// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * 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.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
// OWNER 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.
#ifndef V8_HANDLES_H_
#define V8_HANDLES_H_
#include "apiutils.h"
namespace v8 {
namespace internal {
// ----------------------------------------------------------------------------
// A Handle provides a reference to an object that survives relocation by
// the garbage collector.
// Handles are only valid within a HandleScope.
// When a handle is created for an object a cell is allocated in the heap.
template<class T>
class Handle {
public:
INLINE(Handle(T** location)) { location_ = location; }
INLINE(explicit Handle(T* obj));
INLINE(Handle()) : location_(NULL) {}
// Constructor for handling automatic up casting.
// Ex. Handle<JSFunction> can be passed when Handle<Object> is expected.
template <class S> Handle(Handle<S> handle) {
#ifdef DEBUG
T* a = NULL;
S* b = NULL;
a = b; // Fake assignment to enforce type checks.
USE(a);
#endif
location_ = reinterpret_cast<T**>(handle.location());
}
INLINE(T* operator ->() const) { return operator*(); }
// Check if this handle refers to the exact same object as the other handle.
bool is_identical_to(const Handle<T> other) const {
return operator*() == *other;
}
// Provides the C++ dereference operator.
INLINE(T* operator*() const);
// Returns the address to where the raw pointer is stored.
T** location() const {
ASSERT(location_ == NULL ||
reinterpret_cast<Address>(*location_) != kZapValue);
return location_;
}
template <class S> static Handle<T> cast(Handle<S> that) {
T::cast(*that);
return Handle<T>(reinterpret_cast<T**>(that.location()));
}
static Handle<T> null() { return Handle<T>(); }
bool is_null() { return location_ == NULL; }
// Closes the given scope, but lets this handle escape. See
// implementation in api.h.
inline Handle<T> EscapeFrom(v8::HandleScope* scope);
private:
T** location_;
};
// A stack-allocated class that governs a number of local handles.
// After a handle scope has been created, all local handles will be
// allocated within that handle scope until either the handle scope is
// deleted or another handle scope is created. If there is already a
// handle scope and a new one is created, all allocations will take
// place in the new handle scope until it is deleted. After that,
// new handles will again be allocated in the original handle scope.
//
// After the handle scope of a local handle has been deleted the
// garbage collector will no longer track the object stored in the
// handle and may deallocate it. The behavior of accessing a handle
// for which the handle scope has been deleted is undefined.
class HandleScope {
public:
HandleScope() : previous_(current_) {
current_.extensions = 0;
}
~HandleScope() {
Leave(&previous_);
}
// Counts the number of allocated handles.
static int NumberOfHandles();
// Creates a new handle with the given value.
template <typename T>
static inline T** CreateHandle(T* value) {
internal::Object** cur = current_.next;
if (cur == current_.limit) cur = Extend();
// Update the current next field, set the value in the created
// handle, and return the result.
ASSERT(cur < current_.limit);
current_.next = cur + 1;
T** result = reinterpret_cast<T**>(cur);
*result = value;
return result;
}
// Deallocates any extensions used by the current scope.
static void DeleteExtensions();
static Address current_extensions_address();
static Address current_next_address();
static Address current_limit_address();
private:
// Prevent heap allocation or illegal handle scopes.
HandleScope(const HandleScope&);
void operator=(const HandleScope&);
void* operator new(size_t size);
void operator delete(void* size_t);
static v8::ImplementationUtilities::HandleScopeData current_;
const v8::ImplementationUtilities::HandleScopeData previous_;
// Pushes a fresh handle scope to be used when allocating new handles.
static void Enter(
v8::ImplementationUtilities::HandleScopeData* previous) {
*previous = current_;
current_.extensions = 0;
}
// Re-establishes the previous scope state. Should be called only
// once, and only for the current scope.
static void Leave(
const v8::ImplementationUtilities::HandleScopeData* previous) {
if (current_.extensions > 0) {
DeleteExtensions();
}
current_ = *previous;
#ifdef DEBUG
ZapRange(current_.next, current_.limit);
#endif
}
// Extend the handle scope making room for more handles.
static internal::Object** Extend();
// Zaps the handles in the half-open interval [start, end).
static void ZapRange(internal::Object** start, internal::Object** end);
friend class v8::HandleScope;
friend class v8::ImplementationUtilities;
};
// ----------------------------------------------------------------------------
// Handle operations.
// They might invoke garbage collection. The result is an handle to
// an object of expected type, or the handle is an error if running out
// of space or encountering an internal error.
