[EasyUnlock] Port Connection class to native code.

components/proximity_auth/connection.cc

+// Copyright 2014 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 "components/proximity_auth/connection.h"
+
+#include "base/logging.h"
+#include "components/proximity_auth/connection_observer.h"
+#include "components/proximity_auth/permit_message.h"
+
+namespace proximity_auth {
+namespace {
+
+// Most EasyUnlock messages fit easily into 128 bytes.
+const int kInitialBufferCapacity = 128;
+
+}  // namespace
+
+Connection::Connection(const RemoteDevice& remote_device)
+    : remote_device_(remote_device),
+      status_(DISCONNECTED),
+      is_sending_message_(false) {
+}
+
+Connection::~Connection() {
+}
+
+bool Connection::IsConnected() const {
+  return status_ == CONNECTED;
+}
+
+void Connection::SendMessage(scoped_ptr<PermitMessage> message) {
+  if (!IsConnected()) {
+    VLOG(1) << "Cannot send message when disconnected.";
+    return;
+  }
+
+  if (is_sending_message_) {
+    VLOG(1) << "Another message is currently in progress.";
+    return;
+  }
+
+  is_sending_message_ = true;
+  SendMessageImpl(message.Pass());
+}
+
+void Connection::AddObserver(ConnectionObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void Connection::RemoveObserver(ConnectionObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+void Connection::SetStatus(Status status) {
+  if (status_ == status)
+    return;
+
+  received_bytes_ = NULL;
+
+  Status old_status = status_;
+  status_ = status;
+  FOR_EACH_OBSERVER(ConnectionObserver, observers_,
+                    OnConnectionStatusChanged(*this, old_status, status_));
+}
+
+void Connection::OnDidSendMessage(const PermitMessage& message,
+                                  bool success) {
+  if (!is_sending_message_) {
+    VLOG(1) << "Send completed, but no message in progress.";
+    return;
+  }
+
+  FOR_EACH_OBSERVER(
+      ConnectionObserver, observers_, OnSendCompleted(*this, message, success));
+  is_sending_message_ = false;

[Tim Song, 2014/09/05 00:30:33]

move this line up in case an observer wants to send another message in response.

[Ilya Sherman, 2014/09/05 01:02:11]

Done, though that seems a little fragile, since observers can't be guaranteed
that someone else won't preempt them in sending the message.  Maybe
SendMessage() should return a boolean for success vs. failure?

[Tim Song, 2014/09/05 03:10:33]

Alternative, expose a is_sending_message() function.

+}
+
+void Connection::OnBytesReceived(scoped_refptr<net::IOBuffer> io_buffer,
+                                 int bytes_received) {
+  if (!IsConnected()) {
+    VLOG(1) << "Received bytes, but not connected.";
+    return;
+  }
+
+  // Allocate an initial buffer if one does not already exist.
+  if (!received_bytes_) {
+    received_bytes_ = new net::GrowableIOBuffer;
+    received_bytes_->SetCapacity(kInitialBufferCapacity);
+  }
+
+  // Grow the buffer if necessary.
+  if (received_bytes_->RemainingCapacity() < bytes_received)
+    received_bytes_->SetCapacity(received_bytes_->capacity() + bytes_received);
+
+  // TODO(tengs): Clear buffer after a timeout as a guard.

[Tim Song, 2014/09/05 00:30:33]

We can remove this TODO. If the phone sends garbage to us, we probably have
bigger problems anyways.

[Ilya Sherman, 2014/09/05 01:02:11]

Done.

+  memcpy(received_bytes_->data(), io_buffer->data(), bytes_received);
+  received_bytes_->set_offset(received_bytes_->offset() + bytes_received);
+
+  if (HasReceivedCompleteMessage()) {
+    scoped_ptr<PermitMessage> message = DeserializePermitMessage();
+    if (message) {
+      FOR_EACH_OBSERVER(ConnectionObserver, observers_,
+                        OnMessageReceived(*this, *message));
+    }
+
+    // Whether the message was parsed successfully or not, clear the
+    // |received_bytes_| buffer.
+    received_bytes_ = NULL;
+  }
+}
+
+bool Connection::HasReceivedCompleteMessage() {
+  return PermitMessage::IsCompleteMessage(
+      received_bytes_->StartOfBuffer(), received_bytes_->offset());
+}
+
+scoped_ptr<PermitMessage> Connection::DeserializePermitMessage() {
+  return PermitMessage::FromBytes(
+      received_bytes_->StartOfBuffer(), received_bytes_->offset());
+}
+
+}  // namespace proximity_auth