view hgext/remotefilelog/contentstore.py @ 48295:bf11ff22a9af

dirstate-v2: freeze the on-disk format

It seems the format as reached a good balance. With a core of new capabilities
that motivated it initially and enough new feature and room for future
improvement to be a clear progress we can set a milestone for.

Having the format frozen will help the feature to get real life testing, outside
of the test suite.

The feature itself stay experimental but the config gains a new name to avoid
people enable non-frozen version by default.

If too many bugs are reported during the RC we might move the format back to
experimental and drop its support in future version (in favor of a new one)

Differential Revision: https://phab.mercurial-scm.org/D11709

from __future__ import absolute_import

import threading

from mercurial.node import (
    hex,
    sha1nodeconstants,
)
from mercurial.pycompat import getattr
from mercurial import (
    mdiff,
    pycompat,
    revlog,
)
from . import (
    basestore,
    constants,
    shallowutil,
)


class ChainIndicies(object):
    """A static class for easy reference to the delta chain indicies."""

    # The filename of this revision delta
    NAME = 0
    # The mercurial file node for this revision delta
    NODE = 1
    # The filename of the delta base's revision. This is useful when delta
    # between different files (like in the case of a move or copy, we can delta
    # against the original file content).
    BASENAME = 2
    # The mercurial file node for the delta base revision. This is the nullid if
    # this delta is a full text.
    BASENODE = 3
    # The actual delta or full text data.
    DATA = 4


class unioncontentstore(basestore.baseunionstore):
    def __init__(self, *args, **kwargs):
        super(unioncontentstore, self).__init__(*args, **kwargs)

        self.stores = args
        self.writestore = kwargs.get('writestore')

        # If allowincomplete==True then the union store can return partial
        # delta chains, otherwise it will throw a KeyError if a full
        # deltachain can't be found.
        self.allowincomplete = kwargs.get('allowincomplete', False)

    def get(self, name, node):
        """Fetches the full text revision contents of the given name+node pair.
        If the full text doesn't exist, throws a KeyError.

        Under the hood, this uses getdeltachain() across all the stores to build
        up a full chain to produce the full text.
        """
        chain = self.getdeltachain(name, node)

        if chain[-1][ChainIndicies.BASENODE] != sha1nodeconstants.nullid:
            # If we didn't receive a full chain, throw
            raise KeyError((name, hex(node)))

        # The last entry in the chain is a full text, so we start our delta
        # applies with that.
        fulltext = chain.pop()[ChainIndicies.DATA]

        text = fulltext
        while chain:
            delta = chain.pop()[ChainIndicies.DATA]
            text = mdiff.patches(text, [delta])

        return text

    @basestore.baseunionstore.retriable
    def getdelta(self, name, node):
        """Return the single delta entry for the given name/node pair."""
        for store in self.stores:
            try:
                return store.getdelta(name, node)
            except KeyError:
                pass

        raise KeyError((name, hex(node)))

    def getdeltachain(self, name, node):
        """Returns the deltachain for the given name/node pair.

        Returns an ordered list of:

          [(name, node, deltabasename, deltabasenode, deltacontent),...]

        where the chain is terminated by a full text entry with a nullid
        deltabasenode.
        """
        chain = self._getpartialchain(name, node)
        while chain[-1][ChainIndicies.BASENODE] != sha1nodeconstants.nullid:
            x, x, deltabasename, deltabasenode, x = chain[-1]
            try:
                morechain = self._getpartialchain(deltabasename, deltabasenode)
                chain.extend(morechain)
            except KeyError:
                # If we allow incomplete chains, don't throw.
                if not self.allowincomplete:
                    raise
                break

        return chain

    @basestore.baseunionstore.retriable
    def getmeta(self, name, node):
        """Returns the metadata dict for given node."""
        for store in self.stores:
            try:
                return store.getmeta(name, node)
            except KeyError:
                pass
        raise KeyError((name, hex(node)))

    def getmetrics(self):
        metrics = [s.getmetrics() for s in self.stores]
        return shallowutil.sumdicts(*metrics)

    @basestore.baseunionstore.retriable
    def _getpartialchain(self, name, node):
        """Returns a partial delta chain for the given name/node pair.

