1 files changed, 110 insertions, 0 deletions
diff --git a/contrib/tools/python3/Lib/_pyrepl/base_eventqueue.py b/contrib/tools/python3/Lib/_pyrepl/base_eventqueue.py
new file mode 100644
index 00000000000..0589a0f437e
--- /dev/null
+++ b/contrib/tools/python3/Lib/_pyrepl/base_eventqueue.py
@@ -0,0 +1,110 @@
+#   Copyright 2000-2008 Michael Hudson-Doyle <[email protected]>
+#                       Armin Rigo
+#
+#                        All Rights Reserved
+#
+#
+# Permission to use, copy, modify, and distribute this software and
+# its documentation for any purpose is hereby granted without fee,
+# provided that the above copyright notice appear in all copies and
+# that both that copyright notice and this permission notice appear in
+# supporting documentation.
+#
+# THE AUTHOR MICHAEL HUDSON DISCLAIMS ALL WARRANTIES WITH REGARD TO
+# THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+# AND FITNESS, IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL,
+# INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+# RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
+# CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+"""
+OS-independent base for an event and VT sequence scanner
+
+See unix_eventqueue and windows_eventqueue for subclasses.
+"""
+
+from collections import deque
+
+from . import keymap
+from .console import Event
+from .trace import trace
+
+class BaseEventQueue:
+    def __init__(self, encoding: str, keymap_dict: dict[bytes, str]) -> None:
+        self.compiled_keymap = keymap.compile_keymap(keymap_dict)
+        self.keymap = self.compiled_keymap
+        trace("keymap {k!r}", k=self.keymap)
+        self.encoding = encoding
+        self.events: deque[Event] = deque()
+        self.buf = bytearray()
+
+    def get(self) -> Event | None:
+        """
+        Retrieves the next event from the queue.
+        """
+        if self.events:
+            return self.events.popleft()
+        else:
+            return None
+
+    def empty(self) -> bool:
+        """
+        Checks if the queue is empty.
+        """
+        return not self.events
+
+    def flush_buf(self) -> bytearray:
+        """
+        Flushes the buffer and returns its contents.
+        """
+        old = self.buf
+        self.buf = bytearray()
+        return old
+
+    def insert(self, event: Event) -> None:
+        """
+        Inserts an event into the queue.
+        """
+        trace('added event {event}', event=event)
+        self.events.append(event)
+
+    def push(self, char: int | bytes) -> None:
+        """
+        Processes a character by updating the buffer and handling special key mappings.
+        """
+        assert isinstance(char, (int, bytes))
+        ord_char = char if isinstance(char, int) else ord(char)
+        char = ord_char.to_bytes()
+        self.buf.append(ord_char)
+
+        if char in self.keymap:
+            if self.keymap is self.compiled_keymap:
+                # sanity check, buffer is empty when a special key comes
+                assert len(self.buf) == 1
+            k = self.keymap[char]
+            trace('found map {k!r}', k=k)
+            if isinstance(k, dict):
+                self.keymap = k
+            else:
+                self.insert(Event('key', k, bytes(self.flush_buf())))
+                self.keymap = self.compiled_keymap
+
+        elif self.buf and self.buf[0] == 27:  # escape
+            # escape sequence not recognized by our keymap: propagate it
+            # outside so that i can be recognized as an M-... key (see also
+            # the docstring in keymap.py
+            trace('unrecognized escape sequence, propagating...')
+            self.keymap = self.compiled_keymap
+            self.insert(Event('key', '\033', b'\033'))
+            for _c in self.flush_buf()[1:]:
+                self.push(_c)
+
+        else:
+            try:
+                decoded = bytes(self.buf).decode(self.encoding)
+            except UnicodeError:
+                return
+            else:
+                self.insert(Event('key', decoded, bytes(self.flush_buf())))
+            self.keymap = self.compiled_keymap