SideBySide2: Add clickable gutters to the right of CodeMirror B

Implementing a panel to the right of the scrollbar that holds fixed
clickable gutters indicating positions of comments and diff chunks.
This is a crude proof-of-concept that requires more tweaking.

Change-Id: Ib705581de407d91c36bfe92cf02dd063736158e1

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

@@ -17,6 +17,7 @@ package com.google.gerrit.client.diff;
 import com.google.gerrit.client.changes.CommentInfo;
 import com.google.gerrit.client.diff.PaddingManager.PaddingWidgetWrapper;
 import com.google.gerrit.client.diff.SideBySide2.DiffChunkInfo;
+import com.google.gerrit.client.diff.SidePanel.GutterWrapper;
 import com.google.gwt.core.client.Scheduler;
 import com.google.gwt.core.client.Scheduler.ScheduledCommand;
 import com.google.gwt.user.client.ui.Composite;
@@ -31,6 +32,7 @@ abstract class CommentBox extends Composite {
   private PaddingWidgetWrapper selfWidgetWrapper;
   private SideBySide2 parent;
   private DiffChunkInfo diffChunkInfo;
+  private GutterWrapper gutterWrapper;
 
   @Override
   protected void onLoad() {
@@ -87,4 +89,12 @@ abstract class CommentBox extends Composite {
   void setParent(SideBySide2 parent) {
     this.parent = parent;
   }
+
+  void setGutterWrapper(GutterWrapper wrapper) {
+    gutterWrapper = wrapper;
+  }
+
+  GutterWrapper getGutterWrapper() {
+    return gutterWrapper;
+  }
 }

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

@@ -48,6 +48,9 @@ class DiffTable extends Composite {
   @UiField
   Element cmB;
 
+  @UiField
+  SidePanel sidePanel;
+
   @UiField
   Element patchsetNavRow;
 

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

@@ -33,6 +33,9 @@ limitations under the License.
     .difftable .CodeMirror pre span {
       padding-bottom: 0.1em;
     }
+    .sidePanelCell {
+      width: 10px;
+    }
     .table {
       width: 100%;
       table-layout: fixed;
@@ -98,26 +101,33 @@ limitations under the License.
     }
   </ui:style>
   <g:HTMLPanel styleName='{style.difftable}'>
-    <table class='{style.table}'>
+    <table>
-      <tr ui:field='patchsetNavRow'>
-        <td ui:field='patchsetNavCellA' class='{style.padding}'>
-          <d:PatchSelectBox2 ui:field='patchSelectBoxA' />
-        </td>
-        <td ui:field='patchsetNavCellB' class='{style.padding}'>
-          <d:PatchSelectBox2 ui:field='patchSelectBoxB' />
-        </td>
-      </tr>
-      <tr ui:field='fileCommentRow'>
-        <td ui:field='fileCommentCellA' class='{style.padding}'>
-          <d:FileCommentPanel ui:field='fileCommentPanelA' />
-        </td>
-        <td ui:field='fileCommentCellB' class='{style.padding}'>
-          <d:FileCommentPanel ui:field='fileCommentPanelB' />
-        </td>
-      </tr>
       <tr>
-        <td ui:field='cmA' class='{style.a}'></td>
+        <td>
-        <td ui:field='cmB' class='{style.b}'></td>
+          <table class='{style.table}'>
+            <tr ui:field='patchsetNavRow'>
+              <td ui:field='patchsetNavCellA' class='{style.padding}'>
+                <d:PatchSelectBox2 ui:field='patchSelectBoxA' />
+              </td>
+              <td ui:field='patchsetNavCellB' class='{style.padding}'>
+                <d:PatchSelectBox2 ui:field='patchSelectBoxB' />
+              </td>
+            </tr>
+            <tr ui:field='fileCommentRow'>
+              <td ui:field='fileCommentCellA' class='{style.padding}'>
+                <d:FileCommentPanel ui:field='fileCommentPanelA' />
+              </td>
+              <td ui:field='fileCommentCellB' class='{style.padding}'>
+                <d:FileCommentPanel ui:field='fileCommentPanelB' />
+              </td>
+            </tr>
+            <tr>
+              <td ui:field='cmA' class='{style.a}'></td>
+              <td ui:field='cmB' class='{style.b}'></td>
+            </tr>
+          </table>
+        </td>
+        <td class='{style.sidePanelCell}'><d:SidePanel ui:field='sidePanel'/></td>
       </tr>
     </table>
   </g:HTMLPanel>

