[PATCH 3/6] winealsa: Use a pipe to signal the end of the record thread.

[Huw Davies]

This means the thread doesn't have to wake every 250ms to test
"end_thread".

Signed-off-by: Huw Davies <huw(a)codeweavers.com>
---
 dlls/winealsa.drv/midi.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/dlls/winealsa.drv/midi.c b/dlls/winealsa.drv/midi.c
index 4cc906b03ca..327d4b7b200 100644
--- a/dlls/winealsa.drv/midi.c
+++ b/dlls/winealsa.drv/midi.c
@@ -54,7 +54,7 @@ static	int 		MIDM_NumDevs = 0;
 
 static	int		numStartedMidiIn = 0;
 
-static int end_thread;
+static int rec_cancel_pipe[2];
 static HANDLE hThread;
 
 static void seq_lock(void)
@@ -162,18 +162,25 @@ static DWORD WINAPI midRecThread(void *arg)
     struct pollfd *pollfd;
     int ret;
 
-    num_fds = snd_seq_poll_descriptors_count(midi_seq, POLLIN);
+    /* Add on one for the read end of the cancel pipe */
+    num_fds = snd_seq_poll_descriptors_count(midi_seq, POLLIN) + 1;
     pollfd = malloc(num_fds * sizeof(struct pollfd));
 
-    while(!end_thread) {
+    while(1) {
+        pollfd[0].fd = rec_cancel_pipe[0];
+        pollfd[0].events = POLLIN;
+
         seq_lock();
-        snd_seq_poll_descriptors(midi_seq, pollfd, num_fds, POLLIN);
+        snd_seq_poll_descriptors(midi_seq, pollfd + 1, num_fds - 1, POLLIN);
         seq_unlock();
 
 	/* Check if an event is present */
-        if (poll(pollfd, num_fds, 250) <= 0)
+        if (poll(pollfd, num_fds, -1) <= 0)
             continue;
 
+        if (pollfd[0].revents & POLLIN) /* cancelled */
+            break;
+
 	do {
             snd_seq_event_t *ev;
 
@@ -259,9 +266,11 @@ static DWORD midOpen(WORD wDevID, LPMIDIOPENDESC lpDesc, DWORD dwFlags)
     TRACE("Input port :%d connected %d:%d\n",port_in,MidiInDev[wDevID].addr.client,MidiInDev[wDevID].addr.port);
 
     if (numStartedMidiIn++ == 0) {
-	end_thread = 0;
+	pipe(rec_cancel_pipe);
 	hThread = CreateThread(NULL, 0, midRecThread, midi_seq, 0, NULL);
 	if (!hThread) {
+            close(rec_cancel_pipe[0]);
+            close(rec_cancel_pipe[1]);
 	    numStartedMidiIn = 0;
 	    WARN("Couldn't create thread for midi-in\n");
 	    midiCloseSeq();
@@ -302,11 +311,13 @@ static DWORD midClose(WORD wDevID)
     }
     if (--numStartedMidiIn == 0) {
 	TRACE("Stopping thread for midi-in\n");
-	end_thread = 1;
+        write(rec_cancel_pipe[1], "x", 1);
 	if (WaitForSingleObject(hThread, 5000) != WAIT_OBJECT_0) {
 	    WARN("Thread end not signaled, force termination\n");
 	    TerminateThread(hThread, 0);
 	}
+        close(rec_cancel_pipe[0]);
+        close(rec_cancel_pipe[1]);
     	TRACE("Stopped thread for midi-in\n");
     }
 
-- 
2.25.1

[Andrew Eikum]

Signed-off-by: Andrew Eikum <aeikum(a)codeweavers.com>

On Fri, Mar 25, 2022 at 08:42:16AM +0000, Huw Davies wrote:
> This means the thread doesn't have to wake every 250ms to test
> "end_thread".
>
> Signed-off-by: Huw Davies <huw(a)codeweavers.com>
> ---
>  dlls/winealsa.drv/midi.c | 25 ++++++++++++++++++-------
>  1 file changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/dlls/winealsa.drv/midi.c b/dlls/winealsa.drv/midi.c
> index 4cc906b03ca..327d4b7b200 100644
> --- a/dlls/winealsa.drv/midi.c
> +++ b/dlls/winealsa.drv/midi.c
> @@ -54,7 +54,7 @@ static	int 		MIDM_NumDevs = 0;
>
> static	int		numStartedMidiIn = 0;
>
> -static int end_thread;
> +static int rec_cancel_pipe[2];
>  static HANDLE hThread;
>
> static void seq_lock(void)
> @@ -162,18 +162,25 @@ static DWORD WINAPI midRecThread(void *arg)
>      struct pollfd *pollfd;
>      int ret;
>
> -    num_fds = snd_seq_poll_descriptors_count(midi_seq, POLLIN);
> +    /* Add on one for the read end of the cancel pipe */
> +    num_fds = snd_seq_poll_descriptors_count(midi_seq, POLLIN) + 1;
>      pollfd = malloc(num_fds * sizeof(struct pollfd));
>
> -    while(!end_thread) {
> +    while(1) {
> +        pollfd[0].fd = rec_cancel_pipe[0];
> +        pollfd[0].events = POLLIN;
> +
>          seq_lock();
> -        snd_seq_poll_descriptors(midi_seq, pollfd, num_fds, POLLIN);
> +        snd_seq_poll_descriptors(midi_seq, pollfd + 1, num_fds - 1, POLLIN);
>          seq_unlock();
>
> /* Check if an event is present */
> -        if (poll(pollfd, num_fds, 250) <= 0)
> +        if (poll(pollfd, num_fds, -1) <= 0)
>              continue;
>
> +        if (pollfd[0].revents & POLLIN) /* cancelled */
> +            break;
> +
>   do {
>              snd_seq_event_t *ev;
>
> @@ -259,9 +266,11 @@ static DWORD midOpen(WORD wDevID, LPMIDIOPENDESC lpDesc, DWORD dwFlags)
>      TRACE("Input port :%d connected %d:%d\n",port_in,MidiInDev[wDevID].addr.client,MidiInDev[wDevID].addr.port);
>
> if (numStartedMidiIn++ == 0) {
> -	end_thread = 0;
> +	pipe(rec_cancel_pipe);
>   hThread = CreateThread(NULL, 0, midRecThread, midi_seq, 0, NULL);
>   if (!hThread) {
> +            close(rec_cancel_pipe[0]);
> +            close(rec_cancel_pipe[1]);
>       numStartedMidiIn = 0;
>       WARN("Couldn't create thread for midi-in\n");
>       midiCloseSeq();
> @@ -302,11 +311,13 @@ static DWORD midClose(WORD wDevID)
>      }
>      if (--numStartedMidiIn == 0) {
>   TRACE("Stopping thread for midi-in\n");
> -	end_thread = 1;
> +        write(rec_cancel_pipe[1], "x", 1);
>   if (WaitForSingleObject(hThread, 5000) != WAIT_OBJECT_0) {
>       WARN("Thread end not signaled, force termination\n");
>       TerminateThread(hThread, 0);
>   }
> +        close(rec_cancel_pipe[0]);
> +        close(rec_cancel_pipe[1]);
>      	TRACE("Stopped thread for midi-in\n");
>      }
>
> -- 
> 2.25.1