[Chromoting] Add a filter that will stop the host sending unnecessary clipboard events to the clien…

remoting/protocol/clipboard_echo_filter.cc

Index: remoting/protocol/clipboard_echo_filter.cc
diff --git a/remoting/protocol/clipboard_echo_filter.cc b/remoting/protocol/clipboard_echo_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d89c43cbb1d51fad35ad141eb3fb69321a0bd37b
--- /dev/null
+++ b/remoting/protocol/clipboard_echo_filter.cc
@@ -0,0 +1,78 @@
+// 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 "remoting/protocol/clipboard_echo_filter.h"
+
+#include "remoting/proto/event.pb.h"
+
+namespace remoting {
+namespace protocol {
+
+ClipboardEchoFilter::ClipboardEchoFilter()
+  : host_stub_(NULL),
+    client_stub_(NULL),
+    client_filter_(this),
+    host_filter_(this) {
+}
+
+ClipboardEchoFilter::~ClipboardEchoFilter() {
+}
+
+void ClipboardEchoFilter::set_client_stub(ClipboardStub* client_stub) {
+  client_stub_ = client_stub;
+}
+
+void ClipboardEchoFilter::set_host_stub(ClipboardStub* host_stub) {
+  host_stub_ = host_stub;
+}
+
+ClipboardStub* ClipboardEchoFilter::client_filter() {
+  return &client_filter_;
+}
+
+ClipboardStub* ClipboardEchoFilter::host_filter() {
+  return &host_filter_;
+}
+
+void ClipboardEchoFilter::InjectClipboardEventToClient(
+    const ClipboardEvent& event) {
+  if (!client_stub_) {
+    return;
+  }
+  if (event.mime_type() == client_latest_mime_type_ &&
+      event.data() == client_latest_data_) {
+    return;
+  }
+  client_stub_->InjectClipboardEvent(event);
+}
+
+void ClipboardEchoFilter::InjectClipboardEventToHost(
+    const ClipboardEvent& event) {
+  client_latest_mime_type_ = event.mime_type();
+  client_latest_data_ = event.data();
+  if (host_stub_) {
+    host_stub_->InjectClipboardEvent(event);
+  }
+}
+
+ClipboardEchoFilter::ClientFilter::ClientFilter(
+    ClipboardEchoFilter* filter) : filter_(filter) {
+}
+
+void ClipboardEchoFilter::ClientFilter::InjectClipboardEvent(
+    const ClipboardEvent& event) {
+  filter_->InjectClipboardEventToClient(event);
+}
+
+ClipboardEchoFilter::HostFilter::HostFilter(
+    ClipboardEchoFilter* filter) : filter_(filter) {
+}
+
+void ClipboardEchoFilter::HostFilter::InjectClipboardEvent(
+    const ClipboardEvent& event) {
+  filter_->InjectClipboardEventToHost(event);
+}
+
+}  // namespace protocol
+}  // namespace remoting