view mercurial/diffhelper.py @ 42073:80103ed2e8ee

crecord: new keys g & G to navigate to the top and bottom respectively

This patch introduces two new keys 'g' and 'G' that helps to navigate to the
top and bottom of the file/hunk/line respectively. This is inline with the shortcuts
used in man, less, more and such tools that makes it convenient to navigate
swiftly.

'g' or HOME navigates to the top most file in the ncurses window.

'G' or END navigates to the bottom most file/hunk/line depending on the whether
the fold is active or not.

If the bottom most file is folded, it navigates to that file and stops there.
If the bottom most file is unfolded, it navigates to the bottom most hunk in
that file and stops there. If the bottom most hunk is unfolded, it navigates to
the bottom most line in that hunk.

Differential Revision: https://phab.mercurial-scm.org/D6178

# 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