Add skipping of common context to CodeMirrorDemo.

Added SkipBar, which handles collapsing and expanding of
common text that is longer than the preferred context.

Added supporting CodeMirror wrappers.

Removed unused addon foldcode.js.

Fixed to not create publishedMap if published is null.

Change-Id: Iabb3481f72529d2dec412de53416235af220d6d8

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

@@ -0,0 +1,166 @@
+//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.gerrit.client.patches.PatchUtil;
+import com.google.gwt.core.client.GWT;
+import com.google.gwt.event.dom.client.ClickEvent;
+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.uibinder.client.UiHandler;
+import com.google.gwt.user.client.ui.Anchor;
+import com.google.gwt.user.client.ui.Composite;
+import com.google.gwt.user.client.ui.HTMLPanel;
+
+import net.codemirror.lib.CodeMirror;
+import net.codemirror.lib.CodeMirror.LineHandle;
+import net.codemirror.lib.Configuration;
+import net.codemirror.lib.LineWidget;
+import net.codemirror.lib.TextMarker;
+import net.codemirror.lib.TextMarker.FromTo;
+
+import java.util.Map;
+
+/** The Widget that handles expanding of skipped lines */
+class SkipBar extends Composite {
+  interface Binder extends UiBinder<HTMLPanel, SkipBar> {}
+  private static Binder uiBinder = GWT.create(Binder.class);
+  private static final int NUM_ROWS_TO_EXPAND = 10;
+  private static final int UP_DOWN_THRESHOLD = 30;
+  private static final Configuration COLLAPSED =
+      Configuration.create().set("collapsed", true);
+
+  private LineWidget widget;
+
+  interface SkipBarStyle extends CssResource {
+    String noExpand();
+  }
+
+  @UiField(provided=true)
+  Anchor skipNum;
+
+  @UiField(provided=true)
+  Anchor upArrow;
+
+  @UiField(provided=true)
+  Anchor downArrow;
+
+  @UiField
+  SkipBarStyle style;
+
+  private TextMarker marker;
+  private SkipBar otherBar;
+  private CodeMirror cm;
+  private int numSkipLines;
+  private Map<LineHandle, Integer> hiddenSkipMap;
+
+  SkipBar(CodeMirror cm, Map<LineHandle, Integer> hiddenSkipMap) {
+    this.cm = cm;
+    this.hiddenSkipMap = hiddenSkipMap;
+    skipNum = new Anchor(true);
+    upArrow = new Anchor(true);
+    downArrow = new Anchor(true);
+    initWidget(uiBinder.createAndBindUi(this));
+  }
+
+  void setWidget(LineWidget widget) {
+    this.widget = widget;
+  }
+
+  void setMarker(TextMarker marker, int length) {
+    this.marker = marker;
+    numSkipLines = length;
+    skipNum.setText(Integer.toString(length));
+    if (checkAndUpdateArrows()) {
+      upArrow.setHTML(PatchUtil.M.expandBefore(NUM_ROWS_TO_EXPAND));
+      downArrow.setHTML(PatchUtil.M.expandAfter(NUM_ROWS_TO_EXPAND));
+    }
+  }
+
+  static void link(SkipBar barA, SkipBar barB) {
+    barA.otherBar = barB;
+    barB.otherBar = barA;
+  }
+
+  private void updateSkipNum() {
+    numSkipLines -= NUM_ROWS_TO_EXPAND;
+    skipNum.setText(String.valueOf(numSkipLines));
+    checkAndUpdateArrows();
+  }
+
+  private boolean checkAndUpdateArrows() {
+    if (numSkipLines <= UP_DOWN_THRESHOLD) {
+      upArrow.addStyleName(style.noExpand());
+      downArrow.addStyleName(style.noExpand());
+      return false;
+    }
+    return true;
+  }
+
+  private void expandAll() {
+    hiddenSkipMap.remove(
+        cm.getLineHandle(marker.find().getTo().getLine()));
+    marker.clear();
+    widget.clear();
+    removeFromParent();
+  }
+
+  private void expandBefore() {
+    FromTo fromTo = marker.find();
+    marker.clear();
+    int oldStart = fromTo.getFrom().getLine();
+    int newStart = oldStart + NUM_ROWS_TO_EXPAND;
+    int end = fromTo.getTo().getLine();
+    marker = cm.markText(CodeMirror.pos(newStart), CodeMirror.pos(end), COLLAPSED);
+    Configuration config = Configuration.create().set("coverGutter", true);
+    LineWidget newWidget = cm.addLineWidget(newStart, getElement(), config);
+    widget.clear();
+    setWidget(newWidget);
+    updateSkipNum();
+    hiddenSkipMap.put(cm.getLineHandle(end), numSkipLines);
+  }
+
+  private void expandAfter() {
+    FromTo fromTo = marker.find();
+    marker.clear();
+    int oldEnd = fromTo.getTo().getLine();
+    int newEnd = oldEnd - NUM_ROWS_TO_EXPAND;
+    marker = cm.markText(CodeMirror.pos(fromTo.getFrom().getLine()),
+        CodeMirror.pos(newEnd),
+        COLLAPSED);
+    updateSkipNum();
+    hiddenSkipMap.remove(cm.getLineHandle(oldEnd));
+    hiddenSkipMap.put(cm.getLineHandle(newEnd), numSkipLines);
+  }
+
+  @UiHandler("skipNum")
+  void onExpandAll(ClickEvent e) {
+    otherBar.expandAll();
+    expandAll();
+  }
+
+  @UiHandler("upArrow")
+  void onExpandBefore(ClickEvent e) {
+    otherBar.expandBefore();
+    expandBefore();
+  }
+
+  @UiHandler("downArrow")
+  void onExpandAfter(ClickEvent e) {
+    otherBar.expandAfter();
+    expandAfter();
+  }
+}