gerrit-gwtui/src/main/java/com/google/gerrit/client/patches/PatchScreen.java - gerrit - Git at Google

 // Copyright (C) 2008 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.patches;

 import static com.google.gerrit.reviewdb.AccountGeneralPreferences.WHOLE_FILE_CONTEXT;

 import com.google.gerrit.client.Dispatcher;
 import com.google.gerrit.client.Gerrit;
 import com.google.gerrit.client.RpcStatus;
 import com.google.gerrit.client.changes.ChangeScreen;
 import com.google.gerrit.client.changes.PatchTable;
 import com.google.gerrit.client.changes.Util;
 import com.google.gerrit.client.rpc.GerritCallback;
 import com.google.gerrit.client.rpc.ScreenLoadCallback;
 import com.google.gerrit.client.ui.ChangeLink;
 import com.google.gerrit.client.ui.InlineHyperlink;
 import com.google.gerrit.client.ui.Screen;
 import com.google.gerrit.common.PageLinks;
 import com.google.gerrit.common.data.PatchScript;
 import com.google.gerrit.common.data.PatchScriptSettings;
 import com.google.gerrit.common.data.PatchSetDetail;
 import com.google.gerrit.prettify.client.ClientSideFormatter;
 import com.google.gerrit.prettify.common.PrettyFactory;
 import com.google.gerrit.reviewdb.Change;
 import com.google.gerrit.reviewdb.Patch;
 import com.google.gerrit.reviewdb.PatchSet;
 import com.google.gwt.event.dom.client.KeyPressEvent;
 import com.google.gwt.event.logical.shared.CloseEvent;
 import com.google.gwt.event.logical.shared.CloseHandler;
 import com.google.gwt.event.logical.shared.OpenEvent;
 import com.google.gwt.event.logical.shared.OpenHandler;
 import com.google.gwt.event.logical.shared.ValueChangeEvent;
 import com.google.gwt.event.logical.shared.ValueChangeHandler;
 import com.google.gwt.event.shared.HandlerRegistration;
 import com.google.gwt.user.client.Command;
 import com.google.gwt.user.client.DeferredCommand;
 import com.google.gwt.user.client.rpc.AsyncCallback;
 import com.google.gwt.user.client.ui.DisclosurePanel;
 import com.google.gwt.user.client.ui.FlowPanel;
 import com.google.gwt.user.client.ui.Grid;
 import com.google.gwt.user.client.ui.HasHorizontalAlignment;
 import com.google.gwt.user.client.ui.Label;
 import com.google.gwt.user.client.ui.Widget;
 import com.google.gwt.user.client.ui.HTMLTable.CellFormatter;
 import com.google.gwtexpui.globalkey.client.GlobalKey;
 import com.google.gwtexpui.globalkey.client.KeyCommand;
 import com.google.gwtexpui.globalkey.client.KeyCommandSet;
 import com.google.gwtexpui.safehtml.client.SafeHtml;
 import com.google.gwtjsonrpc.client.VoidResult;

 public abstract class PatchScreen extends Screen implements
     CommentEditorContainer {
   static final PrettyFactory PRETTY = ClientSideFormatter.FACTORY;

   public static class SideBySide extends PatchScreen {
     public SideBySide(final Patch.Key id, final int patchIndex,
         final PatchTable patchTable) {
       super(id, patchIndex, patchTable);
     }

     @Override
     protected SideBySideTable createContentTable() {
       return new SideBySideTable();
     }

     @Override
     protected PatchScreen.Type getPatchScreenType() {
       return PatchScreen.Type.SIDE_BY_SIDE;
     }
   }

   public static class Unified extends PatchScreen {
     public Unified(final Patch.Key id, final int patchIndex,
         final PatchTable patchTable) {
       super(id, patchIndex, patchTable);
       final PatchScriptSettings s = settingsPanel.getValue();
       s.getPrettySettings().setSyntaxHighlighting(false);
       settingsPanel.setValue(s);
     }

     @Override
     protected UnifiedDiffTable createContentTable() {
       return new UnifiedDiffTable();
     }

     @Override
     protected PatchScreen.Type getPatchScreenType() {
       return PatchScreen.Type.UNIFIED;
     }
   }

