PlzNavigate: AppCache support.

content/browser/appcache/appcache_frame_node_navigation.cc

+// 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 "content/browser/appcache/appcache_frame_node_navigation.h"
+
+#include <map>
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/lazy_instance.h"
+#include "content/browser/appcache/appcache_dispatcher_host.h"
+#include "content/browser/appcache/chrome_appcache_service.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/common/browser_side_navigation_policy.h"
+
+namespace {
+
+typedef std::map<int, content::AppCacheFrameNavigationHandler*>
+    FrameToNavigationHandlerMap;
+base::LazyInstance<FrameToNavigationHandlerMap> g_frame_navigation_handler_map;
+
+// PlzNavigate: Used to generate the host id for a navigation initiated by the
+// browser. Starts at -2 and keeps going down.
+static int g_next_appcache_host_id = -2;
+
+}  // namespace
+
+namespace content {
+
+AppCacheFrameNavigationHandler::AppCacheFrameNavigationHandler(
+    ChromeAppCacheService* appcache_service,
+    int frame_node_id)
+    : frame_node_id_(frame_node_id),
+      appcache_service_(appcache_service),
+      frontend_proxy_(this),
+      commit_received_(false),
+      weak_factory_(this) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  AddRef();
+  g_frame_navigation_handler_map.Get()[frame_node_id] = this;
+}
+
+AppCacheFrameNavigationHandler::~AppCacheFrameNavigationHandler() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+}
+
+// static
+int AppCacheFrameNavigationHandler::BeginNavigation(
+    AppCacheServiceImpl* appcache_service,
+    int frame_node_id) {
+  DCHECK(IsBrowserSideNavigationEnabled());
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  if (!appcache_service)
+    return kAppCacheNoHostId;
+
+  // If we have an existing AppCacheFrameNavigationHandler for the
+  // |frame_node_id| passed in, we have no choice at this point but to
+  // release that instance.
+  // Please note this only happens if the tasks we posted below never
+  // ran.
+  FrameToNavigationHandlerMap::iterator index =
+      g_frame_navigation_handler_map.Get().find(frame_node_id);
+  if (index != g_frame_navigation_handler_map.Get().end()) {
+    if (!index->second->commit_received_)
+      index->second->Release();
+  }
+
+  AppCacheFrameNavigationHandler* navigation_handler =
+      new AppCacheFrameNavigationHandler(
+          static_cast<ChromeAppCacheService*>(appcache_service), frame_node_id);
+  g_frame_navigation_handler_map.Get()[frame_node_id] = navigation_handler;
+
+  int host_id = g_next_appcache_host_id--;
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&AppCacheFrameNavigationHandler::RegisterPendingHostHelper,
+                 navigation_handler->weak_factory_.GetWeakPtr(), host_id));
+
+  return host_id;
+}
+
+// static
+void AppCacheFrameNavigationHandler::CommitNavigation(int frame_node_id,
+                                                      int process_id) {
+  DCHECK(IsBrowserSideNavigationEnabled());
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  DCHECK(g_frame_navigation_handler_map.Get().find(frame_node_id) !=
+         g_frame_navigation_handler_map.Get().end());
+
+  g_frame_navigation_handler_map.Get()[frame_node_id]->commit_received_ = true;
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&AppCacheFrameNavigationHandler::CommitNavigationHelper,
+                 g_frame_navigation_handler_map.Get()[frame_node_id]
+                     ->weak_factory_.GetWeakPtr(),
+                 process_id));
+}
+
+void AppCacheFrameNavigationHandler::FailedNavigation(int frame_node_id) {
+  DCHECK(IsBrowserSideNavigationEnabled());
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+
+  FrameToNavigationHandlerMap::iterator index =
+      g_frame_navigation_handler_map.Get().find(frame_node_id);
+
+  DCHECK(index != g_frame_navigation_handler_map.Get().end());
+
+  index->second->Release();
+}
+
+bool AppCacheFrameNavigationHandler::Send(IPC::Message* msg) {
+  DCHECK(false);
+  return false;
+}
+
+void AppCacheFrameNavigationHandler::RegisterPendingHostHelper(int host_id) {
+  DCHECK(IsBrowserSideNavigationEnabled());
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(!backend_impl_.get());
+  backend_impl_.reset(new AppCacheBackendImpl);
+  backend_impl_->Initialize(appcache_service_.get(), &frontend_proxy_, -1,
+                            frame_node_id_);
+  backend_impl_->RegisterHost(host_id);
+}
+
+void AppCacheFrameNavigationHandler::CommitNavigationHelper(int process_id) {
+  DCHECK(IsBrowserSideNavigationEnabled());
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(backend_impl_.get());
+
+  // When the navigation for a frame tree node commits, we need to switch the
+  // AppCacheBackendImpl instance from a frame based navigation to a process
+  // based navigation. For this we unregister the AppCacheBackendImpl instance
+  // from the AppCache service. We then set the process id in the
+  // AppCacheBackendImpl instance. This ensures that it is registered using
+  // the process id in the AppCacheDispatcherHost::FrameNavigationCommitted()
+  // function.
+  appcache_service_->UnregisterBackendForFrame(backend_impl_.get());
+
+  scoped_refptr<AppCacheDispatcherHost> dispatcher_host =
+      AppCacheDispatcherHost::GetHostForProcess(process_id);
+  if (dispatcher_host.get()) {
+    backend_impl_->set_process_id(process_id);
+    backend_impl_->set_frame_id(-1);
+    dispatcher_host->FrameNavigationCommitted(std::move(backend_impl_));
+  }
+
+  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+                          base::Bind(&AppCacheFrameNavigationHandler::Release,
+                                     base::Unretained(this)));
+  // Don't access any member from here on.
+}
+
+void AppCacheFrameNavigationHandler::DeleteOnCorrectThread() const {
+  if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
+    // The reference to us in the global map needs to be remove in the UI
+    // thread.
+    FrameToNavigationHandlerMap::iterator index =
+        g_frame_navigation_handler_map.Get().find(frame_node_id_);
+    if ((index != g_frame_navigation_handler_map.Get().end()) &&
+        index->second == this) {
+      g_frame_navigation_handler_map.Get().erase(index);
+    }
+  }
+
+  if (BrowserThread::CurrentlyOn(BrowserThread::IO)) {

[michaeln, 2016/11/22 00:17:27]

if we go thru this code path, we do we leave a dangling ptr in the
g_frame_navigation_handler_map?

[ananta, 2016/11/23 04:05:14]

This file has gone

+    delete this;
+    return;
+  }
+
+  if (BrowserThread::IsMessageLoopValid(BrowserThread::IO)) {
+    BrowserThread::DeleteSoon(BrowserThread::IO, FROM_HERE, this);
+    return;
+  }
+
+  // Better to leak than crash on shutdown.
+}
+
+}  // namespace content