Merge pull request #1833 from digitalbazaar/fix-chrome-longlines-slowdown

Make pads with long lines usable with chrome.

src/static/js/ace2_inner.js

@@ -3855,7 +3855,7 @@ function Ace2Inner(){
       }
       else if (type == "keyup")
       {
-        var wait = 200;
+        var wait = 0;
         idleWorkTimer.atLeast(wait);
         idleWorkTimer.atMost(wait);
       }
@@ -3875,7 +3875,7 @@ function Ace2Inner(){
 
       if ((!specialHandled) && (!thisKeyDoesntTriggerNormalize) && (!inInternationalComposition))
       {
-        if (type != "keyup" || !incorpIfQuick())
+        if (type != "keyup")
         {
           observeChangesAroundSelection();
         }

tests/frontend/specs/responsiveness.js

@@ -0,0 +1,80 @@
+// Test for https://github.com/ether/etherpad-lite/issues/1763
+
+// This test fails in Opera, IE and Safari
+// Opera fails due to a weird way of handling the order of execution, yet actual performance seems fine
+// Safari fails due the delay being too great yet the actual performance seems fine
+// Firefox might panic that the script is taking too long so will fail
+// IE will fail due to running out of memory as it can't fit 2M chars in memory.
+
+// Just FYI Google Docs crashes on large docs whilst trying to Save, it's likely the limitations we are
+// experiencing are more to do with browser limitations than improper implementation.
+// A ueber fix for this would be to have a separate lower cpu priority thread that handles operations that aren't
+// visible to the user.
+
+// Adapted from John McLear's original test case.
+
+describe('Responsiveness of Editor', function() {
+  // create a new pad before each test run
+  beforeEach(function(cb) {
+    helper.newPad(cb);
+    this.timeout(6000);
+  });
+  it('Fast response to keypress in pad with large amount of contents', function(done) {
+    var inner$ = helper.padInner$;
+    var chrome$ = helper.padChrome$;
+    var chars = '0000000000'; // row of placeholder chars
+    var amount = 200000; //number of blocks of chars we will insert
+    var length = (amount * (chars.length) +1); // include a counter for each space
+    var text = ''; // the text we're gonna insert
+    this.timeout(amount * 100);
+
+    // get keys to send
+    var keyMultiplier = 10; // multiplier * 10 == total number of key events
+    var keysToSend = '';
+    for(var i=0; i <= keyMultiplier; i++) {
+      keysToSend += chars;
+    }
+
+    var textElement = inner$('div');
+    textElement.sendkeys('{selectall}'); // select all
+    textElement.sendkeys('{del}'); // clear the pad text
+
+    for(var i=0; i <= amount; i++) {
+      text = text + chars + ' '; // add the chars and space to the text contents
+    }
+    inner$('div').first().text(text); // Put the text contents into the pad
+
+    helper.waitFor(function(){ // Wait for the new contents to be on the pad
+      return inner$('div').text().length > length;
+    }).done(function(){
+
+      expect( inner$('div').text().length ).to.be.greaterThan( length ); // has the text changed?
+      var start = new Date().getTime(); // get the start time
+
+      // send some new text to the screen (ensure all 3 key events are sent)
+      var el = inner$('div').first();
+      for(var i = 0; i < keysToSend.length; ++i) {
+        var x = keysToSend.charCodeAt(i);
+        ['keyup', 'keypress', 'keydown'].forEach(function(type) {
+          var e = $.Event(type);
+          e.keyCode = x;
+          el.trigger(e);
+        });
+      }
+
+      helper.waitFor(function(){ // Wait for the ability to process
+        return true; // Ghetto but works for now
+      }).done(function(){
+        var end = new Date().getTime(); // get the current time
+        var delay = end - start; // get the delay as the current time minus the start time
+
+        console.log('delay:', delay);
+        expect(delay).to.be.below(200);
+        done();
+      }, 1000);
+
+    }, 10000);
+  });
+
+});
+