bundle2.unpackermixin: control for underlying file descriptor This patch adds seek(), tell(), and close() implementations for unpackermixin which forward to the file descriptor's implementation if possible. A future patch will use this to make bundle2.unbundlepart seekable, which will in turn make it usable as a file descriptor for bundlerepo.

trydiff: join elements in 'header' list by '\n' It seems natural that each element in the list corresponds to one line of output. That is currently true, but only because each element in the list has a trailing newline. Let's drop those newlines and instead add them when we print the headers.

trydiff: move check for quietness out of diffline() By moving the condition out of diffline(), the call site becomes clearer and diffline() no longer closes on any variables. Note that this changes the value of the header variable from [''] to [], but there is no difference in how these two are treated by the following code. The new value seems more natural anyway.

trydiff: remove dead branch in diffline() Since diffline() is never called when 'revs' is empty, it doesn't need to handle that case.

trydiff: make 'revs' ignored if opts.git is set Instead of setting revs=None to prevent the call to diffline() when opts.git is set, explicitly do not call the function in the git case.

trydiff: remove unused argument to diffline() Now that diffline no longer knows about copies/renames, it only needs one argument for the path.

trydiff: move git-header code out of diffline function This collects more of the code for writing git headers in a single place and makes diffline() close on a few variables less.

_fm1readmarkers: generate list in C This moves perfloadmarkers from ! result: 63866 ! wall 0.239217 comb 0.250000 user 0.240000 sys 0.010000 (best of 42) to ! result: 63866 ! wall 0.218795 comb 0.210000 user 0.210000 sys 0.000000 (best of 46)

obsolete: use parsers.fm1readmarker if it exists for a ~38% perf win This moves perfloadmarkers on my linux workstation (63494 markers from mpm, crew, and myself) performance from ! wall 0.357657 comb 0.360000 user 0.350000 sys 0.010000 (best of 28) to ! wall 0.222345 comb 0.220000 user 0.210000 sys 0.010000 (best of 41) which is a pretty good improvement. On my BSD machine, which is ancient and slow, before: ! wall 3.584964 comb 3.578125 user 3.539062 sys 0.039062 (best of 3) after: ! wall 2.267974 comb 2.265625 user 2.195312 sys 0.070312 (best of 5) I feel like we could do better by moving the whole generator function into C, but I didn't want to tackle that right away.

parsers: add fm1readmarker This lets us do most of the interesting work of parsing obsolete markers in C, which should provide significant time savings. Thanks to Martin von Zweigbergk for some cleanups on this code.