scmutil: add a simple key-value file helper
The purpose of the added class is to serve purposes like save files of shelve
or state files of shelve, rebase and histedit. Keys of these files can be
alphanumeric and start with letters, while values must not contain newlines.
In light of Mercurial's reluctancy to use Python's json module, this tries
to provide a reasonable alternative for a non-nested named data.
Comparing to current approach of storing state in plain text files, where
semantic meaning of lines of text is only determined by their oreder,
simple key-value file allows for reordering lines and thus helps handle
optional values.
Initial use-case I see for this is obs-shelve's shelve files. Later we
can possibly migrate state files to this approach.
The test is in a new file beause I did not figure out where to put it
within existing test suite. If you give me a better idea, I will gladly
follow it.
from __future__ import absolute_import
import unittest
import silenttestrunner
from mercurial import (
error,
scmutil,
)
class mockfile(object):
def __init__(self, name, fs):
self.name = name
self.fs = fs
def __enter__(self):
return self
def __exit__(self, *args, **kwargs):
pass
def write(self, text):
self.fs.contents[self.name] = text
def read(self):
return self.fs.contents[self.name]
class mockvfs(object):
def __init__(self):
self.contents = {}
def read(self, path):
return mockfile(path, self).read()
def readlines(self, path):
return mockfile(path, self).read().split('\n')
def __call__(self, path, mode, atomictemp):
return mockfile(path, self)
class testsimplekeyvaluefile(unittest.TestCase):
def setUp(self):
self.vfs = mockvfs()
def testbasicwriting(self):
d = {'key1': 'value1', 'Key2': 'value2'}
scmutil.simplekeyvaluefile(self.vfs, 'kvfile').write(d)
self.assertEqual(sorted(self.vfs.read('kvfile').split('\n')),
['', 'Key2=value2', 'key1=value1'])
def testinvalidkeys(self):
d = {'0key1': 'value1', 'Key2': 'value2'}
with self.assertRaisesRegexp(error.ProgrammingError,
"keys must start with a letter.*"):
scmutil.simplekeyvaluefile(self.vfs, 'kvfile').write(d)
d = {'key1@': 'value1', 'Key2': 'value2'}
with self.assertRaisesRegexp(error.ProgrammingError, "invalid key.*"):
scmutil.simplekeyvaluefile(self.vfs, 'kvfile').write(d)
def testinvalidvalues(self):
d = {'key1': 'value1', 'Key2': 'value2\n'}
with self.assertRaisesRegexp(error.ProgrammingError, "invalid val.*"):
scmutil.simplekeyvaluefile(self.vfs, 'kvfile').write(d)
def testcorruptedfile(self):
self.vfs.contents['badfile'] = 'ababagalamaga\n'
with self.assertRaisesRegexp(error.CorruptedState,
"dictionary.*element.*"):
scmutil.simplekeyvaluefile(self.vfs, 'badfile').read()
if __name__ == "__main__":
silenttestrunner.main(__name__)