From 13a0f14db71dd22b9a6c7f7039ebf6089144a7f8 Mon Sep 17 00:00:00 2001 From: Paul Davis Date: Mon, 15 Jul 2013 07:52:37 -0400 Subject: Use ::read instead of pread in AudioSource::read_peaks for portability This destroys the atomicity of pread() 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) --- libs/ardour/audiosource.cc | 32 ++++++++++++++++++++++---------- 1 file changed, 22 insertions(+), 10 deletions(-) (limited to 'libs/ardour') diff --git a/libs/ardour/audiosource.cc b/libs/ardour/audiosource.cc index 35b7da2108..776749fb57 100644 --- a/libs/ardour/audiosource.cc +++ b/libs/ardour/audiosource.cc @@ -370,8 +370,9 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, framecnt_t npeaks, framepos_t if (scale == 1.0) { + off_t offset = 0; off_t first_peak_byte = (start / samples_per_file_peak) * sizeof (PeakData); - + ssize_t bytes_to_read = sizeof (PeakData)* npeaks; /* open, read, close */ if ((peakfile_fd = peakfile_descriptor->allocate ()) < 0) { @@ -381,11 +382,16 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, framecnt_t npeaks, framepos_t DEBUG_TRACE (DEBUG::Peaks, "DIRECT PEAKS\n"); -#ifndef WIN32 - nread = ::pread (peakfile_fd, peaks, sizeof (PeakData)* npeaks, first_peak_byte); -#endif + offset = lseek (peakfile_fd, first_peak_byte, SEEK_SET); + + if (offset != first_peak_byte) { + error << string_compose(_("AudioSource: could not seek to correct location in peak file \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg; + return -1; + } + + nread = ::read (peakfile_fd, peaks, bytes_to_read); - if (nread != sizeof (PeakData) * npeaks) { + if (nread != bytes_to_read) { DEBUG_TRACE (DEBUG::Peaks, string_compose ("[%1]: Cannot read peaks from peakfile! (read only %2 not %3 at sample %4 = byte %5 )\n" , _name, nread, npeaks, start, first_peak_byte)); return -1; @@ -448,13 +454,20 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, framecnt_t npeaks, framepos_t uint32_t start_byte = current_stored_peak * sizeof(PeakData); tnp = min ((framecnt_t)(_length/samples_per_file_peak - current_stored_peak), (framecnt_t) expected_peaks); to_read = min (chunksize, tnp); + ssize_t bytes_to_read = sizeof (PeakData) * to_read; DEBUG_TRACE (DEBUG::Peaks, string_compose ("reading %1 bytes from peakfile @ %2\n" - , sizeof (PeakData) * to_read, start_byte)); + , bytes_to_read, start_byte)); -#ifndef WIN32 - if ((nread = ::pread (peakfile_fd, staging.get(), sizeof (PeakData) * to_read, start_byte)) - != sizeof (PeakData) * to_read) { + + off_t offset = lseek (peakfile_fd, start_byte, SEEK_SET); + + if (offset != start_byte) { + error << string_compose(_("AudioSource: could not seek to correct location in peak file \"%1\" (%2)"), peakpath, strerror (errno)) << endmsg; + return -1; + } + + if ((nread = ::read (peakfile_fd, staging.get(), bytes_to_read)) != bytes_to_read) { off_t fend = lseek (peakfile_fd, 0, SEEK_END); @@ -462,7 +475,6 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, framecnt_t npeaks, framepos_t , _name, (nread / sizeof(PeakData)), to_read, g_strerror (errno), start_byte, _length, fend, ((_length - current_frame)/samples_per_file_peak), npeaks)); return -1; } -#endif i = 0; stored_peaks_read = nread / sizeof(PeakData); } -- cgit v1.2.3