split out History

babi/history.py

@@ -0,0 +1,34 @@
+import collections
+import contextlib
+import os.path
+from typing import Dict
+from typing import Generator
+from typing import List
+
+
+class History:
+    def __init__(self) -> None:
+        self._orig_len: Dict[str, int] = collections.defaultdict(int)
+        self.data: Dict[str, List[str]] = collections.defaultdict(list)
+        self.prev: Dict[str, str] = {}
+
+    @contextlib.contextmanager
+    def save(self) -> Generator[None, None, None]:
+        history_dir = os.path.join(
+            os.environ.get('XDG_DATA_HOME') or
+            os.path.expanduser('~/.local/share'),
+            'babi/history',
+        )
+        os.makedirs(history_dir, exist_ok=True)
+        for filename in os.listdir(history_dir):
+            with open(os.path.join(history_dir, filename)) as f:
+                self.data[filename] = f.read().splitlines()
+                self._orig_len[filename] = len(self.data[filename])
+        try:
+            yield
+        finally:
+            for k, v in self.data.items():
+                new_history = v[self._orig_len[k]:]
+                if new_history:
+                    with open(os.path.join(history_dir, k), 'a+') as f:
+                        f.write('\n'.join(new_history) + '\n')

babi/main.py

@@ -14,7 +14,6 @@ import sys
 from typing import Any
 from typing import Callable
 from typing import cast
-from typing import Dict
 from typing import Generator
 from typing import IO
 from typing import List
@@ -27,6 +26,7 @@ from typing import Tuple
 from typing import TypeVar
 from typing import Union
 
+from babi.history import History
 from babi.horizontal_scrolling import line_x
 from babi.horizontal_scrolling import scrolled_line
 from babi.list_spy import ListSpy
@@ -76,34 +76,6 @@ class Key(NamedTuple):
     keyname: bytes
 
 
-class History:
-    def __init__(self) -> None:
-        self._orig_len: Dict[str, int] = collections.defaultdict(int)
-        self.data: Dict[str, List[str]] = collections.defaultdict(list)
-        self.prev: Dict[str, str] = {}
-
-    @contextlib.contextmanager
-    def save(self) -> Generator[None, None, None]:
-        history_dir = os.path.join(
-            os.environ.get('XDG_DATA_HOME') or
-            os.path.expanduser('~/.local/share'),
-            'babi/history',
-        )
-        os.makedirs(history_dir, exist_ok=True)
-        for filename in os.listdir(history_dir):
-            with open(os.path.join(history_dir, filename)) as f:
-                self.data[filename] = f.read().splitlines()
-                self._orig_len[filename] = len(self.data[filename])
-        try:
-            yield
-        finally:
-            for k, v in self.data.items():
-                new_history = v[self._orig_len[k]:]
-                if new_history:
-                    with open(os.path.join(history_dir, k), 'a+') as f:
-                        f.write('\n'.join(new_history) + '\n')
-
-
 def _restore_lines_eof_invariant(lines: MutableSequenceNoSlice) -> None:
     """The file lines will always contain a blank empty string at the end to
     simplify rendering.  This should be called whenever the end of the file