upstream/mercurial-mirror Files · tests/revlog-formatv0.py

posix: always seek to EOF when opening a file in append mode...

posix: always seek to EOF when opening a file in append mode Python 3 already does this, so skip it there. Consider the program: #include <stdio.h> int main() { FILE *f = fopen("narf", "w"); fprintf(f, "narf\n"); fclose(f); f = fopen("narf", "a"); printf("%ld\n", ftell(f)); fprintf(f, "troz\n"); printf("%ld\n", ftell(f)); return 0; } on macOS, FreeBSD, and Linux with glibc, this program prints 5 10 but on musl libc (Alpine Linux and probably others) this prints 0 10 By my reading of https://pubs.opengroup.org/onlinepubs/009695399/functions/fopen.html this is technically correct, specifically: > Opening a file with append mode (a as the first character in the > mode argument) shall cause all subsequent writes to the file to be > forced to the then current end-of-file, regardless of intervening > calls to fseek(). in other words, the file position doesn't really matter in append-mode files, and we can't depend on it being at all meaningful unless we perform a seek() before tell() after open(..., 'a'). Experimentally after a .write() we can do a .tell() and it'll always be reasonable, but I'm unclear from reading the specification if that's a smart thing to rely on. This matches what we do on Windows and what Python 3 does for free, so let's just be consistent. Thanks to Yuya for the idea.

Augie Fackler - - Load All Authors

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      #!/usr/bin/env python

      # Copyright 2010 Intevation GmbH

      # Author(s):

      # Thomas Arendsen Hein <thomas@intevation.de>

      #

      # This software may be used and distributed according to the terms of the

      # GNU General Public License version 2 or any later version.

      """Create a Mercurial repository in revlog format 0

      changeset:   0:a1ef0b125355

      tag:         tip

      user:        user

      date:        Thu Jan 01 00:00:00 1970 +0000

      files:       empty

      description:

      empty file

      """

      from __future__ import absolute_import

      import binascii

      import os

      import sys

      files = [

          (b'formatv0/.hg/00changelog.i',

           b'000000000000004400000000000000000000000000000000000000'

           b'000000000000000000000000000000000000000000000000000000'

           b'0000a1ef0b125355d27765928be600cfe85784284ab3'),

          (b'formatv0/.hg/00changelog.d',

           b'756163613935613961356635353036303562366138343738336237'

           b'61623536363738616436356635380a757365720a3020300a656d70'

           b'74790a0a656d7074792066696c65'),

          (b'formatv0/.hg/00manifest.i',

           b'000000000000003000000000000000000000000000000000000000'

           b'000000000000000000000000000000000000000000000000000000'

           b'0000aca95a9a5f550605b6a84783b7ab56678ad65f58'),

          (b'formatv0/.hg/00manifest.d',

           b'75656d707479006238306465356431333837353835343163356630'

           b'35323635616431343461623966613836643164620a'),

          (b'formatv0/.hg/data/empty.i',

           b'000000000000000000000000000000000000000000000000000000'

           b'000000000000000000000000000000000000000000000000000000'

           b'0000b80de5d138758541c5f05265ad144ab9fa86d1db'),

          (b'formatv0/.hg/data/empty.d',

           b''),

      ]

      def makedirs(name):

          """recursive directory creation"""

          parent = os.path.dirname(name)

          if parent:

              makedirs(parent)

          os.mkdir(name)

      makedirs(os.path.join(*'formatv0/.hg/data'.split('/')))

      for name, data in files:

          f = open(name, 'wb')

          f.write(binascii.unhexlify(data))

          f.close()

      sys.exit(0)

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				#!/usr/bin/env python
				# Copyright 2010 Intevation GmbH
				# Author(s):
				# Thomas Arendsen Hein <thomas@intevation.de>
				#
				# This software may be used and distributed according to the terms of the
				# GNU General Public License version 2 or any later version.

				"""Create a Mercurial repository in revlog format 0

				changeset: 0:a1ef0b125355
				tag: tip
				user: user
				date: Thu Jan 01 00:00:00 1970 +0000
				files: empty
				description:
				empty file
				"""

				from __future__ import absolute_import
				import binascii
				import os
				import sys

				files = [
				(b'formatv0/.hg/00changelog.i',
				b'000000000000004400000000000000000000000000000000000000'
				b'000000000000000000000000000000000000000000000000000000'
				b'0000a1ef0b125355d27765928be600cfe85784284ab3'),
				(b'formatv0/.hg/00changelog.d',
				b'756163613935613961356635353036303562366138343738336237'
				b'61623536363738616436356635380a757365720a3020300a656d70'
				b'74790a0a656d7074792066696c65'),
				(b'formatv0/.hg/00manifest.i',
				b'000000000000003000000000000000000000000000000000000000'
				b'000000000000000000000000000000000000000000000000000000'
				b'0000aca95a9a5f550605b6a84783b7ab56678ad65f58'),
				(b'formatv0/.hg/00manifest.d',
				b'75656d707479006238306465356431333837353835343163356630'
				b'35323635616431343461623966613836643164620a'),
				(b'formatv0/.hg/data/empty.i',
				b'000000000000000000000000000000000000000000000000000000'
				b'000000000000000000000000000000000000000000000000000000'
				b'0000b80de5d138758541c5f05265ad144ab9fa86d1db'),
				(b'formatv0/.hg/data/empty.d',
				b''),
				]

				def makedirs(name):
				"""recursive directory creation"""
				parent = os.path.dirname(name)
				if parent:
				makedirs(parent)
				os.mkdir(name)

				makedirs(os.path.join(*'formatv0/.hg/data'.split('/')))

				for name, data in files:
				f = open(name, 'wb')
				f.write(binascii.unhexlify(data))
				f.close()

				sys.exit(0)