view mercurial/bundlerepo.py @ 14093:ce99d887585f

httprepo: long arguments support (issue2126)

Send the command arguments in the HTTP headers. The command is still part
of the URL. If the server does not have the 'httpheader' capability, the
client will send the command arguments in the URL as it did previously.

Web servers typically allow more data to be placed within the headers than
in the URL, so this approach will:
- Avoid HTTP errors due to using a URL that is too large.
- Allow Mercurial to implement a more efficient wire protocol.

An alternate approach is to send the arguments as part of the request body.
This approach has been rejected because it requires the use of POST
requests, so it would break any existing configuration that relies on the
request type for authentication or caching.

Extensibility:
- The header size is provided by the server, which makes it possible to
  introduce an hgrc setting for it.
- The client ignores the capability value after the first comma, which
  allows more information to be included in the future.

# bundlerepo.py - repository class for viewing uncompressed bundles
#
# Copyright 2006, 2007 Benoit Boissinot <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

"""Repository class for viewing uncompressed bundles.

This provides a read-only repository interface to bundles as if they
were part of the actual repository.
"""

from node import nullid
from i18n import _
import os, struct, tempfile, shutil
import changegroup, util, mdiff, discovery
import localrepo, changelog, manifest, filelog, revlog, error

class bundlerevlog(revlog.revlog):
    def __init__(self, opener, indexfile, bundle,
                 linkmapper=None):
        # How it works:
        # to retrieve a revision, we need to know the offset of
        # the revision in the bundle (an unbundle object).
        #
        # We store this offset in the index (start), to differentiate a
        # rev in the bundle and from a rev in the revlog, we check
        # len(index[r]). If the tuple is bigger than 7, it is a bundle
        # (it is bigger since we store the node to which the delta is)
        #
        revlog.revlog.__init__(self, opener, indexfile)
        self.bundle = bundle
        self.basemap = {}
        def chunkpositer():
            while 1:
                chunk = bundle.chunk()
                if not chunk:
                    break
                pos = bundle.tell()
                yield chunk, pos - len(chunk)
        n = len(self)
        prev = None
        for chunk, start in chunkpositer():
            size = len(chunk)
            if size < 80:
                raise util.Abort(_("invalid changegroup"))
            start += 80
            size -= 80
            node, p1, p2, cs = struct.unpack("20s20s20s20s", chunk[:80])
            if node in self.nodemap:
                prev = node
                continue
            for p in (p1, p2):
                if not p in self.nodemap:
                    raise error.LookupError(p, self.indexfile,
                                            _("unknown parent"))
            if linkmapper is None:
                link = n
            else:
                link = linkmapper(cs)

            if not prev:
                prev = p1
            # start, size, full unc. size, base (unused), link, p1, p2, node
            e = (revlog.offset_type(start, 0), size, -1, -1, link,
                 self.rev(p1), self.rev(p2), node)
            self.basemap[n] = prev
            self.index.insert(-1, e)
            self.nodemap[node] = n
            prev = node
            n += 1

    def inbundle(self, rev):
        """is rev from the bundle"""
        if rev < 0:
            return False
        return rev in self.basemap
    def bundlebase(self, rev):
        return self.basemap[rev]
    def _chunk(self, rev):
        # Warning: in case of bundle, the diff is against bundlebase,
        # not against rev - 1
        # XXX: could use some caching
        if not self.inbundle(rev):
            return revlog.revlog._chunk(self, rev)
        self.bundle.seek(self.start(rev))
        return self.bundle.read(self.length(rev))

    def revdiff(self, rev1, rev2):
        """return or calculate a delta between two revisions"""
        if self.inbundle(rev1) and self.inbundle(rev2):
            # hot path for bundle
            revb = self.rev(self.bundlebase(rev2))
            if revb == rev1:
                return self._chunk(rev2)
        elif not self.inbundle(rev1) and not self.inbundle(rev2):
            return revlog.revlog.revdiff(self, rev1, rev2)

        return mdiff.textdiff(self.revision(self.node(rev1)),
                         self.revision(self.node(rev2)))

    def revision(self, node):
        """return an uncompressed revision of a given"""
        if node == nullid:
            return ""

        text = None
        chain = []
        iter_node = node
        rev = self.rev(iter_node)
        # reconstruct the revision if it is from a changegroup
        while self.inbundle(rev):
            if self._cache and self._cache[0] == iter_node:
                text = self._cache[2]
                break
            chain.append(rev)
            iter_node = self.bundlebase(rev)
            rev = self.rev(iter_node)
        if text is None:
            text = revlog.revlog.revision(self, iter_node)

        while chain:
            delta = self._chunk(chain.pop())
            text = mdiff.patches(text, [delta])

        p1, p2 = self.parents(node)
        if node != revlog.hash(text, p1, p2):
            raise error.RevlogError(_("integrity check failed on %s:%d")
                                     % (self.datafile, self.rev(node)))

        self._cache = (node, self.rev(node), text)
        return text

    def addrevision(self, text, transaction, link, p1=None, p2=None, d=None):
        raise NotImplementedError
    def addgroup(self, revs, linkmapper, transaction):
        raise NotImplementedError
    def strip(self, rev, minlink):
        raise NotImplementedError
    def checksize(self):
        raise NotImplementedError

class bundlechangelog(bundlerevlog, changelog.changelog):
    def __init__(self, opener, bundle):
        changelog.changelog.__init__(self, opener)
        bundlerevlog.__init__(self, opener, self.indexfile, bundle)

