On 20.02.2018 19:49, Raman Shishniou wrote:
On 02/20/2018 07:02 PM, Georg Chini wrote:
On 20.02.2018 16:38, Raman Shyshniou wrote:
Currently the pipe-source will remain running even if no
writer is connected and therefore no data is produced.
This patch adds the autosuspend=<bool> option to prevent this.
Source will stay suspended if no writer is connected.
This option is enabled by default.
---
src/modules/module-pipe-source.c | 279
+++++++++++++++++++++++++++++----------
1 file changed, 212 insertions(+), 67 deletions(-)
I think I need post a simple pseudo code of new thread loop because it
was completely rewritten. There are too many changes in one patch.
It can be difficult to see the whole picture of new main loop.
Well, I applied the patch and looked at the result. I still don't like
the approach.
I would propose this:
auto_suspended = false;
revents = 0
events = POLLIN
for (;;) {
/* This is the part that is run when the source is opened
* or auto suspended
if (SOURCE_IS_OPENED(source) || auto_suspended) {
/* Check if we wake up from user suspend */
if (corkfd >= 0 && !auto_suspended) {
len = 0
close pipe for writing
}
/* We received POLLIN or POLLHUP or both */
if (revents) {
/* Read data from pipe */
len = read data
/* Got data, post it */
if (len > 0) {
if (auto_suspend) {
send unsuspend message
auto_suspend = false
}
post data
/* Got POLLHUP or POLLIN without data, writer disconnected */
} else if (len = 0) {
send suspend message
auto_suspend = true
}
/* else Handle error */
else
handle error
events = POLLIN
}
/* This is the part that is run, when the source is
* suspended by user */
} else {
if (corkfd < 0)
open pipe for writing
events = 0
}
/* This is run always */
run rtpoll
... check errors ...
}
I think this is more consistent with how the other thread functions are
written and also has a clearer structure.
pollfd = NULL;
rtpoll_item = NULL;
chunk.length = 0; // length of pending data in chunk.memblock
chunk.memblock = pa_memblock_new(); // always allocated
for (;;) {
/**************************************************
* run rtpoll
*/
if (chunk.length > 0) {
/* we have a pending data */
if (rtpoll_item) {
/* stop polling pipe
* the only way to be here:
* source was just suspended */
... free rtpoll_item ...
rtpoll_item = NULL;
}
} else {
/* we have no pending data */
if (rtpoll_item == NULL) {
/* start polling pipe
* the only way to be here:
* source was just resumed */
... allocate rtpoll_item, get pollfd ...
pollfd->events = POLLIN;
pollfd->fd = u->fd;
}
}
pa_rtpoll_run()
... check errors ...
if (rtpoll_item) {
/* we polled pipe */
... refresh pollfd ...
} else
/* we are waiting for source state changes */
pollfd = NULL;
/**************************************************
* Read data
*/
if (pollfd && pollfd->revents) {
... read data from pipe ...
if (len > 0) {
chunk.length = len;
/* source is autosuspended? */
if (u->corkfd >= 0) {
... send resume message ...
close(u->corkfd);
u->corkfd = -1;
}
}
if (len == 0) {
/* sourece not autosuspended? */
if (u->corkfd < 0) {
... send suspend message ...
u->corkfd = open(pipe, O_WRONLY);
}
}
if (len < 0) {
... check read error ...
}
}
/**************************************************
* Post data
*/
if (source is opened) {
After an auto-unsuspend, the result of the above comparison is undefined.
It may be that the main thread already processed the unsuspend message,
maybe not.
... post data ...
unref(chunk.memblock);
chunk.memblock = pa_memblock_new();
chunk.length = 0;
}
/* chunk.length can be greater than 0 only if we are suspended right now
* we need to stop polling pipe and wait while state will be changed to
RUNNING or IDLE
* to post pending data */
If we are user suspended right now, the data should never be posted.
Data that is read
while we are user-suspended should be discarded. Data that arrives while
we are
auto-suspended should be posted.
}
I can convert all changes to patch series if you want.
--
Raman
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