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      1 /*
      2  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #ifndef WEBRTC_EXAMPLES_ANDROID_MEDIA_DEMO_JNI_JNI_HELPERS_H_
     12 #define WEBRTC_EXAMPLES_ANDROID_MEDIA_DEMO_JNI_JNI_HELPERS_H_
     13 
     14 // TODO(henrike): this file contains duplication with regards to
     15 // talk/app/webrtc/java/jni/peerconnection_jni.cc. When/if code can be shared
     16 // between trunk/talk and trunk/webrtc remove the duplication.
     17 
     18 #include <android/log.h>
     19 #include <jni.h>
     20 
     21 #include <map>
     22 #include <string>
     23 
     24 #define TAG "WEBRTC-NATIVE"
     25 
     26 // Abort the process if |x| is false, emitting |msg| to logcat.
     27 #define CHECK(x, msg)                                                  \
     28   if (x) {                                                             \
     29   } else {                                                             \
     30     __android_log_print(ANDROID_LOG_ERROR, TAG, "%s:%d: %s", __FILE__, \
     31                         __LINE__, msg);                                \
     32     abort();                                                           \
     33   }
     34 
     35 // Abort the process if |jni| has a Java exception pending, emitting |msg| to
     36 // logcat.
     37 #define CHECK_EXCEPTION(jni, msg) \
     38   if (0) {                        \
     39   } else {                        \
     40     if (jni->ExceptionCheck()) {  \
     41       jni->ExceptionDescribe();   \
     42       jni->ExceptionClear();      \
     43       CHECK(0, msg);              \
     44     }                             \
     45   }
     46 
     47 #define ARRAYSIZE(instance)                                     \
     48   static_cast<int>(sizeof(instance) / sizeof(instance[0]))
     49 
     50 // JNIEnv-helper methods that CHECK success: no Java exception thrown and found
     51 // object/class/method/field is non-null.
     52 jmethodID GetMethodID(JNIEnv* jni, jclass c, const std::string& name,
     53                       const char* signature);
     54 
     55 // Return a |jlong| that will automatically convert back to |ptr| when assigned
     56 // to a |uint64|
     57 jlong jlongFromPointer(void* ptr);
     58 
     59 // Given a (UTF-16) jstring return a new UTF-8 native string.
     60 std::string JavaToStdString(JNIEnv* jni, const jstring& j_string);
     61 
     62 // Android's FindClass() is trickier than usual because the app-specific
     63 // ClassLoader is not consulted when there is no app-specific frame on the
     64 // stack.  Consequently, we only look up classes once in JNI_OnLoad.
     65 // http://developer.android.com/training/articles/perf-jni.html#faq_FindClass
     66 class ClassReferenceHolder {
     67  public:
     68   ClassReferenceHolder(JNIEnv* jni, const char** classes, int size);
     69   ~ClassReferenceHolder();
     70 
     71   void FreeReferences(JNIEnv* jni);
     72 
     73   jclass GetClass(const std::string& name);
     74 
     75  private:
     76   void LoadClass(JNIEnv* jni, const std::string& name);
     77 
     78   std::map<std::string, jclass> classes_;
     79 };
     80 
     81 #endif  // WEBRTC_EXAMPLES_ANDROID_MEDIA_DEMO_JNI_JNI_HELPERS_H_
     82