util/UriQueryParser: new library

src/util/UriQueryParser.cxx

+/*
+ * Copyright 2008-2019 Max Kellermann <max.kellermann@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "UriQueryParser.hxx"
+#include "IterableSplitString.hxx"
+
+StringView
+UriFindRawQueryParameter(StringView query_string, StringView name) noexcept
+{
+	for (StringView i : IterableSplitString(query_string, '&')) {
+		if (i.StartsWith(name)) {
+			if (i.size == name.size)
+				return "";
+
+			if (i[name.size] == '=') {
+				i.skip_front(name.size + 1);
+				return i;
+			}
+		}
+	}
+
+	return nullptr;
+}

src/util/UriQueryParser.hxx

+/*
+ * Copyright 2008-2019 Max Kellermann <max.kellermann@gmail.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef URI_QUERY_PARSER_HXX
+#define URI_QUERY_PARSER_HXX
+
+#include "Compiler.h"
+
+struct StringView;
+
+/**
+ * Find the first query parameter with the given name and return its
+ * raw value (without unescaping).
+ *
+ * @return the raw value (pointing into the #query_string parameter)
+ * or nullptr if the parameter does not exist
+ */
+gcc_pure
+StringView
+UriFindRawQueryParameter(StringView query_string, StringView name) noexcept;
+
+#endif

src/util/meson.build

@@ -18,6 +18,7 @@ util = static_library(
   'FormatString.cxx',
   'Tokenizer.cxx',
   'UriExtract.cxx',
+  'UriQueryParser.cxx',
   'UriRelative.cxx',
   'UriUtil.cxx',
   'LazyRandomEngine.cxx',

test/TestUriQueryParser.cxx

+/*
+ * Unit tests for src/util/
+ */
+
+#include "util/UriQueryParser.hxx"
+#include "util/StringView.hxx"
+
+#include <gtest/gtest.h>
+
+static bool
+operator==(StringView a, StringView b)
+{
+	if (a.IsNull() || b.IsNull())
+		return a.IsNull() == b.IsNull();
+
+	return a.Equals(b);
+}
+
+TEST(UriQueryParser, UriFindRawQueryParameter)
+{
+	const char *q = "foo=1&bar=2&quoted=%20%00+%%&empty1&empty2=";
+	EXPECT_EQ(UriFindRawQueryParameter(q, "doesntexist"),
+		  (const char *)nullptr);
+	EXPECT_EQ(UriFindRawQueryParameter(q, "foo"),
+		  "1");
+	EXPECT_EQ(UriFindRawQueryParameter(q, "bar"),
+		  "2");
+	EXPECT_EQ(UriFindRawQueryParameter(q, "quoted"),
+		  "%20%00+%%");
+	EXPECT_EQ(UriFindRawQueryParameter(q, "empty1"),
+		  "");
+	EXPECT_EQ(UriFindRawQueryParameter(q, "empty2"),
+		  "");
+}

test/meson.build

@@ -38,6 +38,7 @@ test('TestUtil', executable(
   'TestMimeType.cxx',
   'TestSplitString.cxx',
   'TestUriExtract.cxx',
+  'TestUriQueryParser.cxx',
   'TestUriUtil.cxx',
   'test_byte_reverse.cxx',
   include_directories: inc,