bundle2: allow compressed bundle This changeset adds support for a 'compression' parameter in bundle2 streams. When set, it controls the compression algorithm used for the payload part of the bundle2. There is currently no usage of this except in tests.

test-bundle2: dump bundle content using f --hexdump Thanks to Greg Szorc for pointing this out.

treemanifest: rework lazy-copying code (issue4840) The old lazy-copy code formed a chain of copied manifests with each copy. Under typical operation, the stack never got more than a couple of manifests deep and was fine. Under conditions like hgsubversion or convert, the stack could get hundreds of manifests deep, and eventually overflow the recursion limit for Python. I was able to consistently reproduce this by converting an hgsubversion clone of svn's history to treemanifests. This may result in fewer manifests staying in memory during operations like convert when treemanifests are in use, and should make those operations faster since there will be significantly fewer noop function calls going on. A previous attempt (never mailed) of mine to fix this problem tried to simply have all treemanifests only have a loadfunc - that caused somewhat weird problems because the gettext() callable passed into read() wasn't idempotent, so the easy solution is to have a loadfunc and a copyfunc.

manifest: rename treemanifest load functions to ease debugging I'm hunting an infinite recursion bug at the moment, and having both of these methods named just _load is muddying the waters slightly.

manifest: add id(self) to treemanifest __repr__ Also rename __str__ to __repr__ since that's what we really want for pdb.

bundlerepo: let bundle repo look in the _mancache When looking up a base revision, we were ignoring the contents that were already available in the manifest's _mancache. This patch allows us to use that data instead of reading from the revlog. This is useful in our pushrebase extension (which allows rebasing on the server side during a push) because it allows us to prefetch the bundle base manifest before aquiring the repo lock (1 second saving), which means doing less work inside the lock, which means a 20% higher commit rate.

check-seclevel: wrap entry point by function This is intended to narrow scope of local variables. The global _verbose flag will be replaced later by ui.verbose.

check-seclevel: set executable bit as it has shebang

bundle20: extract core payload generation in its own function We are about to allow compressing the core of the bundle2. So we extract the generation of this bits in its own parts to make this compression phases easier in a later changesets.

unbundle20: allow registering handlers for stream level parameters As a comment in the code have been asking for, it is now possible to register piece of code that handle parameters for the stream. I've been wondering is such function should be class methods or not. I eventually went for externally decorated methods to stick with the culture of extensibility from an extensions that apply to bundle2.