AirTV-Qt/qtsingleapplication/src/qtlockedfile_unix.cpp

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  39
  40 #include <string.h>
  41 #include <errno.h>
  42 #include <unistd.h>
  43 #include <fcntl.h>
  44
  45 #include "qtlockedfile.h"
  46
  47 bool QtLockedFile::lock(LockMode mode, bool block)
  48 {
  49     if (!isOpen()) {
  50         qWarning("QtLockedFile::lock(): file is not opened");
  51         return false;
  52     }
  53
  54     if (mode == NoLock)
  55         return unlock();
  56
  57     if (mode == m_lock_mode)
  58         return true;
  59
  60     if (m_lock_mode != NoLock)
  61         unlock();
  62
  63     struct flock fl;
  64     fl.l_whence = SEEK_SET;
  65     fl.l_start = 0;
  66     fl.l_len = 0;
  67     fl.l_type = (mode == ReadLock) ? F_RDLCK : F_WRLCK;
  68     int cmd = block ? F_SETLKW : F_SETLK;
  69     int ret = fcntl(handle(), cmd, &fl);
  70
  71     if (ret == -1) {
  72         if (errno != EINTR && errno != EAGAIN)
  73             qWarning("QtLockedFile::lock(): fcntl: %s", strerror(errno));
  74         return false;
  75     }
  76
  77
  78     m_lock_mode = mode;
  79     return true;
  80 }
  81
  82
  83 bool QtLockedFile::unlock()
  84 {
  85     if (!isOpen()) {
  86         qWarning("QtLockedFile::unlock(): file is not opened");
  87         return false;
  88     }
  89
  90     if (!isLocked())
  91         return true;
  92
  93     struct flock fl;
  94     fl.l_whence = SEEK_SET;
  95     fl.l_start = 0;
  96     fl.l_len = 0;
  97     fl.l_type = F_UNLCK;
  98     int ret = fcntl(handle(), F_SETLKW, &fl);
  99
 100     if (ret == -1) {
 101         qWarning("QtLockedFile::lock(): fcntl: %s", strerror(errno));
 102         return false;
 103     }
 104
 105     m_lock_mode = NoLock;
 106     return true;
 107 }
 108
 109 QtLockedFile::~QtLockedFile()
 110 {
 111     if (isOpen())
 112         unlock();
 113 }
 114