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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/**
* The IterableIterator class is used for WebIDL interfaces that have a
* iterable<> member defined with two types (so a pair iterator). It handles
* the ES6 Iterator-like functions that are generated for the iterable
* interface.
*
* For iterable interfaces with a pair iterator, the implementation class will
* need to implement these two functions:
*
* - size_t GetIterableLength()
* - Returns the number of elements available to iterate over
* - [type] GetValueAtIndex(size_t index)
* - Returns the value at the requested index.
* - [type] GetKeyAtIndex(size_t index)
* - Returns the key at the requested index
*
* Examples of iterable interface implementations can be found in the bindings
* test directory.
*/
#ifndef mozilla_dom_IterableIterator_h
#define mozilla_dom_IterableIterator_h
#include "nsISupports.h"
#include "nsWrapperCache.h"
#include "nsPIDOMWindow.h"
#include "nsCOMPtr.h"
#include "mozilla/dom/ToJSValue.h"
#include "jswrapper.h"
#include "mozilla/dom/IterableIteratorBinding.h"
namespace mozilla {
namespace dom {
class IterableIteratorBase : public nsISupports
{
public:
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_CLASS(IterableIteratorBase)
typedef enum {
Keys = 0,
Values,
Entries
} IterableIteratorType;
IterableIteratorBase() {}
protected:
virtual ~IterableIteratorBase() {}
virtual void UnlinkHelper() = 0;
virtual void TraverseHelper(nsCycleCollectionTraversalCallback& cb) = 0;
};
template <typename T>
class IterableIterator final : public IterableIteratorBase
{
public:
typedef bool (*WrapFunc)(JSContext* aCx,
IterableIterator<T>* aObject,
JS::Handle<JSObject*> aGivenProto,
JS::MutableHandle<JSObject*> aReflector);
explicit IterableIterator(T* aIterableObj,
IterableIteratorType aIteratorType,
WrapFunc aWrapFunc)
: mIterableObj(aIterableObj)
, mIteratorType(aIteratorType)
, mWrapFunc(aWrapFunc)
, mIndex(0)
{
MOZ_ASSERT(mIterableObj);
MOZ_ASSERT(mWrapFunc);
}
void
Next(JSContext* aCx, JS::MutableHandle<JSObject*> aResult, ErrorResult& aRv)
{
JS::Rooted<JS::Value> value(aCx, JS::UndefinedValue());
if (mIndex >= this->mIterableObj->GetIterableLength()) {
DictReturn(aCx, aResult, true, value, aRv);
return;
}
switch (mIteratorType) {
case IterableIteratorType::Keys:
{
if (!ToJSValue(aCx, this->mIterableObj->GetKeyAtIndex(mIndex), &value)) {
aRv.Throw(NS_ERROR_FAILURE);
return;
}
DictReturn(aCx, aResult, false, value, aRv);
break;
}
case IterableIteratorType::Values:
{
if (!ToJSValue(aCx, this->mIterableObj->GetValueAtIndex(mIndex), &value)) {
aRv.Throw(NS_ERROR_FAILURE);
return;
}
DictReturn(aCx, aResult, false, value, aRv);
break;
}
case IterableIteratorType::Entries:
{
JS::Rooted<JS::Value> key(aCx);
if (!ToJSValue(aCx, this->mIterableObj->GetKeyAtIndex(mIndex), &key)) {
aRv.Throw(NS_ERROR_FAILURE);
return;
}
if (!ToJSValue(aCx, this->mIterableObj->GetValueAtIndex(mIndex), &value)) {
aRv.Throw(NS_ERROR_FAILURE);
return;
}
KeyAndValueReturn(aCx, key, value, aResult, aRv);
break;
}
default:
MOZ_CRASH("Invalid iterator type!");
}
++mIndex;
}
bool
WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto, JS::MutableHandle<JSObject*> aObj)
{
return (*mWrapFunc)(aCx, this, aGivenProto, aObj);
}
protected:
static void
DictReturn(JSContext* aCx, JS::MutableHandle<JSObject*> aResult,
bool aDone, JS::Handle<JS::Value> aValue, ErrorResult& aRv)
{
RootedDictionary<IterableKeyOrValueResult> dict(aCx);
dict.mDone = aDone;
dict.mValue = aValue;
JS::Rooted<JS::Value> dictValue(aCx);
if (!ToJSValue(aCx, dict, &dictValue)) {
aRv.Throw(NS_ERROR_FAILURE);
return;
}
aResult.set(&dictValue.toObject());
}
static void
KeyAndValueReturn(JSContext* aCx, JS::Handle<JS::Value> aKey,
JS::Handle<JS::Value> aValue,
JS::MutableHandle<JSObject*> aResult, ErrorResult& aRv)
{
RootedDictionary<IterableKeyAndValueResult> dict(aCx);
dict.mDone = false;
// Dictionary values are a Sequence, which is a FallibleTArray, so we need
// to check returns when appending.
if (!dict.mValue.AppendElement(aKey, mozilla::fallible)) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
if (!dict.mValue.AppendElement(aValue, mozilla::fallible)) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
JS::Rooted<JS::Value> dictValue(aCx);
if (!ToJSValue(aCx, dict, &dictValue)) {
aRv.Throw(NS_ERROR_FAILURE);
return;
}
aResult.set(&dictValue.toObject());
}
protected:
virtual ~IterableIterator() {}
// Since we're templated on a binding, we need to possibly CC it, but can't do
// that through macros. So it happens here.
virtual void UnlinkHelper() final
{
mIterableObj = nullptr;
}
virtual void TraverseHelper(nsCycleCollectionTraversalCallback& cb) override
{
IterableIterator<T>* tmp = this;
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mIterableObj);
}
// Binding Implementation object that we're iterating over.
RefPtr<T> mIterableObj;
// Tells whether this is a key, value, or entries iterator.
IterableIteratorType mIteratorType;
// Function pointer to binding-type-specific Wrap() call for this iterator.
WrapFunc mWrapFunc;
// Current index of iteration.
uint32_t mIndex;
};
} // namespace dom
} // namespace mozilla
#endif // mozilla_dom_IterableIterator_h
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