1 // Copyright 2006-2008 the V8 project authors. All rights reserved. 2 // Redistribution and use in source and binary forms, with or without 3 // modification, are permitted provided that the following conditions are 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 11 // with the distribution. 12 // * Neither the name of Google Inc. nor the names of its 13 // contributors may be used to endorse or promote products derived 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 #ifndef V8_HANDLES_H_ 29 #define V8_HANDLES_H_ 30 31 #include "apiutils.h" 32 33 namespace v8 { 34 namespace internal { 35 36 // ---------------------------------------------------------------------------- 37 // A Handle provides a reference to an object that survives relocation by 38 // the garbage collector. 39 // Handles are only valid within a HandleScope. 40 // When a handle is created for an object a cell is allocated in the heap. 41 42 template<typename T> 43 class Handle { 44 public: 45 INLINE(explicit Handle(T** location)) { location_ = location; } 46 INLINE(explicit Handle(T* obj)); 47 INLINE(Handle(T* obj, Isolate* isolate)); 48 49 INLINE(Handle()) : location_(NULL) {} 50 51 // Constructor for handling automatic up casting. 52 // Ex. Handle<JSFunction> can be passed when Handle<Object> is expected. 53 template <class S> Handle(Handle<S> handle) { 54 #ifdef DEBUG 55 T* a = NULL; 56 S* b = NULL; 57 a = b; // Fake assignment to enforce type checks. 58 USE(a); 59 #endif 60 location_ = reinterpret_cast<T**>(handle.location()); 61 } 62 63 INLINE(T* operator ->() const) { return operator*(); } 64 65 // Check if this handle refers to the exact same object as the other handle. 66 bool is_identical_to(const Handle<T> other) const { 67 return operator*() == *other; 68 } 69 70 // Provides the C++ dereference operator. 71 INLINE(T* operator*() const); 72 73 // Returns the address to where the raw pointer is stored. 74 T** location() const { 75 ASSERT(location_ == NULL || 76 reinterpret_cast<Address>(*location_) != kZapValue); 77 return location_; 78 } 79 80 template <class S> static Handle<T> cast(Handle<S> that) { 81 T::cast(*that); 82 return Handle<T>(reinterpret_cast<T**>(that.location())); 83 } 84 85 static Handle<T> null() { return Handle<T>(); } 86 bool is_null() const { return location_ == NULL; } 87 88 // Closes the given scope, but lets this handle escape. See 89 // implementation in api.h. 90 inline Handle<T> EscapeFrom(v8::HandleScope* scope); 91 92 private: 93 T** location_; 94 }; 95 96 97 // A stack-allocated class that governs a number of local handles. 98 // After a handle scope has been created, all local handles will be 99 // allocated within that handle scope until either the handle scope is 100 // deleted or another handle scope is created. If there is already a 101 // handle scope and a new one is created, all allocations will take 102 // place in the new handle scope until it is deleted. After that, 103 // new handles will again be allocated in the original handle scope. 104 // 105 // After the handle scope of a local handle has been deleted the 106 // garbage collector will no longer track the object stored in the 107 // handle and may deallocate it. The behavior of accessing a handle 108 // for which the handle scope has been deleted is undefined. 109 class HandleScope { 110 public: 111 inline HandleScope(); 112 explicit inline HandleScope(Isolate* isolate); 113 114 inline ~HandleScope(); 115 116 // Counts the number of allocated handles. 117 static int NumberOfHandles(); 118 119 // Creates a new handle with the given value. 120 template <typename T> 121 static inline T** CreateHandle(T* value, Isolate* isolate); 122 123 // Deallocates any extensions used by the current scope. 124 static void DeleteExtensions(Isolate* isolate); 125 126 static Address current_next_address(); 127 static Address current_limit_address(); 128 static Address current_level_address(); 129 130 // Closes the HandleScope (invalidating all handles 131 // created in the scope of the HandleScope) and returns 132 // a Handle backed by the parent scope holding the 133 // value of the argument handle. 