Introduce infrastructure for tracing ScriptWrappables.

third_party/WebKit/Source/bindings/core/v8/ScriptWrappableHeapTracer.cpp

+// Copyright 2016 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 "bindings/core/v8/ScriptWrappableHeapTracer.h"
+
+#include "bindings/core/v8/ActiveScriptWrappable.h"
+#include "bindings/core/v8/DOMDataStore.h"
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "bindings/core/v8/ScriptWrappableVisitor.h"
+#include "bindings/core/v8/WrapperTypeInfo.h"
+#include "platform/heap/HeapPage.h"
+
+namespace blink {
+
+ScriptWrappableHeapTracer::~ScriptWrappableHeapTracer()
+{
+}
+
+void ScriptWrappableHeapTracer::TracePrologue(v8::Isolate* isolate)
+{
+    m_tracingInProgress = true;
+    ScriptWrappableVisitor visitor(isolate, this);
+    ActiveScriptWrappable::traceActiveScriptWrappables(&visitor);
+}
+
+void ScriptWrappableHeapTracer::AddHeaderToUnmark(HeapObjectHeader* header)
+{
+    m_headersToUnmark.append(header);
+}
+
+void ScriptWrappableHeapTracer::TraceEpilogue(v8::Isolate* isolate)
+{
+    for (auto header : m_headersToUnmark)
+        header->unmarkWrapper();
+
+    m_headersToUnmark.clear();
+    m_tracingInProgress = false;
+}
+
+void ScriptWrappableHeapTracer::TraceWrappersFrom(v8::Isolate* isolate, const std::vector<std::pair<void*, void*>>& internalFieldsOfPotentialWrappers)
+{
+    ASSERT(m_tracingInProgress);
+    for (auto pair : internalFieldsOfPotentialWrappers) {
+        TraceWrappersFrom(isolate, pair);
+    }
+}
+
+
+void ScriptWrappableHeapTracer::TraceWrappersFrom(v8::Isolate* isolate, std::pair<void*, void*> internalFields)
+{
+    if (reinterpret_cast<WrapperTypeInfo*>(internalFields.first)->ginEmbedder
+        != gin::GinEmbedder::kEmbedderBlink)
+        return;
+
+    ScriptWrappable* scriptWrappable = reinterpret_cast<ScriptWrappable*>(
+        internalFields.second);
+    uint16_t classId = scriptWrappable->wrapperTypeInfo()->wrapperClassId;
+    if (classId != WrapperTypeInfo::NodeClassId

[haraken, 2016/04/19 04:58:31]

ASSERT(classId == WrapperTypeInfo::NodeClassId || classId -=
WrapperTypeInfo::ObjectClassId);

[Marcel Hlopko, 2016/04/19 12:40:29]

Done.

+        && classId != WrapperTypeInfo::ObjectClassId) {
+        ASSERT_NOT_REACHED();
+        return;
+    }
+
+    ScriptWrappableVisitor visitor(isolate, this);
+    visitor.traceWrappers(scriptWrappable);
+}
+
+void ScriptWrappableHeapTracer::TraceWrappersFrom(v8::Isolate* isolate, v8::Persistent<v8::Object>* handle)

[haraken, 2016/04/19 04:58:31]

Where is this method used?

[Marcel Hlopko, 2016/04/19 12:40:29]

Nowhere, removed.

+{
+    ScriptWrappable* scriptWrappable = toScriptWrappable(*handle);
+    uint16_t classId = scriptWrappable->wrapperTypeInfo()->wrapperClassId;
+    if (classId != WrapperTypeInfo::NodeClassId
+        && classId != WrapperTypeInfo::ObjectClassId) {

[haraken, 2016/04/19 04:58:31]

Ditto.

[Marcel Hlopko, 2016/04/19 12:40:29]

Done.

+        ASSERT_NOT_REACHED();
+        return;
+    }
+
+    ScriptWrappableVisitor visitor(isolate, this);
+    visitor.traceWrappers(scriptWrappable);
+}
+
+void ScriptWrappableHeapTracer::markWrapper(const v8::Persistent<v8::Object>& handle, v8::Isolate* isolate)
+{
+    handle.RegisterExternalReference(isolate);
+}
+
+void ScriptWrappableHeapTracer::markWrappersInAllWorlds(const ScriptWrappable* scriptWrappable, v8::Isolate* isolate)
+{
+    DOMWrapperWorld::markWrappersInAllWorlds(
+        const_cast<ScriptWrappable*>(scriptWrappable), isolate);
+}
+
+}
+