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      1 /*
      2  * Copyright (C) 2005 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 //
     18 // C/C++ logging functions.  See the logging documentation for API details.
     19 //
     20 // We'd like these to be available from C code (in case we import some from
     21 // somewhere), so this has a C interface.
     22 //
     23 // The output will be correct when the log file is shared between multiple
     24 // threads and/or multiple processes so long as the operating system
     25 // supports O_APPEND.  These calls have mutex-protected data structures
     26 // and so are NOT reentrant.  Do not use LOG in a signal handler.
     27 //
     28 #ifndef _LIBS_UTILS_LOG_H
     29 #define _LIBS_UTILS_LOG_H
     30 
     31 #include <cutils/log.h>
     32 #include <sys/types.h>
     33 
     34 #ifdef __cplusplus
     35 
     36 namespace android {
     37 
     38 /*
     39  * A very simple utility that yells in the log when an operation takes too long.
     40  */
     41 class LogIfSlow {
     42 public:
     43     LogIfSlow(const char* tag, android_LogPriority priority,
     44             int timeoutMillis, const char* message);
     45     ~LogIfSlow();
     46 
     47 private:
     48     const char* const mTag;
     49     const android_LogPriority mPriority;
     50     const int mTimeoutMillis;
     51     const char* const mMessage;
     52     const int64_t mStart;
     53 };
     54 
     55 /*
     56  * Writes the specified debug log message if this block takes longer than the
     57  * specified number of milliseconds to run.  Includes the time actually taken.
     58  *
     59  * {
     60  *     ALOGD_IF_SLOW(50, "Excessive delay doing something.");
     61  *     doSomething();
     62  * }
     63  */
     64 #define ALOGD_IF_SLOW(timeoutMillis, message) \
     65     android::LogIfSlow _logIfSlow(LOG_TAG, ANDROID_LOG_DEBUG, timeoutMillis, message);
     66 
     67 } // namespace android
     68 
     69 #endif // __cplusplus
     70 
     71 #endif // _LIBS_UTILS_LOG_H
     72