relink: use `get_unique_pull_path`

The code does not support multiple destination and will probably never do so.
So lets use the dedicated API for this case.

Differential Revision: https://phab.mercurial-scm.org/D10409

hgext/relink.py

@@ -1,211 +1,215 b''
 # Mercurial extension to provide 'hg relink' command
 #
 # Copyright (C) 2007 Brendan Cully <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 """recreates hardlinks between repository clones"""
 from __future__ import absolute_import
 
 import os
 import stat
 
 from mercurial.i18n import _
 from mercurial.pycompat import open
 from mercurial import (
     error,
     hg,
     registrar,
     util,
 )
-from mercurial.utils import stringutil
+from mercurial.utils import (
+    stringutil,
+    urlutil,
+)
 
 cmdtable = {}
 command = registrar.command(cmdtable)
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = b'ships-with-hg-core'
 
 
 @command(
     b'relink', [], _(b'[ORIGIN]'), helpcategory=command.CATEGORY_MAINTENANCE
 )
 def relink(ui, repo, origin=None, **opts):
     """recreate hardlinks between two repositories
 
     When repositories are cloned locally, their data files will be
     hardlinked so that they only use the space of a single repository.
 
     Unfortunately, subsequent pulls into either repository will break
     hardlinks for any files touched by the new changesets, even if
     both repositories end up pulling the same changes.
 
     Similarly, passing --rev to "hg clone" will fail to use any
     hardlinks, falling back to a complete copy of the source
     repository.
 
     This command lets you recreate those hardlinks and reclaim that
     wasted space.
 
     This repository will be relinked to share space with ORIGIN, which
     must be on the same local disk. If ORIGIN is omitted, looks for
     "default-relink", then "default", in [paths].
 
     Do not attempt any read operations on this repository while the
     command is running. (Both repositories will be locked against
     writes.)
     """
     if not util.safehasattr(util, b'samefile') or not util.safehasattr(
         util, b'samedevice'
     ):
         raise error.Abort(_(b'hardlinks are not supported on this system'))
-    src = hg.repository(
-        repo.baseui,
-        ui.expandpath(origin or b'default-relink', origin or b'default'),
-    )
+
+    if origin is None and b'default-relink' in ui.paths:
+        origin = b'default-relink'
+    path, __ = urlutil.get_unique_pull_path(b'relink', repo, ui, origin)
+    src = hg.repository(repo.baseui, path)
     ui.status(_(b'relinking %s to %s\n') % (src.store.path, repo.store.path))
     if repo.root == src.root:
         ui.status(_(b'there is nothing to relink\n'))
         return
 
     if not util.samedevice(src.store.path, repo.store.path):
         # No point in continuing
         raise error.Abort(_(b'source and destination are on different devices'))
 
     with repo.lock(), src.lock():
         candidates = sorted(collect(src, ui))
         targets = prune(candidates, src.store.path, repo.store.path, ui)
         do_relink(src.store.path, repo.store.path, targets, ui)
 
 
 def collect(src, ui):
     seplen = len(os.path.sep)
     candidates = []
     live = len(src[b'tip'].manifest())
     # Your average repository has some files which were deleted before
     # the tip revision. We account for that by assuming that there are
     # 3 tracked files for every 2 live files as of the tip version of
     # the repository.
     #
     # mozilla-central as of 2010-06-10 had a ratio of just over 7:5.
     total = live * 3 // 2
     src = src.store.path
     progress = ui.makeprogress(_(b'collecting'), unit=_(b'files'), total=total)
     pos = 0
     ui.status(
         _(b"tip has %d files, estimated total number of files: %d\n")
         % (live, total)
     )
     for dirpath, dirnames, filenames in os.walk(src):
         dirnames.sort()
         relpath = dirpath[len(src) + seplen :]
         for filename in sorted(filenames):
             if filename[-2:] not in (b'.d', b'.i'):
                 continue
             st = os.stat(os.path.join(dirpath, filename))
             if not stat.S_ISREG(st.st_mode):
                 continue
             pos += 1
             candidates.append((os.path.join(relpath, filename), st))
             progress.update(pos, item=filename)
 
     progress.complete()
     ui.status(_(b'collected %d candidate storage files\n') % len(candidates))
     return candidates
 
 
 def prune(candidates, src, dst, ui):
     def linkfilter(src, dst, st):
         try:
             ts = os.stat(dst)
         except OSError:
             # Destination doesn't have this file?
             return False
         if util.samefile(src, dst):
             return False
         if not util.samedevice(src, dst):
             # No point in continuing
             raise error.Abort(
                 _(b'source and destination are on different devices')
             )
         if st.st_size != ts.st_size:
             return False
         return st
 
     targets = []
     progress = ui.makeprogress(
         _(b'pruning'), unit=_(b'files'), total=len(candidates)
     )
     pos = 0
     for fn, st in candidates:
         pos += 1
         srcpath = os.path.join(src, fn)
         tgt = os.path.join(dst, fn)
         ts = linkfilter(srcpath, tgt, st)
         if not ts:
             ui.debug(b'not linkable: %s\n' % fn)
             continue
         targets.append((fn, ts.st_size))
         progress.update(pos, item=fn)
 
     progress.complete()
     ui.status(
         _(b'pruned down to %d probably relinkable files\n') % len(targets)
     )
     return targets
 
 
 def do_relink(src, dst, files, ui):
     def relinkfile(src, dst):
         bak = dst + b'.bak'
         os.rename(dst, bak)
         try:
             util.oslink(src, dst)
         except OSError:
             os.rename(bak, dst)
             raise
         os.remove(bak)
 
     CHUNKLEN = 65536
     relinked = 0
     savedbytes = 0
 
     progress = ui.makeprogress(
         _(b'relinking'), unit=_(b'files'), total=len(files)
     )
     pos = 0
     for f, sz in files:
         pos += 1
         source = os.path.join(src, f)
         tgt = os.path.join(dst, f)
         # Binary mode, so that read() works correctly, especially on Windows
         sfp = open(source, b'rb')
         dfp = open(tgt, b'rb')
         sin = sfp.read(CHUNKLEN)
         while sin:
             din = dfp.read(CHUNKLEN)
             if sin != din:
                 break
             sin = sfp.read(CHUNKLEN)
         sfp.close()
         dfp.close()
         if sin:
             ui.debug(b'not linkable: %s\n' % f)
             continue
         try:
             relinkfile(source, tgt)
             progress.update(pos, item=f)
             relinked += 1
             savedbytes += sz
         except OSError as inst:
             ui.warn(b'%s: %s\n' % (tgt, stringutil.forcebytestr(inst)))
 
     progress.complete()
 
     ui.status(
         _(b'relinked %d files (%s reclaimed)\n')
         % (relinked, util.bytecount(savedbytes))
     )