[PATCH 04 of 10] branchmap: add the tiprev (cache key) on the branchmap object

Augie Fackler raf at durin42.com
Sun Dec 23 19:21:42 CST 2012


On Dec 21, 2012, at 8:48 PM, Pierre-Yves David <pierre-yves.david at ens-lyon.org> wrote:

> # HG changeset patch
> # User Pierre-Yves David <pierre-yves.david at logilab.fr>
> # Date 1356138386 -3600
> # Node ID 090ada0acddb4486e94fba9c89e25b0624442d0f
> # Parent  ad194a8ab5c15e6d74fe087061ee960f5d6bbf16
> branchmap: add the tiprev (cache key) on the branchmap object
> 
> The actual cache key used on disk is the (tipnode, tiprev) pair. There is no
> reason not to use the revision number for the in memory version.

It feels strange to me to have both tipnode and tiprev on this object, partially because it feels more likely that they'll fall out of sync somehow. Then again, I suppose if that happens then we want the cache to be invalidated anyway?

> 
> diff --git a/mercurial/branchmap.py b/mercurial/branchmap.py
> --- a/mercurial/branchmap.py
> +++ b/mercurial/branchmap.py
> @@ -13,11 +13,11 @@ def read(repo):
>     try:
>         f = repo.opener("cache/branchheads")
>         lines = f.read().split('\n')
>         f.close()
>     except (IOError, OSError):
> -        return branchcache(), nullrev
> +        return branchcache()
> 
>     try:
>         last, lrev = lines.pop(0).split(" ", 1)
>         last, lrev = bin(last), int(lrev)
>         if lrev >= len(repo) or repo[lrev].node() != last:
> @@ -31,17 +31,18 @@ def read(repo):
>             if not node in repo:
>                 raise ValueError('invalidating branch cache because node '+
>                                  '%s does not exist' % node)
>             partial.setdefault(label, []).append(bin(node))
>         partial.tipnode = last
> +        partial.tiprev = lrev
>     except KeyboardInterrupt:
>         raise
>     except Exception, inst:
>         if repo.ui.debugflag:
>             repo.ui.warn(str(inst), '\n')
> -        partial, lrev = branchcache(), nullrev
> -    return partial, lrev
> +        partial = branchcache()
> +    return partial
> 
> def write(repo, branches, tip, tiprev):
>     try:
>         f = repo.opener("cache/branchheads", "w", atomictemp=True)
>         f.write("%s %s\n" % (hex(tip), tiprev))
> @@ -119,35 +120,35 @@ def updatecache(repo):
>     partial = repo._branchcache
>     if partial is not None and partial.tipnode == tip:
>         return
> 
>     if partial is None or partial.tipnode not in cl.nodemap:
> -        partial, lrev = read(repo)
> -    else:
> -        lrev = cl.rev(partial.tipnode)
> +        partial = read(repo)
> 
>     catip = repo._cacheabletip()
> -    # if lrev == catip: cache is already up to date
> -    # if lrev >  catip: we have uncachable element in `partial` can't write
> -    #                   on disk
> -    if lrev < catip:
> -        ctxgen = (repo[r] for r in cl.revs(lrev + 1, catip))
> +    # if partial.tiprev == catip: cache is already up to date
> +    # if partial.tiprev >  catip: we have uncachable element in `partial` can't
> +    #                             write on disk
> +    if partial.tiprev < catip:
> +        ctxgen = (repo[r] for r in cl.revs(partial.tiprev + 1, catip))
>         update(repo, partial, ctxgen)
>         partial.tipnode = cl.node(catip)
> -        write(repo, partial, partial.tipnode, catip)
> -        lrev = catip
> +        partial.tiprev = catip
> +        write(repo, partial, partial.tipnode, partial.tiprev)
>     # If cacheable tip were lower than actual tip, we need to update the
>     # cache up to tip. This update (from cacheable to actual tip) is not
>     # written to disk since it's not cacheable.
>     tiprev = len(repo) - 1
> -    if lrev < tiprev:
> -        ctxgen = (repo[r] for r in cl.revs(lrev + 1, tiprev))
> +    if partial.tiprev < tiprev:
> +        ctxgen = (repo[r] for r in cl.revs(partial.tiprev + 1, tiprev))
>         update(repo, partial, ctxgen)
>         partial.tipnode = cl.node(tiprev)
> +        partial.tiprev = tiprev
>     repo._branchcache = partial
> 
> class branchcache(dict):
>     """A dict like object that hold branches heads cache"""
> 
> -    def __init__(self, entries=(), tipnode=nullid):
> +    def __init__(self, entries=(), tipnode=nullid, tiprev=nullrev):
>         super(branchcache, self).__init__(entries)
>         self.tipnode = tipnode
> +        self.tiprev = tiprev
> diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
> --- a/mercurial/localrepo.py
> +++ b/mercurial/localrepo.py
> @@ -1432,17 +1432,17 @@ class localrepository(object):
>         '''
>         # If we have info, newheadnodes, on how to update the branch cache, do
>         # it, Otherwise, since nodes were destroyed, the cache is stale and this
>         # will be caught the next time it is read.
>         if newheadnodes:
> -            tiprev = len(self) - 1
>             ctxgen = (self[node] for node in newheadnodes
>                       if self.changelog.hasnode(node))
> -            branchmap.update(self, self._branchcache, ctxgen)
> -            self._branchcache.tipnode = self.changelog.tip()
> -            branchmap.write(self, self._branchcache, self._branchcache.tipnode,
> -                            tiprev)
> +            cache = self._branchcache
> +            branchmap.update(self, cache, ctxgen)
> +            cache.tipnode = self.changelog.tip()
> +            cache.tiprev = self.changelog.rev(cache.tipnode)
> +            branchmap.write(self, cache, cache.tipnode, cache.tiprev)
> 
>         # Ensure the persistent tag cache is updated.  Doing it now
>         # means that the tag cache only has to worry about destroyed
>         # heads immediately after a strip/rollback.  That in turn
>         # guarantees that "cachetip == currenttip" (comparing both rev
> @@ -2493,13 +2493,14 @@ class localrepository(object):
> 
>                 if rbheads:
>                     rtiprev = max((int(self.changelog.rev(node))
>                             for node in rbheads))
>                     cache = branchmap.branchcache(rbranchmap,
> -                                                  self[rtiprev].node())
> +                                                  self[rtiprev].node(),
> +                                                  rtiprev)
>                     self._branchcache = cache
> -                    branchmap.write(self, cache, cache.tipnode, rtiprev)
> +                    branchmap.write(self, cache, cache.tipnode, cache.tiprev)
>             self.invalidate()
>             return len(self.heads()) + 1
>         finally:
>             lock.release()
> 



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