dom/security/PolicyTokenizer.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef PolicyTokenizer_h___
   8 #define PolicyTokenizer_h___
   9
  10 #include "nsContentUtils.h"
  11 #include "nsString.h"
  12
  13 /**
  14  * How does the parsing work?
  15  *
  16  * We generate tokens by splitting the policy-string by whitespace and
  17  * semicolon. Interally the tokens are represented as an array of string-arrays:
  18  *
  19  *  [
  20  *    [ name, src, src, src, ... ],
  21  *    [ name, src, src, src, ... ],
  22  *    [ name, src, src, src, ... ]
  23  *  ]
  24  *
  25  * for example:
  26  *  [
  27  *    [ img-src, http://www.example.com, http:www.test.com ],
  28  *    [ default-src, 'self'],
  29  *    [ script-src, 'unsafe-eval', 'unsafe-inline' ],
  30  *  ]
  31  */
  32
  33 using policyTokens = nsTArray<CopyableTArray<nsString>>;
  34
  35 class PolicyTokenizer {
  36  public:
  37   static void tokenizePolicy(const nsAString& aPolicyString,
  38                              policyTokens& outTokens);
  39
  40  private:
  41   PolicyTokenizer(const char16_t* aStart, const char16_t* aEnd);
  42   ~PolicyTokenizer();
  43
  44   inline bool atEnd() { return mCurChar >= mEndChar; }
  45
  46   inline void skipWhiteSpace() {
  47     while (mCurChar < mEndChar && nsContentUtils::IsHTMLWhitespace(*mCurChar)) {
  48       mCurChar++;
  49     }
  50     mCurToken.Truncate();
  51   }
  52
  53   inline void skipWhiteSpaceAndSemicolon() {
  54     while (mCurChar < mEndChar &&
  55            (*mCurChar == ';' || nsContentUtils::IsHTMLWhitespace(*mCurChar))) {
  56       mCurChar++;
  57     }
  58     mCurToken.Truncate();
  59   }
  60
  61   inline bool accept(char16_t aChar) {
  62     NS_ASSERTION(mCurChar < mEndChar, "Trying to dereference mEndChar");
  63     if (*mCurChar == aChar) {
  64       mCurToken.Append(*mCurChar++);
  65       return true;
  66     }
  67     return false;
  68   }
  69
  70   void generateNextToken();
  71   void generateTokens(policyTokens& outTokens);
  72
  73   const char16_t* mCurChar;
  74   const char16_t* mEndChar;
  75   nsString mCurToken;
  76 };
  77
  78 #endif /* PolicyTokenizer_h___ */