ExportLatex.js

/**
 * Copyright 2009 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS-IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


var async = require("ep_etherpad-lite/node_modules/async");
var Changeset = require("ep_etherpad-lite/static/js/Changeset");
var padManager = require("ep_etherpad-lite/node/db/PadManager");
var ERR = require("ep_etherpad-lite/node_modules/async-stacktrace");
var Security = require('ep_etherpad-lite/static/js/security');

function getPadLatex(pad, revNum, callback)
{
  var atext = pad.atext;
  var latex;
  async.waterfall([

  // fetch revision atext
  function (callback)
  {
    if (revNum != undefined)
    {
      pad.getInternalRevisionAText(revNum, function (err, revisionAtext)
      {
        if(ERR(err, callback)) return;
        atext = revisionAtext;
        callback();
      });
    }
    else
    {
      callback(null);
    }
  },

  // convert atext to latex
  function (callback)
  {
    latex = getLatexFromAtext(pad, atext);
    callback(null);
  }],

  // run final callback
  function (err)
  {
    if(ERR(err, callback)) return;
    callback(null, latex);
  });
}

exports.getPadLatex = getPadLatex;

function getLatexFromAtext(pad, atext)
{
  var apool = pad.apool();
  var textLines = atext.text.slice(0, -1).split('\n');
  var attribLines = Changeset.splitAttributionLines(atext.attribs, atext.text);

  var tags = ['textbf', 'textit', 'underline', 'sout'];
  var props = ['bold', 'italic', 'underline', 'strikethrough'];
  var anumMap = {};

  props.forEach(function (propName, i)
  {
    var propTrueNum = apool.putAttrib([propName, true], true);
    if (propTrueNum >= 0)
    {
      anumMap[propTrueNum] = i;
    }
  });

  var headingtags = ['section', 'subsection', 'subsubsection', 'paragraph', 'subparagraph', 'subparagraph'];
  var headingprops = [['heading', 'h1'], ['heading', 'h2'], ['heading', 'h3'], ['heading', 'h4'], ['heading', 'h5'], ['heading', 'h6']];
  var headinganumMap = {};

  headingprops.forEach(function (prop, i)
  {
    var name;
    var value;
    if (typeof prop === 'object') {
      name = prop[0];
      value = prop[1];
    } else {
      name = prop;
      value = true;
    }
    var propTrueNum = apool.putAttrib([name, value], true);
    if (propTrueNum >= 0)
    {
      headinganumMap[propTrueNum] = i;
    }
  });

  function getLineLatex(text, attribs)
  {
    var propVals = [false, false, false];
    var ENTER = 1;
    var STAY = 2;
    var LEAVE = 0;

    // Use order of tags (b/i/u) as order of nesting, for simplicity
    // and decent nesting.  For example,
    // <b>Just bold<b> <b><i>Bold and italics</i></b> <i>Just italics</i>
    // becomes
    // <b>Just bold <i>Bold and italics</i></b> <i>Just italics</i>
    var taker = Changeset.stringIterator(text);
    var assem = Changeset.stringAssembler();

    var openTags = [];
    function emitOpenTag(i)
    {
      openTags.unshift(i);
      assem.append('\\');
      assem.append(tags[i]);
      assem.append('{');
    }

    function emitCloseTag(i)
    {
      openTags.shift();
      assem.append('}');
    }
    
    function orderdCloseTags(tags2close)
    {
      for(var i=0;i<openTags.length;i++)
      {
        for(var j=0;j<tags2close.length;j++)
        {
          if(tags2close[j] == openTags[i])
          {
            emitCloseTag(tags2close[j]);
            i--;
            break;
          }
        }
      }
    }

    // start heading check
    var heading = false;
    var deletedAsterisk = false; // we need to delete * from the beginning of the heading line
    var iter2 = Changeset.opIterator(Changeset.subattribution(attribs, 0, 1));
    if (iter2.hasNext()) {
      var o2 = iter2.next();
      
      // iterate through attributes
      Changeset.eachAttribNumber(o2.attribs, function (a) {
        
        if (a in headinganumMap)
        {
          var i = headinganumMap[a]; // i = 0 => bold, etc.
          heading = headingtags[i];
        }
      });
    }

    if (heading) {
      assem.append('\\'+heading+'{');
    }

    var urls = _findURLs(text);

    var idx = 0;

    function processNextChars(numChars)
    {
      if (numChars <= 0)
      {
        return;
      }

      var iter = Changeset.opIterator(Changeset.subattribution(attribs, idx, idx + numChars));
      idx += numChars;

      while (iter.hasNext())
      {
        var o = iter.next();
        var propChanged = false;
        Changeset.eachAttribNumber(o.attribs, function (a)
        {
          if (a in anumMap)
          {
            var i = anumMap[a]; // i = 0 => bold, etc.
            if (!propVals[i])
            {
              propVals[i] = ENTER;
              propChanged = true;
            }
            else
            {
              propVals[i] = STAY;
            }
          }
        });
        for (var i = 0; i < propVals.length; i++)
        {
          if (propVals[i] === true)
          {
            propVals[i] = LEAVE;
            propChanged = true;
          }
          else if (propVals[i] === STAY)
          {
            propVals[i] = true; // set it back
          }
        }

