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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 condition variable for thread synchronization.
     19  */
     20 
     21 #include "CondVar.h"
     22 #include "NfcJniUtil.h"
     23 
     24 #include <errno.h>
     25 #include <string.h>
     26 
     27 #include <android-base/stringprintf.h>
     28 #include <base/logging.h>
     29 
     30 using android::base::StringPrintf;
     31 
     32 /*******************************************************************************
     33 **
     34 ** Function:        CondVar
     35 **
     36 ** Description:     Initialize member variables.
     37 **
     38 ** Returns:         None.
     39 **
     40 *******************************************************************************/
     41 CondVar::CondVar() {
     42   pthread_condattr_t attr;
     43   pthread_condattr_init(&attr);
     44   pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
     45   memset(&mCondition, 0, sizeof(mCondition));
     46   int const res = pthread_cond_init(&mCondition, &attr);
     47   if (res) {
     48     LOG(ERROR) << StringPrintf("CondVar::CondVar: fail init; error=0x%X", res);
     49   }
     50 }
     51 
     52 /*******************************************************************************
     53 **
     54 ** Function:        ~CondVar
     55 **
     56 ** Description:     Cleanup all resources.
     57 **
     58 ** Returns:         None.
     59 **
     60 *******************************************************************************/
     61 CondVar::~CondVar() {
     62   int const res = pthread_cond_destroy(&mCondition);
     63   if (res) {
     64     LOG(ERROR) << StringPrintf("CondVar::~CondVar: fail destroy; error=0x%X",
     65                                res);
     66   }
     67 }
     68 
     69 /*******************************************************************************
     70 **
     71 ** Function:        wait
     72 **
     73 ** Description:     Block the caller and wait for a condition.
     74 **
     75 ** Returns:         None.
     76 **
     77 *******************************************************************************/
     78 void CondVar::wait(Mutex& mutex) {
     79   int const res = pthread_cond_wait(&mCondition, mutex.nativeHandle());
     80   if (res) {
     81     LOG(ERROR) << StringPrintf("CondVar::wait: fail wait; error=0x%X", res);
     82   }
     83 }
     84 
     85 /*******************************************************************************
     86 **
     87 ** Function:        wait
     88 **
     89 ** Description:     Block the caller and wait for a condition.
     90 **                  millisec: Timeout in milliseconds.
     91 **
     92 ** Returns:         True if wait is successful; false if timeout occurs.
     93 **
     94 *******************************************************************************/
     95 bool CondVar::wait(Mutex& mutex, long millisec) {
     96   bool retVal = false;
     97   struct timespec absoluteTime;
     98 
     99   if (clock_gettime(CLOCK_MONOTONIC, &absoluteTime) == -1) {
    100     LOG(ERROR) << StringPrintf("CondVar::wait: fail get time; errno=0x%X",
    101                                errno);
    102   } else {
    103     absoluteTime.tv_sec += millisec / 1000;
    104     long ns = absoluteTime.tv_nsec + ((millisec % 1000) * 1000000);
    105     if (ns > 1000000000) {
    106       absoluteTime.tv_sec++;
    107       absoluteTime.tv_nsec = ns - 1000000000;
    108     } else
    109       absoluteTime.tv_nsec = ns;
    110   }
    111 
    112   int waitResult =
    113       pthread_cond_timedwait(&mCondition, mutex.nativeHandle(), &absoluteTime);
    114   if ((waitResult != 0) && (waitResult != ETIMEDOUT))
    115     LOG(ERROR) << StringPrintf("CondVar::wait: fail timed wait; error=0x%X",
    116                                waitResult);
    117   retVal = (waitResult == 0);  // waited successfully
    118   return retVal;
    119 }
    120 
    121 /*******************************************************************************
    122 **
    123 ** Function:        notifyOne
    124 **
    125 ** Description:     Unblock the waiting thread.
    126 **
    127 ** Returns:         None.
    128 **
    129 *******************************************************************************/
    130 void CondVar::notifyOne() {
    131   int const res = pthread_cond_signal(&mCondition);
    132   if (res) {
    133     LOG(ERROR) << StringPrintf("CondVar::notifyOne: fail signal; error=0x%X",
    134                                res);
    135   }
    136 }
    137