Add a parser for Link headers

Source/core/loader/LinkHeaderTest.cpp

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "core/loader/LinkHeader.h"
+
+#include <base/macros.h>
+#include <gtest/gtest.h>
+
+namespace blink {
+
+TEST(LinkHeaderTest, Basic)
+{
+    struct TestCase {
+        const char* headerValue;
+        const char* url;
+        const char* rel;
+        bool valid;
+    } cases[] = {
+        {0, "", "", false},
+        {"", "", "", false},
+        {"</images/cat.jpg>; rel=prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg>;rel=prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg>   ;rel=prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg>   ;   rel=prefetch", "/images/cat.jpg", "prefetch", true},
+        {"< /images/cat.jpg>   ;   rel=prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg >   ;   rel=prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg wutwut>   ;   rel=prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg wutwut  \t >   ;   rel=prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg>; rel=prefetch   ", "/images/cat.jpg", "prefetch", true},
+        {"  </images/cat.jpg>; rel=prefetch   ", "/images/cat.jpg", "prefetch", true},
+        {"\t  </images/cat.jpg>; rel=prefetch   ", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg>\t\t ; \trel=prefetch \t  ", "/images/cat.jpg", "prefetch", true},
+        {"\f</images/cat.jpg>\t\t ; \trel=prefetch \t  ", "", "", false},
+        {"</images/cat.jpg>; rel= prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg>; rel =prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg>; rel pel=prefetch", "/images/cat.jpg", "", false},
+        {"< /images/cat.jpg>", "/images/cat.jpg", "", true},
+        {"</images/cat.jpg>; rel =", "/images/cat.jpg", "", false},
+        {"</images/cat.jpg>; wut=sup; rel =prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg>; wut=sup ; rel =prefetch", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg>; wut=sup ; rel =prefetch  \t  ;", "/images/cat.jpg", "prefetch", true},
+        {"</images/cat.jpg> wut=sup ; rel =prefetch  \t  ;", "/images/cat.jpg", "", false},

[Mike West, 2015/01/30 13:55:13]

Can you add some that break expectations? Like, starting '<' but no trailing
'>'? URLs that contain invalid characters or query strings or percent-quoted
'>', etc.

It would also be good to add a layout test that outputs a 'Link' header with
some of these formats just as a "Passes if it doesn't crash" starter set, as
various folks' fuzzers use the LayoutTest directory as a seed. It's better to
get them going on breaking this code earlier rather than later. :)

+    };
+
+    for (size_t i = 0; i < arraysize(cases); ++i) {
+        const char* headerValue = cases[i].headerValue;
+        const char* url = cases[i].url;
+        const char* rel = cases[i].rel;
+        bool valid = cases[i].valid;
+
+        LinkHeader header(headerValue);
+        ASSERT_EQ(valid, header.valid());
+        ASSERT_STREQ(url, header.url().ascii().data());
+        ASSERT_STREQ(rel, header.rel().ascii().data());
+    }
+}
+
+} // namespace blink