Mercurial > hg
view mercurial/diffhelper.py @ 49232:4c57ce494a4e
worker: stop relying on garbage collection to release memoryview
On CPython, before resizing the bytearray, all memoryviews referencing it must
be released. Before this change, we ensured that all references to them were
deleted. On CPython, this was enough to set the reference count to zero, which
results in garbage collecting and releasing them.
On PyPy, releasing the memoryviews is not necessary because they are implemented
differently. If it would be necessary however, ensuring that all references are
deleted would not be suffient because PyPy doesn’t use reference counting.
By using with statements that take care of releasing the memoryviews, we ensure
that the bytearray is resizable without relying on implementation details. So
while this doesn’t fix any observable bug, it increases compatiblity with other
and future Python implementations.
author | Manuel Jacob <me@manueljacob.de> |
---|---|
date | Sat, 21 May 2022 23:31:30 +0200 |
parents | 6000f5b25c9b |
children | d44e3c45f0e4 |
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# 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, pycompat, ) 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 pycompat.xrange(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 pycompat.xrange(alen): if a[i][1:] != b[i + bstart]: return False return True