peak_amplitude_thread fix - #6807

On windows AudioRegionEditor d'tor never returns, stalling or
crashing in pthread_join() after pthread_cancel().
Crashes happen if two thread pools with the same name exist.
(but since the thread has no event loop, no pool is needed)

After showing Region Properties any operation that would close the dialog
will either cause the application to hang indefinitely or terminate.

This also consolidates code: CrossThreadChannel works on windows these days

diff --git a/gtk2_ardour/audio_region_editor.cc b/gtk2_ardour/audio_region_editor.cc
index 3446f58eeeee56cfe57c88e537995901ac52a96a..a5890a656a8b4673491dcb2ef7f217a611483ef1 100644 (file)
--- a/gtk2_ardour/audio_region_editor.cc
+++ b/gtk2_ardour/audio_region_editor.cc
@@ -43,7 +43,6 @@ using namespace Gtkmm2ext;
 static void *
 _peak_amplitude_thread (void* arg)
 {
-       SessionEvent::create_per_thread_pool ("peak amplitude events", 64);
        static_cast<AudioRegionEditor*>(arg)->peak_amplitude_thread ();
        return 0;
 }
@@ -52,11 +51,7 @@ AudioRegionEditor::AudioRegionEditor (Session* s, boost::shared_ptr<AudioRegion>
        : RegionEditor (s, r)
        , _audio_region (r)
        , gain_adjustment(accurate_coefficient_to_dB(_audio_region->scale_amplitude()), -40.0, +40.0, 0.1, 1.0, 0)
-#ifdef PLATFORM_WINDOWS
-       , m_peak_sem ("peak_semaphore", 0)
-#else
        , _peak_channel (false)
-#endif
 {
 
        Gtk::HBox* b = Gtk::manage (new Gtk::HBox);
@@ -92,14 +87,17 @@ AudioRegionEditor::AudioRegionEditor (Session* s, boost::shared_ptr<AudioRegion>
        _peak_amplitude.set_text (_("Calculating..."));
 
        PeakAmplitudeFound.connect (_peak_amplitude_connection, invalidator (*this), boost::bind (&AudioRegionEditor::peak_amplitude_found, this, _1), gui_context ());
-       pthread_create_and_store (X_("peak-amplitude"), &_peak_amplitude_thread_handle, _peak_amplitude_thread, this);
+
+       char name[64];
+       snprintf (name, 64, "peak amplitude-%p", this);
+       pthread_create_and_store (name, &_peak_amplitude_thread_handle, _peak_amplitude_thread, this);
        signal_peak_thread ();
 }
 
 AudioRegionEditor::~AudioRegionEditor ()
 {
        void* v;
-       pthread_cancel_one (_peak_amplitude_thread_handle);
+       _peak_channel.deliver ('t');
        pthread_join (_peak_amplitude_thread_handle, &v);
 }
 
@@ -138,30 +136,20 @@ AudioRegionEditor::gain_adjustment_changed ()
 void
 AudioRegionEditor::signal_peak_thread ()
 {
-#ifdef PLATFORM_WINDOWS
-       m_peak_sem.signal ();
-#else
        _peak_channel.deliver ('c');
-#endif
-}
-
-void
-AudioRegionEditor::wait_for_signal ()
-{
-#ifdef PLATFORM_WINDOWS
-       m_peak_sem.wait ();
-#else
-       char msg;
-       _peak_channel.receive (msg);
-#endif
 }
 
 void
 AudioRegionEditor::peak_amplitude_thread ()
 {
        while (1) {
+               char msg;
                /* await instructions to run */
-               wait_for_signal ();
+               _peak_channel.receive (msg);
+
+               if (msg == 't') {
+                       break;
+               }
 
                /* compute peak amplitude and signal the fact */
                PeakAmplitudeFound (accurate_coefficient_to_dB (_audio_region->maximum_amplitude ())); /* EMIT SIGNAL */

diff --git a/gtk2_ardour/audio_region_editor.h b/gtk2_ardour/audio_region_editor.h
index dd726bdd5429dcb90093f25572b65b9729599175..083a39dfbc736edf973e202febafdbb638790f07 100644 (file)
--- a/gtk2_ardour/audio_region_editor.h
+++ b/gtk2_ardour/audio_region_editor.h
@@ -36,11 +36,7 @@
 
 
 #include "pbd/signals.h"
-#ifdef PLATFORM_WINDOWS
-#include "pbd/semutils.h"
-#else
 #include "pbd/crossthread.h"
-#endif
 
 #include "audio_clock.h"
 #include "ardour_dialog.h"
@@ -78,16 +74,11 @@ class AudioRegionEditor : public RegionEditor
        Gtk::Entry _peak_amplitude;
 
        void signal_peak_thread ();
-       void wait_for_signal ();
        pthread_t _peak_amplitude_thread_handle;
        void peak_amplitude_found (double);
        PBD::Signal1<void, double> PeakAmplitudeFound;
        PBD::ScopedConnection _peak_amplitude_connection;
-#ifdef PLATFORM_WINDOWS
-       PBD::Semaphore m_peak_sem;
-#else
        CrossThreadChannel _peak_channel;
-#endif
 };
 
 #endif /* __gtk_ardour_audio_region_edit_h__ */