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// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/runtime/runtime-utils.h"
#include "src/arguments.h"
#include "src/factory.h"
#include "src/isolate-inl.h"
#include "src/objects-inl.h"
namespace v8 {
namespace internal {
namespace {
// Returns either a FixedArray or, if the given {receiver} has an enum cache
// that contains all enumerable properties of the {receiver} and its prototypes
// have none, the map of the {receiver}. This is used to speed up the check for
// deletions during a for-in.
MaybeHandle<HeapObject> Enumerate(Handle<JSReceiver> receiver) {
Isolate* const isolate = receiver->GetIsolate();
// Test if we have an enum cache for {receiver}.
if (!receiver->IsSimpleEnum()) {
Handle<FixedArray> keys;
ASSIGN_RETURN_ON_EXCEPTION(
isolate, keys,
JSReceiver::GetKeys(receiver, INCLUDE_PROTOS, ENUMERABLE_STRINGS),
HeapObject);
// Test again, since cache may have been built by GetKeys() calls above.
if (!receiver->IsSimpleEnum()) return keys;
}
return handle(receiver->map(), isolate);
}
MaybeHandle<Object> Filter(Handle<JSReceiver> receiver, Handle<Object> key) {
Isolate* const isolate = receiver->GetIsolate();
// TODO(turbofan): Fast case for array indices.
Handle<Name> name;
ASSIGN_RETURN_ON_EXCEPTION(isolate, name, Object::ToName(isolate, key),
Object);
Maybe<bool> result = JSReceiver::HasProperty(receiver, name);
MAYBE_RETURN_NULL(result);
if (result.FromJust()) return name;
return isolate->factory()->undefined_value();
}
} // namespace
RUNTIME_FUNCTION(Runtime_ForInEnumerate) {
HandleScope scope(isolate);
DCHECK_EQ(1, args.length());
CONVERT_ARG_HANDLE_CHECKED(JSReceiver, receiver, 0);
Handle<HeapObject> result;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, Enumerate(receiver));
return *result;
}
RUNTIME_FUNCTION_RETURN_TRIPLE(Runtime_ForInPrepare) {
HandleScope scope(isolate);
DCHECK_EQ(1, args.length());
Handle<JSReceiver> receiver = args.at<JSReceiver>(0);
Handle<Object> cache_type;
if (!Enumerate(receiver).ToHandle(&cache_type)) {
return MakeTriple(isolate->heap()->exception(), nullptr, nullptr);
}
Handle<FixedArray> cache_array;
int cache_length;
if (cache_type->IsMap()) {
Handle<Map> cache_map = Handle<Map>::cast(cache_type);
Handle<DescriptorArray> descriptors(cache_map->instance_descriptors(),
isolate);
cache_length = cache_map->EnumLength();
if (cache_length && descriptors->HasEnumCache()) {
cache_array = handle(descriptors->GetEnumCache(), isolate);
} else {
cache_array = isolate->factory()->empty_fixed_array();
cache_length = 0;
}
} else {
cache_array = Handle<FixedArray>::cast(cache_type);
cache_length = cache_array->length();
cache_type = handle(Smi::FromInt(1), isolate);
}
return MakeTriple(*cache_type, *cache_array, Smi::FromInt(cache_length));
}
RUNTIME_FUNCTION(Runtime_ForInDone) {
SealHandleScope scope(isolate);
DCHECK_EQ(2, args.length());
CONVERT_SMI_ARG_CHECKED(index, 0);
CONVERT_SMI_ARG_CHECKED(length, 1);
DCHECK_LE(0, index);
DCHECK_LE(index, length);
return isolate->heap()->ToBoolean(index == length);
}
RUNTIME_FUNCTION(Runtime_ForInFilter) {
HandleScope scope(isolate);
DCHECK_EQ(2, args.length());
CONVERT_ARG_HANDLE_CHECKED(JSReceiver, receiver, 0);
CONVERT_ARG_HANDLE_CHECKED(Object, key, 1);
Handle<Object> result;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, Filter(receiver, key));
return *result;
}
RUNTIME_FUNCTION(Runtime_ForInNext) {
HandleScope scope(isolate);
DCHECK_EQ(4, args.length());
CONVERT_ARG_HANDLE_CHECKED(JSReceiver, receiver, 0);
CONVERT_ARG_HANDLE_CHECKED(FixedArray, cache_array, 1);
CONVERT_ARG_HANDLE_CHECKED(Object, cache_type, 2);
CONVERT_SMI_ARG_CHECKED(index, 3);
Handle<Object> key = handle(cache_array->get(index), isolate);
// Don't need filtering if expected map still matches that of the receiver.
if (receiver->map() == *cache_type) {
return *key;
}
Handle<Object> result;
ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, Filter(receiver, key));
return *result;
}
RUNTIME_FUNCTION(Runtime_ForInStep) {
SealHandleScope scope(isolate);
DCHECK_EQ(1, args.length());
CONVERT_SMI_ARG_CHECKED(index, 0);
DCHECK_LE(0, index);
DCHECK_LT(index, Smi::kMaxValue);
return Smi::FromInt(index + 1);
}
} // namespace internal
} // namespace v8
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