   // Which patch set id's are being diff'ed
   private static PatchSet.Id diffSideA = null;
   private static PatchSet.Id diffSideB = null;
   private static Boolean historyOpen = null;
   private static final OpenHandler<DisclosurePanel> cacheOpenState =
       new OpenHandler<DisclosurePanel>() {
         @Override
         public void onOpen(OpenEvent<DisclosurePanel> event) {
           historyOpen = true;
         }
       };
   private static final CloseHandler<DisclosurePanel> cacheCloseState =
       new CloseHandler<DisclosurePanel>() {
         @Override
         public void onClose(CloseEvent<DisclosurePanel> event) {
           historyOpen = false;
         }
       };

   // The change id for which the above patch set id's are valid
   private static Change.Id currentChangeId = null;

   protected final Patch.Key patchKey;
   protected PatchTable fileList;
   protected PatchSet.Id idSideA;
   protected PatchSet.Id idSideB;
   protected PatchScriptSettingsPanel settingsPanel;

   private DisclosurePanel historyPanel;
   private HistoryTable historyTable;
   private FlowPanel contentPanel;
   private Label noDifference;
   private AbstractPatchContentTable contentTable;

   private int rpcSequence;
   private PatchScript lastScript;

   /** The index of the file we are currently looking at among the fileList */
   private int patchIndex;

   /** Keys that cause an action on this screen */
   private KeyCommandSet keysNavigation;
   private HandlerRegistration regNavigation;

   /** Link to the screen for the previous file, null if not applicable */
   private InlineHyperlink previousFileLink;

   /** Link to the screen for the next file, null if not applicable */
   private InlineHyperlink nextFileLink;

   private static final char SHORTCUT_PREVIOUS_FILE = '[';
   private static final char SHORTCUT_NEXT_FILE = ']';

   /**
    * How this patch should be displayed in the patch screen.
    */
   public static enum Type {
     UNIFIED, SIDE_BY_SIDE
   }

   protected PatchScreen(final Patch.Key id, final int patchIndex,
       final PatchTable patchTable) {
     patchKey = id;
     fileList = patchTable;

     // If we have any diff side stored, make sure they are applicable to the
     // current change, discard them otherwise.
     //
     Change.Id thisChangeId = id.getParentKey().getParentKey();
     if (currentChangeId != null && !currentChangeId.equals(thisChangeId)) {
       diffSideA = null;
       diffSideB = null;
       historyOpen = null;
     }
     currentChangeId = thisChangeId;
     idSideA = diffSideA; // null here means we're diff'ing from the Base
     idSideB = diffSideB != null ? diffSideB : id.getParentKey();
     this.patchIndex = patchIndex;

     settingsPanel = new PatchScriptSettingsPanel();
     settingsPanel
         .addValueChangeHandler(new ValueChangeHandler<PatchScriptSettings>() {
           @Override
           public void onValueChange(ValueChangeEvent<PatchScriptSettings> event) {
             update(event.getValue());
           }
         });
     settingsPanel.getReviewedCheckBox().addValueChangeHandler(
         new ValueChangeHandler<Boolean>() {
           @Override
           public void onValueChange(ValueChangeEvent<Boolean> event) {
             setReviewedByCurrentUser(event.getValue());
           }
         });
   }

   @Override
   public void notifyDraftDelta(int delta) {
     lastScript = null;
   }

   @Override
   public void remove(CommentEditorPanel panel) {
     lastScript = null;
   }

   private void update(PatchScriptSettings s) {
     if (lastScript != null && canReuse(s, lastScript)) {
       lastScript.setSettings(s);
       RpcStatus.INSTANCE.onRpcStart(null);
       settingsPanel.setEnabled(false);
       DeferredCommand.addCommand(new Command() {
         @Override
         public void execute() {
           try {
             onResult(lastScript, false /* not the first time */);
           } finally {
             RpcStatus.INSTANCE.onRpcComplete(null);
           }
         }
       });
     } else {
       refresh(false);
     }
   }

   private boolean canReuse(PatchScriptSettings s, PatchScript last) {
     if (last.getSettings().getWhitespace() != s.getWhitespace()) {
       // Whitespace ignore setting requires server computation.
       return false;
     }

     final int ctx = s.getContext();
     if (ctx == WHOLE_FILE_CONTEXT && !last.getA().isWholeFile()) {
       // We don't have the entire file here, so we can't render it.
       return false;
     }

     if (last.getSettings().getContext() < ctx && !last.getA().isWholeFile()) {
       // We don't have sufficient context.
       return false;
     }

     if (s.getPrettySettings().isSyntaxHighlighting()
         && !last.getA().isWholeFile()) {
       // We need the whole file to syntax highlight accurately.
       return false;
     }

