Move duplicated JavaScript and CSS for diff to common files

src/main/webapp/assets/common/js/gitbucket.js

@@ -66,4 +66,40 @@ function displayErrors(data){
       window.clearInterval(timer);
     });
   };
-})(jQuery);
+})(jQuery);
+
+function diffUsingJS(oldTextId, newTextId, outputId) {
+  // get the baseText and newText values from the two textboxes, and split them into lines
+  var oldText = document.getElementById(oldTextId).value;
+  if(oldText == ''){
+    var oldLines = [];
+  } else {
+    var oldLines = difflib.stringAsLines(oldText);
+  }
+
+  var newText = document.getElementById(newTextId).value
+  if(newText == ''){
+    var newLines = [];
+  } else {
+    var newLines = difflib.stringAsLines(newText);
+  }
+
+  // create a SequenceMatcher instance that diffs the two sets of lines
+  var sm = new difflib.SequenceMatcher(oldLines, newLines);
+
+  // get the opcodes from the SequenceMatcher instance
+  // opcodes is a list of 3-tuples describing what changes should be made to the base text
+  // in order to yield the new text
+  var opcodes = sm.get_opcodes();
+  var diffoutputdiv = document.getElementById(outputId);
+  while (diffoutputdiv.firstChild) diffoutputdiv.removeChild(diffoutputdiv.firstChild);
+
+  // build the diff view and add it to the current DOM
+  diffoutputdiv.appendChild(diffview.buildView({
+    baseTextLines: oldLines,
+    newTextLines: newLines,
+    opcodes: opcodes,
+    contextSize: 4,
+    viewType: 1
+  }));
+}