rstudio/src/cpp/core/markdown/MathJax.cpp at master · UXScripts/rstudio · GitHub

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* MathJax.cpp

* This program is licensed to you under the terms of version 3 of the

* GNU Affero General Public License. This program is distributed WITHOUT

* ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING THOSE OF NON-INFRINGEMENT,

* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Please refer to the

* AGPL (http://www.gnu.org/licenses/agpl-3.0.txt) for more details.

#include "MathJax.hpp"

#include <algorithm>

#include <boost/bind.hpp>

#include <boost/function.hpp>

#include <boost/foreach.hpp>

#include <boost/algorithm/string.hpp>

#include <core/system/System.hpp>

namespace core {

namespace markdown {

namespace {

struct TextRange

{

TextRange(bool process,

const std::string::const_iterator& begin,

const std::string::const_iterator& end)

: process(process), begin(begin), end(end)

{

}

bool process;

std::string::const_iterator begin;

std::string::const_iterator end;

};

TextRange findClosestRange(std::string::const_iterator pos,

const std::vector<TextRange>& ranges)

{

TextRange closestRange = ranges.front();

BOOST_FOREACH(const TextRange& range, ranges)

{

if (std::abs(range.begin - pos) < std::abs(closestRange.begin - pos))

closestRange = range;

}

return closestRange;

}

bool hasLessThanThreeNewlines(const std::string& str)

{

return std::count(str.begin(), str.end(), '\n') < 3;

}

MathJaxFilter::MathJaxFilter(const std::vector<ExcludePattern>& excludePatterns,

std::string* pInput,

std::string* pHTMLOutput)

: pHTMLOutput_(pHTMLOutput)

{

// divide the document into ranges (some of which will be processed

// and some of which will not -- we don't process some regions so that

// we don't need to worry about mathjax ambiguity within code regions)

std::vector<TextRange> ranges;

std::string::const_iterator pos = pInput->begin();

std::string::const_iterator inputEnd = pInput->end();

while (pos != inputEnd)

{

// try all of the exclude patterns

std::vector<TextRange> matchedRanges;

BOOST_FOREACH(const ExcludePattern& pattern, excludePatterns)

{

boost::smatch m;

if (boost::regex_search(pos, inputEnd, m, pattern.begin))

{

// set begin and end (may change if there is an end pattern)

std::string::const_iterator begin = m[0].first;

std::string::const_iterator end = m[0].second;

// check for a second match

if (!pattern.end.empty())

{

if (boost::regex_search(end, inputEnd, m, pattern.end))

{

// update end to be the end of the match

end = m[0].second;

}

else

{

// didn't find a matching end pattern so set the end to the

// end of the document -- this will cause us to exclude the

// rest of the document from processing

end = inputEnd;

}

// add the matched range to our list

matchedRanges.push_back(TextRange(false, begin, end));

}

// if we found at least one matched range then find the closest one,

// add it to our list, and continue

if (!matchedRanges.empty())

{

// find the closest range

TextRange range = findClosestRange(pos, matchedRanges);

// mark everything before the match as requiring processing

ranges.push_back(TextRange(true, pos, range.begin));

// add the range

ranges.push_back(range);

// update the position

pos = range.end;

}

// no match -- consume remaining input and tag it for processing

else

{

ranges.push_back(TextRange(true, pos, pInput->end()));

pos = pInput->end();

}

// now iterate through the ranges and substitute a guid for math blocks

std::string filteredInput;

BOOST_FOREACH(const TextRange& range, ranges)

{

std::string rangeText(range.begin, range.end);

if (range.process)

{

// native mathjax display equations

filter(boost::regex("\\\\\\[([\\s\\S]+?)\\\\\\]"),

&rangeText,

&displayMathBlocks_);

// latex display equations (latex designator optional, used for

// syntactic compatiblity w/ wordpress-style inline equations)

filter(boost::regex("\\${2}(?:latex\\s)?([\\s\\S]+?)\\${2}"),

&rangeText,

&displayMathBlocks_);

// native mathjax inline equations

filter(boost::regex("\\\\\$([\\s\\S]+?)\\\\\$"),

&rangeText,

&inlineMathBlocks_);

// wordpress style inline equations

filter(boost::regex("\\$latex\\s([\\s\\S]+?)\\$"),

&rangeText,

&inlineMathBlocks_);

// Org-mode style inline equations

filter(boost::regex("\\$((?!\\s)[^$]*[^$\\s])\\$(?![\\w\\d`])"),

&hasLessThanThreeNewlines,

&rangeText,

&inlineMathBlocks_);

}

filteredInput.append(rangeText);

}

*pInput = filteredInput;

}

MathJaxFilter::~MathJaxFilter()

{

try

{

std::for_each(

displayMathBlocks_.begin(),

displayMathBlocks_.end(),

boost::bind(&MathJaxFilter::restore, this, _1, "\\[", "\\]"));

std::for_each(

inlineMathBlocks_.begin(),

inlineMathBlocks_.end(),

boost::bind(&MathJaxFilter::restore, this, _1, "\$", "\$"));

}

catch(...)

{

}

void MathJaxFilter::filter(const boost::regex& re,

const boost::function<bool(const std::string&)>& condition,

std::string* pInput,

std::map<std::string,MathBlock>* pMathBlocks)

{

// explicit function type required because the Formatter functor

// supports 3 distinct signatures

boost::function<std::string(

boost::match_results<std::string::const_iterator>)> formatter =

boost::bind(&MathJaxFilter::substitute,

this, condition, _1, pMathBlocks);

*pInput = boost::regex_replace(*pInput, re, formatter);

}

std::string MathJaxFilter::substitute(

const boost::function<bool(const std::string&)>& condition,

boost::match_results<std::string::const_iterator> match,

std::map<std::string,MathBlock>* pMathBlocks)

{

// get the equation

std::string equation = match[1];

// apply additional condition if available

if (condition && !condition(equation))

{

// don't perform any substitution

return match[0];

}

else

{

std::string guid = core::system::generateUuid(false);

std::string suffix = (match.size() > 2) ? std::string(match[2]) : "";

pMathBlocks->insert(std::make_pair(guid, MathBlock(equation,suffix)));

return guid;

}

void MathJaxFilter::restore(

const std::map<std::string,MathBlock>::value_type& block,

const std::string& beginDelim,

const std::string& endDelim)

{

boost::algorithm::replace_first(

*pHTMLOutput_,

block.first,

beginDelim + " " + block.second.equation + " " + endDelim +

block.second.suffix);

}

bool requiresMathjax(const std::string& htmlOutput)

{

boost::regex inlineMathRegex("\\\\\$([\\s\\S]+?)\\\\\$");

if (boost::regex_search(htmlOutput, inlineMathRegex))

return true;

boost::regex displayMathRegex("\\\\\\[([\\s\\S]+?)\\\\\\]");

if (boost::regex_search(htmlOutput, displayMathRegex))

return true;

boost::regex mathmlRegex("<math[>\\s](?s).*?</math>");

if (boost::regex_search(htmlOutput, mathmlRegex))

return true;

return false;

}

} // namespace markdown

} // namespace core

rstudio/src/cpp/core/markdown/MathJax.cpp at master · UXScripts/rstudio · GitHub

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