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| 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. ``AS IS'' AND ANY |
| 14 | + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 15 | + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 16 | + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR |
| 17 | + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 18 | + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 19 | + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| 20 | + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| 21 | + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 22 | + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 23 | + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 24 | + */ |
| 25 | + |
| 26 | +#ifndef JSContext_h |
| 27 | +#define JSContext_h |
| 28 | + |
| 29 | +#include <JavaScriptCore/JavaScript.h> |
| 30 | + |
| 31 | +#if JSC_OBJC_API_ENABLED |
| 32 | + |
| 33 | +@class JSVirtualMachine, JSValue; |
| 34 | + |
| 35 | +/*! |
| 36 | +@interface |
| 37 | +@discussion An instance of JSContext represents a JavaScript execution environment. All |
| 38 | + JavaScript execution takes place within a context. |
| 39 | + JSContext is also used to manage the life-cycle of objects within the |
| 40 | + JavaScript virtual machine. Every instance of JSValue is associated with a |
| 41 | + JSContext via a strong reference. The JSValue will keep the JSContext it |
| 42 | + references alive so long as the JSValue remains alive. When all of the JSValues |
| 43 | + that reference a particular JSContext have been deallocated the JSContext |
| 44 | + will be deallocated unless it has been previously retained. |
| 45 | +*/ |
| 46 | +NS_CLASS_AVAILABLE(10_9, 7_0) |
| 47 | +@interface JSContext : NSObject |
| 48 | + |
| 49 | +/*! |
| 50 | +@methodgroup Creating New JSContexts |
| 51 | +*/ |
| 52 | +/*! |
| 53 | +@method |
| 54 | +@abstract Create a JSContext. |
| 55 | +@result The new context. |
| 56 | +*/ |
| 57 | +- (instancetype)init; |
| 58 | + |
| 59 | +/*! |
| 60 | +@method |
| 61 | +@abstract Create a JSContext in the specified virtual machine. |
| 62 | +@param virtualMachine The JSVirtualMachine in which the context will be created. |
| 63 | +@result The new context. |
| 64 | +*/ |
| 65 | +- (instancetype)initWithVirtualMachine:(JSVirtualMachine *)virtualMachine; |
| 66 | + |
| 67 | +/*! |
| 68 | +@methodgroup Evaluating Scripts |
| 69 | +*/ |
| 70 | +/*! |
| 71 | +@method |
| 72 | +@abstract Evaluate a string of JavaScript code. |
| 73 | +@param script A string containing the JavaScript code to evaluate. |
| 74 | +@result The last value generated by the script. |
| 75 | +*/ |
| 76 | +- (JSValue *)evaluateScript:(NSString *)script; |
| 77 | + |
| 78 | +/*! |
| 79 | +@methodgroup Callback Accessors |
| 80 | +*/ |
| 81 | +/*! |
| 82 | +@method |
| 83 | +@abstract Get the JSContext that is currently executing. |
| 84 | +@discussion This method may be called from within an Objective-C block or method invoked |
| 85 | + as a callback from JavaScript to retrieve the callback's context. Outside of |
| 86 | + a callback from JavaScript this method will return nil. |
| 87 | +@result The currently executing JSContext or nil if there isn't one. |
| 88 | +*/ |
| 89 | ++ (JSContext *)currentContext; |
| 90 | + |
| 91 | +/*! |
| 92 | +@method |
| 93 | +@abstract Get the <code>this</code> value of the currently executing method. |
| 94 | +@discussion This method may be called from within an Objective-C block or method invoked |
| 95 | + as a callback from JavaScript to retrieve the callback's this value. Outside |
| 96 | + of a callback from JavaScript this method will return nil. |
| 97 | +@result The current <code>this</code> value or nil if there isn't one. |
| 98 | +*/ |
| 99 | ++ (JSValue *)currentThis; |
| 100 | + |
| 101 | +/*! |
| 102 | +@method |
| 103 | +@abstract Get the arguments to the current callback. |
| 104 | +@discussion This method may be called from within an Objective-C block or method invoked |
| 105 | + as a callback from JavaScript to retrieve the callback's arguments, objects |
| 106 | + in the returned array are instances of JSValue. Outside of a callback from |
| 107 | + JavaScript this method will return nil. |
| 108 | +@result An NSArray of the arguments nil if there is no current callback. |
| 109 | +*/ |
| 110 | ++ (NSArray *)currentArguments; |
| 111 | + |
| 112 | +/*! |
| 113 | +@methodgroup Global Properties |
| 114 | +*/ |
| 115 | +/*! |
| 116 | +@property |
| 117 | +@abstract Get the global object of the context. |
| 118 | +@discussion This method retrieves the global object of the JavaScript execution context. |
| 119 | + Instances of JSContext originating from WebKit will return a reference to the |
| 120 | + WindowProxy object. |
