compositor-worker: Introduce CompositorProxy.

Source/core/dom/CompositorProxy.cpp

+// Copyright 2015 The Chromium 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 "config.h"
+#include "core/dom/CompositorProxy.h"
+
+#include "bindings/core/v8/ExceptionMessages.h"
+#include "bindings/core/v8/ExceptionState.h"
+#include "core/dom/ExecutionContext.h"
+
+namespace blink {
+
+typedef WTF::HashMap<uint64_t, Element*> ElementMap;
+static ElementMap* gElementMap = 0;
+
+typedef WTF::HashMap<Element*, uint64_t> ElementIdMap;
+static ElementIdMap* gElementIdMap = 0;
+
+static uint64_t nextCompositorProxyId()
+{
+    static uint64_t s_nextId = 0;
+    return ++s_nextId;
+}
+
+static uint64_t compositorProxyIdForElement(Element* element)
+{
+    ASSERT(gElementIdMap);
+    if (!gElementIdMap->contains(element))
+        gElementIdMap->add(element, nextCompositorProxyId());
+    return gElementIdMap->get(element);
+}
+
+static struct {
+    const char* name;
+    CompositorProxy::Attributes attribute;
+} allowedAttributes[] = {
+    { "opacity", CompositorProxy::Attributes::OPACITY },
+    { "scrolltop", CompositorProxy::Attributes::SCROLL_TOP },
+    { "touch", CompositorProxy::Attributes::TOUCH },
+    { "transform", CompositorProxy::Attributes::TRANSFORM },
+};
+
+CompositorProxy* CompositorProxy::create(ExecutionContext* context, Element* element, Vector<String>& attributeArray, ExceptionState& exceptionState)
+{
+    if (!context->isDocument()) {
+        exceptionState.throwTypeError(ExceptionMessages::failedToConstruct("CompositorProxy", "Can only be created from the main context."));
+        exceptionState.throwIfNeeded();
+        return nullptr;
+    }
+
+    uint32_t attributeFlags = 0;
+    for (const auto& attribute : attributeArray) {
+        Attributes currentAttribute = Attributes::NONE;
+        for (unsigned i = 0; i < arraysize(allowedAttributes); ++i) {
+            if (attribute.lower() == allowedAttributes[i].name) {
+                currentAttribute = allowedAttributes[i].attribute;
+            }
+        }
+        if (currentAttribute == Attributes::NONE) {
+            exceptionState.throwTypeError("Unknown attribute'" + attribute + "'");
+            exceptionState.throwIfNeeded();
+            return nullptr;
+        }
+        attributeFlags |= static_cast<uint32_t>(currentAttribute);
+    }
+
+    ASSERT(attributeFlags);
+    if (!gElementMap) {
+        ASSERT(!gElementIdMap);
+        gElementMap = new ElementMap;
+        gElementIdMap = new ElementIdMap;
+    } else {
+        ASSERT(gElementIdMap);
+    }
+    return new CompositorProxy(element, attributeFlags);
+}
+
+CompositorProxy* CompositorProxy::create(uint64_t elementId, uint32_t attributeFlags)
+{
+    ASSERT(!isMainThread());
+#ifndef NDEBUG
+    uint32_t sanityCheckAttributes = attributeFlags;
+    for (unsigned i = 0; i < arraysize(allowedAttributes); ++i) {
+        sanityCheckAttributes &= ~static_cast<uint32_t>(allowedAttributes[i].attribute);
+    }
+    ASSERT(!sanityCheckAttributes);
+#endif
+    return new CompositorProxy(elementId, attributeFlags);
+}
+
+CompositorProxy::CompositorProxy(Element* element, uint32_t attributeFlags)
+    : m_elementId(compositorProxyIdForElement(element))
+    , m_attributes(attributeFlags)
+{
+    ASSERT(isMainThread());
+    ASSERT(gElementMap);
+    gElementMap->add(m_elementId, element);
+}
+
+CompositorProxy::CompositorProxy(uint64_t elementId, uint32_t attributeFlags)
+    : m_elementId(elementId)
+    , m_attributes(attributeFlags)
+{
+}
+
+CompositorProxy::~CompositorProxy()
+{
+}
+
+void CompositorProxy::notifyElementGone(Element* element)
+{
+    ASSERT(isMainThread());
+    if (!gElementMap)
+        return;
+
+    gElementMap->remove(gElementIdMap->take(element));
+}
+
+} // namespace blink