showbase: add back clampScalar and PriorityCallbacks to PythonUtil

These were removed by 88dbb31daa02779405ef5326677eefb5cf93f3c8 under the assumption that they were not used, but it has recently come to my attention that there is still code out there that uses these.

PriorityCallbacks has been updated to be compatible with Python 3 by only comparing the priority, rather than the (priority, callback) tuple. This also has the side-effect of ditching the bisect dependency.

Also moves testing code from the source to the unit tests.

direct/src/showbase/PythonUtil.py

@@ -10,7 +10,7 @@ __all__ = ['indent',
 'bound', 'clamp', 'lerp', 'average', 'addListsByValue',
 'boolEqual', 'lineupPos', 'formatElapsedSeconds', 'solveQuadratic',
 'findPythonModule', 'mostDerivedLast',
-'weightedChoice', 'randFloat', 'normalDistrib',
+'clampScalar', 'weightedChoice', 'randFloat', 'normalDistrib',
 'weightedRand', 'randUint31', 'randInt32',
 'SerialNumGen', 'serialNum', 'uniqueName', 'Enum', 'Singleton',
 'SingletonError', 'printListEnum', 'safeRepr',
@@ -178,27 +178,6 @@ class Queue:
     def __len__(self):
         return len(self.__list)
 
-if __debug__ and __name__ == '__main__':
-    q = Queue()
-    assert q.isEmpty()
-    q.clear()
-    assert q.isEmpty()
-    q.push(10)
-    assert not q.isEmpty()
-    q.push(20)
-    assert not q.isEmpty()
-    assert len(q) == 2
-    assert q.front() == 10
-    assert q.back() == 20
-    assert q.top() == 10
-    assert q.top() == 10
-    assert q.pop() == 10
-    assert len(q) == 1
-    assert not q.isEmpty()
-    assert q.pop() == 20
-    assert len(q) == 0
-    assert q.isEmpty()
-
 
 def indent(stream, numIndents, str):
     """
@@ -1130,6 +1109,23 @@ def findPythonModule(module):
 
     return None
 
+def clampScalar(value, a, b):
+    # calling this ought to be faster than calling both min and max
+    if a < b:
+        if value < a:
+            return a
+        elif value > b:
+            return b
+        else:
+            return value
+    else:
+        if value < b:
+            return b
+        elif value > a:
+            return a
+        else:
+            return value
+
 def weightedChoice(choiceList, rng=random.random, sum=None):
     """given a list of (weight, item) pairs, chooses an item based on the
     weights. rng must return 0..1. if you happen to have the sum of the
@@ -2313,36 +2309,6 @@ def flywheel(*args, **kArgs):
         pass
     return flywheel
 
-if __debug__ and __name__ == '__main__':
-    f = flywheel(['a','b','c','d'], countList=[11,20,3,4])
-    obj2count = {}
-    for obj in f:
-        obj2count.setdefault(obj, 0)
-        obj2count[obj] += 1
-    assert obj2count['a'] == 11
-    assert obj2count['b'] == 20
-    assert obj2count['c'] == 3
-    assert obj2count['d'] == 4
-
-    f = flywheel([1,2,3,4], countFunc=lambda x: x*2)
-    obj2count = {}
-    for obj in f:
-        obj2count.setdefault(obj, 0)
-        obj2count[obj] += 1
-    assert obj2count[1] == 2
-    assert obj2count[2] == 4
-    assert obj2count[3] == 6
-    assert obj2count[4] == 8
-
-    f = flywheel([1,2,3,4], countFunc=lambda x: x, scale = 3)
-    obj2count = {}
-    for obj in f:
-        obj2count.setdefault(obj, 0)
-        obj2count[obj] += 1
-    assert obj2count[1] == 1 * 3
-    assert obj2count[2] == 2 * 3
-    assert obj2count[3] == 3 * 3
-    assert obj2count[4] == 4 * 3
 
 if __debug__:
     def quickProfile(name="unnamed"):
@@ -2687,11 +2653,36 @@ def unescapeHtmlString(s):
         result += char
     return result
 
