An example of Unity native plugin of webrtc for Windows OS

Unity native plugin has to use Pinvoke technology in its APIs
This plugin dll can also be used by Windows C# applications other than
Unity.

BUG=webrtc:7389

Review-Url: https://codereview.webrtc.org/2823783002
Cr-Commit-Position: refs/heads/master@{#18108}

webrtc/examples/unityplugin/unity_plugin_apis.cc

@@ -0,0 +1,185 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/examples/unityplugin/unity_plugin_apis.h"
+
+#include <map>
+#include <string>
+
+#include "webrtc/examples/unityplugin/simple_peer_connection.h"
+
+namespace {
+static int g_peer_connection_id = 1;
+static std::map<int, rtc::scoped_refptr<SimplePeerConnection>>
+    g_peer_connection_map;
+}  // namespace
+
+int CreatePeerConnection() {
+  g_peer_connection_map[g_peer_connection_id] =
+      new rtc::RefCountedObject<SimplePeerConnection>();
+
+  if (!g_peer_connection_map[g_peer_connection_id]->InitializePeerConnection(
+          false))
+    return -1;
+
+  return g_peer_connection_id++;
+}
+
+bool ClosePeerConnection(int peer_connection_id) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  g_peer_connection_map[peer_connection_id]->DeletePeerConnection();
+  g_peer_connection_map.erase(peer_connection_id);
+  return true;
+}
+
+bool AddStream(int peer_connection_id, bool audio_only) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  g_peer_connection_map[peer_connection_id]->AddStreams(audio_only);
+  return true;
+}
+
+bool AddDataChannel(int peer_connection_id) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  return g_peer_connection_map[peer_connection_id]->CreateDataChannel();
+}
+
+bool CreateOffer(int peer_connection_id) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  return g_peer_connection_map[peer_connection_id]->CreateOffer();
+}
+
+bool CreateAnswer(int peer_connection_id) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  return g_peer_connection_map[peer_connection_id]->CreateAnswer();
+}
+
+bool SendDataViaDataChannel(int peer_connection_id, const char* data) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  std::string s(data);
+  g_peer_connection_map[peer_connection_id]->SendDataViaDataChannel(s);
+
+  return true;
+}
+
+bool SetAudioControl(int peer_connection_id, bool is_mute, bool is_record) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  g_peer_connection_map[peer_connection_id]->SetAudioControl(is_mute,
+                                                             is_record);
+  return true;
+}
+
+// Register callback functions.
+bool RegisterOnVideoFramReady(int peer_connection_id,
+                              VIDEOFRAMEREADY_CALLBACK callback) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  g_peer_connection_map[peer_connection_id]->RegisterOnVideoFramReady(callback);
+  return true;
+}
+
+bool RegisterOnLocalDataChannelReady(int peer_connection_id,
+                                     LOCALDATACHANNELREADY_CALLBACK callback) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  g_peer_connection_map[peer_connection_id]->RegisterOnLocalDataChannelReady(
+      callback);
+  return true;
+}
+
+bool RegisterOnDataFromDataChannelReady(
+    int peer_connection_id,
+    DATAFROMEDATECHANNELREADY_CALLBACK callback) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  g_peer_connection_map[peer_connection_id]->RegisterOnDataFromDataChannelReady(
+      callback);
+  return true;
+}
+
+bool RegisterOnFailure(int peer_connection_id, FAILURE_CALLBACK callback) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  g_peer_connection_map[peer_connection_id]->RegisterOnFailure(callback);
+  return true;
+}
+
+bool RegisterOnAudioBusReady(int peer_connection_id,
+                             AUDIOBUSREADY_CALLBACK callback) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  g_peer_connection_map[peer_connection_id]->RegisterOnAudioBusReady(callback);
+  return true;
+}
+
+// Singnaling channel related functions.
+bool RegisterOnLocalSdpReadytoSend(int peer_connection_id,
+                                   LOCALSDPREADYTOSEND_CALLBACK callback) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  g_peer_connection_map[peer_connection_id]->RegisterOnLocalSdpReadytoSend(
+      callback);
+  return true;
+}
+
+bool RegisterOnIceCandiateReadytoSend(
+    int peer_connection_id,
+    ICECANDIDATEREADYTOSEND_CALLBACK callback) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  g_peer_connection_map[peer_connection_id]->RegisterOnIceCandiateReadytoSend(
+      callback);
+  return true;
+}
+
+int ReceivedSdp(int peer_connection_id, const char* sdp) {
+  // Create a peer_connection if no one exists.
+  int id = -1;
+  if (g_peer_connection_map.count(peer_connection_id)) {
+    id = peer_connection_id;
+  } else {
+    id = g_peer_connection_id++;
+    g_peer_connection_map[id] =
+        new rtc::RefCountedObject<SimplePeerConnection>();
+    if (!g_peer_connection_map[id]->InitializePeerConnection(true))
+      return -1;
+  }
+
+  g_peer_connection_map[id]->ReceivedSdp(sdp);
+  return id;
+}
+
+bool ReceivedIceCandidate(int peer_connection_id, const char* ice_candidate) {
+  if (!g_peer_connection_map.count(peer_connection_id))
+    return false;
+
+  return g_peer_connection_map[peer_connection_id]->ReceivedIceCandidate(
+      ice_candidate);
+}