Implement a parser for Content-Disposition header fields

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

+/*
+ * Copyright (C) 2011 Google Inc. All rights reserved.
+ * Copyright (C) 2012 Intel Corporation. All rights reserved.
+ *
+ * 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.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * 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 COPYRIGHT
+ * OWNER 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 "platform/network/ParsedParameterizedContentHeaderField.h"
+
+#include "platform/wtf/text/StringBuilder.h"
+#include "platform/wtf/text/StringView.h"
+
+namespace blink {
+
+using Mode = ParsedParameterizedContentHeaderField::Mode;
+
+namespace {
+
+bool IsTokenCharacter(Mode mode, UChar c) {
+  if (c >= 128)
+    return false;
+  if (c < 0x20)
+    return false;
+
+  switch (c) {
+    case ' ':
+    case ';':
+    case '"':
+      return false;
+    case '(':
+    case ')':
+    case '<':
+    case '>':
+    case '@':
+    case ',':
+    case ':':
+    case '\\':
+    case '/':
+    case '[':
+    case ']':
+    case '?':
+    case '=':
+      return mode == Mode::kRelaxed;
+    default:
+      return true;
+  }
+}
+
+}  // namespace
+
+ParsedParameterizedContentHeaderField::Input::Input(const String& header_field)
+    : index_(0u), input_(header_field) {}
+
+bool ParsedParameterizedContentHeaderField::Input::Consume(char c) {
+  DCHECK_NE(c, ' ');
+
+  SkipSpaces();
+  if (IsConsumed())
+    return false;
+
+  ++index_;

[horo, 2017/05/15 05:57:54]

Why you don't use |c|?

[e_hakkinen, 2017/05/18 09:35:48]

Due to too much refactoring. Fixed.

+  return true;
+}
+
+bool ParsedParameterizedContentHeaderField::Input::ConsumeQuotedString(
+    String& output) {
+  StringBuilder builder;
+
+  DCHECK_EQ('"', input_[index_]);
+  ++index_;
+
+  while (!IsConsumed()) {
+    if (input_[index_] == '"') {
+      output = builder.ToString();
+      ++index_;
+      return true;
+    }
+    if (input_[index_] == '\\') {
+      ++index_;
+      if (IsConsumed())
+        return false;
+    }
+    builder.Append(input_[index_]);
+    ++index_;
+  }
+  return false;
+}
+
+bool ParsedParameterizedContentHeaderField::Input::ConsumeToken(
+    Mode mode,
+    StringView& output) {
+  DCHECK(output.IsNull());
+
+  SkipSpaces();
+
+  auto start = index_;
+  while (!IsConsumed() && IsTokenCharacter(mode, input_[index_]))
+    ++index_;
+
+  if (start == index_)
+    return false;
+
+  output = StringView(input_, start, index_ - start);
+  return true;
+}
+
+bool ParsedParameterizedContentHeaderField::Input::ConsumeTokenOrQuotedString(
+    Mode mode,
+    String& output) {
+  SkipSpaces();
+  if (IsConsumed())
+    return false;
+
+  if (input_[index_] == '"')
+    return ConsumeQuotedString(output);
+
+  StringView view;
+  if (!ConsumeToken(mode, view))
+    return false;
+  output = view.ToString();
+  return true;
+}
+
+void ParsedParameterizedContentHeaderField::Input::SkipSpaces() {
+  while (!IsConsumed() && input_[index_] == ' ')
+    ++index_;
+}
+
+ParsedParameterizedContentHeaderField::ParsedParameterizedContentHeaderField()
+    : is_valid_(false) {}
+
+ParsedParameterizedContentHeaderField::ParsedParameterizedContentHeaderField(

[horo, 2017/05/15 05:57:54]

Who call this?
If you want to use it to parse Content-Disposition, you should add
ParsedContentDisposition class.
And the constructor of ParsedContentDisposition should call 
ParsedContentDisposition::Parse() same as the constructor of ParsedContentType.

[e_hakkinen, 2017/05/18 09:35:48]

Anyone wanting to parse any content header field other than Content-Type.
I see the point.

+    const String& header_field,
+    Mode mode)
+    : ParsedParameterizedContentHeaderField() {
+  is_valid_ = Parse(header_field, mode);
+}
+
+String ParsedParameterizedContentHeaderField::ParameterValueForName(
+    const String& name) const {
+  if (!name.ContainsOnlyASCII())
+    return String();
+  return parameters_.at(name.DeprecatedLower());
+}
+
+size_t ParsedParameterizedContentHeaderField::ParameterCount() const {
+  return parameters_.size();
+}
+
+bool ParsedParameterizedContentHeaderField::Parse(const String& header_field,
+                                                  Mode mode) {
+  Input input(header_field);
+
+  StringView type;
+  if (!input.ConsumeToken(Mode::kNormal, type)) {
+    DVLOG(1) << "Failed to find `type' in '" << header_field << "'";
+    return false;
+  }
+  SetType(type.ToString());
+
+  return ParseParameters(input, mode);
+}
+
+// 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
+bool ParsedParameterizedContentHeaderField::ParseParameters(Input& input,
+                                                            Mode mode) {
+  KeyValuePairs map;
+  for (;;) {
+    input.SkipSpaces();
+    if (input.IsConsumed())
+      break;
+
+    if (!input.Consume(';')) {
+      DVLOG(1) << "Failed to find ';'";
+      return false;
+    }
+
+    StringView key;
+    String value;
+    if (!input.ConsumeToken(Mode::kNormal, key)) {
+      DVLOG(1) << "Invalid content parameter name. (at " << input.Index()
+               << ")";
+      return false;
+    }
+    if (!input.Consume('=')) {
+      DVLOG(1) << "Failed to find '='";
+      return false;
+    }
+    if (!input.ConsumeTokenOrQuotedString(mode, value)) {
+      DVLOG(1) << "Invalid content parameter value (at " << input.Index()
+               << ", for '" << key.ToString() << "').";
+      return false;
+    }
+    // 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().DeprecatedLower();
+    if (mode == Mode::kStrict && map.find(key_string) != map.end()) {
+      DVLOG(1) << "Parameter " << key_string << " is defined multiple times.";
+      return false;
+    }
+    map.Set(key_string, value);
+  }
+  parameters_ = std::move(map);
+  return true;
+}
+
+}  // namespace blink