treemanifest: add walksubtrees api
Adds a new function to treemanifest that allows walking over the directories in
the tree. Currently it only accepts a matcher to prune the walk, but in the
future it will also accept a list of trees and will only walk over subtrees that
differ from the versions in the list. This will be useful for identifying what
parts of the tree are new to this revision, which is useful when deciding the
minimal set of trees to send to a client given that they have a certain tree
already.
Since this is intended for an extension to use, the only current consumer is a
test. In the future this function may be useful for implementing other
algorithms like diff and changegroup generation.
from __future__ import absolute_import
import silenttestrunner
import unittest
from mercurial import util
class contextmanager(object):
def __init__(self, name, trace):
self.name = name
self.entered = False
self.exited = False
self.trace = trace
def __enter__(self):
self.entered = True
self.trace(('enter', self.name))
return self
def __exit__(self, exc_type, exc_val, exc_tb):
self.exited = exc_type, exc_val, exc_tb
self.trace(('exit', self.name))
def __repr__(self):
return '<ctx %r>' % self.name
class ctxerror(Exception):
pass
class raise_on_enter(contextmanager):
def __enter__(self):
self.trace(('raise', self.name))
raise ctxerror(self.name)
class raise_on_exit(contextmanager):
def __exit__(self, exc_type, exc_val, exc_tb):
self.trace(('raise', self.name))
raise ctxerror(self.name)
def ctxmgr(name, trace):
return lambda: contextmanager(name, trace)
class test_ctxmanager(unittest.TestCase):
def test_basics(self):
trace = []
addtrace = trace.append
with util.ctxmanager(ctxmgr('a', addtrace), ctxmgr('b', addtrace)) as c:
a, b = c.enter()
c.atexit(addtrace, ('atexit', 'x'))
c.atexit(addtrace, ('atexit', 'y'))
self.assertEqual(trace, [('enter', 'a'), ('enter', 'b'),
('atexit', 'y'), ('atexit', 'x'),
('exit', 'b'), ('exit', 'a')])
def test_raise_on_enter(self):
trace = []
addtrace = trace.append
def go():
with util.ctxmanager(ctxmgr('a', addtrace),
lambda: raise_on_enter('b', addtrace)) as c:
c.enter()
addtrace('unreachable')
self.assertRaises(ctxerror, go)
self.assertEqual(trace, [('enter', 'a'), ('raise', 'b'), ('exit', 'a')])
def test_raise_on_exit(self):
trace = []
addtrace = trace.append
def go():
with util.ctxmanager(ctxmgr('a', addtrace),
lambda: raise_on_exit('b', addtrace)) as c:
c.enter()
addtrace('running')
self.assertRaises(ctxerror, go)
self.assertEqual(trace, [('enter', 'a'), ('enter', 'b'), 'running',
('raise', 'b'), ('exit', 'a')])
if __name__ == '__main__':
silenttestrunner.main(__name__)