Split StreamState class out of SegmentBuffer (#60423)

This refactoring was pulled out of https://github.com/home-assistant/core/pull/53676 as an
initial step towards reverting the addition of the SegmentBuffer class, which will be
unrolled back into a for loop.

The StreamState class holds the persistent state in stream that is used across stream worker
instantiations, e.g. state across a retry or url expiration, which primarily handles
discontinuities. By itself, this PR is not a large win until follow up PRs further simplify
the SegmentBuffer class.

tests/components/stream/conftest.py

@@ -23,7 +23,7 @@ import async_timeout
 import pytest
 
 from homeassistant.components.stream.core import Segment, StreamOutput
-from homeassistant.components.stream.worker import SegmentBuffer
+from homeassistant.components.stream.worker import StreamState
 
 TEST_TIMEOUT = 7.0  # Lower than 9s home assistant timeout
 
@@ -34,7 +34,7 @@ class WorkerSync:
     def __init__(self):
         """Initialize WorkerSync."""
         self._event = None
-        self._original = SegmentBuffer.discontinuity
+        self._original = StreamState.discontinuity
 
     def pause(self):
         """Pause the worker before it finalizes the stream."""
@@ -45,7 +45,7 @@ class WorkerSync:
         logging.debug("waking blocked worker")
         self._event.set()
 
-    def blocking_discontinuity(self, stream: SegmentBuffer):
+    def blocking_discontinuity(self, stream_state: StreamState):
         """Intercept call to pause stream worker."""
         # Worker is ending the stream, which clears all output buffers.
         # Block the worker thread until the test has a chance to verify
@@ -55,7 +55,7 @@ class WorkerSync:
             self._event.wait()
 
         # Forward to actual implementation
-        self._original(stream)
+        self._original(stream_state)
 
 
 @pytest.fixture()
@@ -63,7 +63,7 @@ def stream_worker_sync(hass):
     """Patch StreamOutput to allow test to synchronize worker stream end."""
     sync = WorkerSync()
     with patch(
-        "homeassistant.components.stream.worker.SegmentBuffer.discontinuity",
+        "homeassistant.components.stream.worker.StreamState.discontinuity",
         side_effect=sync.blocking_discontinuity,
         autospec=True,
     ):

tests/components/stream/test_worker.py

@@ -38,8 +38,8 @@ from homeassistant.components.stream.const import (
 )
 from homeassistant.components.stream.core import StreamSettings
 from homeassistant.components.stream.worker import (
-    SegmentBuffer,
     StreamEndedError,
+    StreamState,
     StreamWorkerError,
     stream_worker,
 )
@@ -255,6 +255,12 @@ class MockPyAv:
         return self.container
 
 
+def run_worker(hass, stream, stream_source):
+    """Run the stream worker under test."""
+    stream_state = StreamState(hass, stream.outputs)
+    stream_worker(stream_source, {}, stream_state, threading.Event())
+
+
 async def async_decode_stream(hass, packets, py_av=None):
     """Start a stream worker that decodes incoming stream packets into output segments."""
     stream = Stream(hass, STREAM_SOURCE, {})
@@ -268,9 +274,8 @@ async def async_decode_stream(hass, packets, py_av=None):
         "homeassistant.components.stream.core.StreamOutput.put",
         side_effect=py_av.capture_buffer.capture_output_segment,
     ):
-        segment_buffer = SegmentBuffer(hass, stream.outputs)
         try:
-            stream_worker(STREAM_SOURCE, {}, segment_buffer, threading.Event())
+            run_worker(hass, stream, STREAM_SOURCE)
         except StreamEndedError:
             # Tests only use a limited number of packets, then the worker exits as expected. In
             # production, stream ending would be unexpected.
@@ -288,8 +293,7 @@ async def test_stream_open_fails(hass):
     stream.add_provider(HLS_PROVIDER)
     with patch("av.open") as av_open, pytest.raises(StreamWorkerError):
         av_open.side_effect = av.error.InvalidDataError(-2, "error")
-        segment_buffer = SegmentBuffer(hass, stream.outputs)
-        stream_worker(STREAM_SOURCE, {}, segment_buffer, threading.Event())
+        run_worker(hass, stream, STREAM_SOURCE)
         await hass.async_block_till_done()
         av_open.assert_called_once()
 
@@ -695,10 +699,7 @@ async def test_worker_log(hass, caplog):
 
     with patch("av.open") as av_open, pytest.raises(StreamWorkerError) as err:
         av_open.side_effect = av.error.InvalidDataError(-2, "error")
-        segment_buffer = SegmentBuffer(hass, stream.outputs)
-        stream_worker(
-            "https://abcd:efgh@foo.bar", {}, segment_buffer, threading.Event()
-        )
+        run_worker(hass, stream, "https://abcd:efgh@foo.bar")
         await hass.async_block_till_done()
     assert str(err.value) == "Error opening stream https://****:****@foo.bar"
     assert "https://abcd:efgh@foo.bar" not in caplog.text