zypp/base/CleanerThread.cc

   1 /*---------------------------------------------------------------------\
   2 |                          ____ _   __ __ ___                          |
   3 |                         |__  / \ / / . \ . \                         |
   4 |                           / / \ V /|  _/  _/                         |
   5 |                          / /__ | | | | | |                           |
   6 |                         /_____||_| |_| |_|                           |
   7 |                                                                      |
   8 \---------------------------------------------------------------------*/
   9 /** \file       zypp/base/CleanerThread.cc
  10  */
  11
  12 #include <zypp/base/CleanerThread_p.h>
  13 #include <algorithm>
  14 #include <thread>
  15 #include <mutex>
  16 #include <condition_variable>
  17 #include <chrono>
  18 #include <vector>
  19 #include <sys/types.h>
  20 #include <sys/wait.h>
  21
  22 struct CleanerData
  23 {
  24   static CleanerData &instance ()
  25   {
  26     // C++11 requires that this is thread safe "magic statics"
  27     // this is a intentional leak and will live until the application exits
  28     static CleanerData *data( new CleanerData );
  29     return *data;
  30   }
  31
  32   CleanerData ()
  33   {
  34     std::thread t ( [&](){
  35       this->run();
  36     } );
  37     t.detach(); //we will control the thread otherwise
  38   }
  39
  40   void run ()
  41   {
  42     std::unique_lock<std::mutex> lk( _m );
  43
  44     while ( true )
  45     {
  46       auto filter = []( pid_t pid ){
  47         int status = 0;
  48         int res = waitpid( pid, &status, WNOHANG );
  49          // we either got an error, or the child has exited, remove it from list
  50         bool removeMe = ( res == -1 || res == pid  );
  51         return removeMe;
  52       };
  53       _watchedPIDs.erase( std::remove_if( _watchedPIDs.begin(), _watchedPIDs.end(), filter ), _watchedPIDs.end() );
  54
  55       if ( _watchedPIDs.size() )
  56         _cv.wait_for( lk, std::chrono::milliseconds(100) );
  57       else
  58         _cv.wait( lk );
  59     }
  60   }
  61
  62   std::mutex _m; // < locks all data in CleanerData, do not access it without owning the mutex
  63   std::condition_variable _cv;
  64
  65   std::vector<pid_t> _watchedPIDs;
  66 };
  67
  68
  69 void zypp::CleanerThread::watchPID( pid_t pid_r )
  70 {
  71   CleanerData &data = CleanerData::instance();
  72   {
  73     std::lock_guard<std::mutex> guard( data._m );
  74     data._watchedPIDs.push_back( pid_r );
  75   }
  76   //wake the thread up
  77   data._cv.notify_one();
  78 }