Native sleeper operator.

CHANGES.md

@@ -79,6 +79,7 @@ Changed:
 - Added `settings.protocol.youtube_dl.timeout` to specify timeout when using
   `youtube-dl` protocol (#2827). Use `yt-dlp` as default binary for the
   protocol.
+- The `sleeper` operator is now scripted (#2899).
 
 Fixed:
 

src/core/dune

@@ -216,7 +216,6 @@
   sha1
   shebang
   shine_format
-  sleeper
   source
   speex_format
   srt_decoder

src/libs/stdlib.liq

@@ -42,6 +42,7 @@
 %include "profiler.liq"
 %include "io.liq"
 %include "runtime.liq"
+%include "testing.liq"
 %include "liquidsoap.liq"
 
 set_settings_ref(settings)

src/libs/testing.liq

@@ -0,0 +1,24 @@
+# Sleep regularly, thus inducing delays in the sound production. This is mainly
+# useful for emulating network delays or sources which are slow to produce data,
+# and thus test bufferization and robustness of scripts.
+# @category Source / Testing
+# @flag experimental
+# @param ~every How often we should sleep (in seconds, 0 means every frame).
+# @param ~delay Delay introduced (in seconds).
+# @param ~delay_random Maximum amount of time randomly added to the delay (in seconds).
+# @param s Source in which the delays should be introduced.
+# @method frozen The stream production is frozen while set to `true`.
+def sleeper(~every=0.5, ~delay=0.1, ~delay_random=0., s)
+  last = ref(0.)
+  frozen = ref(false)
+  def f()
+    now = source.time(s)
+    while frozen() do sleep(0.1) end
+    if now + every >= last() then
+      last := now
+      sleep(delay + random.float(max=delay_random))
+    end
+  end
+  s = source.on_frame(s,f)
+  s.{frozen = frozen}
+end