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