| 121 | +@result The global object. |
| 122 | +*/ |
| 123 | +@property (readonly, strong) JSValue *globalObject; |
| 124 | + |
| 125 | +/*! |
| 126 | +@property |
| 127 | +@discussion The <code>exception</code> property may be used to throw an exception to JavaScript. |
| 128 | + |
| 129 | + Before a callback is made from JavaScript to an Objective-C block or method, |
| 130 | + the prior value of the exception property will be preserved and the property |
| 131 | + will be set to nil. After the callback has completed the new value of the |
| 132 | + exception property will be read, and prior value restored. If the new value |
| 133 | + of exception is not nil, the callback will result in that value being thrown. |
| 134 | + |
| 135 | + This property may also be used to check for uncaught exceptions arising from |
| 136 | + API function calls (since the default behaviour of <code>exceptionHandler</code> is to |
| 137 | + assign an uncaught exception to this property). |
| 138 | +
|
| 139 | + If a JSValue originating from a different JSVirtualMachine than this context |
| 140 | + is assigned to this property, an Objective-C exception will be raised. |
| 141 | +*/ |
| 142 | +@property (strong) JSValue *exception; |
| 143 | + |
| 144 | +/*! |
| 145 | +@property |
| 146 | +@discussion If a call to an API function results in an uncaught JavaScript exception, the |
| 147 | + <code>exceptionHandler</code> block will be invoked. The default implementation for the |
| 148 | + exception handler will store the exception to the exception property on |
| 149 | + context. As a consequence the default behaviour is for unhandled exceptions |
| 150 | + occurring within a callback from JavaScript to be rethrown upon return. |
| 151 | + Setting this value to nil will result in all uncaught exceptions thrown from |
| 152 | + the API being silently consumed. |
| 153 | +*/ |
| 154 | +@property (copy) void(^exceptionHandler)(JSContext *context, JSValue *exception); |
| 155 | + |
| 156 | +/*! |
| 157 | +@property |
| 158 | +@discussion All instances of JSContext are associated with a single JSVirtualMachine. The |
| 159 | + virtual machine provides an "object space" or set of execution resources. |
| 160 | +*/ |
| 161 | +@property (readonly, strong) JSVirtualMachine *virtualMachine; |
| 162 | + |
| 163 | +/*! |
| 164 | +@property |
| 165 | +@discussion Name of the JSContext. Exposed when remote debugging the context. |
| 166 | +*/ |
| 167 | +@property (copy) NSString *name; |
| 168 | + |
| 169 | +@end |
| 170 | + |
| 171 | +/*! |
| 172 | +@category |
| 173 | +@discussion Instances of JSContext implement the following methods in order to enable |
| 174 | + support for subscript access by key and index, for example: |
| 175 | +
|
| 176 | +@textblock |
| 177 | + JSContext *context; |
| 178 | + JSValue *v = context[@"X"]; // Get value for "X" from the global object. |
| 179 | + context[@"Y"] = v; // Assign 'v' to "Y" on the global object. |
| 180 | +@/textblock |
| 181 | +
|
| 182 | + An object key passed as a subscript will be converted to a JavaScript value, |
| 183 | + and then the value converted to a string used to resolve a property of the |
| 184 | + global object. |
| 185 | +*/ |
| 186 | +@interface JSContext (SubscriptSupport) |
| 187 | + |
| 188 | +/*! |
| 189 | +method |
| 190 | +@abstract Get a particular property on the global object. |
| 191 | +@param key |
| 192 | +@result The JSValue for the global object's property. |
| 193 | +*/ |
| 194 | +- (JSValue *)objectForKeyedSubscript:(id)key; |
| 195 | + |
| 196 | +/*! |
| 197 | +method |
| 198 | +@abstract Set a particular property on the global object. |
| 199 | +@param object |
| 200 | +@param key |
| 201 | +*/ |
| 202 | +- (void)setObject:(id)object forKeyedSubscript:(NSObject <NSCopying> *)key; |
| 203 | + |
| 204 | +@end |
| 205 | + |
| 206 | +/*! |
| 207 | +@category |
| 208 | +@discussion These functions are for bridging between the C API and the Objective-C API. |
| 209 | +*/ |
| 210 | +@interface JSContext (JSContextRefSupport) |
| 211 | + |
| 212 | +/*! |
| 213 | +@method |
| 214 | +@abstract Create a JSContext, wrapping its C API counterpart. |
| 215 | +@param jsGlobalContextRef |
| 216 | +@result The JSContext equivalent of the provided JSGlobalContextRef. |
| 217 | +*/ |
| 218 | ++ (JSContext *)contextWithJSGlobalContextRef:(JSGlobalContextRef)jsGlobalContextRef; |
| 219 | + |
| 220 | +/*! |
| 221 | +@property |
| 222 | +@abstract Get the C API counterpart wrapped by a JSContext. |
| 223 | +@result The C API equivalent of this JSContext. |
| 224 | +*/ |
| 225 | +@property (readonly) JSGlobalContextRef JSGlobalContextRef; |
| 226 | +@end |
| 227 | + |
| 228 | +#endif |
| 229 | + |
| 230 | +#endif // JSContext_h |
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