SideBySide2: Display icon during selection to insert comment

Since double click doesn't work on CodeMirror but range selection
does, display a small comment box icon above and to the right of the
end of the selection region.  Clicking this icon will create a new
draft comment on the region.

Change-Id: Id0533b698952d707b720b37fb405e78f1e54e7a8

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

@@ -37,6 +37,7 @@ class DiffTable extends Composite {
   private static final Binder uiBinder = GWT.create(Binder.class);
 
   interface DiffTableStyle extends CssResource {
+    String insertCommentIcon();
     String fullscreen();
     String intralineBg();
     String diff();

gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffTable.ui.xml

@@ -23,6 +23,11 @@ limitations under the License.
     @external .cm-keymap-fat-cursor, CodeMirror-cursor;
     @external .cm-searching, .cm-trailingspace, .cm-tab;
 
+    .insertCommentIcon {
+      cursor: pointer;
+      position: absolute;
+      z-index: 150;
+    }
     .fullscreen {
       background-color: #f7f7f7;
       border-bottom: 1px solid #ddd;

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

@@ -54,7 +54,10 @@ import com.google.gwt.core.client.Scheduler.RepeatingCommand;
 import com.google.gwt.core.client.Scheduler.ScheduledCommand;
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.NativeEvent;
+import com.google.gwt.dom.client.Style;
 import com.google.gwt.dom.client.Style.Unit;
+import com.google.gwt.event.dom.client.ClickEvent;
+import com.google.gwt.event.dom.client.ClickHandler;
 import com.google.gwt.event.dom.client.KeyCodes;
 import com.google.gwt.event.dom.client.KeyPressEvent;
 import com.google.gwt.event.logical.shared.ResizeEvent;
@@ -65,6 +68,7 @@ import com.google.gwt.uibinder.client.UiField;
 import com.google.gwt.user.client.Window;
 import com.google.gwt.user.client.rpc.AsyncCallback;
 import com.google.gwt.user.client.ui.FlowPanel;
+import com.google.gwt.user.client.ui.Image;
 import com.google.gwt.user.client.ui.SimplePanel;
 import com.google.gwt.user.client.ui.Widget;
 import com.google.gwtexpui.globalkey.client.GlobalKey;
@@ -73,6 +77,7 @@ import com.google.gwtexpui.globalkey.client.KeyCommandSet;
 import com.google.gwtexpui.globalkey.client.ShowHelpCommand;
 
 import net.codemirror.lib.CodeMirror;
+import net.codemirror.lib.CodeMirror.BeforeSelectionChangeHandler;
 import net.codemirror.lib.CodeMirror.GutterClickHandler;
 import net.codemirror.lib.CodeMirror.LineClassWhere;
 import net.codemirror.lib.CodeMirror.LineHandle;
@@ -83,6 +88,7 @@ import net.codemirror.lib.KeyMap;
 import net.codemirror.lib.LineCharacter;
 import net.codemirror.lib.LineWidget;
 import net.codemirror.lib.ModeInjector;
+import net.codemirror.lib.Rect;
 import net.codemirror.lib.TextMarker;
 import net.codemirror.lib.TextMarker.FromTo;
 
@@ -314,6 +320,7 @@ public class SideBySide2 extends Screen {
   }
 
   private void registerCmEvents(final CodeMirror cm) {
+    cm.on("beforeSelectionChange", onSelectionChange(cm));
     cm.on("cursorActivity", updateActiveLine(cm));
     cm.on("gutterClick", onGutterClick(cm));
     cm.on("renderLine", resizeLinePadding(getSideFromCm(cm)));
@@ -399,6 +406,47 @@ public class SideBySide2 extends Screen {
         .on("Shift-Right", flipCursorSide(cm, false)));
   }
 
