Initial Commit

lib/html5lib/utils.py

@@ -0,0 +1,82 @@
+from __future__ import absolute_import, division, unicode_literals
+
+from types import ModuleType
+
+try:
+    import xml.etree.cElementTree as default_etree
+except ImportError:
+    import xml.etree.ElementTree as default_etree
+
+
+__all__ = ["default_etree", "MethodDispatcher", "isSurrogatePair",
+           "surrogatePairToCodepoint", "moduleFactoryFactory"]
+
+
+class MethodDispatcher(dict):
+    """Dict with 2 special properties:
+
+    On initiation, keys that are lists, sets or tuples are converted to
+    multiple keys so accessing any one of the items in the original
+    list-like object returns the matching value
+
+    md = MethodDispatcher({("foo", "bar"):"baz"})
+    md["foo"] == "baz"
+
+    A default value which can be set through the default attribute.
+    """
+
+    def __init__(self, items=()):
+        # Using _dictEntries instead of directly assigning to self is about
+        # twice as fast. Please do careful performance testing before changing
+        # anything here.
+        _dictEntries = []
+        for name, value in items:
+            if type(name) in (list, tuple, frozenset, set):
+                for item in name:
+                    _dictEntries.append((item, value))
+            else:
+                _dictEntries.append((name, value))
+        dict.__init__(self, _dictEntries)
+        self.default = None
+
+    def __getitem__(self, key):
+        return dict.get(self, key, self.default)
+
+
+# Some utility functions to dal with weirdness around UCS2 vs UCS4
+# python builds
+
+def isSurrogatePair(data):
+    return (len(data) == 2 and
+            ord(data[0]) >= 0xD800 and ord(data[0]) <= 0xDBFF and
+            ord(data[1]) >= 0xDC00 and ord(data[1]) <= 0xDFFF)
+
+
+def surrogatePairToCodepoint(data):
+    char_val = (0x10000 + (ord(data[0]) - 0xD800) * 0x400 +
+                (ord(data[1]) - 0xDC00))
+    return char_val
+
+# Module Factory Factory (no, this isn't Java, I know)
+# Here to stop this being duplicated all over the place.
+
+
+def moduleFactoryFactory(factory):
+    moduleCache = {}
+
+    def moduleFactory(baseModule, *args, **kwargs):
+        if isinstance(ModuleType.__name__, type("")):
+            name = "_%s_factory" % baseModule.__name__
+        else:
+            name = b"_%s_factory" % baseModule.__name__
+
+        if name in moduleCache:
+            return moduleCache[name]
+        else:
+            mod = ModuleType(name)
+            objs = factory(baseModule, *args, **kwargs)
+            mod.__dict__.update(objs)
+            moduleCache[name] = mod
+            return mod
+
+    return moduleFactory