     return true;
   }

   @Override
   protected void onInitUI() {
     super.onInitUI();

     keysNavigation = new KeyCommandSet(Gerrit.C.sectionNavigation());
     keysNavigation.add(new UpToChangeCommand(0, 'u', PatchUtil.C.upToChange()));
     keysNavigation.add(new FileListCmd(0, 'f', PatchUtil.C.fileList()));

     historyTable = new HistoryTable(this);
     historyPanel = new DisclosurePanel(PatchUtil.C.patchHistoryTitle());
     historyPanel.setContent(historyTable);
     historyPanel.setVisible(false);
     // If the user selected a different patch set than the default for either
     // side, expand the history panel
     historyPanel.setOpen(diffSideA != null || diffSideB != null
         || (historyOpen != null && historyOpen));
     historyPanel.addOpenHandler(cacheOpenState);
     historyPanel.addCloseHandler(cacheCloseState);
     add(historyPanel);
     add(settingsPanel);

     noDifference = new Label(PatchUtil.C.noDifference());
     noDifference.setStyleName(Gerrit.RESOURCES.css().patchNoDifference());
     noDifference.setVisible(false);

     contentTable = createContentTable();
     contentTable.fileList = fileList;

     add(createNextPrevLinks());
     contentPanel = new FlowPanel();
     contentPanel.setStyleName(Gerrit.RESOURCES.css()
         .sideBySideScreenSideBySideTable());
     contentPanel.add(noDifference);
     contentPanel.add(contentTable);
     add(contentPanel);
     add(createNextPrevLinks());

     // This must be done after calling createNextPrevLinks(), which initializes
     // these fields
     if (previousFileLink != null) {
       installLinkShortCut(previousFileLink, SHORTCUT_PREVIOUS_FILE, PatchUtil.C
           .previousFileHelp());
     }
     if (nextFileLink != null) {
       installLinkShortCut(nextFileLink, SHORTCUT_NEXT_FILE, PatchUtil.C
           .nextFileHelp());
     }
   }

   private void installLinkShortCut(final InlineHyperlink link, char shortcut,
       String help) {
     keysNavigation.add(new KeyCommand(0, shortcut, help) {
       @Override
       public void onKeyPress(KeyPressEvent event) {
         link.go();
       }
     });
   }

   void setReviewedByCurrentUser(boolean reviewed) {
     if (fileList != null) {
       fileList.updateReviewedStatus(patchKey, reviewed);
     }

     PatchUtil.DETAIL_SVC.setReviewedByCurrentUser(patchKey, reviewed,
         new AsyncCallback<VoidResult>() {
           @Override
           public void onFailure(Throwable arg0) {
             // nop
           }

           @Override
           public void onSuccess(VoidResult result) {
             // nop
           }
         });
   }

   private Widget createNextPrevLinks() {
     final Grid table = new Grid(1, 3);
     final CellFormatter fmt = table.getCellFormatter();
     table.setStyleName(Gerrit.RESOURCES.css().sideBySideScreenLinkTable());
     fmt.setHorizontalAlignment(0, 0, HasHorizontalAlignment.ALIGN_LEFT);
     fmt.setHorizontalAlignment(0, 1, HasHorizontalAlignment.ALIGN_CENTER);
     fmt.setHorizontalAlignment(0, 2, HasHorizontalAlignment.ALIGN_RIGHT);

     if (fileList != null) {
       previousFileLink =
           fileList.getPreviousPatchLink(patchIndex, getPatchScreenType());
       table.setWidget(0, 0, previousFileLink);

       nextFileLink =
           fileList.getNextPatchLink(patchIndex, getPatchScreenType());
       table.setWidget(0, 2, nextFileLink);
     }

     final ChangeLink up =
         new ChangeLink("", patchKey.getParentKey().getParentKey());
     SafeHtml.set(up, SafeHtml.asis(Util.C.upToChangeIconLink()));
     table.setWidget(0, 1, up);

     return table;
   }

   @Override
   protected void onLoad() {
     super.onLoad();
     refresh(true);
   }

   @Override
   protected void onUnload() {
     if (regNavigation != null) {
       regNavigation.removeHandler();
       regNavigation = null;
     }
     super.onUnload();
   }

