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      1 /*
      2  * Copyright (C) 2010 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
     14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
     17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     23  * THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef JSWeakObjectMapRefPrivate_h
     27 #define JSWeakObjectMapRefPrivate_h
     28 
     29 #include <JavaScriptCore/JSContextRef.h>
     30 #include <JavaScriptCore/JSValueRef.h>
     31 
     32 #ifdef __cplusplus
     33 extern "C" {
     34 #endif
     35 
     36 /*! @typedef JSWeakObjectMapRef A weak map for storing JSObjectRefs */
     37 typedef struct OpaqueJSWeakObjectMap* JSWeakObjectMapRef;
     38 
     39 /*!
     40  @typedef JSWeakMapDestroyedCallback
     41  @abstract The callback invoked when a JSWeakObjectMapRef is being destroyed.
     42  @param map The map that is being destroyed.
     43  @param data The private data (if any) that was associated with the map instance.
     44  */
     45 typedef void (*JSWeakMapDestroyedCallback)(JSWeakObjectMapRef map, void* data);
     46 
     47 /*!
     48  @function
     49  @abstract Creates a weak value map that can be used to reference user defined objects without preventing them from being collected.
     50  @param ctx The execution context to use.
     51  @param data A void* to set as the map's private data. Pass NULL to specify no private data.
     52  @param destructor A function to call when the weak map is destroyed.
     53  @result A JSWeakObjectMapRef bound to the given context, data and destructor.
     54  @discussion The JSWeakObjectMapRef can be used as a storage mechanism to hold custom JS objects without forcing those objects to
     55  remain live as JSValueProtect would.
     56  */
     57 JS_EXPORT JSWeakObjectMapRef JSWeakObjectMapCreate(JSContextRef ctx, void* data, JSWeakMapDestroyedCallback destructor);
     58 
     59 /*!
     60  @function
     61  @abstract Associates a JSObjectRef with the given key in a JSWeakObjectMap.
     62  @param ctx The execution context to use.
     63  @param map The map to operate on.
     64  @param key The key to associate a weak reference with.
     65  @param object The user defined object to associate with the key.
     66  */
     67 JS_EXPORT void JSWeakObjectMapSet(JSContextRef ctx, JSWeakObjectMapRef map, void* key, JSObjectRef);
     68 
     69 /*!
     70  @function
     71  @abstract Retrieves the JSObjectRef associated with a key.
     72  @param ctx The execution context to use.
     73  @param map The map to query.
     74  @param key The key to search for.
     75  @result Either the live object associated with the provided key, or NULL.
     76  */
     77 JS_EXPORT JSObjectRef JSWeakObjectMapGet(JSContextRef ctx, JSWeakObjectMapRef map, void* key);
     78 
     79 #ifdef __cplusplus
     80 }
     81 #endif
     82 
     83 #endif // JSWeakObjectMapPrivate_h
     84