createPatch: function()

in pytheas-core/src/main/resources/js/diff.js [193:276]
59 lines of code
15 McCabe index (conditional complexity)

    createPatch: function(fileName, oldStr, newStr, oldHeader, newHeader) {
      var ret = [];

      ret.push("Index: " + fileName);
      ret.push("===================================================================");
      ret.push("--- " + fileName + (typeof oldHeader === "undefined" ? "" : "\t" + oldHeader));
      ret.push("+++ " + fileName + (typeof newHeader === "undefined" ? "" : "\t" + newHeader));

      var diff = LineDiff.diff(oldStr, newStr);
      if (!diff[diff.length-1].value) {
        diff.pop();   // Remove trailing newline add
      }
      diff.push({value: "", lines: []});   // Append an empty value to make cleanup easier

      function contextLines(lines) {
        return lines.map(function(entry) { return ' ' + entry; });
      }
      function eofNL(curRange, i, current) {
        var last = diff[diff.length-2],
            isLast = i === diff.length-2,
            isLastOfType = i === diff.length-3 && (current.added === !last.added || current.removed === !last.removed);

        // Figure out if this is the last line for the given file and missing NL
        if (!/\n$/.test(current.value) && (isLast || isLastOfType)) {
          curRange.push('\\ No newline at end of file');
        }
      }

      var oldRangeStart = 0, newRangeStart = 0, curRange = [],
          oldLine = 1, newLine = 1;
      for (var i = 0; i < diff.length; i++) {
        var current = diff[i],
            lines = current.lines || current.value.replace(/\n$/, "").split("\n");
        current.lines = lines;

        if (current.added || current.removed) {
          if (!oldRangeStart) {
            var prev = diff[i-1];
            oldRangeStart = oldLine;
            newRangeStart = newLine;
            
            if (prev) {
              curRange = contextLines(prev.lines.slice(-4));
              oldRangeStart -= curRange.length;
              newRangeStart -= curRange.length;
            }
          }
          curRange.push.apply(curRange, lines.map(function(entry) { return (current.added?"+":"-") + entry; }));
          eofNL(curRange, i, current);

          if (current.added) {
            newLine += lines.length;
          } else {
            oldLine += lines.length;
          }
        } else {
          if (oldRangeStart) {
            // Close out any changes that have been output (or join overlapping)
            if (lines.length <= 8 && i < diff.length-2) {
              // Overlapping
              curRange.push.apply(curRange, contextLines(lines));
            } else {
              // end the range and output
              var contextSize = Math.min(lines.length, 4);
              ret.push(
                  "@@ -" + oldRangeStart + "," + (oldLine-oldRangeStart+contextSize)
                  + " +" + newRangeStart + "," + (newLine-newRangeStart+contextSize)
                  + " @@");
              ret.push.apply(ret, curRange);
              ret.push.apply(ret, contextLines(lines.slice(0, contextSize)));
              if (lines.length <= 4) {
                eofNL(ret, i, current);
              }

              oldRangeStart = 0;  newRangeStart = 0; curRange = [];
            }
          }
          oldLine += lines.length;
          newLine += lines.length;
        }
      }

      return ret.join('\n') + '\n';
    },