parser/html/nsHtml5TokenizerLoopPolicies.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #ifndef nsHtml5TokenizerLoopPolicies_h
   6 #define nsHtml5TokenizerLoopPolicies_h
   7
   8 /**
   9  * This policy does not report tokenizer transitions anywhere and does not
  10  * track line and column numbers. To be used for innerHTML.
  11  */
  12 struct nsHtml5FastestPolicy {
  13   static const bool reportErrors = false;
  14   static int32_t transition(nsHtml5Highlighter* aHighlighter, int32_t aState,
  15                             bool aReconsume, int32_t aPos) {
  16     return aState;
  17   }
  18   static void completedNamedCharacterReference(
  19       nsHtml5Highlighter* aHighlighter) {}
  20
  21   static char16_t checkChar(nsHtml5Tokenizer* aTokenizer, char16_t* buf,
  22                             int32_t pos) {
  23     return buf[pos];
  24   }
  25
  26   static void silentCarriageReturn(nsHtml5Tokenizer* aTokenizer) {
  27     aTokenizer->lastCR = true;
  28   }
  29
  30   static void silentLineFeed(nsHtml5Tokenizer* aTokenizer) {}
  31 };
  32
  33 /**
  34  * This policy does not report tokenizer transitions anywhere. To be used
  35  * when _not_ viewing source and when not parsing innerHTML (or other
  36  * script execution-preventing fragment).
  37  */
  38 struct nsHtml5LineColPolicy {
  39   static const bool reportErrors = false;
  40   static int32_t transition(nsHtml5Highlighter* aHighlighter, int32_t aState,
  41                             bool aReconsume, int32_t aPos) {
  42     return aState;
  43   }
  44   static void completedNamedCharacterReference(
  45       nsHtml5Highlighter* aHighlighter) {}
  46
  47   static char16_t checkChar(nsHtml5Tokenizer* aTokenizer, char16_t* buf,
  48                             int32_t pos) {
  49     // The name of this method comes from the validator.
  50     // We aren't checking a char here. We read the next
  51     // UTF-16 code unit and, before returning it, adjust
  52     // the line and column numbers.
  53     char16_t c = buf[pos];
  54     if (MOZ_UNLIKELY(aTokenizer->nextCharOnNewLine)) {
  55       // By changing the line and column here instead
  56       // of doing so eagerly when seeing the line break
  57       // causes the line break itself to be considered
  58       // column-wise at the end of a line.
  59       aTokenizer->line++;
  60       aTokenizer->col = 1;
  61       aTokenizer->nextCharOnNewLine = false;
  62     } else if (MOZ_LIKELY(!NS_IS_LOW_SURROGATE(c))) {
  63       // SpiderMonkey wants to count scalar values
  64       // instead of UTF-16 code units. We omit low
  65       // surrogates from the count so that only the
  66       // high surrogate increments the count for
  67       // two-code-unit scalar values.
  68       //
  69       // It's somewhat questionable from the performance
  70       // perspective to make the human-perceivable column
  71       // count correct for non-BMP characters in the case
  72       // where there is a single scalar value per extended
  73       // grapheme cluster when even on the BMP there are
  74       // various cases where the scalar count doesn't make
  75       // much sense as a human-perceived "column count" due
  76       // to extended grapheme clusters consisting of more
  77       // than one scalar value.
  78       aTokenizer->col++;
  79     }
  80     return c;
  81   }
  82
  83   static void silentCarriageReturn(nsHtml5Tokenizer* aTokenizer) {
  84     aTokenizer->nextCharOnNewLine = true;
  85     aTokenizer->lastCR = true;
  86   }
  87
  88   static void silentLineFeed(nsHtml5Tokenizer* aTokenizer) {
  89     aTokenizer->nextCharOnNewLine = true;
  90   }
  91 };
  92
  93 /**
  94  * This policy reports the tokenizer transitions to a highlighter. To be used
  95  * when viewing source.
  96  */
  97 struct nsHtml5ViewSourcePolicy {
  98   static const bool reportErrors = true;
  99   static int32_t transition(nsHtml5Highlighter* aHighlighter, int32_t aState,
 100                             bool aReconsume, int32_t aPos) {
 101     return aHighlighter->Transition(aState, aReconsume, aPos);
 102   }
 103   static void completedNamedCharacterReference(
 104       nsHtml5Highlighter* aHighlighter) {
 105     aHighlighter->CompletedNamedCharacterReference();
 106   }
 107
 108   static char16_t checkChar(nsHtml5Tokenizer* aTokenizer, char16_t* buf,
 109                             int32_t pos) {
 110     return buf[pos];
 111   }
 112
 113   static void silentCarriageReturn(nsHtml5Tokenizer* aTokenizer) {
 114     aTokenizer->line++;
 115     aTokenizer->lastCR = true;
 116   }
 117
 118   static void silentLineFeed(nsHtml5Tokenizer* aTokenizer) {
 119     aTokenizer->line++;
 120   }
 121 };
 122
 123 #endif  // nsHtml5TokenizerLoopPolicies_h