-if __debug__ and __name__ == '__main__':
-    assert unescapeHtmlString('asdf') == 'asdf'
-    assert unescapeHtmlString('as+df') == 'as df'
-    assert unescapeHtmlString('as%32df') == 'as2df'
-    assert unescapeHtmlString('asdf%32') == 'asdf2'
+class PriorityCallbacks:
+    """ manage a set of prioritized callbacks, and allow them to be invoked in order of priority """
+    def __init__(self):
+        self._callbacks = []
+
+    def clear(self):
+        del self._callbacks[:]
+
+    def add(self, callback, priority=None):
+        if priority is None:
+            priority = 0
+        callbacks = self._callbacks
+        lo = 0
+        hi = len(callbacks)
+        while lo < hi:
+            mid = (lo + hi) // 2
+            if priority < callbacks[mid][0]:
+                hi = mid
+            else:
+                lo = mid + 1
+        item = (priority, callback)
+        callbacks.insert(lo, item)
+        return item
+
+    def remove(self, item):
+        self._callbacks.remove(item)
+
+    def __call__(self):
+        for priority, callback in self._callbacks:
+            callback()
 
 builtins.Functor = Functor
 builtins.Stack = Stack

tests/showbase/test_PythonUtil.py

@@ -0,0 +1,105 @@
+from direct.showbase import PythonUtil
+
+
+def test_queue():
+    q = PythonUtil.Queue()
+    assert q.isEmpty()
+    q.clear()
+    assert q.isEmpty()
+    q.push(10)
+    assert not q.isEmpty()
+    q.push(20)
+    assert not q.isEmpty()
+    assert len(q) == 2
+    assert q.front() == 10
+    assert q.back() == 20
+    assert q.top() == 10
+    assert q.top() == 10
+    assert q.pop() == 10
+    assert len(q) == 1
+    assert not q.isEmpty()
+    assert q.pop() == 20
+    assert len(q) == 0
+    assert q.isEmpty()
+
+
+def test_flywheel():
+    f = PythonUtil.flywheel(['a','b','c','d'], countList=[11,20,3,4])
+    obj2count = {}
+    for obj in f:
+        obj2count.setdefault(obj, 0)
+        obj2count[obj] += 1
+    assert obj2count['a'] == 11
+    assert obj2count['b'] == 20
+    assert obj2count['c'] == 3
+    assert obj2count['d'] == 4
+
+    f = PythonUtil.flywheel([1,2,3,4], countFunc=lambda x: x*2)
+    obj2count = {}
+    for obj in f:
+        obj2count.setdefault(obj, 0)
+        obj2count[obj] += 1
+    assert obj2count[1] == 2
+    assert obj2count[2] == 4
+    assert obj2count[3] == 6
+    assert obj2count[4] == 8
+
+    f = PythonUtil.flywheel([1,2,3,4], countFunc=lambda x: x, scale = 3)
+    obj2count = {}
+    for obj in f:
+        obj2count.setdefault(obj, 0)
+        obj2count[obj] += 1
+    assert obj2count[1] == 1 * 3
+    assert obj2count[2] == 2 * 3
+    assert obj2count[3] == 3 * 3
+    assert obj2count[4] == 4 * 3
+
+
+def test_unescape_html_string():
+    assert PythonUtil.unescapeHtmlString('asdf') == 'asdf'
+    assert PythonUtil.unescapeHtmlString('as+df') == 'as df'
+    assert PythonUtil.unescapeHtmlString('as%32df') == 'as2df'
+    assert PythonUtil.unescapeHtmlString('asdf%32') == 'asdf2'
+
+
+def test_priority_callbacks():
+    l = []
+    def a(l=l):
+        l.append('a')
+    def b(l=l):
+        l.append('b')
+    def c(l=l):
+        l.append('c')
+
+    pc = PythonUtil.PriorityCallbacks()
+    pc.add(a)
+    pc()
+    assert l == ['a']
+
+    del l[:]
+    bItem = pc.add(b)
+    pc()
+    assert 'a' in l
+    assert 'b' in l
+    assert len(l) == 2
+
+    del l[:]
+    pc.remove(bItem)
+    pc()
+    assert l == ['a']
+
+    del l[:]
+    pc.add(c, 2)
+    bItem = pc.add(b, 10)
+    pc()
+    assert l == ['a', 'c', 'b']
+
+    del l[:]
+    pc.remove(bItem)
+    pc()
+    assert l == ['a', 'c']
+
+    del l[:]
+    pc.clear()
+    pc()
+    assert len(l) == 0