intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 46 insertions, 0 deletions

diff --git a/contrib/python/prompt-toolkit/py3/prompt_toolkit/clipboard/in_memory.py b/contrib/python/prompt-toolkit/py3/prompt_toolkit/clipboard/in_memory.py
new file mode 100644
index 00000000000..1902e36a55f
--- /dev/null
+++ b/contrib/python/prompt-toolkit/py3/prompt_toolkit/clipboard/in_memory.py
@@ -0,0 +1,46 @@
+from collections import deque
+from typing import Deque, Optional
+
+from .base import Clipboard, ClipboardData
+
+__all__ = [
+    "InMemoryClipboard",
+]
+
+
+class InMemoryClipboard(Clipboard):
+    """
+    Default clipboard implementation.
+    Just keep the data in memory.
+
+    This implements a kill-ring, for Emacs mode.
+    """
+
+    def __init__(
+        self, data: Optional[ClipboardData] = None, max_size: int = 60
+    ) -> None:
+
+        assert max_size >= 1
+
+        self.max_size = max_size
+        self._ring: Deque[ClipboardData] = deque()
+
+        if data is not None:
+            self.set_data(data)
+
+    def set_data(self, data: ClipboardData) -> None:
+        self._ring.appendleft(data)
+
+        while len(self._ring) > self.max_size:
+            self._ring.pop()
+
+    def get_data(self) -> ClipboardData:
+        if self._ring:
+            return self._ring[0]
+        else:
+            return ClipboardData()
+
+    def rotate(self) -> None:
+        if self._ring:
+            # Add the very first item at the end.
+            self._ring.append(self._ring.popleft())