journal: add share extension support

Rather than put everything into one journal file, split entries up in *shared*
and *local* entries. Working copy changes are local to a specific working copy,
so should remain local only. Other entries are shared with the source if so
configured when the share was created.

When unsharing, any shared journale entries are copied across.

tests/test-journal-share.t

@@ -0,0 +1,153 b''
+Journal extension test: tests the share extension support
+
+  $ cat >> testmocks.py << EOF
+  > # mock out util.getuser() and util.makedate() to supply testable values
+  > import os
+  > from mercurial import util
+  > def mockgetuser():
+  >     return 'foobar'
+  > 
+  > def mockmakedate():
+  >     filename = os.path.join(os.environ['TESTTMP'], 'testtime')
+  >     try:
+  >         with open(filename, 'rb') as timef:
+  >             time = float(timef.read()) + 1
+  >     except IOError:
+  >         time = 0.0
+  >     with open(filename, 'wb') as timef:
+  >         timef.write(str(time))
+  >     return (time, 0)
+  > 
+  > util.getuser = mockgetuser
+  > util.makedate = mockmakedate
+  > EOF
+
+  $ cat >> $HGRCPATH << EOF
+  > [extensions]
+  > journal=
+  > share=
+  > testmocks=`pwd`/testmocks.py
+  > [remotenames]
+  > rename.default=remote
+  > EOF
+
+  $ hg init repo
+  $ cd repo
+  $ hg bookmark bm
+  $ touch file0
+  $ hg commit -Am 'file0 added'
+  adding file0
+  $ hg journal --all
+  previous locations of the working copy and bookmarks:
+  5640b525682e  .         commit -Am 'file0 added'
+  5640b525682e  bm        commit -Am 'file0 added'
+
+A shared working copy initially receives the same bookmarks and working copy
+
+  $ cd ..
+  $ hg share repo shared1
+  updating working directory
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ cd shared1
+  $ hg journal --all
+  previous locations of the working copy and bookmarks:
+  5640b525682e  .         share repo shared1
+
+unless you explicitly share bookmarks
+
+  $ cd ..
+  $ hg share --bookmarks repo shared2
+  updating working directory
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ cd shared2
+  $ hg journal --all
+  previous locations of the working copy and bookmarks:
+  5640b525682e  .         share --bookmarks repo shared2
+  5640b525682e  bm        commit -Am 'file0 added'
+
+Moving the bookmark in the original repository is only shown in the repository
+that shares bookmarks
+
+  $ cd ../repo
+  $ touch file1
+  $ hg commit -Am "file1 added"
+  adding file1
+  $ cd ../shared1
+  $ hg journal --all
+  previous locations of the working copy and bookmarks:
+  5640b525682e  .         share repo shared1
+  $ cd ../shared2
+  $ hg journal --all
+  previous locations of the working copy and bookmarks:
+  6432d239ac5d  bm        commit -Am 'file1 added'
+  5640b525682e  .         share --bookmarks repo shared2
+  5640b525682e  bm        commit -Am 'file0 added'
+
+But working copy changes are always 'local'
+
+  $ cd ../repo
+  $ hg up 0
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  (leaving bookmark bm)
+  $ hg journal --all
+  previous locations of the working copy and bookmarks:
+  5640b525682e  .         up 0
+  6432d239ac5d  .         commit -Am 'file1 added'
+  6432d239ac5d  bm        commit -Am 'file1 added'
+  5640b525682e  .         commit -Am 'file0 added'
+  5640b525682e  bm        commit -Am 'file0 added'
+  $ cd ../shared2
+  $ hg journal --all
+  previous locations of the working copy and bookmarks:
+  6432d239ac5d  bm        commit -Am 'file1 added'
+  5640b525682e  .         share --bookmarks repo shared2
+  5640b525682e  bm        commit -Am 'file0 added'
+  $ hg up tip
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg up 0
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  $ hg journal
+  previous locations of '.':
+  5640b525682e  up 0
+  6432d239ac5d  up tip
+  5640b525682e  share --bookmarks repo shared2
+
+Unsharing works as expected; the journal remains consistent
+
+  $ cd ../shared1
+  $ hg unshare
+  $ hg journal --all
+  previous locations of the working copy and bookmarks:
+  5640b525682e  .         share repo shared1
+  $ cd ../shared2
+  $ hg unshare
+  $ hg journal --all
+  previous locations of the working copy and bookmarks:
+  5640b525682e  .         up 0
+  6432d239ac5d  .         up tip
+  6432d239ac5d  bm        commit -Am 'file1 added'
+  5640b525682e  .         share --bookmarks repo shared2
+  5640b525682e  bm        commit -Am 'file0 added'
+
+New journal entries in the source repo no longer show up in the other working copies
+
+  $ cd ../repo
+  $ hg bookmark newbm -r tip
+  $ hg journal newbm
+  previous locations of 'newbm':
+  6432d239ac5d  bookmark newbm -r tip
+  $ cd ../shared2
+  $ hg journal newbm
+  previous locations of 'newbm':
+  no recorded locations
+
+This applies for both directions
+
+  $ hg bookmark shared2bm -r tip
+  $ hg journal shared2bm
+  previous locations of 'shared2bm':
+  6432d239ac5d  bookmark shared2bm -r tip
+  $ cd ../repo
+  $ hg journal shared2bm
+  previous locations of 'shared2bm':
+  no recorded locations

