revlog: change _inline from a function to a variable

revlog: simplify addrevision - remove unused defaults for p1, p2, and text - reduce some if/else - use better variable names - remove some extra variables - remove some obsolete corner tests - simply first entry handling for revlogng - simply inline vs outofline writeout

revlog: some codingstyle cleanups

revlog: add a magic null revision to our index We expand our index by one entry so that index[nullrev] points to a unique entry, the null revision. This naturally eliminates numerous extra tests in the performance-sensitive index access functions, most of which are now trivial again. Adding new entries is now done with insert(-1, e) rather than append(e).

revlog: change accesses to index entry elements to use positive offsets

revlog: parse revlogv0 indexes into v1 internally This lets us eliminate lots of special case code in our performance-sensitive index accessors.

revlog: only allow lazy parsing with revlogng files This will allow us to store indices in memory in a single entry format

revlog: simplify the v1 immediate parser - read all the data at once (large files are handled by the lazy parser) - cache the entire file for inline revlogs - simplify looping

revlog: set the threshold for lazy parsing higher A typical machine can parse a 1MB index in well under a second

revlog: simplify the v0 parser