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.  Any objects that are intended to be stored in a weak map must be user defined objects that

    56  remove themselves from the map in their finalizer.

    57  */

    58 JS_EXPORT JSWeakObjectMapRef JSWeakObjectMapCreate(JSContextRef ctx, void* data, JSWeakMapDestroyedCallback destructor);

    59 

    60 /*!

    61  @function

    62  @abstract Associates a JSObjectRef with the given key in a JSWeakObjectMap.

    63  @param ctx The execution context to use.

    64  @param map The map to operate on.

    65  @param key The key to associate a weak reference with.

    66  @param object The user defined object to associate with the key.

    67  */

    68 JS_EXPORT void JSWeakObjectMapSet(JSContextRef ctx, JSWeakObjectMapRef map, void* key, JSObjectRef);

    69 

    70 /*!

    71  @function

    72  @abstract Retrieves the JSObjectRef associated with a key.

    73  @param ctx The execution context to use.

    74  @param map The map to query.

    75  @param key The key to search for.

    76  @result Either the live object associated with the provided key, or NULL.

    77  */

    78 JS_EXPORT JSObjectRef JSWeakObjectMapGet(JSContextRef ctx, JSWeakObjectMapRef map, void* key);

    79 

    80 /*!

    81  @function

    82  @abstract Clears the association between a key and an object in a JSWeakObjectMapRef

    83  @param ctx The execution context to use.

    84  @param map The map to clear the key association from.

    85  @param key The key to use.

    86  @param object The old object value.

    87  @result Returns true if the key/object association was present in map, and has been removed.

    88  */

    89 JS_EXPORT bool JSWeakObjectMapClear(JSContextRef ctx, JSWeakObjectMapRef map, void* key, JSObjectRef object);

    90 

    91 #ifdef __cplusplus

    92 }

    93 #endif

    94 

    95 #endif // JSWeakObjectMapPrivate_h