Implement a parser for Content-Disposition header fields

third_party/WebKit/Source/platform/network/HeaderFieldTokenizer.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/HeaderFieldTokenizer.h"
+
+#include "platform/wtf/text/StringBuilder.h"
+#include "platform/wtf/text/StringView.h"
+
+namespace blink {
+
+namespace {
+
+using Mode = HeaderFieldTokenizer::Mode;
+
+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
+
+HeaderFieldTokenizer::HeaderFieldTokenizer(const String& header_field)
+    : index_(0u), input_(header_field) {}
+
+HeaderFieldTokenizer::HeaderFieldTokenizer(HeaderFieldTokenizer&&) = default;
+
+bool HeaderFieldTokenizer::Consume(char c) {
+  DCHECK_NE(c, ' ');
+
+  SkipSpaces();
+  if (IsConsumed() || input_[index_] != c)
+    return false;
+
+  ++index_;
+  return true;
+}
+
+bool HeaderFieldTokenizer::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 HeaderFieldTokenizer::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 HeaderFieldTokenizer::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 HeaderFieldTokenizer::SkipSpaces() {
+  while (!IsConsumed() && input_[index_] == ' ')
+    ++index_;
+}
+
+}  // namespace blink