diff2html/src/line-by-line-printer.js

/*
 *
 * LineByLinePrinter (line-by-line-printer.js)
 * Author: rtfpessoa
 *
 */

(function() {

  var diffParser = require('./diff-parser.js').DiffParser;
  var printerUtils = require('./printer-utils.js').PrinterUtils;
  var utils = require('./utils.js').Utils;
  var Rematch = require('./rematch.js').Rematch;

  var nunjucksUtils = require('./nunjucks-utils.js').NunjucksUtils;
  var baseTemplatesPath = 'line-by-line';

  function LineByLinePrinter(config) {
    this.config = config;
  }

  LineByLinePrinter.prototype.makeFileDiffHtml = function(file, diffs) {
    return nunjucksUtils.render(baseTemplatesPath, 'file-diff.html', {'file': file, 'diffs': diffs});
  };

  LineByLinePrinter.prototype.makeLineByLineHtmlWrapper = function(content) {
    return nunjucksUtils.render(baseTemplatesPath, 'wrapper.html', {'content': content});
  };

  LineByLinePrinter.prototype.generateLineByLineJsonHtml = function(diffFiles) {
    var that = this;
    var htmlDiffs = diffFiles.map(function(file) {
      var diffs;
      if (file.blocks.length) {
        diffs = that._generateFileHtml(file);
      } else {
        diffs = that._generateEmptyDiff();
      }
      return that.makeFileDiffHtml(file, diffs);
    });

    return this.makeLineByLineHtmlWrapper(htmlDiffs.join('\n'));
  };

  var matcher = Rematch.rematch(function(a, b) {
    var amod = a.content.substr(1);
    var bmod = b.content.substr(1);

    return Rematch.distance(amod, bmod);
  });

  LineByLinePrinter.prototype.makeColumnLineNumberHtml = function(block) {
    return nunjucksUtils.render(baseTemplatesPath, 'column-line-number.html', {block: block});
  };

  LineByLinePrinter.prototype._generateFileHtml = function(file) {
    var that = this;
    return file.blocks.map(function(block) {

      var lines = that.makeColumnLineNumberHtml(block);
      var oldLines = [];
      var newLines = [];

      function processChangeBlock() {
        var matches;
        var insertType;
        var deleteType;

        var doMatching = that.config.matching === 'lines' || that.config.matching === 'words';

        if (doMatching) {
          matches = matcher(oldLines, newLines);
          insertType = diffParser.LINE_TYPE.INSERT_CHANGES;
          deleteType = diffParser.LINE_TYPE.DELETE_CHANGES;
        } else {
          matches = [[oldLines, newLines]];
          insertType = diffParser.LINE_TYPE.INSERTS;
          deleteType = diffParser.LINE_TYPE.DELETES;
        }

        matches.forEach(function(match) {
          oldLines = match[0];
          newLines = match[1];

          var processedOldLines = [];
          var processedNewLines = [];

          var common = Math.min(oldLines.length, newLines.length);

          var oldLine, newLine;
          for (var j = 0; j < common; j++) {
            oldLine = oldLines[j];
            newLine = newLines[j];

            that.config.isCombined = file.isCombined;
            var diff = printerUtils.diffHighlight(oldLine.content, newLine.content, that.config);

            processedOldLines +=
              that.makeLineHtml(deleteType, oldLine.oldNumber, oldLine.newNumber,
                diff.first.line, diff.first.prefix);
            processedNewLines +=
              that.makeLineHtml(insertType, newLine.oldNumber, newLine.newNumber,
                diff.second.line, diff.second.prefix);
          }

          lines += processedOldLines + processedNewLines;
          lines += that._processLines(oldLines.slice(common), newLines.slice(common));
        });

        oldLines = [];
        newLines = [];
      }

      for (var i = 0; i < block.lines.length; i++) {
        var line = block.lines[i];
        var escapedLine = utils.escape(line.content);

        if (line.type !== diffParser.LINE_TYPE.INSERTS &&
          (newLines.length > 0 || (line.type !== diffParser.LINE_TYPE.DELETES && oldLines.length > 0))) {
          processChangeBlock();
        }

        if (line.type === diffParser.LINE_TYPE.CONTEXT) {
          lines += that.makeLineHtml(line.type, line.oldNumber, line.newNumber, escapedLine);
        } else if (line.type === diffParser.LINE_TYPE.INSERTS && !oldLines.length) {
          lines += that.makeLineHtml(line.type, line.oldNumber, line.newNumber, escapedLine);
        } else if (line.type === diffParser.LINE_TYPE.DELETES) {
          oldLines.push(line);
        } else if (line.type === diffParser.LINE_TYPE.INSERTS && Boolean(oldLines.length)) {
          newLines.push(line);
        } else {
          console.error('Unknown state in html line-by-line generator');
          processChangeBlock();
        }
      }

      processChangeBlock();

      return lines;
    }).join('\n');
  };

  LineByLinePrinter.prototype._processLines = function(oldLines, newLines) {
    var lines = '';

    for (var i = 0; i < oldLines.length; i++) {
      var oldLine = oldLines[i];
      var oldEscapedLine = utils.escape(oldLine.content);
      lines += this.makeLineHtml(oldLine.type, oldLine.oldNumber, oldLine.newNumber, oldEscapedLine);
    }

    for (var j = 0; j < newLines.length; j++) {
      var newLine = newLines[j];
      var newEscapedLine = utils.escape(newLine.content);
      lines += this.makeLineHtml(newLine.type, newLine.oldNumber, newLine.newNumber, newEscapedLine);
    }

    return lines;
  };

  LineByLinePrinter.prototype.makeLineHtml = function(type, oldNumber, newNumber, content, prefix) {
    return nunjucksUtils.render(baseTemplatesPath, 'line.html',
      {
        type: type,
        oldNumber: oldNumber,
        newNumber: newNumber,
        prefix: prefix,
        content: content
      });
  };

  LineByLinePrinter.prototype._generateEmptyDiff = function() {
    return nunjucksUtils.render(baseTemplatesPath, 'empty-diff.html', {});
  };

  module.exports.LineByLinePrinter = LineByLinePrinter;

})();