void NormalizeProperties(Handle<JSObject> object,
PropertyNormalizationMode mode,
int expected_additional_properties);
void NormalizeElements(Handle<JSObject> object);
void TransformToFastProperties(Handle<JSObject> object,
int unused_property_fields);
void FlattenString(Handle<String> str);
Handle<Object> SetProperty(Handle<JSObject> object,
Handle<String> key,
Handle<Object> value,
PropertyAttributes attributes);
Handle<Object> SetProperty(Handle<Object> object,
Handle<Object> key,
Handle<Object> value,
PropertyAttributes attributes);
Handle<Object> ForceSetProperty(Handle<JSObject> object,
Handle<Object> key,
Handle<Object> value,
PropertyAttributes attributes);
Handle<Object> SetNormalizedProperty(Handle<JSObject> object,
Handle<String> key,
Handle<Object> value,
PropertyDetails details);
Handle<Object> ForceDeleteProperty(Handle<JSObject> object,
Handle<Object> key);
Handle<Object> IgnoreAttributesAndSetLocalProperty(Handle<JSObject> object,
Handle<String> key,
Handle<Object> value,
PropertyAttributes attributes);
Handle<Object> SetPropertyWithInterceptor(Handle<JSObject> object,
Handle<String> key,
Handle<Object> value,
PropertyAttributes attributes);
Handle<Object> SetElement(Handle<JSObject> object,
uint32_t index,
Handle<Object> value);
Handle<Object> GetProperty(Handle<JSObject> obj,
const char* name);
Handle<Object> GetProperty(Handle<Object> obj,
Handle<Object> key);
Handle<Object> GetPropertyWithInterceptor(Handle<JSObject> receiver,
Handle<JSObject> holder,
Handle<String> name,
PropertyAttributes* attributes);
Handle<Object> GetPrototype(Handle<Object> obj);
Handle<Object> SetPrototype(Handle<JSObject> obj, Handle<Object> value);
// Return the object's hidden properties object. If the object has no hidden
// properties and create_if_needed is true, then a new hidden property object
// will be allocated. Otherwise the Heap::undefined_value is returned.
Handle<Object> GetHiddenProperties(Handle<JSObject> obj, bool create_if_needed);
Handle<Object> DeleteElement(Handle<JSObject> obj, uint32_t index);
Handle<Object> DeleteProperty(Handle<JSObject> obj, Handle<String> prop);
Handle<Object> LookupSingleCharacterStringFromCode(uint32_t index);
Handle<JSObject> Copy(Handle<JSObject> obj);
Handle<FixedArray> AddKeysFromJSArray(Handle<FixedArray>,
Handle<JSArray> array);
// Get the JS object corresponding to the given script; create it
// if none exists.
Handle<JSValue> GetScriptWrapper(Handle<Script> script);
// Script line number computations.
void InitScriptLineEnds(Handle<Script> script);
int GetScriptLineNumber(Handle<Script> script, int code_position);
// Computes the enumerable keys from interceptors. Used for debug mirrors and
// by GetKeysInFixedArrayFor below.
v8::Handle<v8::Array> GetKeysForNamedInterceptor(Handle<JSObject> receiver,
Handle<JSObject> object);
v8::Handle<v8::Array> GetKeysForIndexedInterceptor(Handle<JSObject> receiver,
Handle<JSObject> object);
enum KeyCollectionType { LOCAL_ONLY, INCLUDE_PROTOS };
// Computes the enumerable keys for a JSObject. Used for implementing
// "for (n in object) { }".
Handle<FixedArray> GetKeysInFixedArrayFor(Handle<JSObject> object,
KeyCollectionType type);
Handle<JSArray> GetKeysFor(Handle<JSObject> object);
Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object,
bool cache_result);
// Computes the union of keys and return the result.
// Used for implementing "for (n in object) { }"
Handle<FixedArray> UnionOfKeys(Handle<FixedArray> first,
Handle<FixedArray> second);
Handle<String> SubString(Handle<String> str, int start, int end);
// Sets the expected number of properties for the function's instances.
void SetExpectedNofProperties(Handle<JSFunction> func, int nof);
// Sets the prototype property for a function instance.
void SetPrototypeProperty(Handle<JSFunction> func, Handle<JSObject> value);
// Sets the expected number of properties based on estimate from compiler.
void SetExpectedNofPropertiesFromEstimate(Handle<SharedFunctionInfo> shared,
int estimate);
void SetExpectedNofPropertiesFromEstimate(Handle<JSFunction> func,
int estimate);
Handle<JSGlobalProxy> ReinitializeJSGlobalProxy(
Handle<JSFunction> constructor,
Handle<JSGlobalProxy> global);
Handle<Object> SetPrototype(Handle<JSFunction> function,
Handle<Object> prototype);
// Does lazy compilation of the given function. Returns true on success and
// false if the compilation resulted in a stack overflow.
enum ClearExceptionFlag { KEEP_EXCEPTION, CLEAR_EXCEPTION };
bool EnsureCompiled(Handle<SharedFunctionInfo> shared,
ClearExceptionFlag flag);
bool CompileLazyShared(Handle<SharedFunctionInfo> shared,
ClearExceptionFlag flag);
bool CompileLazy(Handle<JSFunction> function,
Handle<Object> receiver,
ClearExceptionFlag flag);
bool CompileLazyInLoop(Handle<JSFunction> function,
Handle<Object> receiver,
ClearExceptionFlag flag);
// Returns the lazy compilation stub for argc arguments.
Handle<Code> ComputeLazyCompile(int argc);
class NoHandleAllocation BASE_EMBEDDED {
public:
#ifndef DEBUG
NoHandleAllocation() {}
~NoHandleAllocation() {}
#else
inline NoHandleAllocation();
inline ~NoHandleAllocation();
private:
int extensions_;
#endif
};
// ----------------------------------------------------------------------------
// Stack allocated wrapper call for optimizing adding multiple
// properties to an object.
class OptimizedObjectForAddingMultipleProperties BASE_EMBEDDED {
public:
OptimizedObjectForAddingMultipleProperties(Handle<JSObject> object,
int expected_property_count,
bool condition = true);
~OptimizedObjectForAddingMultipleProperties();
private:
bool has_been_transformed_; // Tells whether the object has been transformed.
int unused_property_fields_; // Captures the unused number of field.
Handle<JSObject> object_; // The object being optimized.
};
} } // namespace v8::internal
#endif // V8_HANDLES_H_