121 lines
2.8 KiB
Python
121 lines
2.8 KiB
Python
from __future__ import unicode_literals
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from abc import ABCMeta, abstractmethod
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from six import with_metaclass
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import datetime
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import os
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__all__ = (
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'FileHistory',
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'History',
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'InMemoryHistory',
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)
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class History(with_metaclass(ABCMeta, object)):
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"""
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Base ``History`` interface.
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"""
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@abstractmethod
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def append(self, string):
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" Append string to history. "
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@abstractmethod
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def __getitem__(self, key):
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" Return one item of the history. It should be accessible like a `list`. "
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@abstractmethod
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def __iter__(self):
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" Iterate through all the items of the history. Cronologically. "
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@abstractmethod
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def __len__(self):
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" Return the length of the history. "
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def __bool__(self):
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"""
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Never evaluate to False, even when the history is empty.
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(Python calls __len__ if __bool__ is not implemented.)
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This is mainly to allow lazy evaluation::
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x = history or InMemoryHistory()
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"""
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return True
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__nonzero__ = __bool__ # For Python 2.
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class InMemoryHistory(History):
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"""
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:class:`.History` class that keeps a list of all strings in memory.
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"""
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def __init__(self):
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self.strings = []
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def append(self, string):
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self.strings.append(string)
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def __getitem__(self, key):
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return self.strings[key]
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def __iter__(self):
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return iter(self.strings)
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def __len__(self):
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return len(self.strings)
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class FileHistory(History):
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"""
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:class:`.History` class that stores all strings in a file.
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"""
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def __init__(self, filename):
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self.strings = []
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self.filename = filename
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self._load()
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def _load(self):
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lines = []
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def add():
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if lines:
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# Join and drop trailing newline.
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string = ''.join(lines)[:-1]
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self.strings.append(string)
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if os.path.exists(self.filename):
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with open(self.filename, 'rb') as f:
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for line in f:
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line = line.decode('utf-8')
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if line.startswith('+'):
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lines.append(line[1:])
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else:
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add()
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lines = []
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add()
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def append(self, string):
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self.strings.append(string)
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# Save to file.
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with open(self.filename, 'ab') as f:
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def write(t):
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f.write(t.encode('utf-8'))
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write('\n# %s\n' % datetime.datetime.now())
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for line in string.split('\n'):
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write('+%s\n' % line)
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def __getitem__(self, key):
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return self.strings[key]
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def __iter__(self):
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return iter(self.strings)
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def __len__(self):
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return len(self.strings)
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