[battor agent] Add option to log serial communication

tools/battor_agent/battor_connection_impl.cc

 // Copyright 2015 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 "tools/battor_agent/battor_connection_impl.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
+#include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/thread_task_runner_handle.h"
 #include "device/serial/buffer.h"
 #include "device/serial/serial_io_handler.h"
 #include "net/base/io_buffer.h"
+#include "tools/battor_agent/serial_utils.h"
 
+using std::endl;
 using std::vector;
 
 namespace battor {
 
 namespace {
 
+// The command line switch used to specify a file to which serial communication
+// is logged.
+const char kSerialLogPathSwitch[] = "battor-serial-log";
+
 // Serial configuration parameters for the BattOr.
 const uint32_t kBattOrBitrate = 2000000;
 const device::serial::DataBits kBattOrDataBits =
     device::serial::DataBits::EIGHT;
 const device::serial::ParityBit kBattOrParityBit =
     device::serial::ParityBit::NONE;
 const device::serial::StopBits kBattOrStopBit = device::serial::StopBits::ONE;
 const bool kBattOrCtsFlowControl = true;
 const bool kBattOrHasCtsFlowControl = true;
 // The maximum BattOr message is 50kB long.
@@ skipping 20 matching lines @@
 }  // namespace
 
 BattOrConnectionImpl::BattOrConnectionImpl(
     const std::string& path,
     BattOrConnection::Listener* listener,
     scoped_refptr<base::SingleThreadTaskRunner> file_thread_task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> ui_thread_task_runner)
     : BattOrConnection(listener),
       path_(path),
       file_thread_task_runner_(file_thread_task_runner),
-      ui_thread_task_runner_(ui_thread_task_runner) {}
+      ui_thread_task_runner_(ui_thread_task_runner) {
+  std::string serial_log_path =
+      base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+          kSerialLogPathSwitch);
+  if (!serial_log_path.empty()) {
+    serial_log_.open(serial_log_path.c_str(),
+                     std::fstream::out | std::fstream::trunc);
+    serial_log_ << std::boolalpha;
+  }
+}
 
 BattOrConnectionImpl::~BattOrConnectionImpl() {}
 
 void BattOrConnectionImpl::Open() {
   if (io_handler_) {
     OnOpened(true);
     return;
   }
 
   io_handler_ = CreateIoHandler();
 
   device::serial::ConnectionOptions options;
   options.bitrate = kBattOrBitrate;
   options.data_bits = kBattOrDataBits;
   options.parity_bit = kBattOrParityBit;
   options.stop_bits = kBattOrStopBit;
   options.cts_flow_control = kBattOrCtsFlowControl;
   options.has_cts_flow_control = kBattOrHasCtsFlowControl;
 
+  serial_log_ << "Opening serial connection." << endl << endl;
   io_handler_->Open(path_, options,
                     base::Bind(&BattOrConnectionImpl::OnOpened, AsWeakPtr()));
 }
 
 void BattOrConnectionImpl::OnOpened(bool success) {
+  serial_log_ << "Serial connection open finished with success: " << success
+              << "." << endl
+              << endl;
+
   if (!success)
     Close();
 
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::Bind(&Listener::OnConnectionOpened,
                             base::Unretained(listener_), success));
 }
 
 void BattOrConnectionImpl::Close() {
+  serial_log_ << "Serial connection closed." << endl << endl;
   io_handler_ = nullptr;
 }
 
 void BattOrConnectionImpl::SendBytes(BattOrMessageType type,
                                      const void* buffer,
                                      size_t bytes_to_send) {
   const char* bytes = reinterpret_cast<const char*>(buffer);
 
   // Reserve a send buffer with enough extra bytes for the start, type, end, and
   // escape bytes.
   vector<char> data;
   data.reserve(2 * bytes_to_send + 3);
 
   data.push_back(BATTOR_CONTROL_BYTE_START);
   data.push_back(type);
 
   for (size_t i = 0; i < bytes_to_send; i++) {
     if (bytes[i] == BATTOR_CONTROL_BYTE_START ||
         bytes[i] == BATTOR_CONTROL_BYTE_END) {
       data.push_back(BATTOR_CONTROL_BYTE_ESCAPE);
     }
 
     data.push_back(bytes[i]);
   }
 
   data.push_back(BATTOR_CONTROL_BYTE_END);
 
+  serial_log_ << "Bytes sent: " << CharVectorToString(data) << "." << endl
+              << endl;
+
   pending_write_length_ = data.size();
   io_handler_->Write(base::WrapUnique(new device::SendBuffer(
       data, base::Bind(&BattOrConnectionImpl::OnBytesSent, AsWeakPtr()))));
 }
 
 void BattOrConnectionImpl::ReadMessage(BattOrMessageType type) {
   pending_read_message_type_ = type;
   size_t max_bytes_to_read = GetMaxBytesForMessageType(type);
 
   // Check the left-over bytes from the last read to make sure that we don't
   // already have a full message.
   BattOrMessageType parsed_type;
   std::unique_ptr<vector<char>> bytes(new vector<char>());
   bytes->reserve(max_bytes_to_read);
 
