bmstore: add handling of the active bookmark

This further centralizes the handling of bookmark storage, and will
help get some lingering bookmarks business out of localrepo. Right
now, this change implies reading of the active bookmark to also imply
reading all bookmarks from disk - for users with many many bookmarks
this may be a measurable performance hit. In that case, we should
migrate bmstore to be able to lazy-read its properties from disk
rather than having to eagerly read them, but I decided to avoid doing
that to try and avoid some potentially complicated filecache decorator
issues.

This doesn't move the logic for writing the active bookmark into a
transaction, though that is probably the correct next step. Since the
API probably needs to morph a little more, I didn't bother marking
bookmarks.{activate,deactivate} as deprecated yet.

mercurial/bookmarks.py

@@ -44,16 +44,15 b' def _getbkfile(repo):'
 class bmstore(dict):
     """Storage for bookmarks.
 
-    This object should do all bookmark reads and writes, so that it's
-    fairly simple to replace the storage underlying bookmarks without
-    having to clone the logic surrounding bookmarks.
+    This object should do all bookmark-related reads and writes, so
+    that it's fairly simple to replace the storage underlying
+    bookmarks without having to clone the logic surrounding
+    bookmarks. This type also should manage the active bookmark, if
+    any.
 
     This particular bmstore implementation stores bookmarks as
     {hash}\s{name}\n (the same format as localtags) in
     .hg/bookmarks. The mapping is stored as {name: nodeid}.
-
-    This class does NOT handle the "active" bookmark state at this
-    time.
     """
 
     def __init__(self, repo):
@@ -79,6 +78,20 b' class bmstore(dict):'
             if inst.errno != errno.ENOENT:
                 raise
         self._clean = True
+        self._active = _readactive(repo, self)
+        self._aclean = True
+
+    @property
+    def active(self):
+        return self._active
+
+    @active.setter
+    def active(self, mark):
+        if mark is not None and mark not in self:
+            raise AssertionError('bookmark %s does not exist!' % mark)
+
+        self._active = mark
+        self._aclean = False
 
     def __setitem__(self, *args, **kwargs):
         self._clean = False
@@ -107,6 +120,9 b' class bmstore(dict):'
         '''
         msg = 'bm.write() is deprecated, use bm.recordchange(transaction)'
         self._repo.ui.deprecwarn(msg, '3.7')
+        # TODO: writing the active bookmark should probably also use a
+        # transaction.
+        self._writeactive()
         if self._clean:
             return
         repo = self._repo
@@ -128,8 +144,10 b' class bmstore(dict):'
 
     def _writerepo(self, repo):
         """Factored out for extensibility"""
-        if repo._activebookmark not in self:
-            deactivate(repo)
+        rbm = repo._bookmarks
+        if rbm.active not in self:
+            rbm.active = None
+            rbm._writeactive()
 
         wlock = repo.wlock()
         try:
@@ -146,12 +164,33 b' class bmstore(dict):'
         finally:
             wlock.release()
 
+    def _writeactive(self):
+        if self._aclean:
+            return
+        wlock = self._repo.wlock()
+        try:
+            if self._active is not None:
+                f = self._repo.vfs('bookmarks.current', 'w', atomictemp=True)
+                try:
+                    f.write(encoding.fromlocal(self._active))
+                finally:
+                    f.close()
+            else:
+                try:
+                    self._repo.vfs.unlink('bookmarks.current')
+                except OSError as inst:
+                    if inst.errno != errno.ENOENT:
+                        raise
+        finally:
+            wlock.release()
+        self._aclean = True
+
     def _write(self, fp):
         for name, node in self.iteritems():
             fp.write("%s %s\n" % (hex(node), encoding.fromlocal(name)))
         self._clean = True
 
-def readactive(repo):
+def _readactive(repo, marks):
     """
     Get the active bookmark. We can have an active bookmark that updates
     itself as we commit. This function returns the name of that bookmark.
@@ -172,7 +211,7 b' def readactive(repo):'
         # static-http which only tries to load the file when we try
         # to read from it.
         mark = encoding.tolocal((file.readlines() or [''])[0])
-        if mark == '' or mark not in repo._bookmarks:
+        if mark == '' or mark not in marks:
             mark = None
     except IOError as inst:
         if inst.errno != errno.ENOENT:
@@ -188,35 +227,15 b' def activate(repo, mark):'
     follow new commits that are made.
     The name is recorded in .hg/bookmarks.current
     """
-    if mark not in repo._bookmarks:
-        raise AssertionError('bookmark %s does not exist!' % mark)
-
-    active = repo._activebookmark
-    if active == mark:
-        return
-
-    wlock = repo.wlock()
-    try:
-        file = repo.vfs('bookmarks.current', 'w', atomictemp=True)
-        file.write(encoding.fromlocal(mark))
-        file.close()
-    finally:
-        wlock.release()
-    repo._activebookmark = mark
+    repo._bookmarks.active = mark
+    repo._bookmarks._writeactive()
 
 def deactivate(repo):
     """
     Unset the active bookmark in this repository.
     """
-    wlock = repo.wlock()
-    try:
-        repo.vfs.unlink('bookmarks.current')
-        repo._activebookmark = None
-    except OSError as inst:
-        if inst.errno != errno.ENOENT:
-            raise
-    finally:
-        wlock.release()
+    repo._bookmarks.active = None
+    repo._bookmarks._writeactive()
 
 def isactivewdirparent(repo):
     """
@@ -266,7 +285,7 b' def update(repo, parents, node):'
     deletefrom = parents
     marks = repo._bookmarks
     update = False
-    active = repo._activebookmark
+    active = marks.active
     if not active:
         return False
 

mercurial/cmdutil.py

@@ -2530,13 +2530,14 b' def amend(ui, repo, commitfunc, old, ext'
             # First, do a regular commit to record all changes in the working
             # directory (if there are any)
             ui.callhooks = False
-            activebookmark = repo._activebookmark
+            activebookmark = repo._bookmarks.active
             try:
-                repo._activebookmark = None
+                repo._bookmarks.active = None
                 opts['message'] = 'temporary amend commit for %s' % old
                 node = commit(ui, repo, commitfunc, pats, opts)
             finally:
-                repo._activebookmark = activebookmark
+                repo._bookmarks.active = activebookmark
+                repo._bookmarks.recordchange(tr)
                 ui.callhooks = True
             ctx = repo[node]
 

mercurial/localrepo.py

@@ -459,13 +459,13 b' class localrepository(object):'
             pass
         return proxycls(self, name)
 
-    @repofilecache('bookmarks')
+    @repofilecache('bookmarks', 'bookmarks.current')
     def _bookmarks(self):
         return bookmarks.bmstore(self)
 
-    @repofilecache('bookmarks.current')
+    @property
     def _activebookmark(self):
-        return bookmarks.readactive(self)
+        return self._bookmarks.active
 
     def bookmarkheads(self, bookmark):
         name = bookmark.split('@', 1)[0]