qutebrowser/qutebrowser/misc/editor.py
2017-10-18 20:19:09 +02:00

216 lines
7.8 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/>.
"""Launcher for an external editor."""
import os
import tempfile
from PyQt5.QtCore import pyqtSignal, pyqtSlot, QObject, QProcess
from qutebrowser.config import config
from qutebrowser.utils import message, log
from qutebrowser.misc import guiprocess
class ExternalEditor(QObject):
"""Class to simplify editing a text in an external editor.
Attributes:
_text: The current text before the editor is opened.
_filename: The name of the file to be edited.
_remove_file: Whether the file should be removed when the editor is
closed.
_proc: The GUIProcess of the editor.
"""
editing_finished = pyqtSignal(str)
def __init__(self, parent=None):
super().__init__(parent)
self._filename = None
self._proc = None
self._remove_file = None
def _cleanup(self):
"""Clean up temporary files after the editor closed."""
assert self._remove_file is not None
if self._filename is None or not self._remove_file:
# Could not create initial file.
return
try:
if self._proc.exit_status() != QProcess.CrashExit:
os.remove(self._filename)
except OSError as e:
# NOTE: Do not replace this with "raise CommandError" as it's
# executed async.
message.error("Failed to delete tempfile... ({})".format(e))
@pyqtSlot(int, QProcess.ExitStatus)
def on_proc_closed(self, exitcode, exitstatus):
"""Write the editor text into the form field and clean up tempfile.
Callback for QProcess when the editor was closed.
"""
log.procs.debug("Editor closed")
if exitstatus != QProcess.NormalExit:
# No error/cleanup here, since we already handle this in
# on_proc_error.
return
try:
if exitcode != 0:
return
encoding = config.val.editor.encoding
try:
with open(self._filename, 'r', encoding=encoding) as f:
text = f.read()
except OSError as e:
# NOTE: Do not replace this with "raise CommandError" as it's
# executed async.
message.error("Failed to read back edited file: {}".format(e))
return
log.procs.debug("Read back: {}".format(text))
self.editing_finished.emit(text)
finally:
self._cleanup()
@pyqtSlot(QProcess.ProcessError)
def on_proc_error(self, _err):
self._cleanup()
def edit(self, text, caret_position=0):
"""Edit a given text.
Args:
text: The initial text to edit.
caret_position: The position of the caret in the text.
"""
if self._filename is not None:
raise ValueError("Already editing a file!")
try:
# Close while the external process is running, as otherwise systems
# with exclusive write access (e.g. Windows) may fail to update
# the file from the external editor, see
# https://github.com/qutebrowser/qutebrowser/issues/1767
with tempfile.NamedTemporaryFile(
mode='w', prefix='qutebrowser-editor-',
encoding=config.val.editor.encoding,
delete=False) as fobj:
if text:
fobj.write(text)
self._filename = fobj.name
except OSError as e:
message.error("Failed to create initial file: {}".format(e))
return
self._remove_file = True
line, column = self._calc_line_and_column(text, caret_position)
self._start_editor(line=line, column=column)
def edit_file(self, filename):
"""Edit the file with the given filename."""
self._filename = filename
self._remove_file = False
self._start_editor()
def _start_editor(self, line=1, column=1):
"""Start the editor with the file opened as self._filename.
Args:
line: the line number to pass to the editor
column: the column number to pass to the editor
"""
self._proc = guiprocess.GUIProcess(what='editor', parent=self)
self._proc.finished.connect(self.on_proc_closed)
self._proc.error.connect(self.on_proc_error)
editor = config.val.editor.command
executable = editor[0]
args = [self._sub_placeholder(arg, line, column) for arg in editor[1:]]
log.procs.debug("Calling \"{}\" with args {}".format(executable, args))
self._proc.start(executable, args)
def _calc_line_and_column(self, text, caret_position):
"""Calculate line and column numbers given a text and caret position
Both line and column are 1-based indexes, because that's what most
editors use as line and column starting index. By "most" we mean at
least vim, nvim, gvim, emacs, atom, sublimetext, notepad++, brackets,
visual studio, QtCreator and so on.
To find the line we just count how many newlines there are before the
caret and add 1.
To find the column we calculate the difference between the caret and
the last newline before the caret.
For example in the text `aaa\nbb|bbb` (| represents the caret):
caret_position = 6
text[:caret_position] = `aaa\nbb`
text[:caret_position].count('\n') = 1
caret_position - text[:caret_position].rfind('\n') = 3
Thus line, column = 2, 3, and the caret is indeed in the second
line, third column
Args:
text: the text for which the numbers must be calculated
caret_position: the position of the caret in the text
Return:
A (line, column) tuple of (int, int)
"""
line = text[:caret_position].count('\n') + 1
column = caret_position - text[:caret_position].rfind('\n')
return (line, column)
def _sub_placeholder(self, possible_placeholder, line, column):
"""Substitute a single placeholder.
If the `possible_placeholder` input to this function is valid it will
be substituted with the appropriate value, otherwise it will be left
unchanged.
Args:
possible_placeholder: an argument of editor.command.
line: the previously-calculated line number for the text caret
column: the previously-calculated column number for the text caret
Return:
The substituted placeholder or the original argument
"""
replacements = {
'{}': self._filename,
'{file}': self._filename,
'{line}': str(line),
'{line0}': str(line-1),
'{column}': str(column),
'{column0}': str(column-1)
}
# The for loop would create a copy anyway, this should be more legible
ph = possible_placeholder
for old, new in replacements.items():
ph = ph.replace(old, new)
return ph