Still referencing list.

[siva, 2014/03/12 22:38:54]

Done.

         CURRENT_FUNC);
   }
-  callbacks.Remove(callback);
+  isolate->set_gc_epilogue_callback(NULL);
   return Api::Success();
 }
 
 
 // --- Initialization and Globals ---
 
 DART_EXPORT const char* Dart_VersionString() {
   return Version::String();
 }
 
@@ skipping 3820 matching lines @@
 
 
 DART_EXPORT void Dart_RegisterRootServiceRequestCallback(
     const char* name,
     Dart_ServiceRequestCallback callback,
     void* user_data) {
   Service::RegisterRootEmbedderCallback(name, callback, user_data);
 }
 
 }  // namespace dart