From 5330c541ca7e6c158b96267dd7a7ba1e99a76268 Mon Sep 17 00:00:00 2001
From: Niels Martin Hansen <nielsm@aegisub.org>
Date: Sat, 21 Jun 2008 21:13:00 +0000
Subject: [PATCH] Possible fix for #719

Originally committed to SVN as r2210.
---
 aegisub/audio_player_dsound.cpp | 45 +++++++++++++++++++++------------
 aegisub/audio_player_dsound.h   |  3 +--
 2 files changed, 30 insertions(+), 18 deletions(-)

diff --git a/aegisub/audio_player_dsound.cpp b/aegisub/audio_player_dsound.cpp
index 21fe1647a..96f658631 100644
--- a/aegisub/audio_player_dsound.cpp
+++ b/aegisub/audio_player_dsound.cpp
@@ -48,7 +48,6 @@
 ///////////////
 // Constructor
 DirectSoundPlayer::DirectSoundPlayer() {
-	playing = false;
 	volume = 1.0f;
 	playPos = 0;
 	startPos = 0;
@@ -261,7 +260,6 @@ void DirectSoundPlayer::Play(int64_t start,int64_t count) {
 	// Play
 	buffer->SetCurrentPosition(0);
 	res = buffer->Play(0,0,play_flag);
-	if (SUCCEEDED(res)) playing = true;
 	startTime = GetTickCount();
 
 	// Update timer
@@ -276,18 +274,15 @@ void DirectSoundPlayer::Stop(bool timerToo) {
 	if (thread) {
 		if (thread->IsAlive()) {
 			thread->Stop();
-			// The thread is detached so it kills/deletes itself after being stopped
-			//thread->Wait();
 		}
 		thread = NULL;
 	}
-	// The thread is now guaranteed dead and there are no concurrency problems to worry about
+	// The thread should now stop filling the buffer soon enough that we can safely stop the buffer
+	// and possibly start having soomething else filling it soon.
 
-	// Stop
-	if (buffer) buffer->Stop(); // the thread should have done this already
+	if (buffer) buffer->Stop();
 
 	// Reset variables
-	playing = false;
 	playPos = 0;
 	startPos = 0;
 	endPos = 0;
@@ -303,7 +298,7 @@ void DirectSoundPlayer::Stop(bool timerToo) {
 ///////////
 // Set end
 void DirectSoundPlayer::SetEndPosition(int64_t pos) {
-	if (playing) endPos = pos;
+	if (IsPlaying()) endPos = pos;
 }
 
 
@@ -318,8 +313,8 @@ void DirectSoundPlayer::SetCurrentPosition(int64_t pos) {
 ////////////////////////
 // Get current position
 int64_t DirectSoundPlayer::GetCurrentPosition() {
-	// Check if buffer is loaded
-	if (!buffer || !playing) return 0;
+	// Assume position 0 if we aren't playing currently
+	if (!IsPlaying()) return 0;
 
 	// FIXME: this should be based on not duration played but actual sample being heard
 	// (during vidoeo playback, cur_frame might get changed to resync)
@@ -329,6 +324,20 @@ int64_t DirectSoundPlayer::GetCurrentPosition() {
 }
 
 
+///////////////////////////////////////
+// Check whether the buffer is playing
+bool DirectSoundPlayer::IsPlaying() {
+	if (!buffer) return false;
+
+	DWORD status = 0;
+	if (SUCCEEDED(buffer->GetStatus(&status))) {
+		return !!(status & DSBSTATUS_PLAYING);
+	} else {
+		return false;
+	}
+}
+
+
 //////////////////////
 // Thread constructor
 DirectSoundPlayerThread::DirectSoundPlayerThread(DirectSoundPlayer *par) : wxThread(wxTHREAD_DETACHED) {
@@ -350,6 +359,10 @@ wxThread::ExitCode DirectSoundPlayerThread::Entry() {
 	// Every thread that uses COM must initialise it
 	CoInitialize(0);
 
+	// Make sure we have the buffer available as long as we're alive
+	parent->buffer->AddRef();
+	IDirectSoundBuffer8 *buffer = parent->buffer;
+
 	// Wake up thread every half second to fill buffer as needed
 	// This more or less assumes the buffer is at least one second long
 	while (WaitForSingleObject(stopnotify, 50) == WAIT_TIMEOUT) {
@@ -367,18 +380,18 @@ wxThread::ExitCode DirectSoundPlayerThread::Entry() {
 		DWORD size1, size2;
 		DWORD playpos;
 		HRESULT res;
-		res = parent->buffer->GetCurrentPosition(&playpos, NULL);
+		res = buffer->GetCurrentPosition(&playpos, NULL);
 		if (FAILED(res)) break;
 		int toWrite = playpos - parent->offset;
 		while (toWrite < 0) toWrite += parent->bufSize;
-		res = parent->buffer->Lock(parent->offset, toWrite, &buf1, &size1, &buf2, &size2, 0);
+		res = buffer->Lock(parent->offset, toWrite, &buf1, &size1, &buf2, &size2, 0);
 		if (FAILED(res)) break;
 		if (size1) memset(buf1, 0, size1);
 		if (size2) memset(buf2, 0, size2);
 		if (size1) wxLogDebug(_T("DS blnk: %05ld -> %05ld"), (unsigned long)parent->playPos+bytesFilled, (unsigned long)parent->playPos+bytesFilled+size1);
 		if (size2) wxLogDebug(_T("DS blnk: %05ld => %05ld"), (unsigned long)parent->playPos+bytesFilled+size1, (unsigned long)parent->playPos+bytesFilled+size1+size2);
 		bytesFilled += size1 + size2;
-		parent->buffer->Unlock(buf1, size1, buf2, size2);
+		buffer->Unlock(buf1, size1, buf2, size2);
 		if (bytesFilled > parent->bufSize) break;
 		parent->offset = (parent->offset + size1 + size2) % parent->bufSize;
 	}
@@ -387,8 +400,8 @@ wxThread::ExitCode DirectSoundPlayerThread::Entry() {
 
 	wxLogDebug(_T("DS thread dead"));
 
-	parent->playing = false;
-	parent->buffer->Stop();
+	// Our owner is responsible for stopping the buffer
+	buffer->Release();
 
 	// And un-init COM since we inited it
 	CoUninitialize();
diff --git a/aegisub/audio_player_dsound.h b/aegisub/audio_player_dsound.h
index 9b96bcb88..1af89c735 100644
--- a/aegisub/audio_player_dsound.h
+++ b/aegisub/audio_player_dsound.h
@@ -90,7 +90,6 @@ class DirectSoundPlayer : public AudioPlayer {
 	friend class DirectSoundPlayerThread;
 
 private:
-	volatile bool playing;
 	float volume;
 	int offset;
 	DWORD bufSize;
@@ -116,7 +115,7 @@ public:
 
 	void Play(int64_t start,int64_t count);
 	void Stop(bool timerToo=true);
-	bool IsPlaying() { return playing; }
+	bool IsPlaying();
 
 	int64_t GetStartPosition() { return startPos; }
 	int64_t GetEndPosition() { return endPos; }