   @Override
   public void registerKeys() {
     super.registerKeys();
     contentTable.setRegisterKeys(contentTable.isVisible());
     regNavigation = GlobalKey.add(this, keysNavigation);
   }

   protected abstract AbstractPatchContentTable createContentTable();

   protected abstract PatchScreen.Type getPatchScreenType();

   protected void refresh(final boolean isFirst) {
     final int rpcseq = ++rpcSequence;
     lastScript = null;
     settingsPanel.setEnabled(false);
     PatchUtil.DETAIL_SVC.patchScript(patchKey, idSideA, idSideB, //
         settingsPanel.getValue(), new ScreenLoadCallback<PatchScript>(this) {
           @Override
           protected void preDisplay(final PatchScript result) {
             if (rpcSequence == rpcseq) {
               onResult(result, isFirst);
             }
           }

           @Override
           public void onFailure(final Throwable caught) {
             if (rpcSequence == rpcseq) {
               settingsPanel.setEnabled(true);
               super.onFailure(caught);
             }
           }
         });
   }

   private void onResult(final PatchScript script, final boolean isFirst) {
     final Change.Key cid = script.getChangeId();
     final String path = patchKey.get();
     String fileName = path;
     final int last = fileName.lastIndexOf('/');
     if (last >= 0) {
       fileName = fileName.substring(last + 1);
     }

     setWindowTitle(PatchUtil.M.patchWindowTitle(cid.abbreviate(), fileName));
     setPageTitle(PatchUtil.M.patchPageTitle(cid.abbreviate(), path));

     historyTable.display(script.getHistory());
     historyPanel.setVisible(true);

     // True if there are differences between the two patch sets
     boolean hasEdits = !script.getEdits().isEmpty();
     // True if this change is a mode change or a pure rename/copy
     boolean hasMeta = !script.getPatchHeader().isEmpty();

     boolean hasDifferences = hasEdits || hasMeta;
     boolean pureMetaChange = !hasEdits && hasMeta;

     if (contentTable instanceof SideBySideTable && pureMetaChange) {
       // User asked for SideBySide (or a link guessed, wrong) and we can't
       // show a binary or pure-rename change there accurately. Switch to
       // the unified view instead.
       //
       contentTable.removeFromParent();
       contentTable = new UnifiedDiffTable();
       contentTable.fileList = fileList;
       contentPanel.add(contentTable);
       setToken(Dispatcher.toPatchUnified(patchKey));
     }

     if (hasDifferences) {
       contentTable.display(patchKey, idSideA, idSideB, script);
       contentTable.display(script.getCommentDetail());
       contentTable.finishDisplay();
     }
     showPatch(hasDifferences);
     settingsPanel.setEnableSmallFileFeatures(!script.isHugeFile());
     settingsPanel.setEnableIntralineDifference(script.hasIntralineDifference());
     settingsPanel.setEnabled(true);
     lastScript = script;

     // Mark this file reviewed as soon we display the diff screen
     if (Gerrit.isSignedIn() && isFirst) {
       settingsPanel.getReviewedCheckBox().setValue(true);
       setReviewedByCurrentUser(true /* reviewed */);
     }
   }

   private void showPatch(final boolean showPatch) {
     noDifference.setVisible(!showPatch);
     contentTable.setVisible(showPatch);
     contentTable.setRegisterKeys(isCurrentView() && showPatch);
   }

   public void setSideA(PatchSet.Id patchSetId) {
     idSideA = patchSetId;
     diffSideA = patchSetId;
   }

   public void setSideB(PatchSet.Id patchSetId) {
     idSideB = patchSetId;
     diffSideB = patchSetId;
   }

   public class UpToChangeCommand extends KeyCommand {
     public UpToChangeCommand(int mask, int key, String help) {
       super(mask, key, help);
     }

     @Override
     public void onKeyPress(final KeyPressEvent event) {
       final Change.Id ck = patchKey.getParentKey().getParentKey();
       Gerrit.display(PageLinks.toChange(ck), new ChangeScreen(ck));
     }
   }

   public class FileListCmd extends KeyCommand {
     public FileListCmd(int mask, int key, String help) {
       super(mask, key, help);
     }