        A partial chain is a chain that may not be terminated in a full-text.
        """
        for store in self.stores:
            try:
                return store.getdeltachain(name, node)
            except KeyError:
                pass

        raise KeyError((name, hex(node)))

    def add(self, name, node, data):
        raise RuntimeError(
            b"cannot add content only to remotefilelog contentstore"
        )

    def getmissing(self, keys):
        missing = keys
        for store in self.stores:
            if missing:
                missing = store.getmissing(missing)
        return missing

    def addremotefilelognode(self, name, node, data):
        if self.writestore:
            self.writestore.addremotefilelognode(name, node, data)
        else:
            raise RuntimeError(b"no writable store configured")

    def markledger(self, ledger, options=None):
        for store in self.stores:
            store.markledger(ledger, options)


class remotefilelogcontentstore(basestore.basestore):
    def __init__(self, *args, **kwargs):
        super(remotefilelogcontentstore, self).__init__(*args, **kwargs)
        self._threaddata = threading.local()

    def get(self, name, node):
        # return raw revision text
        data = self._getdata(name, node)

        offset, size, flags = shallowutil.parsesizeflags(data)
        content = data[offset : offset + size]

        ancestormap = shallowutil.ancestormap(data)
        p1, p2, linknode, copyfrom = ancestormap[node]
        copyrev = None
        if copyfrom:
            copyrev = hex(p1)

        self._updatemetacache(node, size, flags)

        # lfs tracks renames in its own metadata, remove hg copy metadata,
        # because copy metadata will be re-added by lfs flag processor.
        if flags & revlog.REVIDX_EXTSTORED:
            copyrev = copyfrom = None
        revision = shallowutil.createrevlogtext(content, copyfrom, copyrev)
        return revision

    def getdelta(self, name, node):
        # Since remotefilelog content stores only contain full texts, just
        # return that.
        revision = self.get(name, node)
        return (
            revision,
            name,
            sha1nodeconstants.nullid,
            self.getmeta(name, node),
        )

    def getdeltachain(self, name, node):
        # Since remotefilelog content stores just contain full texts, we return
        # a fake delta chain that just consists of a single full text revision.
        # The nullid in the deltabasenode slot indicates that the revision is a
        # fulltext.
        revision = self.get(name, node)
        return [(name, node, None, sha1nodeconstants.nullid, revision)]

    def getmeta(self, name, node):
        self._sanitizemetacache()
        if node != self._threaddata.metacache[0]:
            data = self._getdata(name, node)
            offset, size, flags = shallowutil.parsesizeflags(data)
            self._updatemetacache(node, size, flags)
        return self._threaddata.metacache[1]

    def add(self, name, node, data):
        raise RuntimeError(
            b"cannot add content only to remotefilelog contentstore"
        )

    def _sanitizemetacache(self):
        metacache = getattr(self._threaddata, 'metacache', None)
        if metacache is None:
            self._threaddata.metacache = (None, None)  # (node, meta)

    def _updatemetacache(self, node, size, flags):
        self._sanitizemetacache()
        if node == self._threaddata.metacache[0]:
            return
        meta = {constants.METAKEYFLAG: flags, constants.METAKEYSIZE: size}
        self._threaddata.metacache = (node, meta)


class remotecontentstore(object):
    def __init__(self, ui, fileservice, shared):
        self._fileservice = fileservice
        # type(shared) is usually remotefilelogcontentstore
        self._shared = shared

    def get(self, name, node):
        self._fileservice.prefetch(
            [(name, hex(node))], force=True, fetchdata=True
        )
        return self._shared.get(name, node)

    def getdelta(self, name, node):
        revision = self.get(name, node)
        return (
            revision,
            name,
            sha1nodeconstants.nullid,
            self._shared.getmeta(name, node),
        )

    def getdeltachain(self, name, node):
        # Since our remote content stores just contain full texts, we return a
        # fake delta chain that just consists of a single full text revision.
        # The nullid in the deltabasenode slot indicates that the revision is a
        # fulltext.
        revision = self.get(name, node)
        return [(name, node, None, sha1nodeconstants.nullid, revision)]

    def getmeta(self, name, node):
        self._fileservice.prefetch(
            [(name, hex(node))], force=True, fetchdata=True
        )
        return self._shared.getmeta(name, node)

