repository: establish API for emitting revision deltas With our revision delta and revision delta request interfaces defined, it is now time to define a method on storage interfaces for using them. So far, the only storage interface that is well-defined and used is file storage. So that is the only interface we need to add a method on. We define an ``emitrevisiondeltas()`` method that takes an iterable of ``irevisiondeltarequest``s and turns them into ``irevisiondelta`` instances. changegroup._handlerevisiondeltarequest() and the looping logic from changegroup.deltagroup() has effectively been moved to revlog.emitrevisiondeltas(). Our filelog wrapper class proxies its emitrevisiondeltas() to the internal revlog instance. The simple store test extension used to verify sanity of storage abstractions has also implemented emitrevisiondeltas() for file storage and the test harness when run with this extension doesn't seem to exhibit any regressions. Rather than create a shared type to represent revision deltas, each storage backend has its own type and the class name identifies where the revision delta was derived from. Differential Revision: https://phab.mercurial-scm.org/D4226

repository: formalize interfaces for revision deltas and requests Now that we've sufficiently abstracted how revision deltas are produced in changegroup code, we can now start the process of formalizing that as part of the interfaces defined in the repository module. This commit essentially converts the revisiondelta and revisiondeltarequest classes into well-defined interfaces. This is not strictly necessary. But I want all types formalized by the storage interface to have interfaces. This makes it much easier to test for interface conformance and for implementing new storage backends. Because the interface is documented, comments and docstrings from changegroup.py have been dropped. Differential Revision: https://phab.mercurial-scm.org/D4225

changegroup: move node sorting into deltagroup() The 3 callers of deltagroup() all sort nodes and convert to integer revs immediately before calling deltagroup(). Stepping back a bit, aside from the constraints on node ordering that always apply (namely that a node must follow its ancestor), it makes sense for sorting to be an implementation detail of the store. Moving the sorting into deltagroup() will open the door for moving sorting into a storage API. The test for the changelog in deltagroup() to impact the sorting method is a bit hacky. I suspect this will be resolved once we establish a formal interface for delta group generation and port changelog to it. Differential Revision: https://phab.mercurial-scm.org/D4224

cext: fix truncation warnings in revlog on Windows

cext: fix revlog compiler error on Windows

shortest: use nodetree for finding shortest node within revset This speeds up `hg log -T '{shortest(node,1)}\n'` in my repo from 12s to 4.5s. That's very close to the 4.1s it takes without the disambiguation revset configured. My repo has 69.5k revisions, of which 550 were in the configured revset ("not public()"). Differential Revision: https://phab.mercurial-scm.org/D4120