Add Android Camera To Unity Plugin

webrtc/examples/unityplugin/classreferenceholder.cc

+/*
+ *  Copyright 2015 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/classreferenceholder.h"
+
+#include <utility>
+
+#include "webrtc/sdk/android/src/jni/jni_helpers.h"
+
+namespace unity_plugin {
+
+// ClassReferenceHolder holds global reference to Java classes in app/webrtc.
+class ClassReferenceHolder {
+ public:
+  explicit ClassReferenceHolder(JNIEnv* jni);
+  ~ClassReferenceHolder();
+
+  void FreeReferences(JNIEnv* jni);
+  jclass GetClass(const std::string& name);
+
+  void LoadClass(JNIEnv* jni, const std::string& name);
+
+ private:
+  std::map<std::string, jclass> classes_;
+};
+
+// Allocated in LoadGlobalClassReferenceHolder(),
+// freed in FreeGlobalClassReferenceHolder().
+static ClassReferenceHolder* g_class_reference_holder = nullptr;
+
+void LoadGlobalClassReferenceHolder() {
+  RTC_CHECK(g_class_reference_holder == nullptr);
+  g_class_reference_holder = new ClassReferenceHolder(webrtc_jni::GetEnv());
+}
+
+void FreeGlobalClassReferenceHolder() {
+  g_class_reference_holder->FreeReferences(
+      webrtc_jni::AttachCurrentThreadIfNeeded());
+  delete g_class_reference_holder;
+  g_class_reference_holder = nullptr;
+}
+
+ClassReferenceHolder::ClassReferenceHolder(JNIEnv* jni) {
+  LoadClass(jni, "org/webrtc/UnityUtility");
+}
+
+ClassReferenceHolder::~ClassReferenceHolder() {
+  RTC_CHECK(classes_.empty()) << "Must call FreeReferences() before dtor!";
+}
+
+void ClassReferenceHolder::FreeReferences(JNIEnv* jni) {
+  for (std::map<std::string, jclass>::const_iterator it = classes_.begin();
+       it != classes_.end(); ++it) {
+    jni->DeleteGlobalRef(it->second);
+  }
+  classes_.clear();
+}
+
+jclass ClassReferenceHolder::GetClass(const std::string& name) {
+  std::map<std::string, jclass>::iterator it = classes_.find(name);
+  RTC_CHECK(it != classes_.end()) << "Unexpected GetClass() call for: " << name;
+  return it->second;
+}
+
+void ClassReferenceHolder::LoadClass(JNIEnv* jni, const std::string& name) {
+  jclass localRef = jni->FindClass(name.c_str());
+  CHECK_EXCEPTION(jni) << "error during FindClass: " << name;
+  RTC_CHECK(localRef) << name;
+  jclass globalRef = reinterpret_cast<jclass>(jni->NewGlobalRef(localRef));
+  CHECK_EXCEPTION(jni) << "error during NewGlobalRef: " << name;
+  RTC_CHECK(globalRef) << name;
+  bool inserted = classes_.insert(std::make_pair(name, globalRef)).second;
+  RTC_CHECK(inserted) << "Duplicate class name: " << name;
+}
+
+// Returns a global reference guaranteed to be valid for the lifetime of the
+// process.
+jclass FindClass(JNIEnv* jni, const char* name) {
+  return g_class_reference_holder->GetClass(name);
+}
+
+}  // namespace unity_plugin