hgext/journal.py

@@ -1,374 +1,493 b''
 # journal.py
 #
 # Copyright 2014-2016 Facebook, Inc.
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 """Track previous positions of bookmarks (EXPERIMENTAL)
 
 This extension adds a new command: `hg journal`, which shows you where
 bookmarks were previously located.
 
 """
 
 from __future__ import absolute_import
 
 import collections
+import errno
 import os
 import weakref
 
 from mercurial.i18n import _
 
 from mercurial import (
     bookmarks,
     cmdutil,
     commands,
     dirstate,
     dispatch,
     error,
     extensions,
+    hg,
     localrepo,
     lock,
     node,
     util,
 )
 
+from . import share
+
 cmdtable = {}
 command = cmdutil.command(cmdtable)
 
 # Note for extension authors: ONLY specify testedwith = 'internal' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'internal'
 
 # storage format version; increment when the format changes
 storageversion = 0
 
 # namespaces
 bookmarktype = 'bookmark'
 wdirparenttype = 'wdirparent'
+# In a shared repository, what shared feature name is used
+# to indicate this namespace is shared with the source?
+sharednamespaces = {
+    bookmarktype: hg.sharedbookmarks,
+}
 
 # Journal recording, register hooks and storage object
 def extsetup(ui):
     extensions.wrapfunction(dispatch, 'runcommand', runcommand)
     extensions.wrapfunction(bookmarks.bmstore, '_write', recordbookmarks)
     extensions.wrapfunction(
         dirstate.dirstate, '_writedirstate', recorddirstateparents)
     extensions.wrapfunction(
         localrepo.localrepository.dirstate, 'func', wrapdirstate)
+    extensions.wrapfunction(hg, 'postshare', wrappostshare)
+    extensions.wrapfunction(hg, 'copystore', unsharejournal)
 
 def reposetup(ui, repo):
     if repo.local():
         repo.journal = journalstorage(repo)
 
 def runcommand(orig, lui, repo, cmd, fullargs, *args):
     """Track the command line options for recording in the journal"""
     journalstorage.recordcommand(*fullargs)
     return orig(lui, repo, cmd, fullargs, *args)
 
 # hooks to record dirstate changes
 def wrapdirstate(orig, repo):
     """Make journal storage available to the dirstate object"""
     dirstate = orig(repo)
     if util.safehasattr(repo, 'journal'):
         dirstate.journalstorage = repo.journal
     return dirstate
 
 def recorddirstateparents(orig, dirstate, dirstatefp):
     """Records all dirstate parent changes in the journal."""
     if util.safehasattr(dirstate, 'journalstorage'):
         old = [node.nullid, node.nullid]
         nodesize = len(node.nullid)
         try:
             # The only source for the old state is in the dirstate file still
             # on disk; the in-memory dirstate object only contains the new
             # state. dirstate._opendirstatefile() switches beteen .hg/dirstate
             # and .hg/dirstate.pending depending on the transaction state.
             with dirstate._opendirstatefile() as fp:
                 state = fp.read(2 * nodesize)
             if len(state) == 2 * nodesize:
                 old = [state[:nodesize], state[nodesize:]]
         except IOError:
             pass
 
         new = dirstate.parents()
         if old != new:
             # only record two hashes if there was a merge
             oldhashes = old[:1] if old[1] == node.nullid else old
             newhashes = new[:1] if new[1] == node.nullid else new
             dirstate.journalstorage.record(
                 wdirparenttype, '.', oldhashes, newhashes)
 
     return orig(dirstate, dirstatefp)
 
 # hooks to record bookmark changes (both local and remote)
 def recordbookmarks(orig, store, fp):
     """Records all bookmark changes in the journal."""
     repo = store._repo
     if util.safehasattr(repo, 'journal'):
         oldmarks = bookmarks.bmstore(repo)
         for mark, value in store.iteritems():
             oldvalue = oldmarks.get(mark, node.nullid)
             if value != oldvalue:
                 repo.journal.record(bookmarktype, mark, oldvalue, value)
     return orig(store, fp)
 
