Implement a parser for Content-Disposition header fields

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

+// 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.
+
+#include "platform/network/ParsedContentHeaderFieldParameters.h"
+
+#include "platform/network/HeaderFieldTokenizer.h"
+#include "platform/wtf/text/StringBuilder.h"
+#include "platform/wtf/text/StringView.h"
+
+namespace blink {
+
+ParsedContentHeaderFieldParameters::ParsedContentHeaderFieldParameters()
+    : is_valid_(false) {}
+
+// static
+ParsedContentHeaderFieldParameters
+ParsedContentHeaderFieldParameters::CreateForTesting(const String& input,
+                                                     Mode mode) {
+  ParsedContentHeaderFieldParameters parameters;
+  parameters.ParseParameters(HeaderFieldTokenizer(input), mode);
+  return parameters;
+}
+
+String ParsedContentHeaderFieldParameters::ParameterValueForName(
+    const String& name) const {
+  if (!name.ContainsOnlyASCII())
+    return String();
+  return parameters_.at(name.LowerASCII());
+}
+
+size_t ParsedContentHeaderFieldParameters::ParameterCount() const {
+  return parameters_.size();
+}
+
+// parameters := *(";" parameter)
+//
+// From http://tools.ietf.org/html/rfc2045#section-5.1:
+//
+// parameter := attribute "=" value
+//
+// attribute := token
+//              ; Matching of attributes
+//              ; is ALWAYS case-insensitive.
+//
+// value := token / quoted-string
+//
+// token := 1*<any (US-ASCII) CHAR except SPACE, CTLs,
+//             or tspecials>
+//
+// tspecials :=  "(" / ")" / "<" / ">" / "@" /
+//               "," / ";" / ":" / "\" / <">
+//               "/" / "[" / "]" / "?" / "="
+//               ; Must be in quoted-string,
+//               ; to use within parameter values
+void ParsedContentHeaderFieldParameters::ParseParameters(
+    HeaderFieldTokenizer tokenizer,
+    Mode mode) {
+  DCHECK(!is_valid_);
+  DCHECK(parameters_.IsEmpty());
+
+  KeyValuePairs map;
+  for (;;) {
+    tokenizer.SkipSpaces();
+    if (tokenizer.IsConsumed())
+      break;
+
+    if (!tokenizer.Consume(';')) {
+      DVLOG(1) << "Failed to find ';'";
+      return;
+    }
+
+    StringView key;
+    String value;
+    if (!tokenizer.ConsumeToken(Mode::kNormal, key)) {
+      DVLOG(1) << "Invalid content parameter name. (at " << tokenizer.Index()
+               << ")";
+      return;
+    }
+    if (!tokenizer.Consume('=')) {
+      DVLOG(1) << "Failed to find '='";
+      return;
+    }
+    if (!tokenizer.ConsumeTokenOrQuotedString(mode, value)) {
+      DVLOG(1) << "Invalid content parameter value (at " << tokenizer.Index()
+               << ", for '" << key.ToString() << "').";
+      return;
+    }
+    // As |key| is parsed as a token, it consists of ascii characters
+    // and hence we don't need to care about non-ascii lowercasing.
+    DCHECK(key.ToString().ContainsOnlyASCII());
+    String key_string = key.ToString().LowerASCII();
+    if (mode == Mode::kStrict && map.find(key_string) != map.end()) {
+      DVLOG(1) << "Parameter " << key_string << " is defined multiple times.";
+      return;
+    }
+    map.Set(key_string, value);
+  }
+  parameters_ = std::move(map);
+  is_valid_ = true;
+}
+
+}  // namespace blink