RFR: 8286867: Update #getGlyphCode return a negative number

[Tomator]

On Tue, 28 Jun 2022 12:33:52 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> When I used BlueJ, I found a problem with Chinese display. /javafx.graphics/com/sun/javafx/font/CompositeGlyphMapper.java#getGlyphCode may return a negative number when no font library is specified in Linux,and this could cause java.lang.ArrayIndexOutOfBoundsException error.So javafx.graphics/com/sun/prism/impl/GlyphCache.java#getCachedGlyph  shou check the glyphCode.
>> The crash demo like this:
>> `import javafx.application.Application;
>> import javafx.scene.Scene;
>> import javafx.scene.control.Menu;
>> import javafx.scene.control.MenuBar;
>> import javafx.scene.control.MenuItem;
>> import javafx.scene.layout.BorderPane;
>> import javafx.stage.Stage;
>> 
>> public class MenuExample extends Application {
>>     public static void main(String[] args) {  
>>     launch(args);  
>>         }  
>>   
>>     @Override  
>>     public void start(Stage primaryStage) throws Exception {
>>         BorderPane root = new BorderPane();
>>         Scene scene = new Scene(root,200,300);
>>         MenuBar menubar = new MenuBar();
>>         Menu FileMenu = new Menu("文本");
>>         MenuItem filemenu1=new MenuItem("新建");
>>         MenuItem filemenu2=new MenuItem("Save");  
>>         MenuItem filemenu3=new MenuItem("Exit");  
>>         Menu EditMenu=new Menu("Edit");  
>>         MenuItem EditMenu1=new MenuItem("Cut");  
>>         MenuItem EditMenu2=new MenuItem("Copy");  
>>         MenuItem EditMenu3=new MenuItem("Paste");  
>>         EditMenu.getItems().addAll(EditMenu1,EditMenu2,EditMenu3);  
>>         root.setTop(menubar);  
>>         FileMenu.getItems().addAll(filemenu1,filemenu2,filemenu3);  
>>         menubar.getMenus().addAll(FileMenu,EditMenu);  
>>         primaryStage.setScene(scene);  
>>         primaryStage.setTitle("TEST");
>>         primaryStage.show();  
>>           
>>     }     
>> }  `
>> 
>> the error:
>> `java.lang.ArrayIndexOutOfBoundsException: Index -25 out of bounds for length 32
>>         at com.sun.prism.impl.GlyphCache.getCachedGlyph(GlyphCache.java:332)
>>         at com.sun.prism.impl.GlyphCache.render(GlyphCache.java:148)
>>         at com.sun.prism.impl.ps.BaseShaderGraphics.drawString(BaseShaderGraphics.java:2101)
>>         at com.sun.javafx.sg.prism.NGText.renderText(NGText.java:312)
>>         at com.sun.javafx.sg.prism.NGText.renderContent2D(NGText.java:270)
>>         at com.sun.javafx.sg.prism.NGShape.renderContent(NGShape.java:261)
>>         at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2072)
>>         at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
>>         at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:270)
>>         at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:578)
>>         at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2072)
>>         at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
>>         at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:270)
>>         at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:578)
>>         at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2072)
>>         at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
>>         at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:270)
>>         at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:578)
>>         at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2072)
>>         at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
>>         at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:270)
>>         at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:578)
>>         at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2072)
>>         at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
>>         at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:270)
>>         at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:578)
>>         at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:2072)
>>         at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1964)
>>         at com.sun.javafx.tk.quantum.ViewPainter.doPaint(ViewPainter.java:479)
>>         at com.sun.javafx.tk.quantum.ViewPainter.paintImpl(ViewPainter.java:328)
>>         at com.sun.javafx.tk.quantum.PresentingPainter.run(PresentingPainter.java:91)
>> `
>
> modules/javafx.graphics/src/main/java/com/sun/prism/impl/GlyphCache.java line 242:
> 
>> 240: 
>> 241:     private GlyphData getCachedGlyph(int glyphCode, int subPixel) {
>> 242:         if (glyphCode < 0) {return null;}
> 
> Have you ensured that all callers are prepared to deal with a `null` return value?
> 
> Minor: Please format this according to code conventions:
> 
> 
>         if (glyphCode < 0) {
>             return null;
>         }

`if (!packer.add(rect)) { if (PULSE_LOGGING_ENABLED) { PulseLogger.incrementCounter("Font Glyph Cache Cleared"); } // If add fails,clear up the cache. Try add again. clearAll(); if (!packer.add(rect)) { if (PrismSettings.verbose) { System.out.println(rect + " won't fit in GlyphCache"); } return null; } }

`
The line 298  also return null,so return nul is ok

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PR: https://git.openjdk.org/jfx/pull/795