        // now each member of propVal is in {false,LEAVE,ENTER,true}
        // according to what happens at start of span
        if (propChanged)
        {
          // leaving bold (e.g.) also leaves italics, etc.
          var left = false;
          for (var i = 0; i < propVals.length; i++)
          {
            var v = propVals[i];
            if (!left)
            {
              if (v === LEAVE)
              {
                left = true;
              }
            }
            else
            {
              if (v === true)
              {
                propVals[i] = STAY; // tag will be closed and re-opened
              }
            }
          }

          var tags2close = [];

          for (var i = propVals.length - 1; i >= 0; i--)
          {
            if (propVals[i] === LEAVE)
            {
              //emitCloseTag(i);
              tags2close.push(i);
              propVals[i] = false;
            }
            else if (propVals[i] === STAY)
            {
              //emitCloseTag(i);
              tags2close.push(i);
            }
          }
          
          orderdCloseTags(tags2close);
          
          for (var i = 0; i < propVals.length; i++)
          {
            if (propVals[i] === ENTER || propVals[i] === STAY)
            {
              emitOpenTag(i);
              propVals[i] = true;
            }
          }
          // propVals is now all {true,false} again
        } // end if (propChanged)
        var chars = o.chars;
        if (o.lines)
        {
          chars--; // exclude newline at end of line, if present
        }
        
        var s = taker.take(chars);
        
        //removes the characters with the code 12. Don't know where they come 
        //from but they break the abiword parser and are completly useless
        s = s.replace(String.fromCharCode(12), "");

        // delete * if this line is a heading
        if (heading && !deletedAsterisk) {
          s = s.substring(1);
          deletedAsterisk = true;
        }
        
        assem.append(s);
      } // end iteration over spans in line
      
      var tags2close = [];
      for (var i = propVals.length - 1; i >= 0; i--)
      {
        if (propVals[i])
        {
          tags2close.push(i);
          propVals[i] = false;
        }
      }
      
      orderdCloseTags(tags2close);
    } // end processNextChars

    if (urls)
    {
      urls.forEach(function (urlData)
      {
        var startIndex = urlData[0];
        var url = urlData[1];
        var urlLength = url.length;
        processNextChars(startIndex - idx);
        assem.append('\\url{');
        processNextChars(urlLength);
        assem.append('}');
      });
    }

    processNextChars(text.length - idx);

    if (heading) {
      assem.append('}');
    }

    // replace &, _
    assem = assem.toString();
    assem = assem.replace(/\&/g, '\\&');
    assem = assem.replace(/\_/g, '\\_'); // this breaks latex math mode: $\sum_i^j$ becomes $\sum\_i^j$

    return assem;
  } // end getLineLatex
  var pieces = [];

  // Need to deal with constraints imposed on HTML lists; can
  // only gain one level of nesting at once, can't change type
  // mid-list, etc.
  // People might use weird indenting, e.g. skip a level,
  // so we want to do something reasonable there.  We also
  // want to deal gracefully with blank lines.
  // => keeps track of the parents level of indentation
  var lists = []; // e.g. [[1,'bullet'], [3,'bullet'], ...]
  for (var i = 0; i < textLines.length; i++)
  {
    var line = _analyzeLine(textLines[i], attribLines[i], apool);
    var lineContent = getLineLatex(line.text, line.aline);
            
    if (line.listLevel)//If we are inside a list
    {
      // do list stuff
      var whichList = -1; // index into lists or -1
      if (line.listLevel)
      {
        whichList = lists.length;
        for (var j = lists.length - 1; j >= 0; j--)
        {
          if (line.listLevel <= lists[j][0])
          {
            whichList = j;
          }
        }
      }