     @Override
     public void onKeyPress(final KeyPressEvent event) {
       if (fileList == null || fileList.isAttached()) {
         final PatchSet.Id psid = patchKey.getParentKey();
         fileList = new PatchTable();
         fileList.setSavePointerId("PatchTable " + psid);
         Util.DETAIL_SVC.patchSetDetail(psid,
             new GerritCallback<PatchSetDetail>() {
               public void onSuccess(final PatchSetDetail result) {
                 fileList.display(psid, result.getPatches());
               }
             });
       }

       final PatchBrowserPopup p = new PatchBrowserPopup(patchKey, fileList);
       p.open();
     }
   }
 }
	// Copyright (C) 2008 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.patches;

	import static com.google.gerrit.reviewdb.AccountGeneralPreferences.WHOLE_FILE_CONTEXT;

	import com.google.gerrit.client.Dispatcher;
	import com.google.gerrit.client.Gerrit;
	import com.google.gerrit.client.RpcStatus;
	import com.google.gerrit.client.changes.ChangeScreen;
	import com.google.gerrit.client.changes.PatchTable;
	import com.google.gerrit.client.changes.Util;
	import com.google.gerrit.client.rpc.GerritCallback;
	import com.google.gerrit.client.rpc.ScreenLoadCallback;
	import com.google.gerrit.client.ui.ChangeLink;
	import com.google.gerrit.client.ui.InlineHyperlink;
	import com.google.gerrit.client.ui.Screen;
	import com.google.gerrit.common.PageLinks;
	import com.google.gerrit.common.data.PatchScript;
	import com.google.gerrit.common.data.PatchScriptSettings;
	import com.google.gerrit.common.data.PatchSetDetail;
	import com.google.gerrit.prettify.client.ClientSideFormatter;
	import com.google.gerrit.prettify.common.PrettyFactory;
	import com.google.gerrit.reviewdb.Change;
	import com.google.gerrit.reviewdb.Patch;
	import com.google.gerrit.reviewdb.PatchSet;
	import com.google.gwt.event.dom.client.KeyPressEvent;
	import com.google.gwt.event.logical.shared.CloseEvent;
	import com.google.gwt.event.logical.shared.CloseHandler;
	import com.google.gwt.event.logical.shared.OpenEvent;
	import com.google.gwt.event.logical.shared.OpenHandler;
	import com.google.gwt.event.logical.shared.ValueChangeEvent;
	import com.google.gwt.event.logical.shared.ValueChangeHandler;
	import com.google.gwt.event.shared.HandlerRegistration;
	import com.google.gwt.user.client.Command;
	import com.google.gwt.user.client.DeferredCommand;
	import com.google.gwt.user.client.rpc.AsyncCallback;
	import com.google.gwt.user.client.ui.DisclosurePanel;
	import com.google.gwt.user.client.ui.FlowPanel;
	import com.google.gwt.user.client.ui.Grid;
	import com.google.gwt.user.client.ui.HasHorizontalAlignment;
	import com.google.gwt.user.client.ui.Label;
	import com.google.gwt.user.client.ui.Widget;
	import com.google.gwt.user.client.ui.HTMLTable.CellFormatter;
	import com.google.gwtexpui.globalkey.client.GlobalKey;
	import com.google.gwtexpui.globalkey.client.KeyCommand;
	import com.google.gwtexpui.globalkey.client.KeyCommandSet;
	import com.google.gwtexpui.safehtml.client.SafeHtml;
	import com.google.gwtjsonrpc.client.VoidResult;

	public abstract class PatchScreen extends Screen implements
	CommentEditorContainer {
	static final PrettyFactory PRETTY = ClientSideFormatter.FACTORY;

	public static class SideBySide extends PatchScreen {
	public SideBySide(final Patch.Key id, final int patchIndex,
	final PatchTable patchTable) {
	super(id, patchIndex, patchTable);
	}

	@Override
	protected SideBySideTable createContentTable() {
	return new SideBySideTable();
	}

	@Override
	protected PatchScreen.Type getPatchScreenType() {
	return PatchScreen.Type.SIDE_BY_SIDE;
	}
	}

	public static class Unified extends PatchScreen {
	public Unified(final Patch.Key id, final int patchIndex,
	final PatchTable patchTable) {
	super(id, patchIndex, patchTable);
	final PatchScriptSettings s = settingsPanel.getValue();
	s.getPrettySettings().setSyntaxHighlighting(false);
	settingsPanel.setValue(s);
	}

	@Override
	protected UnifiedDiffTable createContentTable() {
	return new UnifiedDiffTable();
	}

	@Override
	protected PatchScreen.Type getPatchScreenType() {
	return PatchScreen.Type.UNIFIED;
	}
	}

	// Which patch set id's are being diff'ed
	private static PatchSet.Id diffSideA = null;
	private static PatchSet.Id diffSideB = null;
	private static Boolean historyOpen = null;
	private static final OpenHandler<DisclosurePanel> cacheOpenState =
	new OpenHandler<DisclosurePanel>() {
	@Override
	public void onOpen(OpenEvent<DisclosurePanel> event) {
	historyOpen = true;
	}
	};
	private static final CloseHandler<DisclosurePanel> cacheCloseState =
	new CloseHandler<DisclosurePanel>() {
	@Override
	public void onClose(CloseEvent<DisclosurePanel> event) {
	historyOpen = false;
	}
	};

