Mercurial > hg > shenandoah-preopenjdk-archive > openjdk8 > jdk
changeset 283:52f4ad84d5f0
6640532: Graphics.getFontMetrics() throws NullPointerException
Summary: NIO usage needs to be robust against Thread.interrupt()
Reviewed-by: tdv
author | prr |
---|---|
date | Fri, 07 Mar 2008 12:13:17 -0800 |
parents | 8266cb7549d3 |
children | 73d443d6c863 e4abdd4c2303 |
files | src/share/classes/sun/font/FontManager.java test/java/awt/font/Threads/FontThread.java |
diffstat | 2 files changed, 124 insertions(+), 21 deletions(-) [+] |
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--- a/src/share/classes/sun/font/FontManager.java Fri Feb 29 20:04:01 2008 -0800 +++ b/src/share/classes/sun/font/FontManager.java Fri Mar 07 12:13:17 2008 -0800 @@ -93,7 +93,6 @@ */ private static final int CHANNELPOOLSIZE = 20; private static int lastPoolIndex = 0; - private static int poolSize = 0; private static FileFont fontFileCache[] = new FileFont[CHANNELPOOLSIZE]; /* Need to implement a simple linked list scheme for fast @@ -283,29 +282,32 @@ private static native void initIDs(); public static void addToPool(FileFont font) { - boolean added = false; + + FileFont fontFileToClose = null; + int freeSlot = -1; + synchronized (fontFileCache) { - /* use poolSize to quickly detect if there's any free slots. - * This is a performance tweak based on the assumption that - * if this is executed at all often, its because there are many - * fonts being used and the pool will be full, and we will save - * a fruitless iteration + /* Avoid duplicate entries in the pool, and don't close() it, + * since this method is called only from within open(). + * Seeing a duplicate is most likely to happen if the thread + * was interrupted during a read, forcing perhaps repeated + * close and open calls and it eventually it ends up pointing + * at the same slot. */ - if (poolSize < CHANNELPOOLSIZE) { - for (int i=0; i<CHANNELPOOLSIZE; i++) { - if (fontFileCache[i] == null) { - fontFileCache[i] = font; - poolSize++; - added = true; - break; - } + for (int i=0;i<CHANNELPOOLSIZE;i++) { + if (fontFileCache[i] == font) { + return; + } + if (fontFileCache[i] == null && freeSlot < 0) { + freeSlot = i; } - assert added; + } + if (freeSlot >= 0) { + fontFileCache[freeSlot] = font; + return; } else { - // is it possible for this to be the same font? - assert fontFileCache[lastPoolIndex] != font; - /* replace with new font, poolSize is unchanged. */ - fontFileCache[lastPoolIndex].close(); + /* replace with new font. */ + fontFileToClose = fontFileCache[lastPoolIndex]; fontFileCache[lastPoolIndex] = font; /* lastPoolIndex is updated so that the least recently opened * file will be closed next. @@ -313,6 +315,19 @@ lastPoolIndex = (lastPoolIndex+1) % CHANNELPOOLSIZE; } } + /* Need to close the font file outside of the synchronized block, + * since its possible some other thread is in an open() call on + * this font file, and could be holding its lock and the pool lock. + * Releasing the pool lock allows that thread to continue, so it can + * then release the lock on this font, allowing the close() call + * below to proceed. + * Also, calling close() is safe because any other thread using + * the font we are closing() synchronizes all reading, so we + * will not close the file while its in use. + */ + if (fontFileToClose != null) { + fontFileToClose.close(); + } } /* @@ -334,7 +349,6 @@ for (int i=0; i<CHANNELPOOLSIZE; i++) { if (fontFileCache[i] == font) { fontFileCache[i] = null; - poolSize--; } } }
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/test/java/awt/font/Threads/FontThread.java Fri Mar 07 12:13:17 2008 -0800 @@ -0,0 +1,89 @@ +/* + * Copyright 2007 Sun Microsystems, Inc. All Rights Reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + */ + + +/* @test + * @summary verify thread interruption doesn't affect font file reading. + * @bug 6640532 + */ + +import java.awt.*; + +public class FontThread extends Thread { + + String fontName = "Dialog"; + static FontThread thread1; + static FontThread thread2; + static FontThread thread3; + + public static void main(String args[]) throws Exception { + thread1 = new FontThread("SansSerif"); + thread2 = new FontThread("Serif"); + thread3 = new FontThread("Monospaced"); + thread1.dometrics(60); // load classes first + thread1.start(); + thread2.start(); + thread3.start(); + InterruptThread ithread = new InterruptThread(); + ithread.setDaemon(true); + ithread.start(); + thread1.join(); + thread2.join(); + thread3.join(); + } + + FontThread(String font) { + super(); + this.fontName = font; + } + + public void run() { + System.out.println("started "+fontName); System.out.flush(); + dometrics(4000); + System.out.println("done "+fontName); System.out.flush(); + } + + private void dometrics(int max) { + Font f = new Font(fontName, Font.PLAIN, 12); + FontMetrics fm = Toolkit.getDefaultToolkit().getFontMetrics(f); + for (char i=0;i<max;i++) { + if (f.canDisplay(i)) fm.charWidth(i); + } + } + + static class InterruptThread extends Thread { + public void run() { + while (true) { + try { + Thread.sleep(1); + } catch (InterruptedException e) { + } + thread1.interrupt(); + thread2.interrupt(); + thread3.interrupt(); + } + } + } +} + +