[apple/javascriptcore.git] / API / JSManagedValue.h

/*
 * Copyright (C) 2013 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef JSManagedValue_h
#define JSManagedValue_h

#import <JavaScriptCore/JSBase.h>
#import <JavaScriptCore/WebKitAvailability.h>

#if JSC_OBJC_API_ENABLED

@class JSValue;
@class JSContext;

/*!
@interface
@discussion JSManagedValue represents a "conditionally retained" JSValue. 
 "Conditionally retained" means that as long as either the JSManagedValue's 
 JavaScript value is reachable through the JavaScript object graph
 or the JSManagedValue object is reachable through the external Objective-C 
 object graph as reported to the JSVirtualMachine using 
 addManagedReference:withOwner:, the corresponding JavaScript value will 
 be retained. However, if neither of these conditions are true, the 
 corresponding JSValue will be released and set to nil.

 The primary use case for JSManagedValue is for safely referencing JSValues 
 from the Objective-C heap. It is incorrect to store a JSValue into an 
 Objective-C heap object, as this can very easily create a reference cycle, 
 keeping the entire JSContext alive.
*/ 
#ifndef JSC_OBJC_API_AVAILABLE_MAC_OS_X_1080
NS_CLASS_AVAILABLE(10_9, 7_0)
#else
OBJC_VISIBLE
#endif
@interface JSManagedValue : NSObject

/*!
@method
@abstract Create a JSManagedValue from a JSValue.
@param value
@result The new JSManagedValue.
*/
+ (JSManagedValue *)managedValueWithValue:(JSValue *)value;
+ (JSManagedValue *)managedValueWithValue:(JSValue *)value andOwner:(id)owner NS_AVAILABLE(10_10, 8_0);

/*!
@method
@abstract Create a JSManagedValue.
@param value
@result The new JSManagedValue.
*/
- (instancetype)initWithValue:(JSValue *)value;

/*!
@property
@abstract Get the JSValue from the JSManagedValue.
@result The corresponding JSValue for this JSManagedValue or 
 nil if the JSValue has been collected.
*/
@property (readonly, strong) JSValue *value;

@end

#endif // JSC_OBJC_API_ENABLED

#endif // JSManagedValue_h
Commit	Line	Data
93a37866 A	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>
81345200	30	#import <JavaScriptCore/WebKitAvailability.h>
93a37866 A	31
	32	#if JSC_OBJC_API_ENABLED
	33
	34	@class JSValue;
	35	@class JSContext;
	36
81345200 A	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
93a37866	54	NS_CLASS_AVAILABLE(10_9, 7_0)
81345200 A	55	#else
	56	OBJC_VISIBLE
	57	#endif
93a37866 A	58	@interface JSManagedValue : NSObject
93a37866 A	59
81345200 A	60	/*!
	61	@method
	62	@abstract Create a JSManagedValue from a JSValue.
	63	@param value
	64	@result The new JSManagedValue.
	65	*/
93a37866	66	+ (JSManagedValue )managedValueWithValue:(JSValue )value;
81345200	67	+ (JSManagedValue )managedValueWithValue:(JSValue )value andOwner:(id)owner NS_AVAILABLE(10_10, 8_0);
93a37866	68
81345200 A	69	/*!
	70	@method
	71	@abstract Create a JSManagedValue.
	72	@param value
	73	@result The new JSManagedValue.
	74	*/
	75	- (instancetype)initWithValue:(JSValue *)value;
93a37866	76
81345200 A	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;
93a37866 A	84
	85	@end
	86
	87	#endif // JSC_OBJC_API_ENABLED
	88
	89	#endif // JSManagedValue_h