+  private BeforeSelectionChangeHandler onSelectionChange(final CodeMirror cm) {
+    return new BeforeSelectionChangeHandler() {
+      private Image icon;
+
+      @Override
+      public void handle(CodeMirror cm, LineCharacter anchor, LineCharacter head) {
+        if (anchor == head
+            || (anchor.getLine() == head.getLine()
+             && anchor.getCh() == head.getCh())) {
+          if (icon != null) {
+            icon.setVisible(false);
+          }
+          return;
+        } else if (icon == null) {
+          init(anchor);
+        }
+
+        icon.setVisible(true);
+        Rect r = cm.charCoords(head, "local");
+        Style s = icon.getElement().getStyle();
+        s.setTop((int) (r.top() - icon.getOffsetHeight() + 2), Unit.PX);
+        s.setLeft((int) (r.right() - icon.getOffsetWidth() / 2), Unit.PX);
+      }
+
+      private void init(LineCharacter anchor) {
+        icon = new Image(Gerrit.RESOURCES.draftComments());
+        icon.setTitle(PatchUtil.C.commentInsert());
+        icon.setStyleName(DiffTable.style.insertCommentIcon());
+        icon.addClickHandler(new ClickHandler() {
+          @Override
+          public void onClick(ClickEvent event) {
+            icon.setVisible(false);
+            insertNewDraft(cm).run();
+          }
+        });
+        add(icon);
+        cm.addWidget(anchor, icon.getElement(), false);
+      }
+    };
+  }
+
   @Override
   public void registerKeys() {
     super.registerKeys();

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

@@ -133,6 +133,7 @@ class SkipBar extends Composite {
   void expandAll() {
     clearMarkerAndWidget();
     removeFromParent();
+    updateSelection();
   }
 
   private void expandBefore() {
@@ -148,6 +149,7 @@ class SkipBar extends Composite {
         .set("noHScroll", true);
     setWidget(cm.addLineWidget(newStart - 1, getElement(), config));
     updateSkipNum();
+    updateSelection();
   }
 
   private void expandAfter() {
@@ -167,6 +169,14 @@ class SkipBar extends Composite {
       setWidget(cm.addLineWidget(newEnd + 1, getElement(), config));
     }
     updateSkipNum();
+    updateSelection();
+  }
+
+  private void updateSelection() {
+    if (cm.somethingSelected()) {
+      FromTo sel = cm.getSelectedRange();
+      cm.setSelection(sel.getFrom(), sel.getTo());
+    }
   }
 
   @UiHandler("skipNum")

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

@@ -138,6 +138,10 @@ public class CodeMirror extends JavaScriptObject {
     return this.heightAtLine(line, mode);
   }-*/;
 
+  public final native Rect charCoords(LineCharacter pos, String mode) /*-{
+    return this.charCoords(pos, mode);
+  }-*/;
+
   public final native CodeMirrorDoc getDoc() /*-{
     return this.getDoc();
   }-*/;
@@ -197,6 +201,12 @@ public class CodeMirror extends JavaScriptObject {
     }));
   }-*/;
 
+  public final native void on(String event, BeforeSelectionChangeHandler handler) /*-{
+    this.on(event, $entry(function(cm, e) {
+      handler.@net.codemirror.lib.CodeMirror.BeforeSelectionChangeHandler::handle(Lnet/codemirror/lib/CodeMirror;Lnet/codemirror/lib/LineCharacter;Lnet/codemirror/lib/LineCharacter;)(cm,e.anchor,e.head);
+    }));
+  }-*/;
+
   public final native LineCharacter getCursor() /*-{
     return this.getCursor();
   }-*/;
@@ -209,8 +219,12 @@ public class CodeMirror extends JavaScriptObject {
     return FromTo.create(getCursor("start"), getCursor("end"));
   }
 
-  public final native void setSelection(LineCharacter lineCh) /*-{
-    this.setSelection(lineCh);
+  public final native void setSelection(LineCharacter anchor) /*-{
+    this.setSelection(anchor);
+  }-*/;
+
+  public final native void setSelection(LineCharacter anchor, LineCharacter head) /*-{
+    this.setSelection(anchor, head);
   }-*/;
 
   public final native void setCursor(LineCharacter lineCh) /*-{
@@ -345,4 +359,8 @@ public class CodeMirror extends JavaScriptObject {
     public void handle(CodeMirror instance, int line, String gutter,
         NativeEvent clickEvent);
   }
+
+  public interface BeforeSelectionChangeHandler {
+    public void handle(CodeMirror instance, LineCharacter anchor, LineCharacter head);
+  }
 }

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

@@ -0,0 +1,28 @@
+// Copyright (C) 2013 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package net.codemirror.lib;
+
+import com.google.gwt.core.client.JavaScriptObject;
+
+/** {left, right, top, bottom} objects used within CodeMirror. */
+public class Rect extends JavaScriptObject {
+  public final native double left() /*-{ return this.left }-*/;
+  public final native double right() /*-{ return this.right }-*/;
+  public final native double top() /*-{ return this.top }-*/;
+  public final native double bottom() /*-{ return this.bottom }-*/;
+
+  protected Rect() {
+  }
+}