text: /*
   * Copyright (C) 2008 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #define LOG_TAG "UEventObserver"
  //#define LOG_NDEBUG 0
  
  #include "utils/Log.h"
  
  #include "hardware_legacy/uevent.h"
  #include "jni.h"
  #include <nativehelper/JNIHelp.h>
  #include "core_jni_helpers.h"
  
  #include <utils/Mutex.h>
  #include <utils/Vector.h>
  #include <utils/String8.h>
  #include <nativehelper/ScopedUtfChars.h>
  
  namespace android {
  
  static Mutex gMatchesMutex;
  static Vector<String8> gMatches;
  
  static void nativeSetup(JNIEnv *env, jclass clazz) {
      if (!uevent_init()) {
          jniThrowException(env, "java/lang/RuntimeException",
                  "Unable to open socket for UEventObserver");
      }
  }
  
  static bool isMatch(const char* buffer, size_t length) {
      AutoMutex _l(gMatchesMutex);
  
      for (size_t i = 0; i < gMatches.size(); i++) {
          const String8& match = gMatches.itemAt(i);
  
          // Consider all zero-delimited fields of the buffer.
          const char* field = buffer;
          const char* end = buffer + length + 1;
          do {
              if (strstr(field, match.string())) {
                  ALOGV("Matched uevent message with pattern: %s", match.string());
                  return true;
              }
              field += strlen(field) + 1;
          } while (field != end);
      }
      return false;
  }
  
  static jstring nativeWaitForNextEvent(JNIEnv *env, jclass clazz) {
      char buffer[1024];
  
      for (;;) {
          int length = uevent_next_event(buffer, sizeof(buffer) - 1);
          if (length <= 0) {
              return NULL;
          }
          buffer[length] = '\0';
  
          ALOGV("Received uevent message: %s", buffer);
  
          if (isMatch(buffer, length)) {
              // Assume the message is ASCII.
              jchar message[length];
              for (int i = 0; i < length; i++) {
                  message[i] = buffer[i];
              }
              return env->NewString(message, length);
          }
      }
  }
  
  static void nativeAddMatch(JNIEnv* env, jclass clazz, jstring matchStr) {
      ScopedUtfChars match(env, matchStr);
  
      AutoMutex _l(gMatchesMutex);
      gMatches.add(String8(match.c_str()));
  }
  
  static void nativeRemoveMatch(JNIEnv* env, jclass clazz, jstring matchStr) {
      ScopedUtfChars match(env, matchStr);
  
      AutoMutex _l(gMatchesMutex);
      for (size_t i = 0; i < gMatches.size(); i++) {
          if (gMatches.itemAt(i) == match.c_str()) {
              gMatches.removeAt(i);
              break; // only remove first occurrence
          }
      }
  }
  
  static const JNINativeMethod gMethods[] = {
      { "nativeSetup", "()V",
              (void *)nativeSetup },
      { "nativeWaitForNextEvent", "()Ljava/lang/String;",
              (void *)nativeWaitForNextEvent },
      { "nativeAddMatch", "(Ljava/lang/String;)V",
              (void *)nativeAddMatch },
      { "nativeRemoveMatch", "(Ljava/lang/String;)V",
              (void *)nativeRemoveMatch },
  };
  
  
  int register_android_os_UEventObserver(JNIEnv *env)
  {
      FindClassOrDie(env, "android/os/UEventObserver");
  
      return RegisterMethodsOrDie(env, "android/os/UEventObserver", gMethods, NELEM(gMethods));
  }
  
  }   // namespace android
  