Get encoding reparsing actually working

html5lib/html5parser.py

@@ -89,12 +89,11 @@ def _parse(self, stream, innerHTML=False, container="div",
                                               parser=self, **kwargs)
         self.reset()
 
-        while True:
-            try:
-                self.mainLoop()
-                break
-            except ReparseException:
-                self.reset()
+        try:
+            self.mainLoop()
+        except ReparseException:
+            self.reset()
+            self.mainLoop()
 
     def reset(self):
         self.tree.reset()

html5lib/inputstream.py

@@ -509,8 +509,8 @@ def changeEncoding(self, newEncoding):
             self.charEncoding = (self.charEncoding[0], "certain")
         else:
             self.rawStream.seek(0)
-            self.reset()
             self.charEncoding = (newEncoding, "certain")
+            self.reset()
             raise ReparseException("Encoding changed from %s to %s" % (self.charEncoding[0], newEncoding))
 
     def detectBOM(self):

html5lib/tests/test_encoding.py

@@ -12,6 +12,28 @@
 from html5lib import HTMLParser, inputstream
 
 
+def test_basic_prescan_length():
+    data = "<title>Caf\u00E9</title><!--a--><meta charset='utf-8'>".encode('utf-8')
+    pad = 1024 - len(data) + 1
+    data = data.replace(b"-a-", b"-" + (b"a" * pad) + b"-")
+    assert len(data) == 1024  # Sanity
+    stream = inputstream.HTMLBinaryInputStream(data, chardet=False)
+    assert 'utf-8' == stream.charEncoding[0].name
+
+
+def test_parser_reparse():
+    data = "<title>Caf\u00E9</title><!--a--><meta charset='utf-8'>".encode('utf-8')
+    pad = 10240 - len(data) + 1
+    data = data.replace(b"-a-", b"-" + (b"a" * pad) + b"-")
+    assert len(data) == 10240  # Sanity
+    stream = inputstream.HTMLBinaryInputStream(data, chardet=False)
+    assert 'windows-1252' == stream.charEncoding[0].name
+    p = HTMLParser(namespaceHTMLElements=False)
+    doc = p.parse(data, useChardet=False)
+    assert 'utf-8' == p.documentEncoding
+    assert doc.find(".//title").text == "Caf\u00E9"
+
+
 def runParserEncodingTest(data, encoding):
     p = HTMLParser()
     assert p.documentEncoding is None