1 files changed, 79 insertions, 0 deletions
diff --git a/src/prompt_toolkit/input/defaults.py b/src/prompt_toolkit/input/defaults.py
new file mode 100644
index 0000000..483eeb2
--- /dev/null
+++ b/src/prompt_toolkit/input/defaults.py
@@ -0,0 +1,79 @@
+from __future__ import annotations
+
+import io
+import sys
+from typing import ContextManager, TextIO
+
+from .base import DummyInput, Input, PipeInput
+
+__all__ = [
+    "create_input",
+    "create_pipe_input",
+]
+
+
+def create_input(stdin: TextIO | None = None, always_prefer_tty: bool = False) -> Input:
+    """
+    Create the appropriate `Input` object for the current os/environment.
+
+    :param always_prefer_tty: When set, if `sys.stdin` is connected to a Unix
+        `pipe`, check whether `sys.stdout` or `sys.stderr` are connected to a
+        pseudo terminal. If so, open the tty for reading instead of reading for
+        `sys.stdin`. (We can open `stdout` or `stderr` for reading, this is how
+        a `$PAGER` works.)
+    """
+    if sys.platform == "win32":
+        from .win32 import Win32Input
+
+        # If `stdin` was assigned `None` (which happens with pythonw.exe), use
+        # a `DummyInput`. This triggers `EOFError` in the application code.
+        if stdin is None and sys.stdin is None:
+            return DummyInput()
+
+        return Win32Input(stdin or sys.stdin)
+    else:
+        from .vt100 import Vt100Input
+
+        # If no input TextIO is given, use stdin/stdout.
+        if stdin is None:
+            stdin = sys.stdin
+
+            if always_prefer_tty:
+                for obj in [sys.stdin, sys.stdout, sys.stderr]:
+                    if obj.isatty():
+                        stdin = obj
+                        break
+
+        # If we can't access the file descriptor for the selected stdin, return
+        # a `DummyInput` instead. This can happen for instance in unit tests,
+        # when `sys.stdin` is patched by something that's not an actual file.
+        # (Instantiating `Vt100Input` would fail in this case.)
+        try:
+            stdin.fileno()
+        except io.UnsupportedOperation:
+            return DummyInput()
+
+        return Vt100Input(stdin)
+
+
+def create_pipe_input() -> ContextManager[PipeInput]:
+    """
+    Create an input pipe.
+    This is mostly useful for unit testing.
+
+    Usage::
+
+        with create_pipe_input() as input:
+            input.send_text('inputdata')
+
+    Breaking change: In prompt_toolkit 3.0.28 and earlier, this was returning
+    the `PipeInput` directly, rather than through a context manager.
+    """
+    if sys.platform == "win32":
+        from .win32_pipe import Win32PipeInput
+
+        return Win32PipeInput.create()
+    else:
+        from .posix_pipe import PosixPipeInput
+
+        return PosixPipeInput.create()