Google Code Issue 215: Properly detect seekable streams

jcarlosgarciasegovia · gsnedders · commit aed6279aaeda · 2013-05-02T23:15:57.000+01:00
This patch removes the hack that tests for sys.stdin to determine if
the stream is seekable (it has tell() and seek() but it is not
seekable), by actually calling tell() and seek().
diff --git a/html5lib/inputstream.py b/html5lib/inputstream.py
@@ -202,10 +202,9 @@ def openStream(self, source):
         else:
             stream = StringIO(source)
 
-        if (  # not isinstance(stream, BufferedIOBase) and
-            not(hasattr(stream, "tell") and
-                hasattr(stream, "seek")) or
-                stream is sys.stdin):
+        try:
+            stream.seek(stream.tell())
+        except:
             stream = BufferedStream(stream)
 
         return stream
@@ -437,8 +436,9 @@ def openStream(self, source):
         else:
             stream = BytesIO(source)
 
-        if (not(hasattr(stream, "tell") and hasattr(stream, "seek")) or
-                stream is sys.stdin):
+        try:
+            stream.seek(stream.tell())
+        except:
             stream = BufferedStream(stream)
 
         return stream
