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sebastinassebastinas
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Move History to seperate file and improve error handling (fixes bpython#434)
A new method append_reload_and_write is added that handles read and write failures better. Signed-off-by: Sebastian Ramacher <sebastian+dev@ramacher.at>
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‎bpython/history.py‎

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# The MIT License
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#
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# Copyright (c) 2009-2015 the bpython authors.
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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import codecs
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import os
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from bpython.translations import _
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class History(object):
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"""Stores readline-style history and current place in it"""
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def __init__(self, entries=None, duplicates=True, hist_size=100):
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if entries is None:
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self.entries = ['']
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else:
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self.entries = list(entries)
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self.index = 0 # how many lines back in history is currently selected
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# where 0 is the saved typed line, 1 the prev entered line
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self.saved_line = '' # what was on the prompt before using history
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self.duplicates = duplicates
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self.hist_size = hist_size
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def append(self, line):
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self.append_to(self.entries, line)
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def append_to(self, entries, line):
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line = line.rstrip('\n')
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if line:
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if not self.duplicates:
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# remove duplicates
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try:
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while True:
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entries.remove(line)
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except ValueError:
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pass
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entries.append(line)
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def first(self):
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"""Move back to the beginning of the history."""
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if not self.is_at_end:
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self.index = len(self.entries)
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return self.entries[-self.index]
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def back(self, start=True, search=False, target=None, include_current=False):
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"""Move one step back in the history."""
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if target is None:
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target = self.saved_line
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if not self.is_at_end:
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if search:
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self.index += self.find_partial_match_backward(target, include_current)
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elif start:
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self.index += self.find_match_backward(target, include_current)
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else:
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self.index += 1
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return self.entry
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@property
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def entry(self):
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"""The current entry, which may be the saved line"""
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return self.entries[-self.index] if self.index else self.saved_line
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@property
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def entries_by_index(self):
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return list(reversed(self.entries + [self.saved_line]))
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def find_match_backward(self, search_term, include_current=False):
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for idx, val in enumerate(self.entries_by_index[self.index + (0 if include_current else 1):]):
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if val.startswith(search_term):
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return idx + (0 if include_current else 1)
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return 0
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def find_partial_match_backward(self, search_term, include_current=False):
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for idx, val in enumerate(self.entries_by_index[self.index + (0 if include_current else 1):]):
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if search_term in val:
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return idx + (0 if include_current else 1)
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return 0
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def forward(self, start=True, search=False, target=None, include_current=False):
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"""Move one step forward in the history."""
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if target is None:
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target = self.saved_line
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if self.index > 1:
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if search:
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self.index -= self.find_partial_match_forward(target, include_current)
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elif start:
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self.index -= self.find_match_forward(target, include_current)
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else:
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self.index -= 1
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return self.entry
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else:
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self.index = 0
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return self.saved_line
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def find_match_forward(self, search_term, include_current=False):
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#TODO these are no longer efficient, because we realize the whole list. Does this matter?
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for idx, val in enumerate(reversed(self.entries_by_index[:max(0, self.index - (1 if include_current else 0))])):
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if val.startswith(search_term):
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return idx + (0 if include_current else 1)
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return self.index
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def find_partial_match_forward(self, search_term, include_current=False):
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for idx, val in enumerate(reversed(self.entries_by_index[:max(0, self.index - (1 if include_current else 0))])):
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if search_term in val:
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return idx + (0 if include_current else 1)
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return self.index
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def last(self):
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"""Move forward to the end of the history."""
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if not self.is_at_start:
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self.index = 0
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return self.entries[0]
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@property
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def is_at_end(self):
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return self.index >= len(self.entries) or self.index == -1
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@property
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def is_at_start(self):
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return self.index == 0
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def enter(self, line):
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if self.index == 0:
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self.saved_line = line
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@classmethod
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def from_filename(cls, filename):
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history = cls()
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history.load(filename)
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return history
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def reset(self):
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self.index = 0
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self.saved_line = ''
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def load(self, filename, encoding):
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with codecs.open(filename, 'r', encoding, 'ignore') as hfile:
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self.entries = self.load_from(hfile)
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def load_from(self, fd):
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entries = []
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for line in fd:
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self.append_to(entries, line)
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return entries
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def save(self, filename, encoding, lines=0):
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with codecs.open(filename, 'w', encoding, 'ignore') as hfile:
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self.save_to(hfile, self.entries, lines)
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def save_to(self, fd, entries=None, lines=0):
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if entries is None:
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entries = self.entries
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for line in entries[-lines:]:
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fd.write(line)
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fd.write('\n')
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def append_reload_and_write(self, s, filename, encoding):
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if not self.hist_size:
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return self.append(s)
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try:
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with codecs.open(filename, 'rw+', encoding, 'ignore') as hfile:
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# read entries
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hfile.seek(0, os.SEEK_SET)
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entries = self.load_from(hfile)
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self.append_to(entries, s)
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# write new entries
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hfile.seek(0, os.SEEK_SET)
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hfile.truncate()
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self.save_to(hfile, entries, self.hist_size)
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self.entries = entries
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except EnvironmentError as err:
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raise RuntimeError(_('Error occurded while writing to file %s (%s)')
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% (filename, err.strerror))
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else:
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if len(self.entries) == 0:
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# Make sure that entries contains at least one element. If the
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# file and s are empty, this can occur.
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self.entries = ['']

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