SideBySide2: Save all drafts when leaving / semi-auto focus on drafts

Keep track of all unsaved drafts and save them when leaving the page.

Using CodeMirror's "redraw" event, autofocus on the editArea of a
Draftbox when scrolled into viewportMargin. This works smoothly for
the common case where a user starts typing a draft, scrolls around to
view the file, and scrolls back to continue typing. Even if the user
forgets to scroll back and accidentally pressed "u" or "a", the draft
will be saved, minimizing potential frustration.

Change-Id: Idde88aaeb01e46f85734b48caad1de7c9b2ffba3

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DraftBox.java

@@ -18,6 +18,7 @@ import com.google.gerrit.client.FormatUtil;
 import com.google.gerrit.client.changes.CommentApi;
 import com.google.gerrit.client.changes.CommentInfo;
 import com.google.gerrit.client.changes.CommentInput;
+import com.google.gerrit.client.rpc.CallbackGroup;
 import com.google.gerrit.client.rpc.GerritCallback;
 import com.google.gerrit.client.ui.CommentLinkProcessor;
 import com.google.gerrit.reviewdb.client.PatchSet;
@@ -175,7 +176,7 @@ class DraftBox extends CommentBox {
     resizePaddingWidget();
   }
 
-  private boolean isEdit() {
+  boolean isEdit() {
     return UIObject.isVisible(p_edit);
   }
 
@@ -205,6 +206,7 @@ class DraftBox extends CommentBox {
     } else {
       expandTimer.cancel();
     }
+    parent.updateUnsaved(this, edit);
     resizePaddingWidget();
   }
 
@@ -257,10 +259,10 @@ class DraftBox extends CommentBox {
   @UiHandler("save")
   void onSave(ClickEvent e) {
     e.stopPropagation();
-    onSave();
+    save(null);
   }
 
-  private void onSave() {
+  void save(CallbackGroup group) {
     String message = editArea.getValue().trim();
     if (message.length() == 0) {
       return;
@@ -280,6 +282,7 @@ class DraftBox extends CommentBox {
         if (autoClosed) {
           setOpen(false);
         }
+        parent.updateUnsaved(DraftBox.this, false);
       }
 
       @Override
@@ -289,9 +292,10 @@ class DraftBox extends CommentBox {
       }
     };
     if (original.id() == null) {
-      CommentApi.createDraft(psId, input, cb);
+      CommentApi.createDraft(psId, input, group == null ? cb : group.add(cb));
     } else {
-      CommentApi.updateDraft(psId, original.id(), input, cb);
+      CommentApi.updateDraft(
+          psId, original.id(), input, group == null ? cb : group.add(cb));
     }
     getCm().focus();
   }
@@ -342,7 +346,7 @@ class DraftBox extends CommentBox {
         case 's':
         case 'S':
           e.preventDefault();
-          onSave();
+          save(null);
           return;
       }
     } else if (e.getNativeKeyCode() == KeyCodes.KEY_ESCAPE && !isDirty()) {

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/SideBySide2.java

@@ -87,8 +87,10 @@ import java.util.Collections;
 import java.util.Comparator;
 import java.util.EnumSet;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 public class SideBySide2 extends Screen {
   interface Binder extends UiBinder<FlowPanel, SideBySide2> {}
@@ -127,6 +129,7 @@ public class SideBySide2 extends Screen {
   private Map<LineHandle, LinePaddingWidgetWrapper> linePaddingOnOtherSideMap;
   private List<DiffChunkInfo> diffChunks;
   private List<SkippedLine> skips;
+  private Set<DraftBox> unsaved;
   private int context;
 
   private KeyCommandSet keysNavigation;
@@ -150,6 +153,7 @@ public class SideBySide2 extends Screen {
     }
     context = pref.getContext();
 
+    unsaved = new HashSet<DraftBox>();
     handlers = new ArrayList<HandlerRegistration>(6);
     // TODO: Re-implement necessary GlobalKey bindings.
     addDomHandler(GlobalKey.STOP_PROPAGATION, KeyPressEvent.getType());
@@ -248,6 +252,7 @@ public class SideBySide2 extends Screen {
   protected void onUnload() {
     super.onUnload();
 
+    saveAllDrafts(null);
     removeKeyHandlerRegs();
     if (resizeHandler != null) {
       resizeHandler.removeHandler();
@@ -602,7 +607,7 @@ public class SideBySide2 extends Screen {
     return box;
   }
 
-  CommentBox addCommentBox(CommentInfo info, CommentBox box) {
+  CommentBox addCommentBox(CommentInfo info, final CommentBox box) {
     box.setParent(this);
     diffTable.add(box);
     DisplaySide side = box.getSide();
@@ -649,6 +654,17 @@ public class SideBySide2 extends Screen {
         box instanceof DraftBox
           ? SidePanel.GutterType.DRAFT
           : SidePanel.GutterType.COMMENT));
+    if (box instanceof DraftBox) {
+      boxWidget.onRedraw(new Runnable() {
+        @Override
+        public void run() {
+          DraftBox draftBox = (DraftBox) box;
+          if (draftBox.isEdit()) {
+            draftBox.editArea.setFocus(true);
+          }
+        }
+      });
+    }
     return box;
   }
 
@@ -659,6 +675,21 @@ public class SideBySide2 extends Screen {
       List<PublishedBox> list = linePublishedBoxesMap.get(handle);
       lineActiveBoxMap.put(handle, list.get(list.size() - 1));
     }
+    unsaved.remove(box);
+  }
+
+  void updateUnsaved(DraftBox box, boolean isUnsaved) {
+    if (isUnsaved) {
+      unsaved.add(box);
+    } else {
+      unsaved.remove(box);
+    }
+  }
+
+  private void saveAllDrafts(CallbackGroup cb) {
+    for (DraftBox box : unsaved) {
+      box.save(cb);
+    }
   }
 
   void addFileCommentBox(CommentBox box) {
@@ -1054,15 +1085,30 @@ public class SideBySide2 extends Screen {
   private Runnable upToChange(final boolean openReplyBox) {
     return new Runnable() {
       public void run() {
-        String b = base != null ? String.valueOf(base.get()) : null;
-        String rev = String.valueOf(revision.get());
-        Gerrit.display(
-          PageLinks.toChange(changeId, rev),
-          new ChangeScreen2(changeId, b, rev, openReplyBox));
+        if (unsaved.isEmpty()) {
+          goUpToChange(openReplyBox);
+        } else {
+          CallbackGroup group = new CallbackGroup();
+          saveAllDrafts(group);
+          group.addFinal(new GerritCallback<Void>() {
+            @Override
+            public void onSuccess(Void result) {
+              goUpToChange(openReplyBox);
+            }
+          }).onSuccess(null);
+        }
       }
     };
   }
 
+  private void goUpToChange(boolean openReplyBox) {
+    String b = base != null ? String.valueOf(base.get()) : null;
+    String rev = String.valueOf(revision.get());
+    Gerrit.display(
+      PageLinks.toChange(changeId, rev),
+      new ChangeScreen2(changeId, b, rev, openReplyBox));
+  }
+
   private Runnable openClosePublished(final CodeMirror cm) {
     return new Runnable() {
       @Override

gerrit-gwtui/src/main/java/net/codemirror/lib/LineWidget.java

@@ -25,6 +25,12 @@ public class LineWidget extends JavaScriptObject {
   public final native void clear() /*-{ this.clear(); }-*/;
   public final native void changed() /*-{ this.changed(); }-*/;
 
+  public final native void onRedraw(Runnable thunk) /*-{
+    this.on("redraw", $entry(function() {
+      thunk.@java.lang.Runnable::run()();
+    }));
+  }-*/;
+
   public final native void onFirstRedraw(Runnable thunk) /*-{
     var w = this;
     var h = $entry(function() {