Mercurial > hg
changeset 24122:da14b8eba806
revlog: special case expanding full-replacement deltas received by exchange
When a delta received through exchange is added to a revlog, it will very
often be expanded to a full text by applying the delta to its base. If
that delta is of a particular form, we can avoid decoding the base revision.
This avoids an exception if the base revision is censored.
For background and broader design of the censorship feature, see:
http://mercurial.selenic.com/wiki/CensorPlan
| author | Mike Edgar <adgar@google.com> |
|---|---|
| date | Fri, 06 Feb 2015 01:38:16 +0000 |
| parents | 9d0b6ef92eb2 |
| children | eb2d41c6ec37 |
| files | mercurial/revlog.py |
| diffstat | 1 files changed, 12 insertions(+), 2 deletions(-) [+] |
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--- a/mercurial/revlog.py Tue Feb 10 16:17:15 2015 -0800 +++ b/mercurial/revlog.py Fri Feb 06 01:38:16 2015 +0000 @@ -1233,8 +1233,18 @@ if dfh: dfh.flush() ifh.flush() - basetext = self.revision(self.node(cachedelta[0])) - btext[0] = mdiff.patch(basetext, cachedelta[1]) + baserev = cachedelta[0] + delta = cachedelta[1] + # special case deltas which replace entire base; no need to decode + # base revision. this neatly avoids censored bases, which throw when + # they're decoded. + hlen = struct.calcsize(">lll") + if delta[:hlen] == mdiff.replacediffheader(self.rawsize(baserev), + len(delta) - hlen): + btext[0] = delta[hlen:] + else: + basetext = self.revision(self.node(baserev)) + btext[0] = mdiff.patch(basetext, delta) try: self.checkhash(btext[0], p1, p2, node) if flags & REVIDX_ISCENSORED: