Improves performance of http.body.Body.readline()

gunicorn/http/body.py

@@ -228,24 +228,20 @@ class Body(object):
             return ""
 
         line = self.buf.getvalue()
+        self.buf.truncate(0)
+        if len(line) < size:
+            line += self.reader.read(size - len(line))
+        extra_buf_data = line[size:]
+        line = line[:size]
+
         idx = line.find("\n")
         if idx >= 0:
             ret = line[:idx+1]
-            self.buf.truncate(0)
             self.buf.write(line[idx+1:])
+            self.buf.write(extra_buf_data)
             return ret
-
-        self.buf.truncate(0)
-        ch = ""
-        buf = [line]
-        lsize = len(line)
-        while lsize < size and ch != "\n":
-            ch = self.reader.read(1)
-            if not len(ch):
-                break
-            lsize += 1
-            buf.append(ch)
-        return "".join(buf)
+        self.buf.write(extra_buf_data)
+        return line
 
     def readlines(self, size=None):
         ret = []

tests/004-test-http-body.py

@@ -0,0 +1,61 @@
+from StringIO import StringIO
+
+import t
+from gunicorn.http.body import Body
+
+
+def assert_readline(payload, size, expected):
+    body = Body(StringIO(payload))
+    t.eq(body.readline(size), expected)
+
+
+def test_readline_empty_body():
+    assert_readline("", None, "")
+    assert_readline("", 1, "")
+
+
+def test_readline_zero_size():
+    assert_readline("abc", 0, "")
+    assert_readline("\n", 0, "")
+
+
+def test_readline_new_line_before_size():
+    body = Body(StringIO("abc\ndef"))
+    t.eq(body.readline(4), "abc\n")
+    t.eq(body.readline(), "def")
+
+
+def test_readline_new_line_after_size():
+    body = Body(StringIO("abc\ndef"))
+    t.eq(body.readline(2), "ab")
+    t.eq(body.readline(), "c\n")
+
+
+def test_readline_no_new_line():
+    body = Body(StringIO("abcdef"))
+    t.eq(body.readline(), "abcdef")
+    body = Body(StringIO("abcdef"))
+    t.eq(body.readline(2), "ab")
+    t.eq(body.readline(2), "cd")
+    t.eq(body.readline(2), "ef")
+
+
+def test_readline_buffer_loaded():
+    reader = StringIO("abc\ndef")
+    body = Body(reader)
+    body.read(1) # load internal buffer
+    reader.write("g\nhi")
+    reader.seek(7)
+    t.eq(body.readline(), "bc\n")
+    t.eq(body.readline(), "defg\n")
+    t.eq(body.readline(), "hi")
+
+
+def test_readline_buffer_loaded_with_size():
+    body = Body(StringIO("abc\ndef"))
+    body.read(1) # load internal buffer
+    t.eq(body.readline(2), "bc")
+    t.eq(body.readline(2), "\n")
+    t.eq(body.readline(2), "de")
+    t.eq(body.readline(2), "f")
+