    def add(self, name, node, data):
        raise RuntimeError(b"cannot add to a remote store")

    def getmissing(self, keys):
        return keys

    def markledger(self, ledger, options=None):
        pass


class manifestrevlogstore(object):
    def __init__(self, repo):
        self._store = repo.store
        self._svfs = repo.svfs
        self._revlogs = dict()
        self._cl = revlog.revlog(self._svfs, radix=b'00changelog.i')
        self._repackstartlinkrev = 0

    def get(self, name, node):
        return self._revlog(name).rawdata(node)

    def getdelta(self, name, node):
        revision = self.get(name, node)
        return revision, name, self._cl.nullid, self.getmeta(name, node)

    def getdeltachain(self, name, node):
        revision = self.get(name, node)
        return [(name, node, None, self._cl.nullid, revision)]

    def getmeta(self, name, node):
        rl = self._revlog(name)
        rev = rl.rev(node)
        return {
            constants.METAKEYFLAG: rl.flags(rev),
            constants.METAKEYSIZE: rl.rawsize(rev),
        }

    def getancestors(self, name, node, known=None):
        if known is None:
            known = set()
        if node in known:
            return []

        rl = self._revlog(name)
        ancestors = {}
        missing = {node}
        for ancrev in rl.ancestors([rl.rev(node)], inclusive=True):
            ancnode = rl.node(ancrev)
            missing.discard(ancnode)

            p1, p2 = rl.parents(ancnode)
            if p1 != self._cl.nullid and p1 not in known:
                missing.add(p1)
            if p2 != self._cl.nullid and p2 not in known:
                missing.add(p2)

            linknode = self._cl.node(rl.linkrev(ancrev))
            ancestors[rl.node(ancrev)] = (p1, p2, linknode, b'')
            if not missing:
                break
        return ancestors

    def getnodeinfo(self, name, node):
        cl = self._cl
        rl = self._revlog(name)
        parents = rl.parents(node)
        linkrev = rl.linkrev(rl.rev(node))
        return (parents[0], parents[1], cl.node(linkrev), None)

    def add(self, *args):
        raise RuntimeError(b"cannot add to a revlog store")

    def _revlog(self, name):
        rl = self._revlogs.get(name)
        if rl is None:
            revlogname = b'00manifesttree'
            if name != b'':
                revlogname = b'meta/%s/00manifest' % name
            rl = revlog.revlog(self._svfs, radix=revlogname)
            self._revlogs[name] = rl
        return rl

    def getmissing(self, keys):
        missing = []
        for name, node in keys:
            mfrevlog = self._revlog(name)
            if node not in mfrevlog.nodemap:
                missing.append((name, node))

        return missing

    def setrepacklinkrevrange(self, startrev, endrev):
        self._repackstartlinkrev = startrev
        self._repackendlinkrev = endrev

    def markledger(self, ledger, options=None):
        if options and options.get(constants.OPTION_PACKSONLY):
            return
        treename = b''
        rl = revlog.revlog(self._svfs, radix=b'00manifesttree')
        startlinkrev = self._repackstartlinkrev
        endlinkrev = self._repackendlinkrev
        for rev in pycompat.xrange(len(rl) - 1, -1, -1):
            linkrev = rl.linkrev(rev)
            if linkrev < startlinkrev:
                break
            if linkrev > endlinkrev:
                continue
            node = rl.node(rev)
            ledger.markdataentry(self, treename, node)
            ledger.markhistoryentry(self, treename, node)

        for t, path, size in self._store.datafiles():
            if path[:5] != b'meta/' or path[-2:] != b'.i':
                continue

            treename = path[5 : -len(b'/00manifest')]

            rl = revlog.revlog(self._svfs, indexfile=path[:-2])
            for rev in pycompat.xrange(len(rl) - 1, -1, -1):
                linkrev = rl.linkrev(rev)
                if linkrev < startlinkrev:
                    break
                if linkrev > endlinkrev:
                    continue
                node = rl.node(rev)
                ledger.markdataentry(self, treename, node)
                ledger.markhistoryentry(self, treename, node)

    def cleanup(self, ledger):
        pass