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1: /* GtkMainThread.java -- Wrapper for the GTK main thread, and some utilities. 2: Copyright (C) 2006 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package gnu.java.awt.peer.gtk; 40: 41: import gnu.java.awt.peer.NativeEventLoopRunningEvent; 42: 43: /** 44: * The Java thread representing the native GTK main loop, that is, 45: * GtkMainThread.mainThread, terminates when GtkToolkit.gtkMain() 46: * returns. That happens in response to the last window peer being 47: * disposed (see GtkWindowPeer.dispose). 48: * 49: * When GtkMainThread.destroyWindow is called for the last window, it 50: * in turn calls GtkMainThread.endMainThread, which calls gtk_quit. 51: * gtk_quit signals gtk_main to return, which causes GtkMainThread.run 52: * to return. 53: * 54: * There should only be one native GTK main loop running at any given 55: * time. In order to safely start and stop the GTK main loop, we use 56: * a running flag and corresponding runningLock. startMainThread will 57: * not return until the native GTK main loop has started, as confirmed 58: * by the native set_running_flag callback setting the running flag to 59: * true. Without this protection, gtk_quit could be called before the 60: * main loop has actually started, which causes GTK assertion 61: * failures. Likewise endMainThread will not return until the native 62: * GTK main loop has ended. 63: * 64: * post_running_flag_callback is called during gtk_main initialization 65: * and no window can be created before startMainThread returns. This 66: * ensures that calling post_running_flag_callback is the first action 67: * taken by the native GTK main loop. 68: * 69: * GtkMainThread.mainThread is started when the window count goes from 70: * zero to one. 71: * 72: * GtkMainThread keeps the AWT event queue informed of its status by 73: * posting NativeEventLoopRunningEvents. The AWT event queue uses 74: * this status to determine whether or not the AWT exit conditions 75: * have been met (see EventQueue.isShutdown). 76: */ 77: public class GtkMainThread extends Thread 78: { 79: /** Count of the number of open windows */ 80: private static int numberOfWindows = 0; 81: 82: /** Lock for the above */ 83: private static Object nWindowsLock = new Object(); 84: 85: /** Indicates whether or not the GTK main loop is running. */ 86: private static boolean running = false; 87: 88: /** Lock for the above. */ 89: private static Object runningLock = new Object(); 90: 91: /** The main thread instance (singleton) */ 92: public static GtkMainThread mainThread; 93: 94: /** Constructs a main thread */ 95: private GtkMainThread() 96: { 97: super("GTK main thread"); 98: } 99: 100: public void run () 101: { 102: GtkToolkit.gtkMain (); 103: } 104: 105: private static void setRunning(boolean running) 106: { 107: synchronized (runningLock) 108: { 109: GtkMainThread.running = running; 110: runningLock.notifyAll(); 111: } 112: } 113: 114: private static void startMainThread() 115: { 116: synchronized (runningLock) 117: { 118: if (!running) 119: { 120: mainThread = new GtkMainThread(); 121: mainThread.start(); 122: 123: while (!running) 124: { 125: try 126: { 127: runningLock.wait(); 128: } 129: catch (InterruptedException e) 130: { 131: System.err.println ("GtkMainThread.startMainThread:" 132: + " interrupted while waiting " 133: + " for GTK main loop to start"); 134: } 135: } 136: GtkGenericPeer.q() 137: .postEvent(new NativeEventLoopRunningEvent(Boolean.TRUE)); 138: } 139: } 140: } 141: 142: private static void endMainThread() 143: { 144: synchronized (runningLock) 145: { 146: if (running) 147: { 148: GtkToolkit.gtkQuit(); 149: 150: while (running) 151: { 152: try 153: { 154: runningLock.wait(); 155: } 156: catch (InterruptedException e) 157: { 158: System.err.println ("GtkMainThread.endMainThread:" 159: + " interrupted while waiting " 160: + " for GTK main loop to stop"); 161: } 162: } 163: GtkGenericPeer.q() 164: .postEvent(new NativeEventLoopRunningEvent(Boolean.FALSE)); 165: } 166: } 167: } 168: 169: public static void createWindow() 170: { 171: synchronized (nWindowsLock) 172: { 173: if (numberOfWindows == 0) 174: startMainThread(); 175: numberOfWindows++; 176: } 177: } 178: 179: public static void destroyWindow() 180: { 181: synchronized (nWindowsLock) 182: { 183: numberOfWindows--; 184: if (numberOfWindows == 0) 185: endMainThread(); 186: } 187: } 188: }