[PATCH 2 of 2 V3] move tags.cache and branchheads.cache to a collected cache folder .hg/caches/

[Jason Harris]

# HG changeset patch
# User jfh <jason at jasonfharris.com>
# Date 1294119540 -3600
# Node ID 129f5c8fcf76598918c68f39b4156b10d84fa08e
# Parent  65a39818367f9657a291cade204e7f574e919dbc
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 convenient 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.

Part II: Refactor requested by Adrian Buehlmann.

Adrian asked that these changes to move the caches into their own directory, be
wrapped up in a new copener.

diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -33,6 +33,7 @@
         self.auditor = util.path_auditor(self.root, self._checknested)
         self.opener = util.opener(self.path)
         self.wopener = util.opener(self.root)
+        self.copener = util.opener(os.path.join(self.path, "caches"))
         self.baseui = baseui
         self.ui = baseui.copy()
 
@@ -93,6 +94,7 @@
         self.sopener = self.store.opener
         self.sjoin = self.store.join
         self.opener.createmode = self.store.createmode
+        self.copener.createmode = self.store.createmode
         self._applyrequirements(requirements)
         if create:
             self._writerequirements()
@@ -439,8 +441,7 @@
     def _readbranchcache(self):
         partial = {}
         try:
-            fn = os.path.join("caches", "branchheads.cache")
-            f = self.opener(fn)
+            f = self.copener("branchheads.cache")
             lines = f.read().split('\n')
             f.close()
         except (IOError, OSError):
@@ -468,8 +469,7 @@
 
     def _writebranchcache(self, branches, tip, tiprev):
         try:
-            fn = os.path.join("caches", "branchheads.cache")
-            f = self.opener(fn, "w", atomictemp=True)
+            f = self.copener("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/statichttprepo.py b/mercurial/statichttprepo.py
--- a/mercurial/statichttprepo.py
+++ b/mercurial/statichttprepo.py
@@ -90,6 +90,7 @@
 
         opener = build_opener(ui, authinfo)
         self.opener = opener(self.path)
+        self.copener = opener(self.path + "/caches")
 
         # find requirements
         try:
diff --git a/mercurial/tags.py b/mercurial/tags.py
--- a/mercurial/tags.py
+++ b/mercurial/tags.py
@@ -155,7 +155,7 @@
     set, caller is responsible for reading tag info from each head.'''
 
     try:
-        cachefile = repo.opener(os.path.join('caches', 'tags.cache'), 'r')
+        cachefile = repo.copener('tags.cache', 'r')
         # force reading the file for static-http
         cachelines = iter(cachefile)
     except IOError:
@@ -252,8 +252,7 @@
 def _writetagcache(ui, repo, heads, tagfnode, cachetags):
 
     try:
-        fn = os.path.join('caches', 'tags.cache')
-        cachefile = repo.opener(fn, 'w', atomictemp=True)
+        cachefile = repo.copener('tags.cache', 'w', atomictemp=True)
     except (OSError, IOError):
         return