import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

dom/bindings/IterableIterator.h

@@ -0,0 +1,204 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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