chore: import upstream snapshot with attribution

python/mirage/io/async_line_iterator.py

@@ -0,0 +1,50 @@
+# ========= Copyright 2026 @ Strukto.AI All Rights Reserved. =========
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ========= Copyright 2026 @ Strukto.AI All Rights Reserved. =========
+
+from collections.abc import AsyncIterator
+
+
+class AsyncLineIterator:
+
+    def __init__(self, source: AsyncIterator[bytes]) -> None:
+        self._source = source
+        self._buf = b""
+        self._exhausted = False
+
+    def __aiter__(self) -> "AsyncLineIterator":
+        return self
+
+    async def __anext__(self) -> bytes:
+        line = await self.readline()
+        if line is None:
+            raise StopAsyncIteration
+        return line
+
+    async def readline(self) -> bytes | None:
+        """Return next line (without trailing newline), or None at EOF."""
+        while b"\n" not in self._buf:
+            if self._exhausted:
+                if self._buf:
+                    remaining = self._buf
+                    self._buf = b""
+                    return remaining
+                return None
+            try:
+                chunk = await self._source.__anext__()
+            except StopAsyncIteration:
+                self._exhausted = True
+                continue
+            self._buf += chunk
+        line, self._buf = self._buf.split(b"\n", 1)
+        return line