Implement a parser for Content-Disposition header fields

third_party/WebKit/Source/platform/network/ParsedContentHeaderFieldParameters.h

+// Copyright 2017 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.
+
+#ifndef ParsedContentHeaderFieldParameters_h
+#define ParsedContentHeaderFieldParameters_h
+
+#include "platform/PlatformExport.h"
+#include "platform/wtf/Allocator.h"
+#include "platform/wtf/HashMap.h"
+#include "platform/wtf/text/StringHash.h"
+
+namespace blink {
+
+class HeaderFieldTokenizer;
+
+// Parses content header field parameters as specified in RFC2045 and stores
+// them. It is used internally by ParsedContent* classes.
+// FIXME: add support for comments.
+class PLATFORM_EXPORT ParsedContentHeaderFieldParameters final {
+  STACK_ALLOCATED();
+
+ public:
+  // When |Relaxed| is specified, the parser parses parameter values in a sloppy
+  // manner, i.e., only ';' and '"' are treated as special characters.
+  // See https://chromiumcodereview.appspot.com/23043002.
+  // When |Strict| is specified, the parser does not allow multiple values
+  // for the same parameter. Some RFCs based on RFC2045 (e.g. RFC6838) note that
+  // "It is an error for a specific parameter to be specified more than once."
+  enum class Mode {
+    kNormal,
+    kRelaxed,
+    kStrict,
+  };
+
+  ParsedContentHeaderFieldParameters();
+
+  // Note that in the case of multiple values for the same name, the last value
+  // is returned.
+  String ParameterValueForName(const String&) const;
+  size_t ParameterCount() const;
+
+  bool IsValid() const { return is_valid_; }
+
+  void ParseParameters(HeaderFieldTokenizer, Mode);
+
+  static ParsedContentHeaderFieldParameters CreateForTesting(
+      const String&,
+      Mode = Mode::kNormal);
+
+ private:
+  typedef HashMap<String, String> KeyValuePairs;
+  bool is_valid_;
+  KeyValuePairs parameters_;
+};
+
+}  // namespace blink
+
+#endif