Mercurial > public > mercurial-scm > hg-stable

diff mercurial/revlog.py @ 24255:4bfe9f2d9761

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revlog: addgroup checks if incoming deltas add censored revs, sets flag bit A censored revision stored in a revlog should have the censored revlog index flag bit set. This implies we must know if a revision is censored before we add it to the revlog. When adding revisions from exchanged deltas, we would prefer to determine this flag without decoding every single full text. This change introduces a heuristic based on assumptions around the Mercurial delta format and filelog metadata. Since deltas which produce a censored revision must be full-replacement deltas, we can read the delta's first bytes to check the filelog metadata. Since "censored" is the alphabetically first filelog metadata key, censored filelog revisions have a well-known prefix we can look for. For more on the design and background of the censorship feature, see: http://mercurial.selenic.com/wiki/CensorPlan
author Mike Edgar <adgar@google.com>
date Wed, 14 Jan 2015 15:16:08 -0500
parents eb2d41c6ec37
children 27e3ba73fbb1
line wrap: on
line diff
--- a/mercurial/revlog.py	Fri Mar 06 22:43:47 2015 -0800
+++ b/mercurial/revlog.py	Wed Jan 14 15:16:08 2015 -0500
@@ -1386,7 +1386,10 @@
             transaction.add(self.indexfile, isize, r)
             transaction.add(self.datafile, end)
             dfh = self.opener(self.datafile, "a")
-
+        def flush():
+            if dfh:
+                dfh.flush()
+            ifh.flush()
         try:
             # loop through our set of deltas
             chain = None
@@ -1430,9 +1433,13 @@
                         raise error.CensoredBaseError(self.indexfile,
                                                       self.node(baserev))
 
+                flags = REVIDX_DEFAULT_FLAGS
+                if self._peek_iscensored(baserev, delta, flush):
+                    flags |= REVIDX_ISCENSORED
+
                 chain = self._addrevision(node, None, transaction, link,
-                                          p1, p2, REVIDX_DEFAULT_FLAGS,
-                                          (baserev, delta), ifh, dfh)
+                                          p1, p2, flags, (baserev, delta),
+                                          ifh, dfh)
                 if not dfh and not self._inline:
                     # addrevision switched from inline to conventional
                     # reopen the index
@@ -1450,6 +1457,10 @@
         """Check if a file revision is censored."""
         return False
 
+    def _peek_iscensored(self, baserev, delta, flush):
+        """Quickly check if a delta produces a censored revision."""
+        return False
+
     def getstrippoint(self, minlink):
         """find the minimum rev that must be stripped to strip the linkrev