pa_mac_core_blocking: fix hang when running stream stopped

One thread was filling the buffer while
another thread was waiting for it to be empty.

Add thread safety warnings.

Fix ticket #252

test/patest_write_stop_hang_illegal.c

@@ -0,0 +1,166 @@
+/** @file patest_write_stop_threads.c
+	@brief Call Pa_StopStream() from another thread to see if PortAudio hangs.
+	@author Bjorn Roche of XO Audio (www.xoaudio.com)
+	@author Ross Bencina
+	@author Phil Burk
+*/
+/*
+ * $Id$
+ *
+ * This program uses the PortAudio Portable Audio Library.
+ * For more information see: http://www.portaudio.com/
+ * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
+ * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/*
+ * The text above constitutes the entire PortAudio license; however,
+ * the PortAudio community also makes the following non-binding requests:
+ *
+ * Any person wishing to distribute modifications to the Software is
+ * requested to send the modifications to the original developer so that
+ * they can be incorporated into the canonical version. It is also
+ * requested that these non-binding requests be included along with the
+ * license above.
+ */
+
+#include <stdio.h>
+#include <math.h>
+#include <memory.h>
+/* pthread may only be available on Mac and Linux. */
+#include <pthread.h>
+#include "portaudio.h"
+
+#define SAMPLE_RATE         (44100)
+#define FRAMES_PER_BUFFER   (4096)
+
+static float s_buffer[FRAMES_PER_BUFFER][2]; /* stereo output buffer */
+
+/**
+ * WARNING: PortAudio is NOT thread safe. DO NOT call PortAudio
+ * from multiple threads without synchronization. This test uses
+ * PA in an ILLEGAL WAY in order to try to flush out potential hang bugs.
+ * The test calls Pa_WriteStream() and Pa_StopStream() simultaneously
+ * from separate threads in order to try to cause Pa_StopStream() to hang.
+ * In the main thread we write to the stream in a loop.
+ * Then try stopping PA from another thread to see if it hangs.
+ *
+ * @note: Do not expect this test to pass. The test is only here
+ * as a debugging aid for hang bugs. Since this test uses PA in an
+ * illegal way, it may fail for reasons that are not PA bugs.
+ */
+
+/* Wait for awhile then abort the stream. */
+void *stop_thread_proc(void *arg)
+{
+    PaStream *stream = (PaStream *)arg;
+    PaTime time;
+    for (int i = 0; i < 20; i++)
+    {
+        time = Pa_GetStreamTime( stream );
+        printf("Stream time = %f\n", time);
+        fflush(stdout);
+        Pa_Sleep(100);
+    }
+    printf("Call Pa_StopStream()\n");
+    fflush(stdout);
+    /* ILLEGAL unsynchronised call to PA, see comment above */
+    PaError err = Pa_StopStream( stream );
+    printf("Pa_StopStream() returned %d\n", err);
+    fflush(stdout);
+
+    return stream;
+}
+
+int main(void);
+int main(void)
+{
+    PaStreamParameters outputParameters;
+    PaStream *stream;
+    PaError err;
+    int result;
+    pthread_t thread;
+
+    printf( "PortAudio Test: output silence and stop from another thread. SR = %d, BufSize = %d\n",
+            SAMPLE_RATE, FRAMES_PER_BUFFER);
+
+    err = Pa_Initialize();
+    if( err != paNoError ) goto error;
+
+    outputParameters.device = Pa_GetDefaultOutputDevice(); /* default output device */
+    outputParameters.channelCount = 2;       /* stereo output */
+    outputParameters.sampleFormat = paFloat32; /* 32 bit floating point output */
+    outputParameters.suggestedLatency = Pa_GetDeviceInfo( outputParameters.device )->defaultHighOutputLatency * 5;
+    outputParameters.hostApiSpecificStreamInfo = NULL;
+
+    /* open the stream */
+    err = Pa_OpenStream(
+              &stream,
+              NULL, /* no input */
+              &outputParameters,
+              SAMPLE_RATE,
+              FRAMES_PER_BUFFER,
+              paClipOff,      /* we won't output out of range samples so don't bother clipping them */
+              NULL, /* no callback, use blocking API */
+              NULL ); /* no callback, so no callback userData */
+    if( err != paNoError ) goto error;
+
+    result = pthread_create(&thread, NULL /* attributes */, stop_thread_proc, stream);
+
+    /* start the stream */
+    err = Pa_StartStream( stream );
+    if( err != paNoError ) goto error;
+
+    /* clear buffer */
+    memset( s_buffer, 0, sizeof(s_buffer) );
+
+    /* play the silent buffer many times */
+    while( Pa_IsStreamActive(stream) > 0 )
+    {
+        err = Pa_WriteStream( stream, s_buffer, FRAMES_PER_BUFFER );
+        printf("Pa_WriteStream returns %d = %s\n", err, Pa_GetErrorText( err ));
+        if( err != paNoError )
+        {
+            err = paNoError;
+            break;
+        };
+    }
+
+    printf("Try to join the thread that called Pa_StopStream().\n");
+    result = pthread_join( thread, NULL );
+    printf("pthread_join returned %d\n", result);
+
+    /* close, and terminate */
+    printf("Call Pa_CloseStream\n");
+    err = Pa_CloseStream( stream );
+    if( err != paNoError ) goto error;
+
+    Pa_Terminate();
+    printf("Test finished.\n");
+
+    return err;
+error:
+    Pa_Terminate();
+    fprintf( stderr, "An error occured while using the portaudio stream\n" );
+    fprintf( stderr, "Error number: %d\n", err );
+    fprintf( stderr, "Error message: %s\n", Pa_GetErrorText( err ) );
+    return err;
+}