	// The change id for which the above patch set id's are valid
	private static Change.Id currentChangeId = null;

	protected final Patch.Key patchKey;
	protected PatchTable fileList;
	protected PatchSet.Id idSideA;
	protected PatchSet.Id idSideB;
	protected PatchScriptSettingsPanel settingsPanel;

	private DisclosurePanel historyPanel;
	private HistoryTable historyTable;
	private FlowPanel contentPanel;
	private Label noDifference;
	private AbstractPatchContentTable contentTable;

	private int rpcSequence;
	private PatchScript lastScript;

	/** The index of the file we are currently looking at among the fileList */
	private int patchIndex;

	/** Keys that cause an action on this screen */
	private KeyCommandSet keysNavigation;
	private HandlerRegistration regNavigation;

	/** Link to the screen for the previous file, null if not applicable */
	private InlineHyperlink previousFileLink;

	/** Link to the screen for the next file, null if not applicable */
	private InlineHyperlink nextFileLink;

	private static final char SHORTCUT_PREVIOUS_FILE = '[';
	private static final char SHORTCUT_NEXT_FILE = ']';

	/**
	* How this patch should be displayed in the patch screen.
	*/
	public static enum Type {
	UNIFIED, SIDE_BY_SIDE
	}

	protected PatchScreen(final Patch.Key id, final int patchIndex,
	final PatchTable patchTable) {
	patchKey = id;
	fileList = patchTable;

	// If we have any diff side stored, make sure they are applicable to the
	// current change, discard them otherwise.
	//
	Change.Id thisChangeId = id.getParentKey().getParentKey();
	if (currentChangeId != null && !currentChangeId.equals(thisChangeId)) {
	diffSideA = null;
	diffSideB = null;
	historyOpen = null;
	}
	currentChangeId = thisChangeId;
	idSideA = diffSideA; // null here means we're diff'ing from the Base
	idSideB = diffSideB != null ? diffSideB : id.getParentKey();
	this.patchIndex = patchIndex;

	settingsPanel = new PatchScriptSettingsPanel();
	settingsPanel
	.addValueChangeHandler(new ValueChangeHandler<PatchScriptSettings>() {
	@Override
	public void onValueChange(ValueChangeEvent<PatchScriptSettings> event) {
	update(event.getValue());
	}
	});
	settingsPanel.getReviewedCheckBox().addValueChangeHandler(
	new ValueChangeHandler<Boolean>() {
	@Override
	public void onValueChange(ValueChangeEvent<Boolean> event) {
	setReviewedByCurrentUser(event.getValue());
	}
	});
	}

	@Override
	public void notifyDraftDelta(int delta) {
	lastScript = null;
	}

	@Override
	public void remove(CommentEditorPanel panel) {
	lastScript = null;
	}

	private void update(PatchScriptSettings s) {
	if (lastScript != null && canReuse(s, lastScript)) {
	lastScript.setSettings(s);
	RpcStatus.INSTANCE.onRpcStart(null);
	settingsPanel.setEnabled(false);
	DeferredCommand.addCommand(new Command() {
	@Override
	public void execute() {
	try {
	onResult(lastScript, false /* not the first time */);
	} finally {
	RpcStatus.INSTANCE.onRpcComplete(null);
	}
	}
	});
	} else {
	refresh(false);
	}
	}

	private boolean canReuse(PatchScriptSettings s, PatchScript last) {
	if (last.getSettings().getWhitespace() != s.getWhitespace()) {
	// Whitespace ignore setting requires server computation.
	return false;
	}

	final int ctx = s.getContext();
	if (ctx == WHOLE_FILE_CONTEXT && !last.getA().isWholeFile()) {
	// We don't have the entire file here, so we can't render it.
	return false;
	}

	if (last.getSettings().getContext() < ctx && !last.getA().isWholeFile()) {
	// We don't have sufficient context.
	return false;
	}

	if (s.getPrettySettings().isSyntaxHighlighting()
	&& !last.getA().isWholeFile()) {
	// We need the whole file to syntax highlight accurately.
	return false;
	}

	return true;
	}

	@Override
	protected void onInitUI() {
	super.onInitUI();