class bundlemanifest(bundlerevlog, manifest.manifest):
    def __init__(self, opener, bundle, linkmapper):
        manifest.manifest.__init__(self, opener)
        bundlerevlog.__init__(self, opener, self.indexfile, bundle,
                              linkmapper)

class bundlefilelog(bundlerevlog, filelog.filelog):
    def __init__(self, opener, path, bundle, linkmapper):
        filelog.filelog.__init__(self, opener, path)
        bundlerevlog.__init__(self, opener, self.indexfile, bundle,
                              linkmapper)

class bundlerepository(localrepo.localrepository):
    def __init__(self, ui, path, bundlename):
        self._tempparent = None
        try:
            localrepo.localrepository.__init__(self, ui, path)
        except error.RepoError:
            self._tempparent = tempfile.mkdtemp()
            localrepo.instance(ui, self._tempparent, 1)
            localrepo.localrepository.__init__(self, ui, self._tempparent)

        if path:
            self._url = 'bundle:' + util.expandpath(path) + '+' + bundlename
        else:
            self._url = 'bundle:' + bundlename

        self.tempfile = None
        f = util.posixfile(bundlename, "rb")
        self.bundle = changegroup.readbundle(f, bundlename)
        if self.bundle.compressed():
            fdtemp, temp = tempfile.mkstemp(prefix="hg-bundle-",
                                            suffix=".hg10un", dir=self.path)
            self.tempfile = temp
            fptemp = os.fdopen(fdtemp, 'wb')

            try:
                fptemp.write("HG10UN")
                while 1:
                    chunk = self.bundle.read(2**18)
                    if not chunk:
                        break
                    fptemp.write(chunk)
            finally:
                fptemp.close()

            f = util.posixfile(self.tempfile, "rb")
            self.bundle = changegroup.readbundle(f, bundlename)

        # dict with the mapping 'filename' -> position in the bundle
        self.bundlefilespos = {}

    @util.propertycache
    def changelog(self):
        c = bundlechangelog(self.sopener, self.bundle)
        self.manstart = self.bundle.tell()
        return c

    @util.propertycache
    def manifest(self):
        self.bundle.seek(self.manstart)
        m = bundlemanifest(self.sopener, self.bundle, self.changelog.rev)
        self.filestart = self.bundle.tell()
        return m

    @util.propertycache
    def manstart(self):
        self.changelog
        return self.manstart

    @util.propertycache
    def filestart(self):
        self.manifest
        return self.filestart

    def url(self):
        return self._url

    def file(self, f):
        if not self.bundlefilespos:
            self.bundle.seek(self.filestart)
            while 1:
                chunk = self.bundle.chunk()
                if not chunk:
                    break
                self.bundlefilespos[chunk] = self.bundle.tell()
                while 1:
                    c = self.bundle.chunk()
                    if not c:
                        break

        if f[0] == '/':
            f = f[1:]
        if f in self.bundlefilespos:
            self.bundle.seek(self.bundlefilespos[f])
            return bundlefilelog(self.sopener, f, self.bundle,
                                 self.changelog.rev)
        else:
            return filelog.filelog(self.sopener, f)

    def close(self):
        """Close assigned bundle file immediately."""
        self.bundle.close()
        if self.tempfile is not None:
            os.unlink(self.tempfile)
        if self._tempparent:
            shutil.rmtree(self._tempparent, True)

    def cancopy(self):
        return False

    def getcwd(self):
        return os.getcwd() # always outside the repo

def instance(ui, path, create):
    if create:
        raise util.Abort(_('cannot create new bundle repository'))
    parentpath = ui.config("bundle", "mainreporoot", "")
    if parentpath:
        # Try to make the full path relative so we get a nice, short URL.
        # In particular, we don't want temp dir names in test outputs.
        cwd = os.getcwd()
        if parentpath == cwd:
            parentpath = ''
        else:
            cwd = os.path.join(cwd,'')
            if parentpath.startswith(cwd):
                parentpath = parentpath[len(cwd):]
    u = util.url(path)
    path = u.localpath()
    if u.scheme == 'bundle':
        s = path.split("+", 1)
        if len(s) == 1:
            repopath, bundlename = parentpath, s[0]
        else:
            repopath, bundlename = s
    else:
        repopath, bundlename = parentpath, path
    return bundlerepository(ui, repopath, bundlename)

def getremotechanges(ui, repo, other, revs=None, bundlename=None,
                     force=False):
    tmp = discovery.findcommonincoming(repo, other, heads=revs, force=force)
    common, incoming, rheads = tmp
    if not incoming:
        try:
            os.unlink(bundlename)
        except OSError:
            pass
        return other, None, None, None

    bundle = None
    if bundlename or not other.local():
        # create a bundle (uncompressed if other repo is not local)

        if revs is None and other.capable('changegroupsubset'):
            revs = rheads

        if other.capable('getbundle'):
            cg = other.getbundle('incoming', common=common, heads=revs)
        elif revs is None:
            cg = other.changegroup(incoming, "incoming")
        else:
            cg = other.changegroupsubset(incoming, revs, 'incoming')
        bundletype = other.local() and "HG10BZ" or "HG10UN"
        fname = bundle = changegroup.writebundle(cg, bundlename, bundletype)
        # keep written bundle?
        if bundlename:
            bundle = None
        if not other.local():
            # use the created uncompressed bundlerepo
            other = bundlerepository(ui, repo.root, fname)
    return (other, common, incoming, bundle)