134 template <typename T> 135 Handle<T> CloseAndEscape(Handle<T> handle_value); 136 137 Isolate* isolate() { return isolate_; } 138 139 private: 140 // Prevent heap allocation or illegal handle scopes. 141 HandleScope(const HandleScope&); 142 void operator=(const HandleScope&); 143 void* operator new(size_t size); 144 void operator delete(void* size_t); 145 146 inline void CloseScope(); 147 148 Isolate* isolate_; 149 Object** prev_next_; 150 Object** prev_limit_; 151 152 // Extend the handle scope making room for more handles. 153 static internal::Object** Extend(); 154 155 // Zaps the handles in the half-open interval [start, end). 156 static void ZapRange(internal::Object** start, internal::Object** end); 157 158 friend class v8::HandleScope; 159 friend class v8::ImplementationUtilities; 160 }; 161 162 163 // ---------------------------------------------------------------------------- 164 // Handle operations. 165 // They might invoke garbage collection. The result is an handle to 166 // an object of expected type, or the handle is an error if running out 167 // of space or encountering an internal error. 168 169 void NormalizeProperties(Handle<JSObject> object, 170 PropertyNormalizationMode mode, 171 int expected_additional_properties); 172 void NormalizeElements(Handle<JSObject> object); 173 void TransformToFastProperties(Handle<JSObject> object, 174 int unused_property_fields); 175 void NumberDictionarySet(Handle<NumberDictionary> dictionary, 176 uint32_t index, 177 Handle<Object> value, 178 PropertyDetails details); 179 180 // Flattens a string. 181 void FlattenString(Handle<String> str); 182 183 // Flattens a string and returns the underlying external or sequential 184 // string. 185 Handle<String> FlattenGetString(Handle<String> str); 186 187 Handle<Object> SetProperty(Handle<JSObject> object, 188 Handle<String> key, 189 Handle<Object> value, 190 PropertyAttributes attributes, 191 StrictModeFlag strict_mode); 192 193 Handle<Object> SetProperty(Handle<Object> object, 194 Handle<Object> key, 195 Handle<Object> value, 196 PropertyAttributes attributes, 197 StrictModeFlag strict_mode); 198 199 Handle<Object> ForceSetProperty(Handle<JSObject> object, 200 Handle<Object> key, 201 Handle<Object> value, 202 PropertyAttributes attributes); 203 204 Handle<Object> SetNormalizedProperty(Handle<JSObject> object, 205 Handle<String> key, 206 Handle<Object> value, 207 PropertyDetails details); 208 209 Handle<Object> ForceDeleteProperty(Handle<JSObject> object, 210 Handle<Object> key); 211 212 Handle<Object> SetLocalPropertyIgnoreAttributes( 213 Handle<JSObject> object, 214 Handle<String> key, 215 Handle<Object> value, 216 PropertyAttributes attributes); 217 218 // Used to set local properties on the object we totally control 219 // and which therefore has no accessors and alikes. 220 void SetLocalPropertyNoThrow(Handle<JSObject> object, 221 Handle<String> key, 222 Handle<Object> value, 223 PropertyAttributes attributes = NONE); 224 225 Handle<Object> SetPropertyWithInterceptor(Handle<JSObject> object, 226 Handle<String> key, 227 Handle<Object> value, 228 PropertyAttributes attributes, 229 StrictModeFlag strict_mode); 230 231 MUST_USE_RESULT Handle<Object> SetElement(Handle<JSObject> object, 232 uint32_t index, 233 Handle<Object> value, 234 StrictModeFlag strict_mode); 235 236 Handle<Object> SetOwnElement(Handle<JSObject> object, 237 uint32_t index, 238 Handle<Object> value, 239 StrictModeFlag strict_mode); 240 241 Handle<Object> GetProperty(Handle<JSObject> obj, 242 const char* name); 243 244 Handle<Object> GetProperty(Handle<Object> obj, 245 Handle<Object> key); 246 247 Handle<Object> GetProperty(Handle<JSObject> obj, 248 Handle<String> name, 249 LookupResult* result); 250 251 252 Handle<Object> GetElement(Handle<Object> obj, 253 uint32_t index); 254 255 Handle<Object> GetPropertyWithInterceptor(Handle<JSObject> receiver, 256 Handle<JSObject> holder, 257 Handle<String> name, 258 PropertyAttributes* attributes); 259 260 Handle<Object> GetPrototype(Handle<Object> obj); 261 262 Handle<Object> SetPrototype(Handle<JSObject> obj, Handle<Object> value); 263 264 // Return the object's hidden properties object. If the object has no hidden 265 // properties and create_if_needed is true, then a new hidden property object 266 // will be allocated. Otherwise the Heap::undefined_value is returned. 