contrib/python-hook-examples.py

revset: use decorator to register a function as revset predicate

Using decorator can localize changes for adding (or removing) a revset
predicate function in source code.

It is also useful to pick predicates up for specific purpose. For
example, subsequent patch marks predicates as "safe" by decorator.

This patch defines 'parsefuncdecl()' in 'funcregistrar' class, because
this implementation can be uesd by other decorator class for fileset
predicate and template function.

'''
Examples of useful python hooks for Mercurial.
'''
from mercurial import patch, util

def diffstat(ui, repo, **kwargs):
    '''Example usage:

    [hooks]
    commit.diffstat = python:/path/to/this/file.py:diffstat
    changegroup.diffstat = python:/path/to/this/file.py:diffstat
    '''
    if kwargs.get('parent2'):
        return
    node = kwargs['node']
    first = repo[node].p1().node()
    if 'url' in kwargs:
        last = repo['tip'].node()
    else:
        last = node
    diff = patch.diff(repo, first, last)
    ui.write(patch.diffstat(util.iterlines(diff)))