[PATCH] move tags.cache and branchheads.cache to a collected cache folder .hg/caches/

[Adrian Buehlmann]

On 2010-12-24 23:22, Jason Harris wrote:
> # HG changeset patch
> # User jfh <jason at jasonfharris.com>
> # Date 1293195683 -3600
> # Node ID 53a4b25e7165c3842c8cd9e376a4240738070aab
> # Parent  5314cbb775f6e2034be96bc64a54a0ec7c553a19
> move tags.cache and branchheads.cache to a collected cache folder .hg/caches/
> 
> The generation of cache files like tags.cache and branchheads.cache is not an
> actual reflection of things changing in the whole of the .hg directory (like eg
> a commit or a rebase or something) but instead these cache files are just part
> of bookkeeping. As such its convienant to allow various clients to ignore file
> events to do with these cache files which would otherwise cause a double
> refresh. Eg one refresh might occur after a commit, but the act of refreshing
> after the commit would cause Mercurial to generate a new branchheads.cache which
> would then cause a second refresh, for clients.
> 
> However if these cache files are moved into a directory like eg .hg/caches/ then
> GUI clients on OSX (and possibly other platforms) can happily ignore file events
> in this cache directory.

Sounds reasonable.

Perhaps you can implement it a bit differently though. See inline
comment below

> diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
> --- a/mercurial/localrepo.py
> +++ b/mercurial/localrepo.py
> @@ -439,7 +439,7 @@
>      def _readbranchcache(self):
>          partial = {}
>          try:
> -            f = self.opener("branchheads.cache")
> +            f = self.opener(os.path.join("caches","branchheads.cache"))

What about setting up an new cache opener ('copener') and using it like this

               f = self.copener("branchheads")

I envision having the cacheopener's base directory in '.hg/cache'. Also,
we can drop the '.cache' suffix on the files in there while we're at it.

>              lines = f.read().split('\n')
>              f.close()
>          except (IOError, OSError):
> @@ -467,7 +467,7 @@
>  
>      def _writebranchcache(self, branches, tip, tiprev):
>          try:
> -            f = self.opener("branchheads.cache", "w", atomictemp=True)
> +            f = self.opener(os.path.join("caches","branchheads.cache"), "w", atomictemp=True)
>              f.write("%s %s\n" % (hex(tip), tiprev))
>              for label, nodes in branches.iteritems():
>                  for node in nodes:
> diff --git a/mercurial/tags.py b/mercurial/tags.py
> --- a/mercurial/tags.py
> +++ b/mercurial/tags.py
> @@ -12,6 +12,7 @@
>  
>  from node import nullid, bin, hex, short
>  from i18n import _
> +import os.path
>  import encoding
>  import error
>  
> @@ -154,7 +155,7 @@
>      set, caller is responsible for reading tag info from each head.'''
>  
>      try:
> -        cachefile = repo.opener('tags.cache', 'r')
> +        cachefile = repo.opener(os.path.join('caches','tags.cache'), 'r')
>          # force reading the file for static-http
>          cachelines = iter(cachefile)
>      except IOError:
> @@ -189,7 +190,7 @@
>                      cachefnode[headnode] = fnode
>          except (ValueError, TypeError):
>              # corruption of tags.cache, just recompute it
> -            ui.warn(_('.hg/tags.cache is corrupt, rebuilding it\n'))
> +            ui.warn(_('.hg/caches/tags.cache is corrupt, rebuilding it\n'))
>              cacheheads = []
>              cacherevs = []
>              cachefnode = {}
> @@ -251,7 +252,7 @@
>  def _writetagcache(ui, repo, heads, tagfnode, cachetags):
>  
>      try:
> -        cachefile = repo.opener('tags.cache', 'w', atomictemp=True)
> +        cachefile = repo.opener(os.path.join('caches','tags.cache'), 'w', atomictemp=True)
>      except (OSError, IOError):
>          return