revlog: use compression engine API for compression This commit swaps in the just-added revlog compressor API into the revlog class. Instead of implementing zlib compression inline in compress(), we now store a cached-on-first-use revlog compressor on each revlog instance and invoke its "compress()" method. As part of this, revlog.compress() has been refactored a bit to use a cleaner code flow and modern formatting (e.g. avoiding parenthesis around returned tuples). On a mozilla-unified repo, here are the "compress" times for a few commands: $ hg perfrevlogchunks -c ! wall 5.772450 comb 5.780000 user 5.780000 sys 0.000000 (best of 3) ! wall 5.795158 comb 5.790000 user 5.790000 sys 0.000000 (best of 3) $ hg perfrevlogchunks -m ! wall 9.975789 comb 9.970000 user 9.970000 sys 0.000000 (best of 3) ! wall 10.019505 comb 10.010000 user 10.010000 sys 0.000000 (best of 3) Compression times did seem to slow down just a little. There are 360,210 changelog revisions and 359,342 manifest revisions. For the changelog, mean time to compress a revision increased from ~16.025us to ~16.088us. That's basically a function call or an attribute lookup. I suppose this is the price you pay for abstraction. It's so low that I'm not concerned.

Mercurial
=========

Mercurial is a fast, easy to use, distributed revision control tool
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Basic install:

 $ make            # see install targets
 $ make install    # do a system-wide install
 $ hg debuginstall # sanity-check setup
 $ hg              # see help

Running without installing:

 $ make local      # build for inplace usage
 $ ./hg --version  # should show the latest version

See https://mercurial-scm.org/ for detailed installation
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