revlog: switch to a C version of headrevs The C implementation is more than 100 times faster than the Python version (which is still available as a fallback). In a repo with 330,000 revs and a stale .hg/cache/tags file, this patch improves the performance of "hg tip" from 2.2 to 1.6 seconds.

perf: rework perfheads and perftags to clear caches The cache clearing makes numbers more reproducible.

parsers: reduce raw_length when truncating When stripping revs, we now update raw_length to correctly reflect the new end of the index.

help: inline helper function used once only

help: remove redundant parameter

help: move some helper functions to help.py

help: remove dependency on ui from some helper functions

hg-ssh: refactor to have main() method Refactor hg-ssh to have a main() function instead of a bunch of top-level statements.

merge with stable

graphlog: turn getlogrevs() into a generator This improves the poor "time to first changeset" compared to the original log command. When running: $ hg log -u user log will enumerate the changelog and display matching revisions when they are found. But: $ hg log -G -u user will first find all revisions matching the user then start to display them. Initially, I considered turning revset.match() into a generator. This is doable but requires a fair amount of work. Instead, cmdutil.increasingwindows() is reused to call the revset matcher repeatedly. This has the nice properties of: - Let us reorder the windows after filtering, which is necessary as the matcher can reorder inputs but is an internal detail not a feature. - Let us feed the matcher with windows in changelog order, which is good for performances. - Have a generator designed for log-like commands, returning small windows at first then batching larger ones. I feel that calling the matcher multiple times is correct, at least with the revsets involved in getlogrevs() because they are: - stateless (no limit()) - respecting f(a|b) = f(a) | f(b), though I have no valid argument about that. Known issues compared to log code: - Calling the revset matcher multiple times can be slow when revset functions have to create expensive data structure for filtering. This will be addressed in a followup. - Predicate combinations like "--user foo --user bar" or "--user foo and --branch bar" are inherently slower because all input revision are checked against the first condition, then against the second, and so forth. log would enumerate the input revisions once and check each of them once against all conditions, which is faster. There are solutions but nothing cheap to implement. Some numbers against mozilla repository: first line total * hg log -u rnewman /Users/pmezard/bin/hg-2.2 0.148s 7.293s /Users/pmezard/bin/hgdev 0.132s 5.747s * hg log -u rnewman -u girard /Users/pmezard/bin/hg-2.2 0.146s 7.323s /Users/pmezard/bin/hgdev 0.136s 11.096s * hg log -l 10 /Users/pmezard/bin/hg-2.2 0.137s 0.153s /Users/pmezard/bin/hgdev 0.128s 0.144s * hg log -l 10 -u rnewman /Users/pmezard/bin/hg-2.2 0.146s 0.265s /Users/pmezard/bin/hgdev 0.133s 0.236s * hg log -b GECKO193a2_20100228_RELBRANCH /Users/pmezard/bin/hg-2.2 2.332s 6.618s /Users/pmezard/bin/hgdev 1.972s 5.543s * hg log xulrunner /Users/pmezard/bin/hg-2.2 5.829s 5.958s /Users/pmezard/bin/hgdev 0.194s 6.017s * hg log --follow xulrunner/build.mk /Users/pmezard/bin/hg-2.2 0.353s 0.438s /Users/pmezard/bin/hgdev 0.394s 0.580s * hg log -u girard tools /Users/pmezard/bin/hg-2.2 5.853s 6.012s /Users/pmezard/bin/hgdev 0.195s 6.030s * hg log -b COMM2000_20110314_RELBRANCH --copies /Users/pmezard/bin/hg-2.2 2.231s 6.653s /Users/pmezard/bin/hgdev 1.897s 5.585s * hg log --follow /Users/pmezard/bin/hg-2.2 0.137s 14.140s /Users/pmezard/bin/hgdev 0.381s 44.246s * hg log --follow -r 80000:90000 /Users/pmezard/bin/hg-2.2 0.127s 1.611s /Users/pmezard/bin/hgdev 0.147s 1.847s * hg log --follow -r 90000:80000 /Users/pmezard/bin/hg-2.2 0.130s 1.702s /Users/pmezard/bin/hgdev 0.368s 6.106s * hg log --follow -r 80000:90000 js/src/jsproxy.cpp /Users/pmezard/bin/hg-2.2 0.343s 0.388s /Users/pmezard/bin/hgdev 0.437s 0.631s * hg log --follow -r 90000:80000 js/src/jsproxy.cpp /Users/pmezard/bin/hg-2.2 0.342s 0.389s /Users/pmezard/bin/hgdev 0.442s 0.628s