path: root/libbe/editor.py

# Bugs Everywhere, a distributed bugtracker
# Copyright (C) 2005 Aaron Bentley and Panometrics, Inc.
# <abentley@panoramicfeedback.com>
#
#    This program 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 2 of the License, or
#    (at your option) any later version.
#
#    This program 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 this program; if not, write to the Free Software
#    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#    MA 02110-1301, USA

import codecs
import locale
import os
import sys
import tempfile
import doctest

default_encoding = sys.getfilesystemencoding() or locale.getpreferredencoding()

comment_marker = u"== Anything below this line will be ignored\n"

class CantFindEditor(Exception):
    def __init__(self):
        Exception.__init__(self, "Can't find editor to get string from")

def editor_string(comment=None, encoding=None):
    """Invokes the editor, and returns the user_produced text as a string

    >>> if "EDITOR" in os.environ:
    ...     del os.environ["EDITOR"]
    >>> if "VISUAL" in os.environ:
    ...     del os.environ["VISUAL"]
    >>> editor_string()
    Traceback (most recent call last):
    CantFindEditor: Can't find editor to get string from
    >>> os.environ["EDITOR"] = "echo bar > "
    >>> editor_string()
    u'bar\\n'
    >>> os.environ["VISUAL"] = "echo baz > "
    >>> editor_string()
    u'baz\\n'
    >>> del os.environ["EDITOR"]
    >>> del os.environ["VISUAL"]
    """
    if encoding == None:
        encoding = default_encoding
    for name in ('VISUAL', 'EDITOR'):
        try:
            editor = os.environ[name]
            break
        except KeyError:
            pass
    else:
        raise CantFindEditor()
    fhandle, fname = tempfile.mkstemp()
    try:
        if comment is not None:
            os.write(fhandle, '\n'+comment_string(comment))
        os.close(fhandle)
        oldmtime = os.path.getmtime(fname)
        os.system("%s %s" % (editor, fname))
        f = codecs.open(fname, "r", encoding)
        output = trimmed_string(f.read())
        f.close()
        if output.rstrip('\n') == "":
            output = None
    finally:
        os.unlink(fname)
    return output


def comment_string(comment):
    """
    >>> comment_string('hello') == comment_marker+"hello"
    True
    """
    return comment_marker + comment


def trimmed_string(instring):
    """
    >>> trimmed_string("hello\\n"+comment_marker)
    u'hello\\n'
    >>> trimmed_string("hi!\\n" + comment_string('Booga'))
    u'hi!\\n'
    """
    out = []
    for line in instring.splitlines(True):
        if line.startswith(comment_marker):
            break
        out.append(line)
    return ''.join(out)

suite = doctest.DocTestSuite()