	keysNavigation = new KeyCommandSet(Gerrit.C.sectionNavigation());
	keysNavigation.add(new UpToChangeCommand(0, 'u', PatchUtil.C.upToChange()));
	keysNavigation.add(new FileListCmd(0, 'f', PatchUtil.C.fileList()));

	historyTable = new HistoryTable(this);
	historyPanel = new DisclosurePanel(PatchUtil.C.patchHistoryTitle());
	historyPanel.setContent(historyTable);
	historyPanel.setVisible(false);
	// If the user selected a different patch set than the default for either
	// side, expand the history panel
	historyPanel.setOpen(diffSideA != null \|\| diffSideB != null
	\|\| (historyOpen != null && historyOpen));
	historyPanel.addOpenHandler(cacheOpenState);
	historyPanel.addCloseHandler(cacheCloseState);
	add(historyPanel);
	add(settingsPanel);

	noDifference = new Label(PatchUtil.C.noDifference());
	noDifference.setStyleName(Gerrit.RESOURCES.css().patchNoDifference());
	noDifference.setVisible(false);

	contentTable = createContentTable();
	contentTable.fileList = fileList;

	add(createNextPrevLinks());
	contentPanel = new FlowPanel();
	contentPanel.setStyleName(Gerrit.RESOURCES.css()
	.sideBySideScreenSideBySideTable());
	contentPanel.add(noDifference);
	contentPanel.add(contentTable);
	add(contentPanel);
	add(createNextPrevLinks());

	// This must be done after calling createNextPrevLinks(), which initializes
	// these fields
	if (previousFileLink != null) {
	installLinkShortCut(previousFileLink, SHORTCUT_PREVIOUS_FILE, PatchUtil.C
	.previousFileHelp());
	}
	if (nextFileLink != null) {
	installLinkShortCut(nextFileLink, SHORTCUT_NEXT_FILE, PatchUtil.C
	.nextFileHelp());
	}
	}

	private void installLinkShortCut(final InlineHyperlink link, char shortcut,
	String help) {
	keysNavigation.add(new KeyCommand(0, shortcut, help) {
	@Override
	public void onKeyPress(KeyPressEvent event) {
	link.go();
	}
	});
	}

	void setReviewedByCurrentUser(boolean reviewed) {
	if (fileList != null) {
	fileList.updateReviewedStatus(patchKey, reviewed);
	}

	PatchUtil.DETAIL_SVC.setReviewedByCurrentUser(patchKey, reviewed,
	new AsyncCallback<VoidResult>() {
	@Override
	public void onFailure(Throwable arg0) {
	// nop
	}

	@Override
	public void onSuccess(VoidResult result) {
	// nop
	}
	});
	}

	private Widget createNextPrevLinks() {
	final Grid table = new Grid(1, 3);
	final CellFormatter fmt = table.getCellFormatter();
	table.setStyleName(Gerrit.RESOURCES.css().sideBySideScreenLinkTable());
	fmt.setHorizontalAlignment(0, 0, HasHorizontalAlignment.ALIGN_LEFT);
	fmt.setHorizontalAlignment(0, 1, HasHorizontalAlignment.ALIGN_CENTER);
	fmt.setHorizontalAlignment(0, 2, HasHorizontalAlignment.ALIGN_RIGHT);

	if (fileList != null) {
	previousFileLink =
	fileList.getPreviousPatchLink(patchIndex, getPatchScreenType());
	table.setWidget(0, 0, previousFileLink);

	nextFileLink =
	fileList.getNextPatchLink(patchIndex, getPatchScreenType());
	table.setWidget(0, 2, nextFileLink);
	}

	final ChangeLink up =
	new ChangeLink("", patchKey.getParentKey().getParentKey());
	SafeHtml.set(up, SafeHtml.asis(Util.C.upToChangeIconLink()));
	table.setWidget(0, 1, up);

	return table;
	}

	@Override
	protected void onLoad() {
	super.onLoad();
	refresh(true);
	}

	@Override
	protected void onUnload() {
	if (regNavigation != null) {
	regNavigation.removeHandler();
	regNavigation = null;
	}
	super.onUnload();
	}

