Implement the infrastructure of creating WorkerFetchContext in worker global scope.

third_party/WebKit/Source/core/loader/WorkerFetchContext.cpp

+// Copyright 2017 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 "core/loader/WorkerFetchContext.h"
+
+#include "core/workers/WorkerGlobalScope.h"
+#include "platform/exported/WrappedResourceRequest.h"
+#include "public/platform/Platform.h"
+#include "public/platform/WebScheduler.h"
+#include "public/platform/WebThread.h"
+#include "public/platform/WebWorkerFetchContext.h"
+
+namespace blink {
+
+namespace {
+
+class WorkerFetchContextInfo final
+    : public GarbageCollectedFinalized<WorkerFetchContextInfo>,
+      public Supplement<WorkerClients> {
+  USING_GARBAGE_COLLECTED_MIXIN(WorkerFetchContextInfo);
+
+ public:
+  static WorkerFetchContextInfo* From(WorkerClients& clients) {
+    return static_cast<WorkerFetchContextInfo*>(
+        Supplement<WorkerClients>::From(clients, SupplementName()));
+  }
+  static const char* SupplementName() { return "WorkerFetchContextInfo"; }
+
+  explicit WorkerFetchContextInfo(
+      std::unique_ptr<WebWorkerFetchContextInfo> info)
+      : info_(std::move(info)) {}
+  virtual ~WorkerFetchContextInfo() {}
+
+  std::unique_ptr<WebWorkerFetchContext> CreateContext() {
+    DCHECK(info_);
+    DCHECK(!IsMainThread());
+    std::unique_ptr<WebWorkerFetchContext> webContext =
+        info_->CreateContext(Platform::Current()
+                                 ->CurrentThread()
+                                 ->Scheduler()
+                                 ->LoadingTaskRunner()
+                                 ->ToSingleThreadTaskRunner());

[nhiroki, 2017/04/14 04:09:24]

FYI: CurrentThread()->Scheduler()->LoadingTaskRunner() is not encouraged after
the per-global-scope scheduler is landed[1]. This should be replaced with...

  TaskRunnerHelper::Get(TaskType::kUnspecedLoading,
global_scope)->ToSingleThreadTaskRunner();

[1] https://codereview.chromium.org/2806623004/

[horo, 2017/04/14 07:22:45]

Acknowledged.
Thank you for letting me know.

+    info_.reset();
+    return webContext;
+  }
+
+  DEFINE_INLINE_VIRTUAL_TRACE() { Supplement<WorkerClients>::Trace(visitor); }
+
+ private:
+  std::unique_ptr<WebWorkerFetchContextInfo> info_;
+};
+
+class WorkerContextSupplement final
+    : public GarbageCollectedFinalized<WorkerContextSupplement>,
+      public Supplement<ExecutionContext> {
+  USING_GARBAGE_COLLECTED_MIXIN(WorkerContextSupplement);
+
+ public:
+  static WorkerContextSupplement* From(ExecutionContext& execution_context) {

[nhiroki, 2017/04/14 04:09:24]

Since ExecutionContext must not be accessed from the non-context thread, can you
add DCHECK(execution_context->IsContextThread()); here?

[horo, 2017/04/14 07:22:45]

Done.

+    if (!execution_context.IsWorkerGlobalScope())
+      return nullptr;
+    WorkerContextSupplement* supplement = static_cast<WorkerContextSupplement*>(
+        Supplement<ExecutionContext>::From(execution_context,
+                                           SupplementName()));
+    if (supplement)
+      return supplement;
+    WorkerClients* clients = ToWorkerGlobalScope(execution_context).Clients();
+    if (!clients)
+      return nullptr;
+    WorkerFetchContextInfo* context_info =
+        WorkerFetchContextInfo::From(*clients);
+    if (!context_info)
+      return nullptr;
+    WorkerFetchContext* worker_fetch_context =
+        new WorkerFetchContext(context_info->CreateContext());
+    supplement = new WorkerContextSupplement(worker_fetch_context);
+    Supplement<ExecutionContext>::ProvideTo(execution_context, SupplementName(),
+                                            supplement);
+    return supplement;
+  }
+  WorkerFetchContext* GetContext() const { return worker_fetch_context_; }
+
+  DEFINE_INLINE_VIRTUAL_TRACE() {
+    visitor->Trace(worker_fetch_context_);
+    Supplement<ExecutionContext>::Trace(visitor);
+  }
+
+ private:
+  explicit WorkerContextSupplement(WorkerFetchContext* workerFetchContext)
+      : worker_fetch_context_(workerFetchContext) {}
+  static const char* SupplementName() { return "WorkerContextSupplement"; }
+  Member<WorkerFetchContext> worker_fetch_context_;
+};
+
+}  // namespace
+
+WorkerFetchContext::~WorkerFetchContext() {}
+
+WorkerFetchContext* WorkerFetchContext::From(
+    ExecutionContext& executionContext) {
+  WorkerContextSupplement* supplement =
+      WorkerContextSupplement::From(executionContext);
+  if (!supplement)
+    return nullptr;
+  return supplement->GetContext();
+}
+
+WorkerFetchContext::WorkerFetchContext(
+    std::unique_ptr<WebWorkerFetchContext> context)
+    : context_(std::move(context)) {}
+
+void WorkerFetchContext::PrepareRequest(ResourceRequest& request,
+                                        RedirectType) {
+  WrappedResourceRequest webreq(request);
+  context_->WillSendRequest(webreq);
+}
+
+WebURLLoader* WorkerFetchContext::CreateURLLoader() {
+  return context_->CreateURLLoader();
+}
+
+bool WorkerFetchContext::IsControlledByServiceWorker() const {
+  return context_->IsControlledByServiceWorker();
+}
+
+void ProvideWorkerFetchContextInfoToWorker(
+    WorkerClients* clients,
+    std::unique_ptr<WebWorkerFetchContextInfo> info) {
+  DCHECK(clients);
+  WorkerFetchContextInfo::ProvideTo(
+      *clients, WorkerFetchContextInfo::SupplementName(),
+      new WorkerFetchContextInfo(std::move(info)));
+}
+
+}  // namespace blink