Mercurial > hg
view mercurial/namespaces.py @ 40626:87a872555e90
revlog: detect incomplete revlog reads
_readsegment() is supposed to return N bytes of revlog revision
data starting at a file offset. Surprisingly, its behavior before
this patch never verified that it actually read and returned N
bytes! Instead, it would perform the read(), then return whatever
data was available. And even more surprisingly, nothing in the
call chain appears to have been validating that it received all
the data it was expecting.
This behavior could lead to partial or incomplete revision chunks
being operated on. This could result in e.g. cached deltas being
applied against incomplete base revisions. The delta application
process would happily perform this operation. Only hash
verification would detect the corruption and save us.
This commit changes the behavior of raw revlog reading to validate
that we actually read() the number of bytes that were requested.
We will raise a more specific error faster, rather than possibly
have it go undetected or manifest later in the call stack, at
delta application or hash verification.
Differential Revision: https://phab.mercurial-scm.org/D5266
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Tue, 13 Nov 2018 12:30:59 -0800 |
parents | 4c0683655599 |
children | 2372284d9457 |
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from __future__ import absolute_import from .i18n import _ from . import ( registrar, templatekw, util, ) def tolist(val): """ a convenience method to return an empty list instead of None """ if val is None: return [] else: return [val] class namespaces(object): """provides an interface to register and operate on multiple namespaces. See the namespace class below for details on the namespace object. """ _names_version = 0 def __init__(self): self._names = util.sortdict() columns = templatekw.getlogcolumns() # we need current mercurial named objects (bookmarks, tags, and # branches) to be initialized somewhere, so that place is here bmknames = lambda repo: repo._bookmarks.keys() bmknamemap = lambda repo, name: tolist(repo._bookmarks.get(name)) bmknodemap = lambda repo, node: repo.nodebookmarks(node) n = namespace("bookmarks", templatename="bookmark", logfmt=columns['bookmark'], listnames=bmknames, namemap=bmknamemap, nodemap=bmknodemap, builtin=True) self.addnamespace(n) tagnames = lambda repo: [t for t, n in repo.tagslist()] tagnamemap = lambda repo, name: tolist(repo._tagscache.tags.get(name)) tagnodemap = lambda repo, node: repo.nodetags(node) n = namespace("tags", templatename="tag", logfmt=columns['tag'], listnames=tagnames, namemap=tagnamemap, nodemap=tagnodemap, deprecated={'tip'}, builtin=True) self.addnamespace(n) bnames = lambda repo: repo.branchmap().keys() bnamemap = lambda repo, name: tolist(repo.branchtip(name, True)) bnodemap = lambda repo, node: [repo[node].branch()] n = namespace("branches", templatename="branch", logfmt=columns['branch'], listnames=bnames, namemap=bnamemap, nodemap=bnodemap, builtin=True) self.addnamespace(n) def __getitem__(self, namespace): """returns the namespace object""" return self._names[namespace] def __iter__(self): return self._names.__iter__() def items(self): return self._names.iteritems() iteritems = items def addnamespace(self, namespace, order=None): """register a namespace namespace: the name to be registered (in plural form) order: optional argument to specify the order of namespaces (e.g. 'branches' should be listed before 'bookmarks') """ if order is not None: self._names.insert(order, namespace.name, namespace) else: self._names[namespace.name] = namespace # we only generate a template keyword if one does not already exist if namespace.name not in templatekw.keywords: templatekeyword = registrar.templatekeyword(templatekw.keywords) @templatekeyword(namespace.name, requires={'repo', 'ctx'}) def generatekw(context, mapping): return templatekw.shownames(context, mapping, namespace.name) def singlenode(self, repo, name): """ Return the 'best' node for the given name. What's best is defined by the namespace's singlenode() function. The first match returned by a namespace in the defined precedence order is used. Raises a KeyError if there is no such node. """ for ns, v in self._names.iteritems(): n = v.singlenode(repo, name) if n: return n raise KeyError(_('no such name: %s') % name) class namespace(object): """provides an interface to a namespace Namespaces are basically generic many-to-many mapping between some (namespaced) names and nodes. The goal here is to control the pollution of jamming things into tags or bookmarks (in extension-land) and to simplify internal bits of mercurial: log output, tab completion, etc. More precisely, we define a mapping of names to nodes, and a mapping from nodes to names. Each mapping returns a list. Furthermore, each name mapping will be passed a name to lookup which might not be in its domain. In this case, each method should return an empty list and not raise an error. This namespace object will define the properties we need: 'name': the namespace (plural form) 'templatename': name to use for templating (usually the singular form of the plural namespace name) 'listnames': list of all names in the namespace (usually the keys of a dictionary) 'namemap': function that takes a name and returns a list of nodes 'nodemap': function that takes a node and returns a list of names 'deprecated': set of names to be masked for ordinary use 'builtin': bool indicating if this namespace is supported by core Mercurial. """ def __init__(self, name, templatename=None, logname=None, colorname=None, logfmt=None, listnames=None, namemap=None, nodemap=None, deprecated=None, builtin=False, singlenode=None): """create a namespace name: the namespace to be registered (in plural form) templatename: the name to use for templating logname: the name to use for log output; if not specified templatename is used colorname: the name to use for colored log output; if not specified logname is used logfmt: the format to use for (i18n-ed) log output; if not specified it is composed from logname listnames: function to list all names namemap: function that inputs a name, output node(s) nodemap: function that inputs a node, output name(s) deprecated: set of names to be masked for ordinary use builtin: whether namespace is implemented by core Mercurial singlenode: function that inputs a name, output best node (or None) """ self.name = name self.templatename = templatename self.logname = logname self.colorname = colorname self.logfmt = logfmt self.listnames = listnames self.namemap = namemap self.nodemap = nodemap if singlenode: self.singlenode = singlenode # if logname is not specified, use the template name as backup if self.logname is None: self.logname = self.templatename # if colorname is not specified, just use the logname as a backup if self.colorname is None: self.colorname = self.logname # if logfmt is not specified, compose it from logname as backup if self.logfmt is None: # i18n: column positioning for "hg log" self.logfmt = ("%s:" % self.logname).ljust(13) + "%s\n" if deprecated is None: self.deprecated = set() else: self.deprecated = deprecated self.builtin = builtin def names(self, repo, node): """method that returns a (sorted) list of names in a namespace that match a given node""" return sorted(self.nodemap(repo, node)) def nodes(self, repo, name): """method that returns a list of nodes in a namespace that match a given name. """ return sorted(self.namemap(repo, name)) def singlenode(self, repo, name): """returns the best node for the given name By default, the best node is the node from nodes() with the highest revision number. It can be overriden by the namespace.""" n = self.namemap(repo, name) if n: # return max revision number if len(n) > 1: cl = repo.changelog maxrev = max(cl.rev(node) for node in n) return cl.node(maxrev) return n[0] return None