Implement weak persistent handles in the Dart API.

runtime/include/dart_api.h

 // Copyright (c) 2011, 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.
 
 #ifndef INCLUDE_DART_API_H_
 #define INCLUDE_DART_API_H_
 
 /** \mainpage Dart Embedding API Reference
  *
  * Dart is a class-based programming language for creating structured
@@ skipping 77 matching lines @@
  * otherwise indicated, callers should assume that all functions in
  * the Dart embedding api return local handles.
  *
  * Persistent handles are allocated within the current isolate. They
  * can be used to store objects across scopes. Persistent handles have
  * the lifetime of the current isolate unless they are explicitly
  * deallocated (see Dart_DeletePersistentHandle).
  */
 typedef struct _Dart_Handle* Dart_Handle;
 
+typedef void (*Dart_PeerFinalizer)(void* peer);

[Ivan Posva, 2011/12/20 01:32:34]

As discussed we should add the Dart_Handle to this as well. Next change though.

+
 /**
  * Is this an error handle?
  *
  * Requires there to be a current isolate.
  */
 DART_EXPORT bool Dart_IsError(const Dart_Handle& handle);
 
 /**
  * Gets the error message from an error handle.
  *
@@ skipping 89 matching lines @@
 DART_EXPORT Dart_Handle Dart_NewPersistentHandle(Dart_Handle object);
 
 /**
  * Deallocates a persistent handle.
  *
  * Requires there to be a current isolate.
  */
 DART_EXPORT void Dart_DeletePersistentHandle(Dart_Handle object);
 
 /**
- * Takes a persistent handle and makes it weak.
+ * Allocates a weak persistent handle for an object.
  *
- * UNIMPLEMENTED.
+ * This handle has the lifetime of the current isolate unless it is
+ * explicitly deallocated by calling Dart_DeletePersistentHandle.
  *
  * Requires there to be a current isolate.
  */
-DART_EXPORT Dart_Handle Dart_MakeWeakPersistentHandle(Dart_Handle object);
-// TODO(turnidge): Needs a "near death" callback here.
-// TODO(turnidge): Add IsWeak, Clear, etc.
+DART_EXPORT Dart_Handle Dart_NewWeakPersistentHandle(
+    Dart_Handle object,
+    void* peer,
+    Dart_PeerFinalizer callback);
 
 /**
- * Takes a weak persistent handle and makes it non-weak.
- *
- * UNIMPLEMENTED.
+ * Is this object a weak persistent handle?
  *
  * Requires there to be a current isolate.
  */
-DART_EXPORT Dart_Handle Dart_MakePersistentHandle(Dart_Handle object);
+DART_EXPORT bool Dart_IsWeakPersistentHandle(Dart_Handle object);
 
 // --- Initialization and Globals ---
 
 /**
  * An isolate creation and initialization callback function.
  *
  * This callback, provided by the embedder, is called when an isolate needs
  * to be created. The callback should create an isolate and load the
  * required scripts for execution.
  *
@@ skipping 643 matching lines @@
  *
  * \param value An array of 32-bit codepoints.
  * \param length The length of the codepoints array.
  *
  * \return The String object if no error occurs. Otherwise returns
  *   an error handle.
  */
 DART_EXPORT Dart_Handle Dart_NewString32(const uint32_t* codepoints,
                                          intptr_t length);
 
-
-typedef void (*Dart_PeerFinalizer)(void* peer);
-
 /**
  * Is this object an external String?
  *
  * An external String is a String which references a fixed array of
  * codepoints which is external to the Dart heap.
  */
 DART_EXPORT bool Dart_IsExternalString(Dart_Handle object);
 
 /**
  * Retrieves the peer pointer associated with an external String.
@@ skipping 484 matching lines @@
 
 // --- Profiling support ----
 
 // External pprof support for gathering and dumping symbolic
 // information that can be used for better profile reports for
 // dynamically generated code.
 DART_EXPORT void Dart_InitPprofSupport();
 DART_EXPORT void Dart_GetPprofSymbolInfo(void** buffer, int* buffer_size);
 
 #endif  // INCLUDE_DART_API_H_