1/* 2 * Copyright (C) 2013 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 JSManagedValue_h 27#define JSManagedValue_h 28 29#import <JavaScriptCore/JSBase.h> 30#import <JavaScriptCore/WebKitAvailability.h> 31 32#if JSC_OBJC_API_ENABLED 33 34@class JSValue; 35@class JSContext; 36 37/*! 38@interface 39@discussion JSManagedValue represents a "conditionally retained" JSValue. 40 "Conditionally retained" means that as long as either the JSManagedValue's 41 JavaScript value is reachable through the JavaScript object graph 42 or the JSManagedValue object is reachable through the external Objective-C 43 object graph as reported to the JSVirtualMachine using 44 addManagedReference:withOwner:, the corresponding JavaScript value will 45 be retained. However, if neither of these conditions are true, the 46 corresponding JSValue will be released and set to nil. 47 48 The primary use case for JSManagedValue is for safely referencing JSValues 49 from the Objective-C heap. It is incorrect to store a JSValue into an 50 Objective-C heap object, as this can very easily create a reference cycle, 51 keeping the entire JSContext alive. 52*/ 53#ifndef JSC_OBJC_API_AVAILABLE_MAC_OS_X_1080 54NS_CLASS_AVAILABLE(10_9, 7_0) 55#else 56OBJC_VISIBLE 57#endif 58@interface JSManagedValue : NSObject 59 60/*! 61@method 62@abstract Create a JSManagedValue from a JSValue. 63@param value 64@result The new JSManagedValue. 65*/ 66+ (JSManagedValue *)managedValueWithValue:(JSValue *)value; 67+ (JSManagedValue *)managedValueWithValue:(JSValue *)value andOwner:(id)owner NS_AVAILABLE(10_10, 8_0); 68 69/*! 70@method 71@abstract Create a JSManagedValue. 72@param value 73@result The new JSManagedValue. 74*/ 75- (instancetype)initWithValue:(JSValue *)value; 76 77/*! 78@property 79@abstract Get the JSValue from the JSManagedValue. 80@result The corresponding JSValue for this JSManagedValue or 81 nil if the JSValue has been collected. 82*/ 83@property (readonly, strong) JSValue *value; 84 85@end 86 87#endif // JSC_OBJC_API_ENABLED 88 89#endif // JSManagedValue_h 90