Add CancelableRequest from Browser

rogerwang · rogerwang · commit dd4b6425d0b0 · 2013-11-17T22:09:58.000+08:00
diff --git a/nw.gypi b/nw.gypi
@@ -156,6 +156,8 @@
         'src/api/window/window.h',
         'src/browser/app_controller_mac.h',
         'src/browser/app_controller_mac.mm',
+        'src/browser/cancelable_request.cc',
+        'src/browser/cancelable_request.h',
         'src/browser/capture_page_helper.h',
         'src/browser/capture_page_helper.cc',
         'src/browser/color_chooser_gtk.cc',
diff --git a/src/browser/cancelable_request.cc b/src/browser/cancelable_request.cc
@@ -0,0 +1,140 @@
+// Copyright (c) 2012 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 "content/nw/src/browser/cancelable_request.h"
+
+CancelableRequestProvider::CancelableRequestProvider()
+    : next_handle_(1) {
+}
+
+CancelableRequestProvider::Handle CancelableRequestProvider::AddRequest(
+    CancelableRequestBase* request,
+    CancelableRequestConsumerBase* consumer) {
+  Handle handle;
+  {
+    base::AutoLock lock(pending_request_lock_);
+
+    handle = next_handle_;
+    pending_requests_[next_handle_] = request;
+    ++next_handle_;
+    DCHECK(next_handle_)
+        << "next_handle_ may have wrapped around to invalid state.";
+  }
+
+  consumer->OnRequestAdded(this, handle);
+
+  request->Init(this, handle, consumer);
+  return handle;
+}
+
+void CancelableRequestProvider::CancelRequest(Handle handle) {
+  base::AutoLock lock(pending_request_lock_);
+  CancelRequestLocked(pending_requests_.find(handle));
+}
+
+CancelableRequestProvider::~CancelableRequestProvider() {
+  // There may be requests whose result callback has not been run yet. We need
+  // to cancel them otherwise they may try and call us back after we've been
+  // deleted, or do other bad things. This can occur on shutdown (or browser
+  // context destruction) when a request is scheduled, completed (but not
+  // dispatched), then the BrowserContext is deleted.
+  base::AutoLock lock(pending_request_lock_);
+  while (!pending_requests_.empty())
+    CancelRequestLocked(pending_requests_.begin());
+}
+
+void CancelableRequestProvider::CancelRequestLocked(
+    const CancelableRequestMap::iterator& item) {
+  pending_request_lock_.AssertAcquired();
+  if (item == pending_requests_.end()) {
+    NOTREACHED() << "Trying to cancel an unknown request";
+    return;
+  }
+
+  item->second->consumer()->OnRequestRemoved(this, item->first);
+  item->second->set_canceled();
+  pending_requests_.erase(item);
+}
+
+void CancelableRequestProvider::RequestCompleted(Handle handle) {
+  CancelableRequestConsumerBase* consumer = NULL;
+  {
+    base::AutoLock lock(pending_request_lock_);
+
+    CancelableRequestMap::iterator i = pending_requests_.find(handle);
+    if (i == pending_requests_.end()) {
+      NOTREACHED() << "Trying to cancel an unknown request";
+      return;
+    }
+    consumer = i->second->consumer();
+
+    // This message should only get sent if the class is not cancelled, or
+    // else the consumer might be gone).
+    DCHECK(!i->second->canceled());
+
+    pending_requests_.erase(i);
+  }
+
+  // Notify the consumer that the request is gone
+  consumer->OnRequestRemoved(this, handle);
+}
+
+// MSVC doesn't like complex extern templates and DLLs.
+#if !defined(COMPILER_MSVC)
+// Emit our most common CancelableRequestConsumer.
+template class CancelableRequestConsumerTSimple<int>;
+
+// And the most common subclass of it.
+template class CancelableRequestConsumerT<int, 0>;
+#endif
+
+CancelableRequestBase::CancelableRequestBase()
+    : provider_(NULL),
+      consumer_(NULL),
+      handle_(0) {
+  callback_thread_ = base::MessageLoop::current();
+}
+
+CancelableRequestBase::~CancelableRequestBase() {
+}
+
+void CancelableRequestBase::Init(CancelableRequestProvider* provider,
+                                 CancelableRequestProvider::Handle handle,
+                                 CancelableRequestConsumerBase* consumer) {
+  DCHECK(handle_ == 0 && provider_ == NULL && consumer_ == NULL);
+  provider_ = provider;
+  consumer_ = consumer;
+  handle_ = handle;
+}
+
+void CancelableRequestBase::DoForward(const base::Closure& forwarded_call,
+                                      bool force_async) {
+  if (force_async || callback_thread_ != base::MessageLoop::current()) {
+    callback_thread_->PostTask(
+        FROM_HERE,
+        base::Bind(&CancelableRequestBase::ExecuteCallback, this,
+                   forwarded_call));
+  } else {
+    // We can do synchronous callbacks when we're on the same thread.
+    ExecuteCallback(forwarded_call);
+  }
+}
+
+void CancelableRequestBase::ExecuteCallback(
+    const base::Closure& forwarded_call) {
+  DCHECK_EQ(callback_thread_, base::MessageLoop::current());
+
+  if (!canceled_.IsSet()) {
+    WillExecute();
+
+    // Execute the callback.
+    forwarded_call.Run();
+  }
+
+  // Notify the provider that the request is complete. The provider will
+  // notify the consumer for us. Note that it is possible for the callback to
+  // cancel this request; we must check canceled again.
+  if (!canceled_.IsSet())
+    NotifyCompleted();
+}
diff --git a/src/browser/cancelable_request.h b/src/browser/cancelable_request.h
