HTMLMetaCharsetParser.cpp [plain text]
#include "config.h"
#include "HTMLMetaCharsetParser.h"
#include "HTMLNames.h"
#include "HTMLParserIdioms.h"
#include "HTMLParserOptions.h"
#include "HTMLTokenizer.h"
#include "TextCodec.h"
#include "TextEncodingRegistry.h"
#include <wtf/text/WTFString.h>
using namespace WTF;
namespace WebCore {
using namespace HTMLNames;
HTMLMetaCharsetParser::HTMLMetaCharsetParser()
: m_tokenizer(HTMLTokenizer::create(HTMLParserOptions(0)))
, m_assumedCodec(newTextCodec(Latin1Encoding()))
, m_inHeadSection(true)
, m_doneChecking(false)
{
}
HTMLMetaCharsetParser::~HTMLMetaCharsetParser()
{
}
static const char charsetString[] = "charset";
static const size_t charsetLength = sizeof("charset") - 1;
String HTMLMetaCharsetParser::extractCharset(const String& value)
{
size_t pos = 0;
unsigned length = value.length();
while (pos < length) {
pos = value.find(charsetString, pos, false);
if (pos == notFound)
break;
pos += charsetLength;
while (pos < length && value[pos] <= ' ')
++pos;
if (value[pos] != '=')
continue;
++pos;
while (pos < length && value[pos] <= ' ')
++pos;
char quoteMark = 0;
if (pos < length && (value[pos] == '"' || value[pos] == '\'')) {
quoteMark = static_cast<char>(value[pos++]);
ASSERT(!(quoteMark & 0x80));
}
if (pos == length)
break;
unsigned end = pos;
while (end < length && ((quoteMark && value[end] != quoteMark) || (!quoteMark && value[end] > ' ' && value[end] != '"' && value[end] != '\'' && value[end] != ';')))
++end;
if (quoteMark && (end == length))
break;
return value.substring(pos, end - pos);
}
return "";
}
bool HTMLMetaCharsetParser::processMeta()
{
const HTMLToken::AttributeList& tokenAttributes = m_token.attributes();
AttributeList attributes;
for (HTMLToken::AttributeList::const_iterator iter = tokenAttributes.begin(); iter != tokenAttributes.end(); ++iter) {
String attributeName = StringImpl::create8BitIfPossible(iter->name);
String attributeValue = StringImpl::create8BitIfPossible(iter->value);
attributes.append(std::make_pair(attributeName, attributeValue));
}
m_encoding = encodingFromMetaAttributes(attributes);
return m_encoding.isValid();
}
TextEncoding HTMLMetaCharsetParser::encodingFromMetaAttributes(const AttributeList& attributes)
{
bool gotPragma = false;
Mode mode = None;
String charset;
for (AttributeList::const_iterator iter = attributes.begin(); iter != attributes.end(); ++iter) {
const AtomicString& attributeName = iter->first;
const String& attributeValue = iter->second;
if (attributeName == http_equivAttr) {
if (equalIgnoringCase(attributeValue, "content-type"))
gotPragma = true;
} else if (charset.isEmpty()) {
if (attributeName == charsetAttr) {
charset = attributeValue;
mode = Charset;
} else if (attributeName == contentAttr) {
charset = extractCharset(attributeValue);
if (charset.length())
mode = Pragma;
}
}
}
if (mode == Charset || (mode == Pragma && gotPragma))
return TextEncoding(stripLeadingAndTrailingHTMLSpaces(charset));
return TextEncoding();
}
static const int bytesToCheckUnconditionally = 1024;
bool HTMLMetaCharsetParser::checkForMetaCharset(const char* data, size_t length)
{
if (m_doneChecking)
return true;
ASSERT(!m_encoding.isValid());
m_input.append(SegmentedString(m_assumedCodec->decode(data, length)));
while (m_tokenizer->nextToken(m_input, m_token)) {
bool end = m_token.type() == HTMLToken::EndTag;
if (end || m_token.type() == HTMLToken::StartTag) {
AtomicString tagName(m_token.name());
if (!end) {
m_tokenizer->updateStateFor(tagName);
if (tagName == metaTag && processMeta()) {
m_doneChecking = true;
return true;
}
}
if (tagName != scriptTag && tagName != noscriptTag
&& tagName != styleTag && tagName != linkTag
&& tagName != metaTag && tagName != objectTag
&& tagName != titleTag && tagName != baseTag
&& (end || tagName != htmlTag) && (end || tagName != headTag)) {
m_inHeadSection = false;
}
}
if (!m_inHeadSection && m_input.numberOfCharactersConsumed() >= bytesToCheckUnconditionally) {
m_doneChecking = true;
return true;
}
m_token.clear();
}
return false;
}
}