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

@@ -224,6 +224,7 @@ class DraftBox extends CommentBox {
     parent.removeDraft(this, side, comment.line() - 1);
     cm.focus();
     getSelfWidgetWrapper().getWidget().clear();
+    getGutterWrapper().remove();
     Scheduler.get().scheduleDeferred(new ScheduledCommand() {
       @Override
       public void execute() {

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

@@ -260,6 +260,7 @@ public class SideBySide2 extends Screen {
       }
     };
     cm.on("renderLine", resizeLinePadding(getSideFromCm(cm)));
+    cm.on("viewportChange", adjustGutters(cm));
     // TODO: Prevent right click from updating the cursor.
     cm.addKeyMap(KeyMap.create()
         .on("'j'", moveCursorDown(cm, 1))
@@ -430,6 +431,13 @@ public class SideBySide2 extends Screen {
         }
         markEdit(cmA, currentA, current.edit_a(), origLineA);
         markEdit(cmB, currentB, current.edit_b(), origLineB);
+        if (aLength == 0 || bLength == 0) {
+          diffTable.sidePanel.addGutter(cmB, origLineB, aLength == 0
+              ? SidePanel.GutterType.INSERT
+              : SidePanel.GutterType.DELETE);
+        } else {
+          diffTable.sidePanel.addGutter(cmB, origLineB, SidePanel.GutterType.EDIT);
+        }
       }
     }
   }
@@ -454,10 +462,15 @@ public class SideBySide2 extends Screen {
 
   DraftBox addDraftBox(CommentInfo info) {
     CodeMirror cm = getCmFromSide(info.side());
-    DraftBox box = new DraftBox(this, cm, commentLinkProcessor, revision, info);
+    final DraftBox box = new DraftBox(this, cm, commentLinkProcessor, revision, info);
     if (info.id() == null) {
-      box.setOpen(true);
+      Scheduler.get().scheduleDeferred(new ScheduledCommand() {
-      box.setEdit(true);
+        @Override
+        public void execute() {
+          box.setOpen(true);
+          box.setEdit(true);
+        }
+      });
     }
     if (!info.has_line()) {
       return box;
@@ -511,6 +524,10 @@ public class SideBySide2 extends Screen {
     if (otherChunk == null) {
       box.setDiffChunkInfo(myChunk);
     }
+    box.setGutterWrapper(diffTable.sidePanel.addGutter(cm, info.line() - 1,
+        box instanceof DraftBox ?
+            SidePanel.GutterType.DRAFT
+          : SidePanel.GutterType.COMMENT));
     return box;
   }
 
@@ -803,6 +820,21 @@ public class SideBySide2 extends Screen {
     }
   }
 
+  private Runnable adjustGutters(final CodeMirror cm) {
+    return new Runnable() {
+      @Override
+      public void run() {
+        Viewport fromTo = cm.getViewport();
+        int size = fromTo.getTo() - fromTo.getFrom() + 1;
+        if (cm.getOldViewportSize() == size) {
+          return;
+        }
+        cm.setOldViewportSize(size);
+        diffTable.sidePanel.adjustGutters(cmB);
+      }
+    };
+  }
+
   private Runnable updateActiveLine(final CodeMirror cm) {
     final CodeMirror other = otherCm(cm);
     return new Runnable() {
@@ -830,9 +862,8 @@ public class SideBySide2 extends Screen {
         cm.addLineClass(handle, LineClassWhere.BACKGROUND, DiffTable.style.activeLineBg());
         LineOnOtherInfo info =
             mapper.lineOnOther(getSideFromCm(cm), cm.getLineNumber(handle));
-        int oLine = info.getLine();
-        LineHandle oLineHandle = other.getLineHandle(oLine);
         if (info.isAligned()) {
+          LineHandle oLineHandle = other.getLineHandle(info.getLine());
           other.setActiveLine(oLineHandle);
           other.addLineClass(oLineHandle, LineClassWhere.WRAP,
               DiffTable.style.activeLine());
@@ -1003,6 +1034,7 @@ public class SideBySide2 extends Screen {
     cmA.refresh();
     cmB.setHeight(Window.getClientHeight() - h);
     cmB.refresh();
+    diffTable.sidePanel.adjustGutters(cmB);
   }
 
   static void setHeightInPx(Element ele, double height) {
@@ -1015,6 +1047,14 @@ public class SideBySide2 extends Screen {
         : null;
   }
 
