Mercurial > hg
view mercurial/branchmap.py @ 18637:ac4dbceeb14a
worker: partition a list (of tasks) into equal-sized chunks
author | Bryan O'Sullivan <bryano@fb.com> |
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date | Sat, 09 Feb 2013 15:51:32 -0800 |
parents | d6b3b36f1db2 |
children | 3e92772d5383 |
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# branchmap.py - logic to computes, maintain and stores branchmap for local repo # # Copyright 2005-2007 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from node import bin, hex, nullid, nullrev import encoding import util, repoview def _filename(repo): """name of a branchcache file for a given repo or repoview""" filename = "cache/branchheads" if repo.filtername: filename = '%s-%s' % (filename, repo.filtername) return filename def read(repo): try: f = repo.opener(_filename(repo)) lines = f.read().split('\n') f.close() except (IOError, OSError): return None try: cachekey = lines.pop(0).split(" ", 2) last, lrev = cachekey[:2] last, lrev = bin(last), int(lrev) filteredhash = None if len(cachekey) > 2: filteredhash = bin(cachekey[2]) partial = branchcache(tipnode=last, tiprev=lrev, filteredhash=filteredhash) if not partial.validfor(repo): # invalidate the cache raise ValueError('tip differs') for l in lines: if not l: continue node, label = l.split(" ", 1) label = encoding.tolocal(label.strip()) if not node in repo: raise ValueError('node %s does not exist' % node) partial.setdefault(label, []).append(bin(node)) except KeyboardInterrupt: raise except Exception, inst: if repo.ui.debugflag: msg = 'invalid branchheads cache' if repo.filtername is not None: msg += ' (%s)' % repo.filtername msg += ': %s\n' repo.ui.warn(msg % inst) partial = None return partial def updatecache(repo): cl = repo.changelog filtername = repo.filtername partial = repo._branchcaches.get(filtername) revs = [] if partial is None or not partial.validfor(repo): partial = read(repo) if partial is None: subsetname = repoview.subsettable.get(filtername) if subsetname is None: partial = branchcache() else: subset = repo.filtered(subsetname) partial = subset.branchmap().copy() extrarevs = subset.changelog.filteredrevs - cl.filteredrevs revs.extend(r for r in extrarevs if r <= partial.tiprev) revs.extend(cl.revs(start=partial.tiprev + 1)) if revs: partial.update(repo, revs) partial.write(repo) assert partial.validfor(repo), filtername repo._branchcaches[repo.filtername] = partial class branchcache(dict): """A dict like object that hold branches heads cache""" def __init__(self, entries=(), tipnode=nullid, tiprev=nullrev, filteredhash=None): super(branchcache, self).__init__(entries) self.tipnode = tipnode self.tiprev = tiprev self.filteredhash = filteredhash def _hashfiltered(self, repo): """build hash of revision filtered in the current cache Tracking tipnode and tiprev is not enough to ensure validaty of the cache as they do not help to distinct cache that ignored various revision bellow tiprev. To detect such difference, we build a cache of all ignored revisions. """ cl = repo.changelog if not cl.filteredrevs: return None key = None revs = sorted(r for r in cl.filteredrevs if r <= self.tiprev) if revs: s = util.sha1() for rev in revs: s.update('%s;' % rev) key = s.digest() return key def validfor(self, repo): """Is the cache content valide regarding a repo - False when cached tipnode are unknown or if we detect a strip. - True when cache is up to date or a subset of current repo.""" try: return ((self.tipnode == repo.changelog.node(self.tiprev)) and (self.filteredhash == self._hashfiltered(repo))) except IndexError: return False def copy(self): """return an deep copy of the branchcache object""" return branchcache(self, self.tipnode, self.tiprev, self.filteredhash) def write(self, repo): try: f = repo.opener(_filename(repo), "w", atomictemp=True) cachekey = [hex(self.tipnode), str(self.tiprev)] if self.filteredhash is not None: cachekey.append(hex(self.filteredhash)) f.write(" ".join(cachekey) + '\n') for label, nodes in sorted(self.iteritems()): for node in nodes: f.write("%s %s\n" % (hex(node), encoding.fromlocal(label))) f.close() except (IOError, OSError, util.Abort): # Abort may be raise by read only opener pass def update(self, repo, revgen): """Given a branchhead cache, self, that may have extra nodes or be missing heads, and a generator of nodes that are at least a superset of heads missing, this function updates self to be correct. """ cl = repo.changelog # collect new branch entries newbranches = {} getbranch = cl.branch for r in revgen: newbranches.setdefault(getbranch(r), []).append(cl.node(r)) # if older branchheads are reachable from new ones, they aren't # really branchheads. Note checking parents is insufficient: # 1 (branch a) -> 2 (branch b) -> 3 (branch a) for branch, newnodes in newbranches.iteritems(): bheads = self.setdefault(branch, []) # Remove candidate heads that no longer are in the repo (e.g., as # the result of a strip that just happened). Avoid using 'node in # self' here because that dives down into branchcache code somewhat # recursively. bheadrevs = [cl.rev(node) for node in bheads if cl.hasnode(node)] newheadrevs = [cl.rev(node) for node in newnodes if cl.hasnode(node)] ctxisnew = bheadrevs and min(newheadrevs) > max(bheadrevs) # Remove duplicates - nodes that are in newheadrevs and are already # in bheadrevs. This can happen if you strip a node whose parent # was already a head (because they're on different branches). bheadrevs = sorted(set(bheadrevs).union(newheadrevs)) # Starting from tip means fewer passes over reachable. If we know # the new candidates are not ancestors of existing heads, we don't # have to examine ancestors of existing heads if ctxisnew: iterrevs = sorted(newheadrevs) else: iterrevs = list(bheadrevs) # This loop prunes out two kinds of heads - heads that are # superseded by a head in newheadrevs, and newheadrevs that are not # heads because an existing head is their descendant. while iterrevs: latest = iterrevs.pop() if latest not in bheadrevs: continue ancestors = set(cl.ancestors([latest], bheadrevs[0])) if ancestors: bheadrevs = [b for b in bheadrevs if b not in ancestors] self[branch] = [cl.node(rev) for rev in bheadrevs] tiprev = max(bheadrevs) if tiprev > self.tiprev: self.tipnode = cl.node(tiprev) self.tiprev = tiprev # There may be branches that cease to exist when the last commit in the # branch was stripped. This code filters them out. Note that the # branch that ceased to exist may not be in newbranches because # newbranches is the set of candidate heads, which when you strip the # last commit in a branch will be the parent branch. droppednodes = [] for branch in self.keys(): nodes = [head for head in self[branch] if cl.hasnode(head)] if not nodes: droppednodes.extend(nodes) del self[branch] if ((not self.validfor(repo)) or (self.tipnode in droppednodes)): # cache key are not valid anymore self.tipnode = nullid self.tiprev = nullrev for heads in self.values(): tiprev = max(cl.rev(node) for node in heads) if tiprev > self.tiprev: self.tipnode = cl.node(tiprev) self.tiprev = tiprev self.filteredhash = self._hashfiltered(repo)