267 Handle<Object> GetHiddenProperties(Handle<JSObject> obj, bool create_if_needed); 268 269 Handle<Object> DeleteElement(Handle<JSObject> obj, uint32_t index); 270 Handle<Object> DeleteProperty(Handle<JSObject> obj, Handle<String> prop); 271 272 Handle<Object> LookupSingleCharacterStringFromCode(uint32_t index); 273 274 Handle<JSObject> Copy(Handle<JSObject> obj); 275 276 Handle<Object> SetAccessor(Handle<JSObject> obj, Handle<AccessorInfo> info); 277 278 Handle<FixedArray> AddKeysFromJSArray(Handle<FixedArray>, 279 Handle<JSArray> array); 280 281 // Get the JS object corresponding to the given script; create it 282 // if none exists. 283 Handle<JSValue> GetScriptWrapper(Handle<Script> script); 284 285 // Script line number computations. 286 void InitScriptLineEnds(Handle<Script> script); 287 // For string calculates an array of line end positions. If the string 288 // does not end with a new line character, this character may optionally be 289 // imagined. 290 Handle<FixedArray> CalculateLineEnds(Handle<String> string, 291 bool with_imaginary_last_new_line); 292 int GetScriptLineNumber(Handle<Script> script, int code_position); 293 // The safe version does not make heap allocations but may work much slower. 294 int GetScriptLineNumberSafe(Handle<Script> script, int code_position); 295 296 // Computes the enumerable keys from interceptors. Used for debug mirrors and 297 // by GetKeysInFixedArrayFor below. 298 v8::Handle<v8::Array> GetKeysForNamedInterceptor(Handle<JSObject> receiver, 299 Handle<JSObject> object); 300 v8::Handle<v8::Array> GetKeysForIndexedInterceptor(Handle<JSObject> receiver, 301 Handle<JSObject> object); 302 303 enum KeyCollectionType { LOCAL_ONLY, INCLUDE_PROTOS }; 304 305 // Computes the enumerable keys for a JSObject. Used for implementing 306 // "for (n in object) { }". 307 Handle<FixedArray> GetKeysInFixedArrayFor(Handle<JSObject> object, 308 KeyCollectionType type); 309 Handle<JSArray> GetKeysFor(Handle<JSObject> object); 310 Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object, 311 bool cache_result); 312 313 // Computes the union of keys and return the result. 314 // Used for implementing "for (n in object) { }" 315 Handle<FixedArray> UnionOfKeys(Handle<FixedArray> first, 316 Handle<FixedArray> second); 317 318 Handle<String> SubString(Handle<String> str, 319 int start, 320 int end, 321 PretenureFlag pretenure = NOT_TENURED); 322 323 324 // Sets the expected number of properties for the function's instances. 325 void SetExpectedNofProperties(Handle<JSFunction> func, int nof); 326 327 // Sets the prototype property for a function instance. 328 void SetPrototypeProperty(Handle<JSFunction> func, Handle<JSObject> value); 329 330 // Sets the expected number of properties based on estimate from compiler. 331 void SetExpectedNofPropertiesFromEstimate(Handle<SharedFunctionInfo> shared, 332 int estimate); 333 334 335 Handle<JSGlobalProxy> ReinitializeJSGlobalProxy( 336 Handle<JSFunction> constructor, 337 Handle<JSGlobalProxy> global); 338 339 Handle<Object> SetPrototype(Handle<JSFunction> function, 340 Handle<Object> prototype); 341 342 Handle<Object> PreventExtensions(Handle<JSObject> object); 343 344 // Does lazy compilation of the given function. Returns true on success and 345 // false if the compilation resulted in a stack overflow. 346 enum ClearExceptionFlag { KEEP_EXCEPTION, CLEAR_EXCEPTION }; 347 348 bool EnsureCompiled(Handle<SharedFunctionInfo> shared, 349 ClearExceptionFlag flag); 350 351 bool CompileLazyShared(Handle<SharedFunctionInfo> shared, 352 ClearExceptionFlag flag); 353 354 bool CompileLazy(Handle<JSFunction> function, ClearExceptionFlag flag); 355 356 bool CompileLazyInLoop(Handle<JSFunction> function, ClearExceptionFlag flag); 357 358 bool CompileOptimized(Handle<JSFunction> function, 359 int osr_ast_id, 360 ClearExceptionFlag flag); 361 362 class NoHandleAllocation BASE_EMBEDDED { 363 public: 364 #ifndef DEBUG 365 NoHandleAllocation() {} 366 ~NoHandleAllocation() {} 367 #else 368 inline NoHandleAllocation(); 369 inline ~NoHandleAllocation(); 370 private: 371 int level_; 372 #endif 373 }; 374 375 } } // namespace v8::internal 376 377 #endif // V8_HANDLES_H_ 378