+  CodeMirror getCmA() {
+    return cmA;
+  }
+
+  CodeMirror getCmB() {
+    return cmB;
+  }
+
   static class EditIterator {
     private final JsArrayString lines;
     private final int startLine;

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

@@ -0,0 +1,168 @@
+//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 com.google.gerrit.client.diff;
+
+import com.google.gwt.core.client.GWT;
+import com.google.gwt.core.client.Scheduler;
+import com.google.gwt.core.client.Scheduler.ScheduledCommand;
+import com.google.gwt.dom.client.Element;
+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.shared.HandlerRegistration;
+import com.google.gwt.resources.client.CssResource;
+import com.google.gwt.uibinder.client.UiBinder;
+import com.google.gwt.uibinder.client.UiField;
+import com.google.gwt.user.client.ui.Composite;
+import com.google.gwt.user.client.ui.HTMLPanel;
+import com.google.gwt.user.client.ui.Label;
+
+import net.codemirror.lib.CodeMirror;
+import net.codemirror.lib.LineCharacter;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/** The Widget that handles the scrollbar gutters */
+class SidePanel extends Composite {
+  interface Binder extends UiBinder<HTMLPanel, SidePanel> {}
+  private static Binder uiBinder = GWT.create(Binder.class);
+
+  interface SidePanelStyle extends CssResource {
+    String gutter();
+    String halfGutter();
+    String comment();
+    String draft();
+    String insert();
+    String delete();
+  }
+
+  enum GutterType {
+    COMMENT, DRAFT, INSERT, DELETE, EDIT;
+  }
+
+  @UiField
+  SidePanelStyle style;
+
+  private List<GutterWrapper> gutters;
+  private CodeMirror cmB;
+
+  SidePanel() {
+    initWidget(uiBinder.createAndBindUi(this));
+    this.gutters = new ArrayList<GutterWrapper>();
+  }
+
+  GutterWrapper addGutter(CodeMirror cm, int line, GutterType type) {
+    Label gutter = new Label();
+    GutterWrapper info = new GutterWrapper(this, gutter, cm, line, type);
+    adjustGutter(info);
+    Element ele = gutter.getElement();
+    gutter.addStyleName(style.gutter());
+    switch (type) {
+      case COMMENT:
+        gutter.addStyleName(style.comment());
+        break;
+      case DRAFT:
+        gutter.addStyleName(style.draft());
+        gutter.setText("*");
+        break;
+      case INSERT:
+        gutter.addStyleName(style.insert());
+        break;
+      case DELETE:
+        gutter.addStyleName(style.delete());
+        break;
+      case EDIT:
+        gutter.addStyleName(style.insert());
+        Label labelLeft = new Label();
+        labelLeft.addStyleName(style.halfGutter());
+        gutter.getElement().appendChild(labelLeft.getElement());
+    }
+    getElement().appendChild(ele);
+    ((HTMLPanel) getWidget()).add(gutter);
+    gutters.add(info);
+    return info;
+  }
+
+  void adjustGutters(CodeMirror cmB) {
+    this.cmB = cmB;
+    Scheduler.get().scheduleDeferred(new ScheduledCommand() {
+      @Override
+      public void execute() {
+        for (GutterWrapper info : gutters) {
+          adjustGutter(info);
+        }
+      }
+    });
+  }
+
+  private void adjustGutter(GutterWrapper wrapper) {
+    if (cmB == null) {
+      return;
+    }
+    final CodeMirror cm = wrapper.cm;
+    final int line = wrapper.line;
+    Label gutter = wrapper.gutter;
+    final double height = cm.heightAtLine(line, "local");
+    final double scrollbarHeight = cmB.getScrollbarV().getClientHeight();
+    double top = height / (double) cmB.getSizer().getClientHeight() *
+        scrollbarHeight +
+        cmB.getScrollbarV().getAbsoluteTop();
+    if (top == 0) {
+      top = -10;
+    }
+    gutter.getElement().getStyle().setTop(top, Unit.PX);
+    wrapper.replaceClickHandler(new ClickHandler() {
+      @Override
+      public void onClick(ClickEvent event) {
+        cm.setCursor(LineCharacter.create(line));
+        cm.scrollToY(Math.max(0, height - scrollbarHeight / 2));
+        cm.focus();
+      }
+    });
+  }
+
+  void removeGutter(GutterWrapper wrapper) {
+    gutters.remove(wrapper);
+  }
+
+  static class GutterWrapper {
+    private SidePanel host;
+    private Label gutter;
+    private CodeMirror cm;
+    private int line;
+    private HandlerRegistration regClick;
+
+    GutterWrapper(SidePanel host, Label anchor, CodeMirror cm, int line,
+        GutterType type) {
+      this.host = host;
+      this.gutter = anchor;
+      this.cm = cm;
+      this.line = line;
+    }
+
+    private void replaceClickHandler(ClickHandler newHandler) {
+      if (regClick != null) {
+        regClick.removeHandler();
+      }
+      regClick = gutter.addClickHandler(newHandler);
+    }
+
+    void remove() {
+      gutter.removeFromParent();
+      host.removeGutter(this);
+    }
+  }
+}

