mercurial/diffhelper.py
author Pierre-Yves David <pierre-yves.david@octobus.net>
Fri, 05 Apr 2024 11:33:47 +0200
changeset 51580 b70628a9aa7e
parent 49284 d44e3c45f0e4
permissions -rw-r--r--
phases: use revision number in new_heads All graph operations will be done using revision numbers, so passing nodes only means they will eventually get converted to revision numbers internally. As part of an effort to align the code on using revision number we make the `phases.newheads` function operated on revision number, taking them as input and using them in returns, instead of the node-id it used to consume and produce. This is part of multiple changesets effort to translate more part of the logic, but is done step by step to facilitate the identification of issue that might arise in mercurial core and extensions. To make the change simpler to handle for third party extensions, we also rename the function, using a more modern form. This will help detecting the different between the node-id version and the rev-num version. I also take this as an opportunity to add some comment about possible performance improvement for the future. They don't matter too much now, but they are worse exploring in a while.

# diffhelper.py - helper routines for patch
#
# Copyright 2009 Olivia Mackall <olivia@selenic.com> 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 .i18n import _

from . import (
    error,
)

MISSING_NEWLINE_MARKER = b'\\ No newline at end of file\n'


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 range(num):
            s = fp.readline()
            if not s:
                raise error.ParseError(_(b'incomplete hunk'))
            if s == MISSING_NEWLINE_MARKER:
                fixnewline(hunk, a, b)
                continue
            if s == b'\n' or s == b'\r\n':
                # Some patches may be missing the control char
                # on empty lines. Supply a leading space.
                s = b' ' + s
            hunk.append(s)
            if s.startswith(b'+'):
                b.append(s[1:])
            elif s.startswith(b'-'):
                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(b'\r\n'):
        hline = l[:-2]
    else:
        hline = l[:-1]

    if hline.startswith((b' ', b'+')):
        b[-1] = hline[1:]
    if hline.startswith((b' ', b'-')):
        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 range(alen):
        if a[i][1:] != b[i + bstart]:
            return False
    return True