	@Override
	public void registerKeys() {
	super.registerKeys();
	contentTable.setRegisterKeys(contentTable.isVisible());
	regNavigation = GlobalKey.add(this, keysNavigation);
	}

	protected abstract AbstractPatchContentTable createContentTable();

	protected abstract PatchScreen.Type getPatchScreenType();

	protected void refresh(final boolean isFirst) {
	final int rpcseq = ++rpcSequence;
	lastScript = null;
	settingsPanel.setEnabled(false);
	PatchUtil.DETAIL_SVC.patchScript(patchKey, idSideA, idSideB, //
	settingsPanel.getValue(), new ScreenLoadCallback<PatchScript>(this) {
	@Override
	protected void preDisplay(final PatchScript result) {
	if (rpcSequence == rpcseq) {
	onResult(result, isFirst);
	}
	}

	@Override
	public void onFailure(final Throwable caught) {
	if (rpcSequence == rpcseq) {
	settingsPanel.setEnabled(true);
	super.onFailure(caught);
	}
	}
	});
	}

	private void onResult(final PatchScript script, final boolean isFirst) {
	final Change.Key cid = script.getChangeId();
	final String path = patchKey.get();
	String fileName = path;
	final int last = fileName.lastIndexOf('/');
	if (last >= 0) {
	fileName = fileName.substring(last + 1);
	}

	setWindowTitle(PatchUtil.M.patchWindowTitle(cid.abbreviate(), fileName));
	setPageTitle(PatchUtil.M.patchPageTitle(cid.abbreviate(), path));

	historyTable.display(script.getHistory());
	historyPanel.setVisible(true);

	// True if there are differences between the two patch sets
	boolean hasEdits = !script.getEdits().isEmpty();
	// True if this change is a mode change or a pure rename/copy
	boolean hasMeta = !script.getPatchHeader().isEmpty();

	boolean hasDifferences = hasEdits \|\| hasMeta;
	boolean pureMetaChange = !hasEdits && hasMeta;

	if (contentTable instanceof SideBySideTable && pureMetaChange) {
	// User asked for SideBySide (or a link guessed, wrong) and we can't
	// show a binary or pure-rename change there accurately. Switch to
	// the unified view instead.
	//
	contentTable.removeFromParent();
	contentTable = new UnifiedDiffTable();
	contentTable.fileList = fileList;
	contentPanel.add(contentTable);
	setToken(Dispatcher.toPatchUnified(patchKey));
	}

	if (hasDifferences) {
	contentTable.display(patchKey, idSideA, idSideB, script);
	contentTable.display(script.getCommentDetail());
	contentTable.finishDisplay();
	}
	showPatch(hasDifferences);
	settingsPanel.setEnableSmallFileFeatures(!script.isHugeFile());
	settingsPanel.setEnableIntralineDifference(script.hasIntralineDifference());
	settingsPanel.setEnabled(true);
	lastScript = script;

	// Mark this file reviewed as soon we display the diff screen
	if (Gerrit.isSignedIn() && isFirst) {
	settingsPanel.getReviewedCheckBox().setValue(true);
	setReviewedByCurrentUser(true /* reviewed */);
	}
	}

	private void showPatch(final boolean showPatch) {
	noDifference.setVisible(!showPatch);
	contentTable.setVisible(showPatch);
	contentTable.setRegisterKeys(isCurrentView() && showPatch);
	}

	public void setSideA(PatchSet.Id patchSetId) {
	idSideA = patchSetId;
	diffSideA = patchSetId;
	}

	public void setSideB(PatchSet.Id patchSetId) {
	idSideB = patchSetId;
	diffSideB = patchSetId;
	}

	public class UpToChangeCommand extends KeyCommand {
	public UpToChangeCommand(int mask, int key, String help) {
	super(mask, key, help);
	}

	@Override
	public void onKeyPress(final KeyPressEvent event) {
	final Change.Id ck = patchKey.getParentKey().getParentKey();
	Gerrit.display(PageLinks.toChange(ck), new ChangeScreen(ck));
	}
	}

	public class FileListCmd extends KeyCommand {
	public FileListCmd(int mask, int key, String help) {
	super(mask, key, help);
	}

	@Override
	public void onKeyPress(final KeyPressEvent event) {
	if (fileList == null \|\| fileList.isAttached()) {
	final PatchSet.Id psid = patchKey.getParentKey();
	fileList = new PatchTable();
	fileList.setSavePointerId("PatchTable " + psid);
	Util.DETAIL_SVC.patchSetDetail(psid,
	new GerritCallback<PatchSetDetail>() {
	public void onSuccess(final PatchSetDetail result) {
	fileList.display(psid, result.getPatches());
	}
	});
	}

	final PatchBrowserPopup p = new PatchBrowserPopup(patchKey, fileList);
	p.open();
	}
	}
	}