Changed FiniteCache which had a bug where calling items() would make it recurse forever with a new LRUCache implementation.
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fabioz
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2e3cfcbd6d
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@ -3,29 +3,9 @@ from ..GraphicsScene import GraphicsScene
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from ..Point import Point
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from .. import functions as fn
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import weakref
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from ..pgcollections import OrderedDict
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import operator, sys
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import operator
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from pyqtgraph.lru_cache import LRUCache
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class FiniteCache(OrderedDict):
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"""Caches a finite number of objects, removing
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least-frequently used items."""
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def __init__(self, length):
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self._length = length
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OrderedDict.__init__(self)
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def __setitem__(self, item, val):
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self.pop(item, None) # make sure item is added to end
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OrderedDict.__setitem__(self, item, val)
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while len(self) > self._length:
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del self[list(self.keys())[0]]
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def __getitem__(self, item):
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val = OrderedDict.__getitem__(self, item)
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del self[item]
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self[item] = val ## promote this key
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return val
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class GraphicsItem(object):
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"""
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@ -38,7 +18,7 @@ class GraphicsItem(object):
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The GraphicsView system places a lot of emphasis on the notion that the graphics within the scene should be device independent--you should be able to take the same graphics and display them on screens of different resolutions, printers, export to SVG, etc. This is nice in principle, but causes me a lot of headache in practice. It means that I have to circumvent all the device-independent expectations any time I want to operate in pixel coordinates rather than arbitrary scene coordinates. A lot of the code in GraphicsItem is devoted to this task--keeping track of view widgets and device transforms, computing the size and shape of a pixel in local item coordinates, etc. Note that in item coordinates, a pixel does not have to be square or even rectangular, so just asking how to increase a bounding rect by 2px can be a rather complex task.
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"""
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_pixelVectorGlobalCache = FiniteCache(100)
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_pixelVectorGlobalCache = LRUCache(100, 70)
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def __init__(self, register=True):
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if not hasattr(self, '_qtBaseClass'):
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116
pyqtgraph/lru_cache.py
Normal file
116
pyqtgraph/lru_cache.py
Normal file
@ -0,0 +1,116 @@
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import operator
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import sys
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import itertools
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_IS_PY3 = sys.version_info[0] == 3
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class LRUCache(object):
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'''
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This LRU cache should be reasonable for short collections (until around 100 items), as it does a
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sort on the items if the collection would become too big (so, it is very fast for getting and
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setting but when its size would become higher than the max size it does one sort based on the
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internal time to decide which items should be removed -- which should be Ok if the resize_to
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isn't too close to the max_size so that it becomes an operation that doesn't happen all the
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time).
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'''
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def __init__(self, max_size=100, resize_to=70):
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'''
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:param int max_size:
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This is the maximum size of the cache. When some item is added and the cache would become
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bigger than this, it's resized to the value passed on resize_to.
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:param int resize_to:
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When a resize operation happens, this is the size of the final cache.
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'''
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assert resize_to < max_size
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self.max_size = max_size
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self.resize_to = resize_to
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self._counter = 0
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self._dict = {}
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if _IS_PY3:
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self._next_time = itertools.count(0).__next__
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else:
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self._next_time = itertools.count(0).next
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def __getitem__(self, key):
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item = self._dict[key]
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item[2] = self._next_time()
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return item[1]
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def __len__(self):
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return len(self._dict)
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def __setitem__(self, key, value):
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item = self._dict.get(key)
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if item is None:
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if len(self._dict) + 1 > self.max_size:
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self._resize_to()
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item = [key, value, self._next_time()]
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self._dict[key] = item
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else:
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item[1] = value
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item[2] = self._next_time()
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def __delitem__(self, key):
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del self._dict[key]
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def get(self, key, default=None):
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try:
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return self[key]
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except KeyError:
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return default
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def clear(self):
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self._dict.clear()
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if _IS_PY3:
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def values(self):
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return [i[1] for i in self._dict.values()]
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def keys(self):
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return [x[0] for x in self._dict.values()]
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def _resize_to(self):
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ordered = sorted(self._dict.values(), key=operator.itemgetter(2))[:self.resize_to]
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for i in ordered:
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del self._dict[i[0]]
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def iteritems(self, access_time=False):
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'''
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:param bool access_time:
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If True sorts the returned items by the internal access time.
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'''
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if access_time:
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for x in sorted(self._dict.values(), key=operator.itemgetter(2)):
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yield x[0], x[1]
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else:
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for x in self._dict.items():
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yield x[0], x[1]
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else:
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def values(self):
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return [i[1] for i in self._dict.itervalues()]
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def keys(self):
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return [x[0] for x in self._dict.itervalues()]
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def _resize_to(self):
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ordered = sorted(self._dict.itervalues(), key=operator.itemgetter(2))[:self.resize_to]
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for i in ordered:
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del self._dict[i[0]]
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def iteritems(self, access_time=False):
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'''
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:param bool access_time:
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If True sorts the returned items by the internal access time.
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'''
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if access_time:
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for x in sorted(self._dict.itervalues(), key=operator.itemgetter(2)):
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yield x[0], x[1]
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else:
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for x in self._dict.iteritems():
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yield x[0], x[1]
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@ -5,4 +5,54 @@ sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')
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## all tests should be defined with this class so we have the option to tweak it later.
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class TestCase(unittest.TestCase):
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pass
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def testLRU(self):
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from pyqtgraph.lru_cache import LRUCache
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lru = LRUCache(2, 1)
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def CheckLru():
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lru[1] = 1
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lru[2] = 2
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lru[3] = 3
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self.assertEqual(2, len(lru))
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self.assertSetEqual(set([2, 3]), set(lru.keys()))
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self.assertSetEqual(set([2, 3]), set(lru.values()))
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lru[2] = 2
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self.assertSetEqual(set([2, 3]), set(lru.values()))
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lru[1] = 1
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self.assertSetEqual(set([2, 1]), set(lru.values()))
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#Iterates from the used in the last access to others based on access time.
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self.assertEqual([(2, 2), (1, 1)], list(lru.iteritems(access_time=True)))
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lru[2] = 2
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self.assertEqual([(1, 1), (2, 2)], list(lru.iteritems(access_time=True)))
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del lru[2]
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self.assertEqual([(1, 1), ], list(lru.iteritems(access_time=True)))
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lru[2] = 2
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self.assertEqual([(1, 1), (2, 2)], list(lru.iteritems(access_time=True)))
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_a = lru[1]
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self.assertEqual([(2, 2), (1, 1)], list(lru.iteritems(access_time=True)))
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_a = lru[2]
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self.assertEqual([(1, 1), (2, 2)], list(lru.iteritems(access_time=True)))
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self.assertEqual(lru.get(2), 2)
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self.assertEqual(lru.get(3), None)
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self.assertEqual([(1, 1), (2, 2)], list(lru.iteritems(access_time=True)))
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lru.clear()
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self.assertEqual([], list(lru.iteritems()))
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CheckLru()
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# Check it twice...
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CheckLru()
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if __name__ == '__main__':
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unittest.main()
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