mercurial/namespaces.py
author FUJIWARA Katsunori <foozy@lares.dti.ne.jp>
Sun, 14 Feb 2016 01:33:55 +0900
changeset 28119 91a827e760df
parent 25961 c0c89b2d07be
child 28567 ca52512ac709
permissions -rw-r--r--
hg: make cachedlocalrepo cache appropriate repoview object Before this patch, 'cachedlocalrepo' always caches "visible" repoview object, because 'cachedlocalrepo' uses "visible" repoview returned by 'hg.repository()' without any additional processing. If the client of 'cachedlocalrepo' wants "served" repoview, some objects to be cached are discarded unintentionally. 1. 'cachedlocalrepo' newly caches "visible" repoview object (call it VIEW1) 2. 'cachedlocalrepo' returns VIEW1 to the client of it at 'fetch()' 3. the client gets "served" repoview object by 'filtered("served")' on VIEW1 (call this "served" repoview VIEW2) 4. accessing to 'repo.changelog' implies: - instantiation of changelog via 'localrepository.changelog' - instantiation of "filtered changelog" via 'repoview.changelog' 5. "filtered changelog" above is cached in VIEW2 6. VIEW2 is discarded after processing, because there is no reference to it 7. 'cachedlocalrepo' returns VIEW1 cached at (1) above to the client at next 'fetch()' 8. 'filtered("served")' on VIEW1 at the client side creates new "served" repoview again, because VIEW1 is "visible" (call this new "served" repoview VIEW3) 9. accessing to 'repo.changelog' implies instantiation of filtered changelog again, because "filtered changelog" is cached in VIEW2 at (5), but not in VIEW3 currently used 10. (go to (7) above) As described above, "served" repoview object and "filtered changelog" cached in it are discarded always, even if the repository itself hasn't been changed since last access. For example, in the case of 'hgweb_mod.hgweb', "newly caching" occurs, when: - all cached objects are already assigned to another threads (in this case, repoview is created in 'cachedlocalrepo.copy()') - or, stat of '00changelog.i' is changed from last access (in this case, repoview is created in 'cachedlocalrepo.fetch()') once changes are pushed via HTTP, this always occurs. The root cause of this inefficiency is that 'cachedlocalrepo' always caches "visible" repoview object, even if the client of it wants another view. To make 'cachedlocalrepo' cache appropriate repoview object, this patch adds additional filtering on the repo object returned by 'hg.repository()'. It is assumed that initial repoview object should be already filtered by expected view. After this patch: - 'filtered("served")' on VIEW1 at (3)/(7) above returns VIEW1 itself, because VIEW1 is now "served", and - VIEW2 and VIEW3 equal VIEW1 - therefore, "filtered changelog" is cached in VIEW1, and reused intentionally

from __future__ import absolute_import

from .i18n import _
from . import (
    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()

        # 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, name: repo.nodebookmarks(name)
        n = namespace("bookmarks", templatename="bookmark",
                      # i18n: column positioning for "hg log"
                      logfmt=_("bookmark:    %s\n"),
                      listnames=bmknames,
                      namemap=bmknamemap, nodemap=bmknodemap)
        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, name: repo.nodetags(name)
        n = namespace("tags", templatename="tag",
                      # i18n: column positioning for "hg log"
                      logfmt=_("tag:         %s\n"),
                      listnames=tagnames,
                      namemap=tagnamemap, nodemap=tagnodemap,
                      deprecated=set(['tip']))
        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",
                      # i18n: column positioning for "hg log"
                      logfmt=_("branch:      %s\n"),
                      listnames=bnames,
                      namemap=bnamemap, nodemap=bnodemap)
        self.addnamespace(n)

    def __getitem__(self, namespace):
        """returns the namespace object"""
        return self._names[namespace]

    def __iter__(self):
        return self._names.__iter__()

    def iteritems(self):
        return self._names.iteritems()

    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:
            def generatekw(**args):
                return templatekw.shownames(namespace.name, **args)

            templatekw.keywords[namespace.name] = generatekw

    def singlenode(self, repo, name):
        """
        Return the 'best' node for the given name. Best means the first node
        in the first nonempty list returned by a name-to-nodes mapping function
        in the defined precedence order.

        Raises a KeyError if there is no such node.
        """
        for ns, v in self._names.iteritems():
            n = v.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]
        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

    """

    def __init__(self, name, templatename=None, logname=None, colorname=None,
                 logfmt=None, listnames=None, namemap=None, nodemap=None,
                 deprecated=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 node, output name(s)
        nodemap: function that inputs a name, output node(s)
        deprecated: set of names to be masked for ordinary use

        """
        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 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

    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))