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/*
* 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. ``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
* 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.
*/
#import <JavaScriptCore/JavaScriptCore.h>
#if JSC_OBJC_API_ENABLED
/*!
@protocol
@abstract JSExport provides a declarative way to export Objective-C objects and
classes -- including properties, instance methods, class methods, and
initializers -- to JavaScript.
@discussion When an Objective-C object is exported to JavaScript, a JavaScript
wrapper object is created.
In JavaScript, inheritance works via a chain of prototype objects.
For each Objective-C class in each JSContext, an object appropriate for use
as a prototype will be provided. For the class NSObject the prototype
will be the Object prototype. For all other Objective-C
classes a prototype will be created. The prototype for a given
Objective-C class will have its internal [Prototype] property set to point to
the prototype created for the Objective-C class's superclass. As such the
prototype chain for a JavaScript wrapper object will reflect the wrapped
Objective-C type's inheritance hierarchy.
JavaScriptCore also produces a constructor for each Objective-C class. The
constructor has a property named 'prototype' that references the prototype,
and the prototype has a property named 'constructor' that references the
constructor.
By default JavaScriptCore does not export any methods or properties from an
Objective-C class to JavaScript; however methods and properties may be exported
explicitly using JSExport. For each protocol that a class conforms to, if the
protocol incorporates the protocol JSExport, JavaScriptCore exports the methods
and properties in that protocol to JavaScript
For each exported instance method JavaScriptCore will assign a corresponding
JavaScript function to the prototype. For each exported Objective-C property
JavaScriptCore will assign a corresponding JavaScript accessor to the prototype.
For each exported class method JavaScriptCore will assign a corresponding
JavaScript function to the constructor. For example:
<pre>
@textblock
@protocol MyClassJavaScriptMethods <JSExport>
- (void)foo;
@end
@interface MyClass : NSObject <MyClassJavaScriptMethods>
- (void)foo;
- (void)bar;
@end
@/textblock
</pre>
Data properties that are created on the prototype or constructor objects have
the attributes: <code>writable:true</code>, <code>enumerable:false</code>, <code>configurable:true</code>.
Accessor properties have the attributes: <code>enumerable:false</code> and <code>configurable:true</code>.
If an instance of <code>MyClass</code> is converted to a JavaScript value, the resulting
wrapper object will (via its prototype) export the method <code>foo</code> to JavaScript,
since the class conforms to the <code>MyClassJavaScriptMethods</code> protocol, and this
protocol incorporates <code>JSExport</code>. <code>bar</code> will not be exported.
JSExport supports properties, arguments, and return values of the following types:
Primitive numbers: signed values up to 32-bits convert using JSValue's
valueWithInt32/toInt32. Unsigned values up to 32-bits convert using JSValue's
valueWithUInt32/toUInt32. All other numeric values convert using JSValue's
valueWithDouble/toDouble.
BOOL: values convert using JSValue's valueWithBool/toBool.
id: values convert using JSValue's valueWithObject/toObject.
Objective-C instance pointers: Pointers convert using JSValue's
valueWithObjectOfClass/toObject.
C structs: C structs for CGPoint, NSRange, CGRect, and CGSize convert using
JSValue's appropriate methods. Other C structs are not supported.
Blocks: Blocks convert using JSValue's valueWithObject/toObject.
All objects that conform to JSExport convert to JavaScript wrapper objects,
even if they subclass classes that would otherwise behave differently. For
example, if a subclass of NSString conforms to JSExport, it converts to
JavaScript as a wrapper object rather than a JavaScript string.
*/
@protocol JSExport
@end
/*!
@define
@abstract Rename a selector when it's exported to JavaScript.
@discussion When a selector that takes one or more arguments is converted to a JavaScript
property name, by default a property name will be generated by performing the
following conversion:
- All colons are removed from the selector
- Any lowercase letter that had followed a colon will be capitalized.
Under the default conversion a selector <code>doFoo:withBar:</code> will be exported as
<code>doFooWithBar</code>. The default conversion may be overriden using the JSExportAs
macro, for example to export a method <code>doFoo:withBar:</code> as <code>doFoo</code>:
<pre>
@textblock
@protocol MyClassJavaScriptMethods <JSExport>
JSExportAs(doFoo,
- (void)doFoo:(id)foo withBar:(id)bar
);
@end
@/textblock
</pre>
Note that the JSExport macro may only be applied to a selector that takes one
or more argument.
*/
#define JSExportAs(PropertyName, Selector) \
@optional Selector __JS_EXPORT_AS__##PropertyName:(id)argument; @required Selector
#endif
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