+# shared repository support
+def _readsharedfeatures(repo):
+    """A set of shared features for this repository"""
+    try:
+        return set(repo.vfs.read('shared').splitlines())
+    except IOError as inst:
+        if inst.errno != errno.ENOENT:
+            raise
+        return set()
+
+def _mergeentriesiter(*iterables, **kwargs):
+    """Given a set of sorted iterables, yield the next entry in merged order
+
+    Note that by default entries go from most recent to oldest.
+    """
+    order = kwargs.pop('order', max)
+    iterables = [iter(it) for it in iterables]
+    # this tracks still active iterables; iterables are deleted as they are
+    # exhausted, which is why this is a dictionary and why each entry also
+    # stores the key. Entries are mutable so we can store the next value each
+    # time.
+    iterable_map = {}
+    for key, it in enumerate(iterables):
+        try:
+            iterable_map[key] = [next(it), key, it]
+        except StopIteration:
+            # empty entry, can be ignored
+            pass
+
+    while iterable_map:
+        value, key, it = order(iterable_map.itervalues())
+        yield value
+        try:
+            iterable_map[key][0] = next(it)
+        except StopIteration:
+            # this iterable is empty, remove it from consideration
+            del iterable_map[key]
+
+def wrappostshare(orig, sourcerepo, destrepo, **kwargs):
+    """Mark this shared working copy as sharing journal information"""
+    orig(sourcerepo, destrepo, **kwargs)
+    with destrepo.vfs('shared', 'a') as fp:
+        fp.write('journal\n')
+
+def unsharejournal(orig, ui, repo, repopath):
+    """Copy shared journal entries into this repo when unsharing"""
+    if (repo.path == repopath and repo.shared() and
+            util.safehasattr(repo, 'journal')):
+        sharedrepo = share._getsrcrepo(repo)
+        sharedfeatures = _readsharedfeatures(repo)
+        if sharedrepo and sharedfeatures > set(['journal']):
+            # there is a shared repository and there are shared journal entries
+            # to copy. move shared date over from source to destination but
+            # move the local file first
+            if repo.vfs.exists('journal'):
+                journalpath = repo.join('journal')
+                util.rename(journalpath, journalpath + '.bak')
+            storage = repo.journal
+            local = storage._open(
+                repo.vfs, filename='journal.bak', _newestfirst=False)
+            shared = (
+                e for e in storage._open(sharedrepo.vfs, _newestfirst=False)
+                if sharednamespaces.get(e.namespace) in sharedfeatures)
+            for entry in _mergeentriesiter(local, shared, order=min):
+                storage._write(repo.vfs, entry)
+
+    return orig(ui, repo, repopath)
+
 class journalentry(collections.namedtuple(
         'journalentry',
         'timestamp user command namespace name oldhashes newhashes')):
     """Individual journal entry
 
     * timestamp: a mercurial (time, timezone) tuple
     * user: the username that ran the command
     * namespace: the entry namespace, an opaque string
     * name: the name of the changed item, opaque string with meaning in the
       namespace
     * command: the hg command that triggered this record
     * oldhashes: a tuple of one or more binary hashes for the old location
     * newhashes: a tuple of one or more binary hashes for the new location
 
     Handles serialisation from and to the storage format. Fields are
     separated by newlines, hashes are written out in hex separated by commas,
     timestamp and timezone are separated by a space.
 
     """
     @classmethod
     def fromstorage(cls, line):
         (time, user, command, namespace, name,
          oldhashes, newhashes) = line.split('\n')
         timestamp, tz = time.split()
         timestamp, tz = float(timestamp), int(tz)
         oldhashes = tuple(node.bin(hash) for hash in oldhashes.split(','))
         newhashes = tuple(node.bin(hash) for hash in newhashes.split(','))
         return cls(
             (timestamp, tz), user, command, namespace, name,
             oldhashes, newhashes)
 
     def __str__(self):
         """String representation for storage"""
         time = ' '.join(map(str, self.timestamp))
         oldhashes = ','.join([node.hex(hash) for hash in self.oldhashes])
         newhashes = ','.join([node.hex(hash) for hash in self.newhashes])
         return '\n'.join((
             time, self.user, self.command, self.namespace, self.name,
             oldhashes, newhashes))
 
 class journalstorage(object):
     """Storage for journal entries
 
+    Entries are divided over two files; one with entries that pertain to the
+    local working copy *only*, and one with entries that are shared across
+    multiple working copies when shared using the share extension.
+
     Entries are stored with NUL bytes as separators. See the journalentry
     class for the per-entry structure.
 
