parser/htmlparser/nsHTMLTags.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "nsHTMLTags.h"
   7 #include "nsCRT.h"
   8 #include "nsReadableUtils.h"
   9 #include "nsString.h"
  10 #include "nsUnicharUtils.h"
  11 #include "mozilla/HashFunctions.h"
  12 #include <algorithm>
  13
  14 using namespace mozilla;
  15
  16 // static array of unicode tag names
  17 #define HTML_TAG(_tag, _classname, _interfacename) (u"" #_tag),
  18 #define HTML_OTHER(_tag)
  19 const char16_t* const nsHTMLTags::sTagNames[] = {
  20 #include "nsHTMLTagList.h"
  21 };
  22 #undef HTML_TAG
  23 #undef HTML_OTHER
  24
  25 int32_t nsHTMLTags::gTableRefCount;
  26 nsHTMLTags::TagStringHash* nsHTMLTags::gTagTable;
  27 nsHTMLTags::TagAtomHash* nsHTMLTags::gTagAtomTable;
  28
  29 #define NS_HTMLTAG_NAME_MAX_LENGTH 10
  30
  31 // static
  32 nsresult nsHTMLTags::AddRefTable(void) {
  33   if (gTableRefCount++ == 0) {
  34     NS_ASSERTION(!gTagTable && !gTagAtomTable, "pre existing hash!");
  35
  36     gTagTable = new TagStringHash(64);
  37     gTagAtomTable = new TagAtomHash(64);
  38
  39     // Fill in gTagTable with the above static char16_t strings as
  40     // keys and the value of the corresponding enum as the value in
  41     // the table.
  42
  43     for (int32_t i = 0; i < NS_HTML_TAG_MAX; ++i) {
  44       const char16_t* tagName = sTagNames[i];
  45       const nsHTMLTag tagValue = static_cast<nsHTMLTag>(i + 1);
  46
  47       // We use AssignLiteral here to avoid a string copy. This is okay
  48       // because this is truly static data.
  49       nsString tmp;
  50       tmp.AssignLiteral(tagName, nsString::char_traits::length(tagName));
  51       gTagTable->InsertOrUpdate(tmp, tagValue);
  52
  53       // All the HTML tag names are static atoms within nsGkAtoms, and they are
  54       // registered before this code is reached.
  55       nsStaticAtom* atom = NS_GetStaticAtom(tmp);
  56       MOZ_ASSERT(atom);
  57       gTagAtomTable->InsertOrUpdate(atom, tagValue);
  58     }
  59
  60 #ifdef DEBUG
  61     // Check all tagNames are lowercase, and that NS_HTMLTAG_NAME_MAX_LENGTH is
  62     // correct.
  63     uint32_t maxTagNameLength = 0;
  64     for (int i = 0; i < NS_HTML_TAG_MAX; ++i) {
  65       const char16_t* tagName = sTagNames[i];
  66
  67       nsAutoString lowerTagName(tagName);
  68       ToLowerCase(lowerTagName);
  69       MOZ_ASSERT(lowerTagName.Equals(tagName));
  70
  71       maxTagNameLength = std::max(NS_strlen(tagName), maxTagNameLength);
  72     }
  73
  74     MOZ_ASSERT(maxTagNameLength == NS_HTMLTAG_NAME_MAX_LENGTH);
  75 #endif
  76   }
  77
  78   return NS_OK;
  79 }
  80
  81 // static
  82 void nsHTMLTags::ReleaseTable(void) {
  83   if (0 == --gTableRefCount) {
  84     delete gTagTable;
  85     delete gTagAtomTable;
  86     gTagTable = nullptr;
  87     gTagAtomTable = nullptr;
  88   }
  89 }
  90
  91 // static
  92 nsHTMLTag nsHTMLTags::StringTagToId(const nsAString& aTagName) {
  93   uint32_t length = aTagName.Length();
  94
  95   if (length > NS_HTMLTAG_NAME_MAX_LENGTH) {
  96     return eHTMLTag_userdefined;
  97   }
  98
  99   // Setup a stack allocated string buffer with the appropriate length.
 100   nsAutoString lowerCase;
 101   lowerCase.SetLength(length);
 102
 103   // Operate on the raw buffers to avoid bounds checks.
 104   auto src = aTagName.BeginReading();
 105   auto dst = lowerCase.BeginWriting();
 106
 107   // Fast lowercasing-while-copying of ASCII characters into a
 108   // nsString buffer.
 109
 110   for (uint32_t i = 0; i < length; i++) {
 111     char16_t c = src[i];
 112
 113     if (c <= 'Z' && c >= 'A') {
 114       c |= 0x20;  // Lowercase the ASCII character.
 115     }
 116
 117     dst[i] = c;  // Copy ASCII character.
 118   }
 119
 120   return CaseSensitiveStringTagToId(lowerCase);
 121 }
 122
 123 #ifdef DEBUG
 124 void nsHTMLTags::TestTagTable() {
 125   const char16_t* tag;
 126   nsHTMLTag id;
 127   RefPtr<nsAtom> atom;
 128
 129   nsHTMLTags::AddRefTable();
 130   // Make sure we can find everything we are supposed to
 131   for (int i = 0; i < NS_HTML_TAG_MAX; ++i) {
 132     tag = sTagNames[i];
 133     const nsAString& tagString = nsDependentString(tag);
 134     id = StringTagToId(tagString);
 135     NS_ASSERTION(id != eHTMLTag_userdefined, "can't find tag id");
 136
 137     nsAutoString uname(tagString);
 138     ToUpperCase(uname);
 139     NS_ASSERTION(id == StringTagToId(uname), "wrong id");
 140
 141     NS_ASSERTION(id == CaseSensitiveStringTagToId(tagString), "wrong id");
 142
 143     atom = NS_Atomize(tag);
 144     NS_ASSERTION(id == CaseSensitiveAtomTagToId(atom), "wrong id");
 145   }
 146
 147   // Make sure we don't find things that aren't there
 148   id = StringTagToId(u"@"_ns);
 149   NS_ASSERTION(id == eHTMLTag_userdefined, "found @");
 150   id = StringTagToId(u"zzzzz"_ns);
 151   NS_ASSERTION(id == eHTMLTag_userdefined, "found zzzzz");
 152
 153   atom = NS_Atomize("@");
 154   id = CaseSensitiveAtomTagToId(atom);
 155   NS_ASSERTION(id == eHTMLTag_userdefined, "found @");
 156   atom = NS_Atomize("zzzzz");
 157   id = CaseSensitiveAtomTagToId(atom);
 158   NS_ASSERTION(id == eHTMLTag_userdefined, "found zzzzz");
 159
 160   ReleaseTable();
 161 }
 162
 163 #endif  // DEBUG