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

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+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.
+-->
+<ui:UiBinder xmlns:ui='urn:ui:com.google.gwt.uibinder'
+    xmlns:g='urn:import:com.google.gwt.user.client.ui'>
+  <ui:style type='com.google.gerrit.client.diff.SidePanel.SidePanelStyle'>
+    .gutter {
+      cursor: pointer;
+      position: fixed;
+      height: 3px;
+      width: 10px;
+      border: 1px solid black;
+    }
+    .halfGutter {
+      cursor: pointer;
+      position: fixed;
+      height: 3px;
+      width: 5px;
+      background-color: #faa;
+    }
+    .comment, .draft {
+      background-color: #e5ecf9;
+    }
+    .draft {
+      text-align: center;
+      font-size: small;
+      line-height: 0.5;
+      color: inherit !important;
+      text-decoration: none !important;
+    }
+    .delete {
+      background-color: #faa;
+    }
+    .insert {
+      background-color: #9f9;
+    }
+  </ui:style>
+  <g:HTMLPanel/>
+</ui:UiBinder>

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

@@ -124,10 +124,18 @@ public class CodeMirror extends JavaScriptObject {
     return this.lineAtHeight(height);
   }-*/;
 
+  public final native int lineAtHeight(double height, String mode) /*-{
+    return this.lineAtHeight(height, mode);
+  }-*/;
+
   public final native double heightAtLine(int line) /*-{
     return this.heightAtLine(line);
   }-*/;
 
+  public final native double heightAtLine(int line, String mode) /*-{
+    return this.heightAtLine(line, mode);
+  }-*/;
+
   public final native CodeMirrorDoc getDoc() /*-{
     return this.getDoc();
   }-*/;
@@ -148,6 +156,14 @@ public class CodeMirror extends JavaScriptObject {
     return this.getViewport();
   }-*/;
 
+  public final native int getOldViewportSize() /*-{
+    return this.state.oldViewportSize || 0;
+  }-*/;
+
+  public final native void setOldViewportSize(int lines) /*-{
+    this.state.oldViewportSize = lines;
+  }-*/;
+
   public final native double getScrollSetAt() /*-{
     return this.state.scrollSetAt || 0;
   }-*/;
@@ -239,6 +255,10 @@ public class CodeMirror extends JavaScriptObject {
     this.focus();
   }-*/;
 
+  public final native int lineCount() /*-{
+    return this.lineCount();
+  }-*/;
+
   /** Hack into CodeMirror to disable unwanted keys */
   public static final native void disableUnwantedKey(String category,
       String name) /*-{
@@ -253,6 +273,18 @@ public class CodeMirror extends JavaScriptObject {
     return this.getGutterElement();
   }-*/;
 
+  public final native Element getScrollerElement() /*-{
+    return this.getScrollerElement();
+  }-*/;
+
+  public final native Element getSizer() /*-{
+    return this.display.sizer;
+  }-*/;
+
+  public final native Element getScrollbarV() /*-{
+    return this.display.scrollbarV;
+  }-*/;
+
   protected CodeMirror() {
   }
 

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

@@ -30,7 +30,6 @@ public class ScrollInfo extends JavaScriptObject {
   public final native double getClientWidth() /*-{ return this.clientWidth; }-*/;
   public final native double getClientHeight() /*-{ return this.clientHeight; }-*/;
 
-
   protected ScrollInfo() {
   }
 }