Commit 47e32d03 authored by dcarney@chromium.org's avatar dcarney@chromium.org

Add EscapableHandleScope to api to fix problems with HandleScope::Close

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/24245005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16965 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
parent a57300fb
......@@ -135,6 +135,7 @@ class DeclaredAccessorDescriptor;
class ObjectOperationDescriptor;
class RawOperationDescriptor;
class CallHandlerHelper;
class EscapableHandleScope;
namespace internal {
class Arguments;
......@@ -401,6 +402,7 @@ template <class T> class Local : public Handle<T> {
friend class Context;
template<class F> friend class internal::CustomArguments;
friend class HandleScope;
friend class EscapableHandleScope;
V8_INLINE static Local<T> New(Isolate* isolate, T* that);
};
......@@ -773,10 +775,7 @@ class V8_EXPORT HandleScope {
~HandleScope();
/**
* Closes the handle scope and returns the value as a handle in the
* previous scope, which is the new current scope after the call.
*/
// TODO(dcarney): deprecated - use EscapableHandleScope::Escape.
template <class T> Local<T> Close(Handle<T> value);
/**
......@@ -794,6 +793,9 @@ class V8_EXPORT HandleScope {
static internal::Object** CreateHandle(internal::HeapObject* value);
private:
V8_INLINE HandleScope() {}
void Initialize(Isolate* isolate);
// Make it hard to create heap-allocated or illegal handle scopes by
// disallowing certain operations.
HandleScope(const HandleScope&);
......@@ -814,19 +816,47 @@ class V8_EXPORT HandleScope {
}
};
void Initialize(Isolate* isolate);
void Leave();
internal::Isolate* isolate_;
internal::Object** prev_next_;
internal::Object** prev_limit_;
// TODO(dcarney): remove this field
// Allow for the active closing of HandleScopes which allows to pass a handle
// from the HandleScope being closed to the next top most HandleScope.
bool is_closed_;
internal::Object** RawClose(internal::Object** value);
friend class ImplementationUtilities;
friend class EscapableHandleScope;
};
/**
* A HandleScope which first allocates a handle in the current scope
* which will be later filled with the escape value.
*/
class V8_EXPORT EscapableHandleScope : public HandleScope {
public:
EscapableHandleScope(Isolate* isolate);
V8_INLINE ~EscapableHandleScope() {}
/**
* Pushes the value into the previous scope and returns a handle to it.
* Cannot be called twice.
*/
template <class T>
V8_INLINE Local<T> Escape(Local<T> value) {
internal::Object** slot =
Escape(reinterpret_cast<internal::Object**>(*value));
return Local<T>(reinterpret_cast<T*>(slot));
}
private:
internal::Object** Escape(internal::Object** escape_value);
internal::Object** escape_slot_;
};
......
......@@ -701,6 +701,26 @@ i::Object** HandleScope::CreateHandle(i::HeapObject* value) {
}
EscapableHandleScope::EscapableHandleScope(Isolate* v8_isolate) {
i::Isolate* isolate = reinterpret_cast<i::Isolate*>(v8_isolate);
escape_slot_ = CreateHandle(isolate, isolate->heap()->the_hole_value());
Initialize(v8_isolate);
}
i::Object** EscapableHandleScope::Escape(i::Object** escape_value) {
ApiCheck(*escape_slot_ == isolate_->heap()->the_hole_value(),
"EscapeableHandleScope::Escape",
"Escape value set twice");
if (escape_value == NULL) {
*escape_slot_ = isolate_->heap()->undefined_value();
return NULL;
}
*escape_slot_ = *escape_value;
return escape_slot_;
}
void Context::Enter() {
i::Handle<i::Context> env = Utils::OpenHandle(this);
i::Isolate* isolate = env->GetIsolate();
......
......@@ -20593,3 +20593,24 @@ THREADED_TEST(FunctionNew) {
CHECK_EQ(v8::Integer::New(17, isolate), result2);
}
TEST(EscapeableHandleScope) {
HandleScope outer_scope(CcTest::isolate());
LocalContext context;
const int runs = 10;
Local<String> values[runs];
for (int i = 0; i < runs; i++) {
v8::EscapableHandleScope inner_scope(CcTest::isolate());
Local<String> value;
if (i != 0) value = v8_str("escape value");
values[i] = inner_scope.Escape(value);
}
for (int i = 0; i < runs; i++) {
Local<String> expected;
if (i != 0) {
CHECK_EQ(v8_str("escape value"), values[i]);
} else {
CHECK(values[i].IsEmpty());
}
}
}
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