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// Copyright 2011 the V8 project authors. All rights reserved.
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// 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.
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// contributors may be used to endorse or promote products derived
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//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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#ifndef V8_HANDLES_H_
#define V8_HANDLES_H_
#include "allocation.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<typename T>
class Handle {
public:
INLINE(explicit Handle(T** location)) { location_ = location; }
INLINE(explicit Handle(T* obj));
INLINE(Handle(T* obj, Isolate* isolate));
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() const { 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_;
};
class HandleScopeImplementer;
// 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:
inline HandleScope();
explicit inline HandleScope(Isolate* isolate);
inline ~HandleScope();
// 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, Isolate* isolate);
// Deallocates any extensions used by the current scope.
static void DeleteExtensions(Isolate* isolate);
static Address current_next_address();
static Address current_limit_address();
static Address current_level_address();
// Closes the HandleScope (invalidating all handles
// created in the scope of the HandleScope) and returns
// a Handle backed by the parent scope holding the
// value of the argument handle.
template <typename T>
Handle<T> CloseAndEscape(Handle<T> handle_value);
Isolate* isolate() { return isolate_; }
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);
inline void CloseScope();
Isolate* isolate_;
Object** prev_next_;
Object** prev_limit_;
// 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::internal::HandleScopeImplementer;
friend class v8::ImplementationUtilities;
};
class DeferredHandles;
class DeferredHandleScope {
public:
explicit DeferredHandleScope(Isolate* isolate);
// The DeferredHandles object returned stores the Handles created
// since the creation of this DeferredHandleScope. The Handles are
// alive as long as the DeferredHandles object is alive.
DeferredHandles* Detach();
~DeferredHandleScope();
private:
Object** prev_limit_;
Object** prev_next_;
HandleScopeImplementer* impl_;
#ifdef DEBUG
bool handles_detached_;
int prev_level_;
#endif
friend class HandleScopeImplementer;
};
// ----------------------------------------------------------------------------
// 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.
// Flattens a string.
void FlattenString(Handle<String> str);
// Flattens a string and returns the underlying external or sequential
// string.
Handle<String> FlattenGetString(Handle<String> str);
int Utf8Length(Handle<String> str);
Handle<Object> SetProperty(Handle<Object> object,
Handle<Object> key,
Handle<Object> value,
PropertyAttributes attributes,
StrictModeFlag strict_mode);
Handle<Object> ForceSetProperty(Handle<JSObject> object,
Handle<Object> key,
Handle<Object> value,
PropertyAttributes attributes);
Handle<Object> ForceDeleteProperty(Handle<JSObject> object,
Handle<Object> key);
Handle<Object> GetProperty(Handle<JSReceiver> 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> SetPrototype(Handle<JSObject> obj, Handle<Object> value);
Handle<Object> LookupSingleCharacterStringFromCode(uint32_t index);
Handle<JSObject> Copy(Handle<JSObject> obj);
Handle<Object> SetAccessor(Handle<JSObject> obj, Handle<AccessorInfo> info);
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. Note that the line number is zero-based.
void InitScriptLineEnds(Handle<Script> script);
// For string calculates an array of line end positions. If the string
// does not end with a new line character, this character may optionally be
// imagined.
Handle<FixedArray> CalculateLineEnds(Handle<String> string,
bool with_imaginary_last_new_line);
int GetScriptLineNumber(Handle<Script> script, int code_position);
// The safe version does not make heap allocations but may work much slower.
int GetScriptLineNumberSafe(Handle<Script> script, int code_position);
int GetScriptColumnNumber(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<JSReceiver> receiver,
Handle<JSObject> object);
v8::Handle<v8::Array> GetKeysForIndexedInterceptor(Handle<JSReceiver> 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<JSReceiver> object,
KeyCollectionType type,
bool* threw);
Handle<JSArray> GetKeysFor(Handle<JSReceiver> object, bool* threw);
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,
PretenureFlag pretenure = NOT_TENURED);
// 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);
Handle<JSGlobalProxy> ReinitializeJSGlobalProxy(
Handle<JSFunction> constructor,
Handle<JSGlobalProxy> global);
Handle<Object> SetPrototype(Handle<JSFunction> function,
Handle<Object> prototype);
Handle<ObjectHashSet> ObjectHashSetAdd(Handle<ObjectHashSet> table,
Handle<Object> key);
Handle<ObjectHashSet> ObjectHashSetRemove(Handle<ObjectHashSet> table,
Handle<Object> key);
Handle<ObjectHashTable> PutIntoObjectHashTable(Handle<ObjectHashTable> table,
Handle<Object> key,
Handle<Object> value);
class NoHandleAllocation BASE_EMBEDDED {
public:
#ifndef DEBUG
NoHandleAllocation() {}
~NoHandleAllocation() {}
#else
inline NoHandleAllocation();
inline ~NoHandleAllocation();
private:
int level_;
#endif
};
} } // namespace v8::internal
#endif // V8_HANDLES_H_