basectx: add an empty class that will be used as a parent of all contexts
At the moment, there is no simple way to check if an object is a context
because there is no common parent class. If there were, we could use
'isinstance' everywhere. Simply having memctx inherit from workingctx or
changectx would allow the use of 'isinstance' but that could lead to some
confusing situations of reading the code since we have three distinct concepts
of a context:
- changectx represents a changeset *already* in the repo, and is therefore immutable
- workingctx represents changes on disk in the working directory
- memctx represents changes solely in memory which may or may not be on disk
Therefore, I propose refactoring context.py to have all three contexts inherit
from a parent class 'basectx'.
from mercurial import util
def printifpresent(d, xs):
for x in xs:
present = x in d
print "'%s' in d: %s" % (x, present)
if present:
print "d['%s']: %s" % (x, d[x])
def test_lrucachedict():
d = util.lrucachedict(4)
d['a'] = 'va'
d['b'] = 'vb'
d['c'] = 'vc'
d['d'] = 'vd'
# all of these should be present
printifpresent(d, ['a', 'b', 'c', 'd'])
# 'a' should be dropped because it was least recently used
d['e'] = 've'
printifpresent(d, ['a', 'b', 'c', 'd', 'e'])
# touch entries in some order (get or set).
d['e']
d['c'] = 'vc2'
d['d']
d['b'] = 'vb2'
# 'e' should be dropped now
d['f'] = 'vf'
printifpresent(d, ['b', 'c', 'd', 'e', 'f'])
if __name__ == '__main__':
test_lrucachedict()