bdiff: don't check border condition in loop This is pretty much a copy of d500ddae7494, just to a different loop. The condition `p == plast` (`plast == a + len - 1`) was only true on the final iteration of the loop. So it was wasteful to check for it on every iteration. We decrease the iteration count by 1 and add an explicit check for `p == plast` after the loop. Again, we see modest wins. From the mozilla-unified repository: $ perfbdiff -m 3041e4d59df2 ! wall 0.035502 comb 0.040000 user 0.040000 sys 0.000000 (best of 100) ! wall 0.030480 comb 0.030000 user 0.030000 sys 0.000000 (best of 100) $ perfbdiff 0e9928989e9c --alldata --count 100 ! wall 4.097394 comb 4.100000 user 4.100000 sys 0.000000 (best of 3) ! wall 3.597798 comb 3.600000 user 3.600000 sys 0.000000 (best of 3) The 2nd example throws a total of ~3.3GB of data at bdiff. This change increases the throughput from ~811 MB/s to ~924 MB/s.

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# A dummy extension that installs an hgweb command that throws an Exception.

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from __future__ import absolute_import

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from mercurial.hgweb import (

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    webcommands,

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)

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def raiseerror(web, req, tmpl):

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    '''Dummy web command that raises an uncaught Exception.'''

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    # Simulate an error after partial response.

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    if 'partialresponse' in req.form:

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        req.respond(200, 'text/plain')

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        req.write('partial content\n')

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    raise AttributeError('I am an uncaught error!')

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def extsetup(ui):

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    setattr(webcommands, 'raiseerror', raiseerror)

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    webcommands.__all__.append('raiseerror')