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      1 /*
      2  * Copyright (C) 2012 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  *  Encapsulate a mutex for thread synchronization.
     19  */
     20 
     21 #include "Mutex.h"
     22 #include "NfcJniUtil.h"
     23 
     24 #include <errno.h>
     25 #include <string.h>
     26 
     27 #include <log/log.h>
     28 
     29 /*******************************************************************************
     30 **
     31 ** Function:        Mutex
     32 **
     33 ** Description:     Initialize member variables.
     34 **
     35 ** Returns:         None.
     36 **
     37 *******************************************************************************/
     38 Mutex::Mutex ()
     39 {
     40     memset (&mMutex, 0, sizeof(mMutex));
     41     int res = pthread_mutex_init (&mMutex, NULL);
     42     if (res != 0)
     43     {
     44         ALOGE("Mutex::Mutex: fail init; error=0x%X", res);
     45     }
     46 }
     47 
     48 
     49 /*******************************************************************************
     50 **
     51 ** Function:        ~Mutex
     52 **
     53 ** Description:     Cleanup all resources.
     54 **
     55 ** Returns:         None.
     56 **
     57 *******************************************************************************/
     58 Mutex::~Mutex ()
     59 {
     60     int res = pthread_mutex_destroy (&mMutex);
     61     if (res != 0)
     62     {
     63         ALOGE("Mutex::~Mutex: fail destroy; error=0x%X", res);
     64     }
     65 }
     66 
     67 
     68 /*******************************************************************************
     69 **
     70 ** Function:        lock
     71 **
     72 ** Description:     Block the thread and try lock the mutex.
     73 **
     74 ** Returns:         None.
     75 **
     76 *******************************************************************************/
     77 void Mutex::lock ()
     78 {
     79     int res = pthread_mutex_lock (&mMutex);
     80     if (res != 0)
     81     {
     82         ALOGE("Mutex::lock: fail lock; error=0x%X", res);
     83     }
     84 }
     85 
     86 
     87 /*******************************************************************************
     88 **
     89 ** Function:        unlock
     90 **
     91 ** Description:     Unlock a mutex to unblock a thread.
     92 **
     93 ** Returns:         None.
     94 **
     95 *******************************************************************************/
     96 void Mutex::unlock ()
     97 {
     98     int res = pthread_mutex_unlock (&mMutex);
     99     if (res != 0)
    100     {
    101         ALOGE("Mutex::unlock: fail unlock; error=0x%X", res);
    102     }
    103 }
    104 
    105 
    106 /*******************************************************************************
    107 **
    108 ** Function:        tryLock
    109 **
    110 ** Description:     Try to lock the mutex.
    111 **
    112 ** Returns:         True if the mutex is locked.
    113 **
    114 *******************************************************************************/
    115 bool Mutex::tryLock ()
    116 {
    117     int res = pthread_mutex_trylock (&mMutex);
    118     if ((res != 0) && (res != EBUSY))
    119     {
    120         ALOGE("Mutex::tryLock: error=0x%X", res);
    121     }
    122     return res == 0;
    123 }
    124 
    125 
    126 /*******************************************************************************
    127 **
    128 ** Function:        nativeHandle
    129 **
    130 ** Description:     Get the handle of the mutex.
    131 **
    132 ** Returns:         Handle of the mutex.
    133 **
    134 *******************************************************************************/
    135 pthread_mutex_t* Mutex::nativeHandle ()
    136 {
    137     return &mMutex;
    138 }
    139 
    140 
    141