From d09099526220fb87ac8c4f6bae298b23744d0dae Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 15 Jan 2010 01:25:42 +0100
Subject: [PATCH] client: implement $PULSE_LATENCY_MSEC

This allows easy overriding of a clients latency setting for debugging
purposes.

http://pulseaudio.org/ticket/753
---
 src/pulse/stream.c | 37 +++++++++++++++++++++++++++++++------
 1 file changed, 31 insertions(+), 6 deletions(-)

diff --git a/src/pulse/stream.c b/src/pulse/stream.c
index a4f34d9..5e42ab2 100644
--- a/src/pulse/stream.c
+++ b/src/pulse/stream.c
@@ -39,6 +39,7 @@
 #include <pulsecore/hashmap.h>
 #include <pulsecore/macro.h>
 #include <pulsecore/core-rtclock.h>
+#include <pulsecore/core-util.h>
 
 #include "fork-detect.h"
 #include "internal.h"
@@ -855,10 +856,28 @@ static void create_stream_complete(pa_stream *s) {
     check_smoother_status(s, TRUE, FALSE, FALSE);
 }
 
-static void automatic_buffer_attr(pa_stream *s, pa_buffer_attr *attr, const pa_sample_spec *ss) {
+static void patch_buffer_attr(pa_stream *s, pa_buffer_attr *attr, pa_stream_flags_t *flags) {
+    const char *e;
+
     pa_assert(s);
     pa_assert(attr);
-    pa_assert(ss);
+
+    if ((e = getenv("PULSE_LATENCY_MSEC"))) {
+        uint32_t ms;
+
+        if (pa_atou(e, &ms) < 0 || ms <= 0)
+            pa_log_debug("Failed to parse $PULSE_LATENCY_MSEC: %s", e);
+        else {
+            attr->maxlength = (uint32_t) -1;
+            attr->tlength = pa_usec_to_bytes(ms * PA_USEC_PER_MSEC, &s->sample_spec);
+            attr->minreq = (uint32_t) -1;
+            attr->prebuf = (uint32_t) -1;
+            attr->fragsize = attr->tlength;
+        }
+
+        if (flags)
+            *flags |= PA_STREAM_ADJUST_LATENCY;
+    }
 
     if (s->context->version >= 13)
         return;
@@ -873,7 +892,7 @@ static void automatic_buffer_attr(pa_stream *s, pa_buffer_attr *attr, const pa_s
         attr->maxlength = 4*1024*1024; /* 4MB is the maximum queue length PulseAudio <= 0.9.9 supported. */
 
     if (attr->tlength == (uint32_t) -1)
-        attr->tlength = (uint32_t) pa_usec_to_bytes(250*PA_USEC_PER_MSEC, ss); /* 250ms of buffering */
+        attr->tlength = (uint32_t) pa_usec_to_bytes(250*PA_USEC_PER_MSEC, &s->sample_spec); /* 250ms of buffering */
 
     if (attr->minreq == (uint32_t) -1)
         attr->minreq = (attr->tlength)/5; /* Ask for more data when there are only 200ms left in the playback buffer */
@@ -1065,15 +1084,16 @@ static int create_stream(
     pa_stream_ref(s);
 
     s->direction = direction;
-    s->flags = flags;
-    s->corked = !!(flags & PA_STREAM_START_CORKED);
 
     if (sync_stream)
         s->syncid = sync_stream->syncid;
 
     if (attr)
         s->buffer_attr = *attr;
-    automatic_buffer_attr(s, &s->buffer_attr, &s->sample_spec);
+    patch_buffer_attr(s, &s->buffer_attr, &flags);
+
+    s->flags = flags;
+    s->corked = !!(flags & PA_STREAM_START_CORKED);
 
     if (flags & PA_STREAM_INTERPOLATE_TIMING) {
         pa_usec_t x;
@@ -2420,6 +2440,7 @@ pa_operation* pa_stream_set_buffer_attr(pa_stream *s, const pa_buffer_attr *attr
     pa_operation *o;
     pa_tagstruct *t;
     uint32_t tag;
+    pa_buffer_attr copy;
 
     pa_assert(s);
     pa_assert(PA_REFCNT_VALUE(s) >= 1);
@@ -2443,6 +2464,10 @@ pa_operation* pa_stream_set_buffer_attr(pa_stream *s, const pa_buffer_attr *attr
             &tag);
     pa_tagstruct_putu32(t, s->channel);
 
+    copy = *attr;
+    patch_buffer_attr(s, &copy, NULL);
+    attr = &copy;
+
     pa_tagstruct_putu32(t, attr->maxlength);
 
     if (s->direction == PA_STREAM_PLAYBACK)
-- 
2.7.4