+  serial_log_
+      << "Checking if a complete message is in the 'already read' buffer."
+      << endl
+      << endl;
+
   if (ParseMessage(&parsed_type, bytes.get())) {
+    serial_log_ << "Complete message found." << endl << endl;
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE,
         base::Bind(&Listener::OnMessageRead, base::Unretained(listener_), true,
                    parsed_type, base::Passed(std::move(bytes))));
     return;
   }
 
+  serial_log_ << "No complete message found." << endl << endl;
   BeginReadBytes(max_bytes_to_read - already_read_buffer_.size());
 }
 
 void BattOrConnectionImpl::Flush() {
   io_handler_->Flush();
   already_read_buffer_.clear();
 }
 
 scoped_refptr<device::SerialIoHandler> BattOrConnectionImpl::CreateIoHandler() {
   return device::SerialIoHandler::Create(file_thread_task_runner_,
                                          ui_thread_task_runner_);
 }
 
 void BattOrConnectionImpl::BeginReadBytes(size_t max_bytes_to_read) {
+  serial_log_ << "Starting read of up to " << max_bytes_to_read << " bytes."
+              << endl
+              << endl;
+
   pending_read_buffer_ =
       make_scoped_refptr(new net::IOBuffer(max_bytes_to_read));
 
   auto on_receive_buffer_filled =
       base::Bind(&BattOrConnectionImpl::OnBytesRead, AsWeakPtr());
 
   io_handler_->Read(base::WrapUnique(new device::ReceiveBuffer(
       pending_read_buffer_, static_cast<uint32_t>(max_bytes_to_read),
       on_receive_buffer_filled)));
 }
 
 void BattOrConnectionImpl::OnBytesRead(int bytes_read,
                                        device::serial::ReceiveError error) {
-  if (bytes_read == 0 || error != device::serial::ReceiveError::NONE) {
-    // If we didn't have a message before, and we weren't able to read any
-    // additional bytes, then there's no valid message available.
+  if (error != device::serial::ReceiveError::NONE) {
+    serial_log_ << "Read failed with error: " << error << "." << endl << endl;
     EndReadBytes(false, BATTOR_MESSAGE_TYPE_CONTROL, nullptr);
     return;
   }
 
+  if (bytes_read == 0) {
+    // If we didn't have a message before, and we weren't able to read any
+    // additional bytes, then there's no valid message available.
+    serial_log_ << "Read failed due to no bytes being read." << endl << endl;
+    EndReadBytes(false, BATTOR_MESSAGE_TYPE_CONTROL, nullptr);
+    return;
+  }
+
+  serial_log_ << bytes_read << " more bytes read: "
+              << CharVectorToString(
+                     vector<char>(pending_read_buffer_->data(),
+                                  pending_read_buffer_->data() + bytes_read))
+              << "." << endl
+              << endl;
+
   already_read_buffer_.insert(already_read_buffer_.end(),
                               pending_read_buffer_->data(),
                               pending_read_buffer_->data() + bytes_read);
 
   BattOrMessageType type;
   std::unique_ptr<vector<char>> bytes(new vector<char>());
   bytes->reserve(GetMaxBytesForMessageType(pending_read_message_type_));
 
   if (!ParseMessage(&type, bytes.get())) {
-    // Even after reading the max number of bytes, we still don't have a valid
-    // message.
+    serial_log_ << "Read failed due to having no complete message after max "
+                   "read length."
+                << endl
+                << endl;

[nednguyen, 2016/05/12 15:44:29]

Let create a Log(const string& message) method instead of copy & paste the
format. In the future, we may add things like timestamp, etc...

     EndReadBytes(false, BATTOR_MESSAGE_TYPE_CONTROL, nullptr);
     return;
   }
 
   if (type != pending_read_message_type_) {
-    // We received a complete message, but it wasn't the type we were expecting.
+    serial_log_ << "Read failed due to receiving a message of the wrong type."
+                << endl
+                << endl;
     EndReadBytes(false, BATTOR_MESSAGE_TYPE_CONTROL, nullptr);
     return;
   }
 
   EndReadBytes(true, type, std::move(bytes));
 }
 
-void BattOrConnectionImpl::EndReadBytes(
-    bool success,
-    BattOrMessageType type,
-    std::unique_ptr<std::vector<char>> bytes) {
+void BattOrConnectionImpl::EndReadBytes(bool success,
+                                        BattOrMessageType type,
+                                        std::unique_ptr<vector<char>> bytes) {
+  serial_log_ << "Read finished with success: " << success << "." << endl
+              << endl;
+
   pending_read_buffer_ = nullptr;
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE,
       base::Bind(&Listener::OnMessageRead, base::Unretained(listener_), success,
                  type, base::Passed(std::move(bytes))));
 }
 
 bool BattOrConnectionImpl::ParseMessage(BattOrMessageType* type,
                                         vector<char>* bytes) {
   if (already_read_buffer_.size() <= 3)
@@ skipping 50 matching lines @@
 void BattOrConnectionImpl::OnBytesSent(int bytes_sent,
                                        device::serial::SendError error) {
   bool success = (error == device::serial::SendError::NONE) &&
                  (pending_write_length_ == static_cast<size_t>(bytes_sent));
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE,
       base::Bind(&Listener::OnBytesSent, base::Unretained(listener_), success));
 }
 
 }  // namespace battor