     The file format starts with an integer version, delimited by a NUL.
 
     This storage uses a dedicated lock; this makes it easier to avoid issues
     with adding entries that added when the regular wlock is unlocked (e.g.
     the dirstate).
 
     """
     _currentcommand = ()
     _lockref = None
 
     def __init__(self, repo):
         self.user = util.getuser()
         self.ui = repo.ui
         self.vfs = repo.vfs
 
+        # is this working copy using a shared storage?
+        self.sharedfeatures = self.sharedvfs = None
+        if repo.shared():
+            features = _readsharedfeatures(repo)
+            sharedrepo = share._getsrcrepo(repo)
+            if sharedrepo is not None and 'journal' in features:
+                self.sharedvfs = sharedrepo.vfs
+                self.sharedfeatures = features
+
     # track the current command for recording in journal entries
     @property
     def command(self):
         commandstr = ' '.join(
             map(util.shellquote, journalstorage._currentcommand))
         if '\n' in commandstr:
             # truncate multi-line commands
             commandstr = commandstr.partition('\n')[0] + ' ...'
         return commandstr
 
     @classmethod
     def recordcommand(cls, *fullargs):
         """Set the current hg arguments, stored with recorded entries"""
         # Set the current command on the class because we may have started
         # with a non-local repo (cloning for example).
         cls._currentcommand = fullargs
 
-    def jlock(self):
+    def jlock(self, vfs):
         """Create a lock for the journal file"""
         if self._lockref and self._lockref():
             raise error.Abort(_('journal lock does not support nesting'))
-        desc = _('journal of %s') % self.vfs.base
+        desc = _('journal of %s') % vfs.base
         try:
-            l = lock.lock(self.vfs, 'journal.lock', 0, desc=desc)
+            l = lock.lock(vfs, 'journal.lock', 0, desc=desc)
         except error.LockHeld as inst:
             self.ui.warn(
                 _("waiting for lock on %s held by %r\n") % (desc, inst.locker))
             # default to 600 seconds timeout
             l = lock.lock(
-                self.vfs, 'journal.lock',
+                vfs, 'journal.lock',
                 int(self.ui.config("ui", "timeout", "600")), desc=desc)
             self.ui.warn(_("got lock after %s seconds\n") % l.delay)
         self._lockref = weakref.ref(l)
         return l
 
     def record(self, namespace, name, oldhashes, newhashes):
         """Record a new journal entry
 
         * namespace: an opaque string; this can be used to filter on the type
           of recorded entries.
         * name: the name defining this entry; for bookmarks, this is the
           bookmark name. Can be filtered on when retrieving entries.
         * oldhashes and newhashes: each a single binary hash, or a list of
           binary hashes. These represent the old and new position of the named
           item.
 
         """
         if not isinstance(oldhashes, list):
             oldhashes = [oldhashes]
         if not isinstance(newhashes, list):
             newhashes = [newhashes]
 
         entry = journalentry(
             util.makedate(), self.user, self.command, namespace, name,
             oldhashes, newhashes)
 
-        with self.jlock():
+        vfs = self.vfs
+        if self.sharedvfs is not None:
+            # write to the shared repository if this feature is being
+            # shared between working copies.
+            if sharednamespaces.get(namespace) in self.sharedfeatures:
+                vfs = self.sharedvfs
+
+        self._write(vfs, entry)
+
+    def _write(self, vfs, entry):
+        with self.jlock(vfs):
             version = None
             # open file in amend mode to ensure it is created if missing
-            with self.vfs('journal', mode='a+b', atomictemp=True) as f:
+            with vfs('journal', mode='a+b', atomictemp=True) as f:
                 f.seek(0, os.SEEK_SET)
                 # Read just enough bytes to get a version number (up to 2
                 # digits plus separator)
                 version = f.read(3).partition('\0')[0]
                 if version and version != str(storageversion):
                     # different version of the storage. Exit early (and not
                     # write anything) if this is not a version we can handle or
                     # the file is corrupt. In future, perhaps rotate the file
                     # instead?
                     self.ui.warn(
                         _("unsupported journal file version '%s'\n") % version)
                     return
                 if not version:
                     # empty file, write version first
                     f.write(str(storageversion) + '\0')
                 f.seek(0, os.SEEK_END)
                 f.write(str(entry) + '\0')
 
     def filtered(self, namespace=None, name=None):
         """Yield all journal entries with the given namespace or name
 
         Both the namespace and the name are optional; if neither is given all
         entries in the journal are produced.
 
