Remote assistance on Chrome OS Part IV - It2MeHost

remoting/host/remoting_me2me_host.cc

 // 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.
 //
 // This file implements a standalone host process for Me2Me.
 
 #include <string>
 
 #include "base/at_exit.h"
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/debug/alias.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
 #include "build/build_config.h"
 #include "crypto/nss_util.h"
 #include "ipc/ipc_channel.h"
 #include "ipc/ipc_channel_proxy.h"
 #include "ipc/ipc_listener.h"
 #include "media/base/media.h"
 #include "net/base/network_change_notifier.h"
 #include "net/socket/client_socket_factory.h"
 #include "net/socket/ssl_server_socket.h"
@@ skipping 220 matching lines @@
 
   void RestartHost();
 
   // Stops the host and shuts down the process with the specified |exit_code|.
   void ShutdownHost(HostExitCodes exit_code);
 
   void ScheduleHostShutdown();
 
   void ShutdownOnNetworkThread();
 
+  void PostPolicyWatcherShutdown();
+
   // Crashes the process in response to a daemon's request. The daemon passes
   // the location of the code that detected the fatal error resulted in this
   // request.
   void OnCrash(const std::string& function_name,
                const std::string& file_name,
                const int& line_number);
 
   scoped_ptr<ChromotingHostContext> context_;
 
   // Created on the UI thread but used from the network thread.
@@ skipping 96 matching lines @@
       exit_code_out_(exit_code_out),
       signal_parent_(false) {
   StartOnUiThread();
 }
 
 HostProcess::~HostProcess() {
   // Verify that UI components have been torn down.
   DCHECK(!config_watcher_);
   DCHECK(!daemon_channel_);
   DCHECK(!desktop_environment_factory_);
-
-  // We might be getting deleted on one of the threads the |host_context| owns,
-  // so we need to post it back to the caller thread to safely join & delete the
-  // threads it contains.  This will go away when we move to AutoThread.
-  // |context_release()| will null |context_| before the method is invoked, so
-  // we need to pull out the task-runner on which to call DeleteSoon first.
-  scoped_refptr<base::SingleThreadTaskRunner> task_runner =
-      context_->ui_task_runner();
-  task_runner->DeleteSoon(FROM_HERE, context_.release());

[Jamie, 2014/10/14 01:18:42]

Why has this been deleted?

[kelvinp, 2014/10/15 23:03:10]

Good catch

 }
 
 bool HostProcess::InitWithCommandLine(const base::CommandLine* cmd_line) {
 #if defined(REMOTING_MULTI_PROCESS)
   // Parse the handle value and convert it to a handle/file descriptor.
   std::string channel_name =
       cmd_line->GetSwitchValueASCII(kDaemonPipeSwitchName);
 
   int pipe_handle = 0;
   if (channel_name.empty() ||
@@ skipping 119 matching lines @@
     LOG(ERROR) << "Failed to apply the configuration.";
     ShutdownHost(kInvalidHostConfigurationExitCode);
     return;
   }
 
   if (state_ == HOST_INITIALIZING) {
     // TODO(sergeyu): Currently OnPolicyUpdate() assumes that host config is
     // already loaded so PolicyWatcher has to be started here. Separate policy
     // loading from policy verifications and move |policy_watcher_|
     // initialization to StartOnNetworkThread().
-    policy_watcher_.reset(
-        policy_hack::PolicyWatcher::Create(context_->file_task_runner()));
+    policy_watcher_.reset(policy_hack::PolicyWatcher::Create(
+        context_.get(), context_->file_task_runner()));
     policy_watcher_->StartWatching(
         base::Bind(&HostProcess::OnPolicyUpdate, base::Unretained(this)));
   } else {
     // Reapply policies that could be affected by a new config.
     ApplyHostDomainPolicy();
     ApplyUsernamePolicy();
 
     if (state_ == HOST_STARTED) {
       // TODO(sergeyu): Here we assume that PIN is the only part of the config
       // that may change while the service is running. Change ApplyConfig() to
@@ skipping 865 matching lines @@
   oauth_token_getter_.reset();
   signal_strategy_.reset();
   network_change_notifier_.reset();
 
   if (state_ == HOST_STOPPING_TO_RESTART) {
     StartHost();
   } else if (state_ == HOST_STOPPING) {
     state_ = HOST_STOPPED;
 
     if (policy_watcher_.get()) {
-      base::WaitableEvent done_event(true, false);
-      policy_watcher_->StopWatching(&done_event);
-      done_event.Wait();
-      policy_watcher_.reset();
+      policy_watcher_->StopWatching(
+          base::Bind(&HostProcess::PostPolicyWatcherShutdown, this));
+    } else {
+      PostPolicyWatcherShutdown();
     }
-
-    config_watcher_.reset();
-
-    // Complete the rest of shutdown on the main thread.
-    context_->ui_task_runner()->PostTask(
-        FROM_HERE,
-        base::Bind(&HostProcess::ShutdownOnUiThread, this));
   } else {
     // This method is only called in STOPPING_TO_RESTART and STOPPING states.
     NOTREACHED();
   }
 }
 
+void HostProcess::PostPolicyWatcherShutdown() {

[rmsousa, 2014/10/14 00:18:25]

nit: OnPolicyWatcherShutdown.
"Post" is an ambiguous term - we typically use it with its verb meaning (i.e. to
post something to a task), so to use it with its adverb meaning (i.e. this will
happen after the policy watcher is shutdown) is confusing.

[kelvinp, 2014/10/15 23:03:10]

Done.

+  policy_watcher_.reset();
+
+  // Complete the rest of shutdown on the main thread.
+  context_->ui_task_runner()->PostTask(
+      FROM_HERE, base::Bind(&HostProcess::ShutdownOnUiThread, this));
+}
+
 void HostProcess::OnCrash(const std::string& function_name,
                           const std::string& file_name,
                           const int& line_number) {
   char message[1024];
   base::snprintf(message, sizeof(message),
                  "Requested by %s at %s, line %d.",
                  function_name.c_str(), file_name.c_str(), line_number);
   base::debug::Alias(message);
 
   // The daemon requested us to crash the process.
@@ skipping 32 matching lines @@
   int exit_code = kSuccessExitCode;
   new HostProcess(context.Pass(), &exit_code);
 
   // Run the main (also UI) message loop until the host no longer needs it.
   message_loop.Run();
 
   return exit_code;
 }
 
 }  // namespace remoting