Replace elements in-place, rather than appending.

Author: Lukasa

hyper/common/headers.py

@@ -184,15 +184,28 @@ def iter_raw(self):
     def replace(self, key, value):
         """
         Replace existing header with new value. If header doesn't exist this
-        method work like ``__setitem__``. Replacing leads to deletion of all 
-        exsiting headers with the same name.
+        method work like ``__setitem__``. Replacing leads to deletion of all
+        existing headers with the same name.
         """
-        try:
-            del self[key]
-        except KeyError:
-            pass
+        key = to_bytestring(key)
+        indices = []
+        for (i, (k, v)) in enumerate(self._items):
+            if _keys_equal(k, key):
+                indices.append(i)
+
+        # If the key isn't present, this is easy: just append and abort early.
+        if not indices:
+            self._items.append((key, value))
+            return
+
+        # Delete all but the first. I swear, this is the correct slicing
+        # syntax!
+        base_index = indices[0]
+        for i in indices[:0:-1]:
+            self._items.pop(i)
 
-        self[key] = value
+        del self._items[base_index]
+        self._items.insert(base_index, (key, value))
 
     def merge(self, other):
         """

test/test_headers.py

@@ -272,8 +272,8 @@ def test_replacing(self):
 
         assert list(h.items()) == [
             (b'name', b'value'),
-            (b'name3', b'value3'),
             (b'name2', b'42'),
+            (b'name3', b'value3'),
             (b'name4', b'other_value'),
         ]
 

test/test_hyper.py

@@ -122,8 +122,8 @@ def test_putheader_replaces_headers(self):
         assert list(s.headers.items()) == [
             (b':method', b'GET'),
             (b':scheme', b'https'),
-            (b':path', b'/'),
             (b':authority', b'www.example.org'),
+            (b':path', b'/'),
             (b'name', b'value2'),
         ]
 
@@ -581,7 +581,7 @@ def test_recv_cb_n_times(self):
 
         def consume_single_frame():
             mutable['counter'] += 1
-            
+
         c._consume_single_frame = consume_single_frame
         c._recv_cb()
 
@@ -779,7 +779,7 @@ def test_streams_can_replace_none_headers(self):
             (b"name", b"value"),
             (b"other_name", b"other_value")
         ]
-        
+
     def test_stream_opening_sends_headers(self):
         def data_callback(frame):
             assert isinstance(frame, HeadersFrame)
@@ -1548,7 +1548,7 @@ def test_connection_error_when_send_out_of_range_frame(self):
 class NullEncoder(object):
     @staticmethod
     def encode(headers):
-        
+
         def to_str(v):
             if is_py2:
                 return str(v)
@@ -1557,7 +1557,7 @@ def to_str(v):
                     v = str(v, 'utf-8')
                 return v
 
-        return '\n'.join("%s%s" % (to_str(name), to_str(val)) 
+        return '\n'.join("%s%s" % (to_str(name), to_str(val))
                          for name, val in headers)