Add `sphinx.util._io`

sphinx/util/_io.py

@@ -0,0 +1,31 @@
+from typing import TYPE_CHECKING
+
+from sphinx.util.console import strip_colors
+
+if TYPE_CHECKING:
+    from typing import Protocol
+
+    class SupportsWrite(Protocol):
+        def write(self, text: str, /) -> None:
+            ...
+
+
+class TeeStripANSI:
+    """File-like object writing to two streams."""
+    def __init__(
+        self,
+        stream_term: SupportsWrite,
+        stream_file: SupportsWrite,
+    ) -> None:
+        self.stream_term = stream_term
+        self.stream_file = stream_file
+
+    def write(self, text: str, /) -> None:
+        self.stream_term.write(text)
+        self.stream_file.write(strip_colors(text))
+
+    def flush(self) -> None:
+        if hasattr(self.stream_term, 'flush'):
+            self.stream_term.flush()
+        if hasattr(self.stream_file, 'flush'):
+            self.stream_file.flush()