      if (whichList >= lists.length)//means we are on a deeper level of indentation than the previous line
      {
        lists.push([line.listLevel, line.listTypeName]);
        if(line.listTypeName == "number")
        {
          pieces.push("\n"+(new Array((line.listLevel-1)*4)).join(' ')+"\\begin{enumerate} \n"+(new Array(line.listLevel*4)).join(' ')+"\\item ", lineContent || "\n");
        }
        else
        {
          pieces.push("\n"+(new Array((line.listLevel-1)*4)).join(' ')+"\\begin{itemize} \n"+(new Array(line.listLevel*4)).join(' ')+"\\item ", lineContent || "\n");
        }
      }
      //the following code *seems* dead after my patch.
      //I keep it just in case I'm wrong...
      /*else if (whichList == -1)//means we are not inside a list
      {
        if (line.text)
        {
          console.log('trace 1');
          // non-blank line, end all lists
          if(line.listTypeName == "number")
          {
            pieces.push(new Array(lists.length + 1).join('</li></ol>'));
          }
          else
          {
            pieces.push(new Array(lists.length + 1).join('</li></ul>'));
          }
          lists.length = 0;
          pieces.push(lineContent, '<br>');
        }
        else
        {
          console.log('trace 2');
          pieces.push('<br><br>');
        }
      }*/
      else//means we are getting closer to the lowest level of indentation
      {
        while (whichList < lists.length - 1)
        {
          if(lists[lists.length - 1][1] == "number")
          {
            pieces.push("\n"+(new Array((line.listLevel-1)*4)).join(' ')+"\\end{enumerate}");
          }
          else
          {
            pieces.push("\n"+(new Array((line.listLevel-1)*4)).join(' ')+"\\end{itemize}");
          }
          lists.length--;
        }
        pieces.push("\n"+(new Array(line.listLevel*4)).join(' ')+"\\item ", lineContent || "\n");
      }
    }
    else//outside any list
    {
      while (lists.length > 0)//if was in a list: close it before
      {
        if(lists[lists.length - 1][1] == "number")
        {
          pieces.push("\n"+(new Array((lists.length-1)*4)).join(' ')+"\\end{enumerate}\n");
        }
        else
        {
          pieces.push("\n"+(new Array((lists.length-1)*4)).join(' ')+"\\end{itemize}\n");
        }
        lists.length--;
      }      
      pieces.push(lineContent, "\n");
    }
  }
  
  for (var k = lists.length - 1; k >= 0; k--)
  {
    if(lists[k][1] == "number")
    {
      pieces.push("\n\\end{enumeratex}\n");
    }
    else
    {
      pieces.push("\n\\end{itemizex}\n");
    }
  }

  return pieces.join("");
}

function _analyzeLine(text, aline, apool)
{
  var line = {};

  // identify list
  var lineMarker = 0;
  line.listLevel = 0;
  if (aline)
  {
    var opIter = Changeset.opIterator(aline);
    if (opIter.hasNext())
    {
      var listType = Changeset.opAttributeValue(opIter.next(), 'list', apool);
      if (listType)
      {
        lineMarker = 1;
        listType = /([a-z]+)([12345678])/.exec(listType);
        if (listType)
        {
          line.listTypeName = listType[1];
          line.listLevel = Number(listType[2]);
        }
      }
    }
  }
  if (lineMarker)
  {
    line.text = text.substring(1);
    line.aline = Changeset.subattribution(aline, 1);
  }
  else
  {
    line.text = text;
    line.aline = aline;
  }

  return line;
}

exports.getPadLatexDocument = function (padId, revNum, callback)
{
  padManager.getPad(padId, function (err, pad)
  {
    if(ERR(err, callback)) return;

    getPadLatex(pad, revNum, function (err, latex)
    {
      if(ERR(err, callback)) return;
      callback(null, latex);
    });
  });
}

// copied from ACE
var _REGEX_WORDCHAR = /[\u0030-\u0039\u0041-\u005A\u0061-\u007A\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u00FF\u0100-\u1FFF\u3040-\u9FFF\uF900-\uFDFF\uFE70-\uFEFE\uFF10-\uFF19\uFF21-\uFF3A\uFF41-\uFF5A\uFF66-\uFFDC]/;
var _REGEX_SPACE = /\s/;
var _REGEX_URLCHAR = new RegExp('(' + /[-:@a-zA-Z0-9_.,~%+\/\\?=&#;()$]/.source + '|' + _REGEX_WORDCHAR.source + ')');
var _REGEX_URL = new RegExp(/(?:(?:https?|s?ftp|ftps|file|smb|afp|nfs|(x-)?man|gopher|txmt):\/\/|mailto:)/.source + _REGEX_URLCHAR.source + '*(?![:.,;])' + _REGEX_URLCHAR.source, 'g');

// returns null if no URLs, or [[startIndex1, url1], [startIndex2, url2], ...]
function _findURLs(text)
{
  _REGEX_URL.lastIndex = 0;
  var urls = null;
  var execResult;
  while ((execResult = _REGEX_URL.exec(text)))
  {
    urls = (urls || []);
    var startIndex = execResult.index;
    var url = execResult[0];
    urls.push([startIndex, url]);
  }

  return urls;
}