view mercurial/diffhelper.py @ 39662:50f46b771921

py3: partially fix pager spawning on Windows

Previously, spinning up the pager crashed because the command and environment
was in bytes.  (See also 543a788eea2d.)  Now it aborts with an invalid handle:

    $ HGMODULEPOLICY=py py -3 ../hg --traceback --config extensions.evolve=!
    Traceback (most recent call last):
    File "c:\Users\Matt\projects\hg\mercurial\ui.py", line 967, in _write
      self.fout.write(''.join(msgs))
    File "c:\Users\Matt\projects\hg\mercurial\windows.py", line 173, in write
      self.fp.write(s[start:end])
    OSError: [WinError 6] The handle is invalid

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "c:\Users\Matt\projects\hg\mercurial\scmutil.py", line 164, in callcatch
        return func()
      File "c:\Users\Matt\projects\hg\mercurial\dispatch.py", line 350, in _runcatchfunc
        return _dispatch(req)
      File "c:\Users\Matt\projects\hg\mercurial\dispatch.py", line 930, in _dispatch
        return commands.help_(ui, 'shortlist')
      File "c:\Users\Matt\projects\hg\mercurial\commands.py", line 2930, in help_
        ui.write(formatted)
      File "c:\Users\Matt\projects\hg\mercurial\ui.py", line 948, in write
        self._writenobuf(*args, **opts)
      File "c:\Users\Matt\projects\hg\mercurial\ui.py", line 960, in _writenobuf
        self._write(*msgs, **opts)
      File "c:\Users\Matt\projects\hg\mercurial\ui.py", line 969, in _write
        raise error.StdioError(err)
    mercurial.error.StdioError: [Errno 9] The handle is invalid
    abort: The handle is invalid

The interesting bit here is that the abort message is marked with ANSI color,
but the OSError is not.

# diffhelper.py - helper routines for patch
#
# Copyright 2009 Matt Mackall <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

from .i18n import _

from . import (
    error,
    pycompat,
)

def addlines(fp, hunk, lena, lenb, a, b):
    """Read lines from fp into the hunk

    The hunk is parsed into two arrays, a and b. a gets the old state of
    the text, b gets the new state. The control char from the hunk is saved
    when inserting into a, but not b (for performance while deleting files.)
    """
    while True:
        todoa = lena - len(a)
        todob = lenb - len(b)
        num = max(todoa, todob)
        if num == 0:
            break
        for i in pycompat.xrange(num):
            s = fp.readline()
            if not s:
                raise error.ParseError(_('incomplete hunk'))
            if s == "\\ No newline at end of file\n":
                fixnewline(hunk, a, b)
                continue
            if s == '\n' or s == '\r\n':
                # Some patches may be missing the control char
                # on empty lines. Supply a leading space.
                s = ' ' + s
            hunk.append(s)
            if s.startswith('+'):
                b.append(s[1:])
            elif s.startswith('-'):
                a.append(s)
            else:
                b.append(s[1:])
                a.append(s)

def fixnewline(hunk, a, b):
    """Fix up the last lines of a and b when the patch has no newline at EOF"""
    l = hunk[-1]
    # tolerate CRLF in last line
    if l.endswith('\r\n'):
        hline = l[:-2]
    else:
        hline = l[:-1]

    if hline.startswith((' ', '+')):
        b[-1] = hline[1:]
    if hline.startswith((' ', '-')):
        a[-1] = hline
    hunk[-1] = hline

def testhunk(a, b, bstart):
    """Compare the lines in a with the lines in b

    a is assumed to have a control char at the start of each line, this char
    is ignored in the compare.
    """
    alen = len(a)
    blen = len(b)
    if alen > blen - bstart or bstart < 0:
        return False
    for i in pycompat.xrange(alen):
        if a[i][1:] != b[i + bstart]:
            return False
    return True