         """
         for entry in self:
             if namespace is not None and entry.namespace != namespace:
                 continue
             if name is not None and entry.name != name:
                 continue
             yield entry
 
     def __iter__(self):
         """Iterate over the storage
 
         Yields journalentry instances for each contained journal record.
 
         """
-        if not self.vfs.exists('journal'):
+        local = self._open(self.vfs)
+
+        if self.sharedvfs is None:
+            return local
+
+        # iterate over both local and shared entries, but only those
+        # shared entries that are among the currently shared features
+        shared = (
+            e for e in self._open(self.sharedvfs)
+            if sharednamespaces.get(e.namespace) in self.sharedfeatures)
+        return _mergeentriesiter(local, shared)
+
+    def _open(self, vfs, filename='journal', _newestfirst=True):
+        if not vfs.exists(filename):
             return
 
-        with self.vfs('journal') as f:
+        with vfs(filename) as f:
             raw = f.read()
 
         lines = raw.split('\0')
         version = lines and lines[0]
         if version != str(storageversion):
             version = version or _('not available')
             raise error.Abort(_("unknown journal file version '%s'") % version)
 
-        # Skip the first line, it's a version number. Reverse the rest.
-        lines = reversed(lines[1:])
+        # Skip the first line, it's a version number. Normally we iterate over
+        # these in reverse order to list newest first; only when copying across
+        # a shared storage do we forgo reversing.
+        lines = lines[1:]
+        if _newestfirst:
+            lines = reversed(lines)
         for line in lines:
             if not line:
                 continue
             yield journalentry.fromstorage(line)
 
 # journal reading
 # log options that don't make sense for journal
 _ignoreopts = ('no-merges', 'graph')
 @command(
     'journal', [
         ('', 'all', None, 'show history for all names'),
         ('c', 'commits', None, 'show commit metadata'),
     ] + [opt for opt in commands.logopts if opt[1] not in _ignoreopts],
     '[OPTION]... [BOOKMARKNAME]')
 def journal(ui, repo, *args, **opts):
     """show the previous position of bookmarks and the working copy
 
     The journal is used to see the previous commits that bookmarks and the
     working copy pointed to. By default the previous locations for the working
     copy.  Passing a bookmark name will show all the previous positions of
     that bookmark. Use the --all switch to show previous locations for all
     bookmarks and the working copy; each line will then include the bookmark
     name, or '.' for the working copy, as well.
 
     By default hg journal only shows the commit hash and the command that was
     running at that time. -v/--verbose will show the prior hash, the user, and
     the time at which it happened.
 
     Use -c/--commits to output log information on each commit hash; at this
     point you can use the usual `--patch`, `--git`, `--stat` and `--template`
     switches to alter the log output for these.
 
     `hg journal -T json` can be used to produce machine readable output.
 
     """
     name = '.'
     if opts.get('all'):
         if args:
             raise error.Abort(
                 _("You can't combine --all and filtering on a name"))
         name = None
     if args:
         name = args[0]
 
     fm = ui.formatter('journal', opts)
 
     if opts.get("template") != "json":
         if name is None:
             displayname = _('the working copy and bookmarks')
         else:
             displayname = "'%s'" % name
         ui.status(_("previous locations of %s:\n") % displayname)
 
     limit = cmdutil.loglimit(opts)
     entry = None
     for count, entry in enumerate(repo.journal.filtered(name=name)):
         if count == limit:
             break
         newhashesstr = ','.join([node.short(hash) for hash in entry.newhashes])
         oldhashesstr = ','.join([node.short(hash) for hash in entry.oldhashes])
 
         fm.startitem()
         fm.condwrite(ui.verbose, 'oldhashes', '%s -> ', oldhashesstr)
         fm.write('newhashes', '%s', newhashesstr)
         fm.condwrite(ui.verbose, 'user', ' %-8s', entry.user)
         fm.condwrite(opts.get('all'), 'name', '  %-8s', entry.name)
 
         timestring = util.datestr(entry.timestamp, '%Y-%m-%d %H:%M %1%2')
         fm.condwrite(ui.verbose, 'date', ' %s', timestring)
         fm.write('command', '  %s\n', entry.command)
 
         if opts.get("commits"):
             displayer = cmdutil.show_changeset(ui, repo, opts, buffered=False)
             for hash in entry.newhashes:
                 try:
                     ctx = repo[hash]
                     displayer.show(ctx)
                 except error.RepoLookupError as e:
                     fm.write('repolookuperror', "%s\n\n", str(e))
             displayer.close()
 
     fm.end()
 
     if entry is None:
         ui.status(_("no recorded locations\n"))