qutebrowser/qutebrowser/misc/lineparser.py
2017-08-06 18:13:49 -04:00

243 lines
7.3 KiB
Python

# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
# Copyright 2014-2017 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
#
# This file is part of qutebrowser.
#
# qutebrowser is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# qutebrowser is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with qutebrowser. If not, see <http://www.gnu.org/licenses/>.
"""Parser for line-based files like histories."""
import os
import os.path
import contextlib
from PyQt5.QtCore import pyqtSlot, pyqtSignal, QObject
from qutebrowser.utils import log, utils, qtutils
from qutebrowser.config import config
class BaseLineParser(QObject):
"""A LineParser without any real data.
Attributes:
_configdir: Directory to read the config from, or None.
_configfile: The config file path.
_fname: Filename of the config.
_binary: Whether to open the file in binary mode.
Signals:
changed: Emitted when the history was changed.
"""
changed = pyqtSignal()
def __init__(self, configdir, fname, *, binary=False, parent=None):
"""Constructor.
Args:
configdir: Directory to read the config from.
fname: Filename of the config file.
binary: Whether to open the file in binary mode.
_opened: Whether the underlying file is open
"""
super().__init__(parent)
self._configdir = configdir
self._configfile = os.path.join(self._configdir, fname)
self._fname = fname
self._binary = binary
self._opened = False
def __repr__(self):
return utils.get_repr(self, constructor=True,
configdir=self._configdir, fname=self._fname,
binary=self._binary)
def _prepare_save(self):
"""Prepare saving of the file.
Return:
True if the file should be saved, False otherwise.
"""
if not os.path.exists(self._configdir):
os.makedirs(self._configdir, 0o755)
return True
def _after_save(self):
"""Log a message after saving is done."""
log.destroy.debug("Saved to {}".format(self._configfile))
@contextlib.contextmanager
def _open(self, mode):
"""Open self._configfile for reading.
Args:
mode: The mode to use ('a'/'r'/'w')
Raises:
IOError: if the file is already open
Yields:
a file object for the config file
"""
assert self._configfile is not None
if self._opened:
raise IOError("Refusing to double-open LineParser.")
self._opened = True
try:
if self._binary:
with open(self._configfile, mode + 'b') as f:
yield f
else:
with open(self._configfile, mode, encoding='utf-8') as f:
yield f
finally:
self._opened = False
def _write(self, fp, data):
"""Write the data to a file.
Args:
fp: A file object to write the data to.
data: The data to write.
"""
if not data:
return
if self._binary:
fp.write(b'\n'.join(data))
fp.write(b'\n')
else:
fp.write('\n'.join(data))
fp.write('\n')
def save(self):
"""Save the history to disk."""
raise NotImplementedError
def clear(self):
"""Clear the contents of the file."""
raise NotImplementedError
class LineParser(BaseLineParser):
"""Parser for configuration files which are simply line-based.
Attributes:
data: A list of lines.
"""
def __init__(self, configdir, fname, *, binary=False, parent=None):
"""Constructor.
Args:
configdir: Directory to read the config from.
fname: Filename of the config file.
binary: Whether to open the file in binary mode.
"""
super().__init__(configdir, fname, binary=binary, parent=parent)
if not os.path.isfile(self._configfile):
self.data = []
else:
log.init.debug("Reading {}".format(self._configfile))
self._read()
def __iter__(self):
return iter(self.data)
def __getitem__(self, key):
return self.data[key]
def _read(self):
"""Read the data from self._configfile."""
with self._open('r') as f:
if self._binary:
self.data = [line.rstrip(b'\n') for line in f]
else:
self.data = [line.rstrip('\n') for line in f]
def save(self):
"""Save the config file."""
if self._opened:
raise IOError("Refusing to double-open LineParser.")
do_save = self._prepare_save()
if not do_save:
return
self._opened = True
try:
assert self._configfile is not None
with qtutils.savefile_open(self._configfile, self._binary) as f:
self._write(f, self.data)
finally:
self._opened = False
self._after_save()
def clear(self):
self.data = []
self.save()
class LimitLineParser(LineParser):
"""A LineParser with a limited count of lines.
Attributes:
_limit: The config option used to limit the maximum number of lines.
"""
def __init__(self, configdir, fname, *, limit, binary=False, parent=None):
"""Constructor.
Args:
configdir: Directory to read the config from, or None.
fname: Filename of the config file.
limit: Config option which contains a limit.
binary: Whether to open the file in binary mode.
"""
super().__init__(configdir, fname, binary=binary, parent=parent)
self._limit = limit
if limit is not None and configdir is not None:
config.instance.changed.connect(self._cleanup_file)
def __repr__(self):
return utils.get_repr(self, constructor=True,
configdir=self._configdir, fname=self._fname,
limit=self._limit, binary=self._binary)
@pyqtSlot(str)
def _cleanup_file(self, option):
"""Delete the file if the limit was changed to 0."""
assert self._configfile is not None
if option != self._limit:
return
value = config.instance.get(option)
if value == 0:
if os.path.exists(self._configfile):
os.remove(self._configfile)
def save(self):
"""Save the config file."""
limit = config.instance.get(self._limit)
if limit == 0:
return
do_save = self._prepare_save()
if not do_save:
return
assert self._configfile is not None
with qtutils.savefile_open(self._configfile, self._binary) as f:
self._write(f, self.data[-limit:])
self._after_save()