[chromedriver] Implement reconnection to DevTools.

chrome/test/chromedriver/devtools_client_impl.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.
 
 #include "chrome/test/chromedriver/devtools_client_impl.h"
 
 #include "base/bind.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "base/logging.h"
@@ skipping 30 matching lines @@
 InspectorEvent::~InspectorEvent() {}
 
 InspectorCommandResponse::InspectorCommandResponse() {}
 
 InspectorCommandResponse::~InspectorCommandResponse() {}
 
 }  // namespace internal
 
 DevToolsClientImpl::DevToolsClientImpl(
     const SyncWebSocketFactory& factory,
-    const std::string& url)
+    const std::string& url,
+    const FrontendCloserFunc& frontend_closer_func)
     : socket_(factory.Run().Pass()),
       url_(url),
+      frontend_closer_func_(frontend_closer_func),
       parser_func_(base::Bind(&internal::ParseInspectorMessage)),
       connected_(false),
       next_id_(1) {}
 
 DevToolsClientImpl::DevToolsClientImpl(
     const SyncWebSocketFactory& factory,
     const std::string& url,
+    const FrontendCloserFunc& frontend_closer_func,
     const ParserFunc& parser_func)
     : socket_(factory.Run().Pass()),
       url_(url),
+      frontend_closer_func_(frontend_closer_func),
       parser_func_(parser_func),
       connected_(false),
       next_id_(1) {}
 
 DevToolsClientImpl::~DevToolsClientImpl() {
   for (ResponseMap::iterator iter = cmd_response_map_.begin();
        iter != cmd_response_map_.end(); ++iter) {
     LOG(WARNING) << "Finished with no response for command " << iter->first;
     delete iter->second;
   }
@@ skipping 37 matching lines @@
   internal::InspectorCommandResponse response;
 
   while (socket_->HasNextMessage() || !conditional_func.Run()) {
     Status status = ReceiveNextMessage(-1, &type, &event, &response);
     if (status.IsError())
       return status;
   }
   return Status(kOk);
 }
 
-Status DevToolsClientImpl::SendCommandInternal(
+Status DevToolsClientImpl::SendCommandToDevTools(

[kkania, 2013/02/22 01:35:24]

the naming of SendCommandToDevTools and SendCommandInternal are a bit arbitrary.
see if you can come up with something that makes more sense.

[chrisgao (Use stgao instead), 2013/02/27 19:29:44]

Change SendCommandInternal to SendCommandWithRetry

     const std::string& method,
     const base::DictionaryValue& params,
-    scoped_ptr<base::DictionaryValue>* result) {
+    scoped_ptr<base::DictionaryValue>* result,
+    int* command_id) {
   if (!connected_) {
     if (!socket_->Connect(url_))
       return Status(kDisconnected, "unable to connect to renderer");
     connected_ = true;
 
     // OnConnected notification will be sent out in method ReceiveNextMessage.
     listeners_for_on_connected_ = listeners_;
   }
 
-  int command_id = next_id_++;
+  int command_id_tmp = next_id_++;
   base::DictionaryValue command;
-  command.SetInteger("id", command_id);
+  command.SetInteger("id", command_id_tmp);
   command.SetString("method", method);
   command.Set("params", params.DeepCopy());
   std::string message;
   base::JSONWriter::Write(&command, &message);
   if (!socket_->Send(message)) {
-    connected_ = false;
-    return Status(kDisconnected, "unable to send message to renderer");
+      connected_ = false;
+      return Status(kDisconnected, "unable to send message to renderer");
   }
+  *command_id = command_id_tmp;
+  return Status(kOk);
+}
+
+Status DevToolsClientImpl::SendCommandInternal(
+    const std::string& method,
+    const base::DictionaryValue& params,
+    scoped_ptr<base::DictionaryValue>* result) {
+  int command_id = -1;
+  Status status = SendCommandToDevTools(method, params, result, &command_id);

[kkania, 2013/02/22 01:35:24]

have you tried this manually? can you try sending a bunch of execute scripts to
a page while you try opening and closing devtools repeatedly and see if you get
any crashes in chrome or errors on the chromedriver side?

[chrisgao (Use stgao instead), 2013/02/27 19:29:44]

If DevTools frontend is opened during re-connection (interrupt the four commands
from trackers' OnConnected event), our code will hang.

If DevTools frontend is opened between commands from client side, it is ok
(tested 20 times with FindElement script) expect that the docked DevTools
frontend UI becomes larger and larger.

+  if (status.code() == kDisconnected) {
+    // Try to close devtools frontend UI and then reconnect.
+    status = frontend_closer_func_.Run();
+    if (status.IsOk())
+      status = SendCommandToDevTools(method, params, result, &command_id);
+  }
+  if (status.IsError())
+    return Status(kDisconnected, "failed to reconnect to DevTools");

[kkania, 2013/02/22 01:35:24]

this error message may not be accurate, right? this may be the first time it
tried to connect and failed.

[chrisgao (Use stgao instead), 2013/02/27 19:29:44]

Oh, yes. Updated message and including the old status.

   return ReceiveCommandResponse(command_id, result);
 }
 
 Status DevToolsClientImpl::ReceiveCommandResponse(
     int command_id,
     scoped_ptr<base::DictionaryValue>* result) {
   internal::InspectorMessageType type;
   internal::InspectorEvent event;
   internal::InspectorCommandResponse response;
   cmd_response_map_[command_id] = NULL;
@@ skipping 106 matching lines @@
     if (unscoped_result)
       command_response->result.reset(unscoped_result->DeepCopy());
     else
       base::JSONWriter::Write(unscoped_error, &command_response->error);
     return true;
   }
   return false;
 }
 
 }  // namespace internal