qutebrowser/qutebrowser/utils/misc.py

# Copyright 2014 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/>.

"""Other utilities which don't fit anywhere else."""

import sys
import os.path

from PyQt5.QtCore import pyqtRemoveInputHook

#import qutebrowser.commands.utils as cmdutils

try:
    # pylint: disable=import-error
    from ipdb import set_trace as pdb_set_trace
except ImportError:
    from pdb import set_trace as pdb_set_trace

import qutebrowser

# FIXME we can';t do this because of circular imports
#@cmdutils.register(name='settrace', hide=True)
def set_trace():
    """Set a tracepoint in the Python debugger that works with Qt.

    Based on http://stackoverflow.com/a/1745965/2085149

    """
    print()
    print("When done debugging, remember to execute:")
    print("  from PyQt5 import QtCore; QtCore.pyqtRestoreInputHook()")
    print("before executing c(ontinue).")
    pyqtRemoveInputHook()
    return pdb_set_trace()


def read_file(filename):
    """Get the contents of a file contained with qutebrowser.

    Args:
        filename: The filename to open as string.

    Return:
        The file contents as string.

    """
    fn = os.path.join(qutebrowser.basedir, filename)
    with open(fn, 'r', encoding='UTF-8') as f:
        return f.read()


def trace_lines(do_trace):
    """Turn on/off printing each executed line.

    Args:
        do_trace: Whether to start tracing (True) or stop it (False).

    """
    def trace(frame, event, _):
        """Trace function passed to sys.settrace."""
        print("{}, {}:{}".format(event, frame.f_code.co_filename,
                                 frame.f_lineno))
        return trace
    if do_trace:
        sys.settrace(trace)
    else:
        sys.settrace(None)