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Differential D563

extensions: add wrappedfunction() context manager
AbandonedPublic

Authored by martinvonz on Aug 29 2017, 1:01 PM.

Details

Reviewers
None
Group Reviewers
hg-reviewers
Summary

Several extensions exist that temporarily want to wrap a function (at
least narrowhg, any many of the extensions in hg-experimental). That's
why we have the unwrapfunction() that was introduced in 19578bb84731
(extensions: add unwrapfunction to undo wrapfunction, 2016-08-10).

This patch adds a simple wrappedfunction() that returns a context
manager.

Diff Detail

Repository
rHG Mercurial
Lint
Lint Skipped
Unit
Unit Tests Skipped

Revision Contents
Changeset List

Diff 1408

mercurial/extensions.py

return wrapper(origfn, *args, **kwargs) return wrapper(origfn, *args, **kwargs)
currcls.__dict__[propname].func = wrap currcls.__dict__[propname].func = wrap
break break
if currcls is object: if currcls is object:
raise AttributeError(r"type '%s' has no property '%s'" % ( raise AttributeError(r"type '%s' has no property '%s'" % (
cls, propname)) cls, propname))
class wrappedfunction(object):
'''context manager for temporarily wrapping a function'''
def __init__(self, container, funcname, wrapper):
assert callable(wrapper)
self._container = container
self._funcname = funcname
self._wrapper = wrapper
def __enter__(self):
wrapfunction(self._container, self._funcname, self._wrapper)
def __exit__(self, exctype, excvalue, traceback):
unwrapfunction(self._container, self._funcname)
def wrapfunction(container, funcname, wrapper): def wrapfunction(container, funcname, wrapper):
'''Wrap the function named funcname in container '''Wrap the function named funcname in container
Replace the funcname member in the given container with the specified Replace the funcname member in the given container with the specified
wrapper. The container is typically a module, class, or instance. wrapper. The container is typically a module, class, or instance.
The wrapper will be called like The wrapper will be called like

tests/test-extensions-wrapfunction.py

msg = str(dummy.getstack()) msg = str(dummy.getstack())
except (ValueError, IndexError) as e: except (ValueError, IndexError) as e:
msg = e.__class__.__name__ msg = e.__class__.__name__
print('unwrap %s: %s: %s' % (getid(w), getid(result), msg)) print('unwrap %s: %s: %s' % (getid(w), getid(result), msg))
batchwrap(wrappers + [wrappers[0]]) batchwrap(wrappers + [wrappers[0]])
batchunwrap([(wrappers[i] if i >= 0 else None) batchunwrap([(wrappers[i] if i >= 0 else None)
for i in [3, None, 0, 4, 0, 2, 1, None]]) for i in [3, None, 0, 4, 0, 2, 1, None]])
wrap0 = extensions.wrappedfunction(dummy, 'getstack', wrappers[0])
wrap1 = extensions.wrappedfunction(dummy, 'getstack', wrappers[1])
# Use them in a different order from how they were created to check that
# the wrapping happens in __enter__, not in __init__
print('context manager', dummy.getstack())
with wrap1:
print('context manager', dummy.getstack())
with wrap0:
print('context manager', dummy.getstack())
print('context manager', dummy.getstack())
print('context manager', dummy.getstack())

tests/test-extensions-wrapfunction.py.out

wrap 0: [0, 'orig'] wrap 0: [0, 'orig']
wrap 1: [1, 0, 'orig'] wrap 1: [1, 0, 'orig']
wrap 2: [2, 1, 0, 'orig'] wrap 2: [2, 1, 0, 'orig']
wrap 3: [3, 2, 1, 0, 'orig'] wrap 3: [3, 2, 1, 0, 'orig']
wrap 4: [4, 3, 2, 1, 0, 'orig'] wrap 4: [4, 3, 2, 1, 0, 'orig']
wrap 0: [0, 4, 3, 2, 1, 0, 'orig'] wrap 0: [0, 4, 3, 2, 1, 0, 'orig']
unwrap 3: 3: [0, 4, 2, 1, 0, 'orig'] unwrap 3: 3: [0, 4, 2, 1, 0, 'orig']
unwrap -: 0: [4, 2, 1, 0, 'orig'] unwrap -: 0: [4, 2, 1, 0, 'orig']
unwrap 0: 0: [4, 2, 1, 'orig'] unwrap 0: 0: [4, 2, 1, 'orig']
unwrap 4: 4: [2, 1, 'orig'] unwrap 4: 4: [2, 1, 'orig']
unwrap 0: -: ValueError unwrap 0: -: ValueError
unwrap 2: 2: [1, 'orig'] unwrap 2: 2: [1, 'orig']
unwrap 1: 1: ['orig'] unwrap 1: 1: ['orig']
unwrap -: -: IndexError unwrap -: -: IndexError
context manager ['orig']
context manager [1, 'orig']
context manager [0, 1, 'orig']
context manager [1, 'orig']
context manager ['orig']