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Use ::write instead of pwrite in AudioSource::compute_and_write_peaks for portability

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This destroys the atomicity of pwrite() and thus suggests that we should do something else to ensure
that multithread access to peakfiles (if it does in fact exist) is safe. OTOH, there may be no
such thing, since they are designed for the GUI, which is single threaded (for now)
This commit is contained in:
Paul Davis 2013-07-15 07:53:45 -04:00
parent 13a0f14db7
commit db3edc4018
1 changed files with 23 additions and 7 deletions
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30
libs/ardour/audiosource.cc
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@ -725,12 +725,18 @@ AudioSource::compute_and_write_peaks (Sample* buf, framecnt_t first_frame, frame
off_t byte = (peak_leftover_frame / fpp) * sizeof (PeakData);
#ifndef WIN32
if (::pwrite (_peakfile_fd, &x, sizeof (PeakData), byte) != sizeof (PeakData)) {
off_t offset = lseek (_peakfile_fd, byte, SEEK_SET);
if (offset != byte) {
error << string_compose(_("%1: could not seek in peak file data (%2)"), _name, strerror (errno)) << endmsg;
return -1;
}
if (::write (_peakfile_fd, &x, sizeof (PeakData)) != sizeof (PeakData)) {
error << string_compose(_("%1: could not write peak file data (%2)"), _name, strerror (errno)) << endmsg;
return -1;
}
#endif
_peak_byte_max = max (_peak_byte_max, (off_t) (byte + sizeof(PeakData)));
{
@ -840,14 +846,24 @@ AudioSource::compute_and_write_peaks (Sample* buf, framecnt_t first_frame, frame
}
}
#ifndef WIN32
if (::pwrite (_peakfile_fd, peakbuf.get(), sizeof (PeakData) * peaks_computed, first_peak_byte) != (ssize_t) (sizeof (PeakData) * peaks_computed)) {
off_t offset = lseek(_peakfile_fd, first_peak_byte, SEEK_SET);
if (offset != first_peak_byte) {
error << string_compose(_("%1: could not seek in peak file data (%2)"), _name, strerror (errno)) << endmsg;
return -1;
}
ssize_t bytes_to_write = sizeof (PeakData) * peaks_computed;
ssize_t bytes_written = ::write (_peakfile_fd, peakbuf.get(), bytes_to_write);
if (bytes_written != bytes_to_write) {
error << string_compose(_("%1: could not write peak file data (%2)"), _name, strerror (errno)) << endmsg;
return -1;
}
#endif
_peak_byte_max = max (_peak_byte_max, (off_t) (first_peak_byte + sizeof(PeakData)*peaks_computed));
_peak_byte_max = max (_peak_byte_max, (off_t) (first_peak_byte + bytes_to_write));
if (frames_done) {
Glib::Threads::Mutex::Lock lm (_peaks_ready_lock);