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Made SWT detection java9+ friendly (we no longer use reflection)

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This commit is contained in:
nathan 2019-05-25 01:40:01 +02:00
parent cea9fb528c
commit d58812acaf
1 changed files with 40 additions and 116 deletions
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156
src/dorkbox/util/Swt.java
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@ -15,17 +15,10 @@
*/
package dorkbox.util;
import java.lang.reflect.Method;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Display;
import org.slf4j.LoggerFactory;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtField;
import javassist.CtMethod;
import javassist.CtNewMethod;
import javassist.Modifier;
/**
* Utility methods for SWT. Some of the methods will be overwritten via Javassist so we don't require a hard dependency on SWT.
* <p>
@ -37,11 +30,9 @@ class Swt {
public final static boolean isLoaded;
public final static boolean isGtk3;
private static final Object currentDisplay;
private static final Display currentDisplay;
private static final Thread currentDisplayThread;
// Methods are cached for performance
private static final Method syncExecMethod;
private static final int version;
static {
@ -49,13 +40,9 @@ class Swt {
boolean isSwtGtk3_ = false;
try {
java.lang.reflect.Method m = ClassLoader.class.getDeclaredMethod("findLoadedClass", String.class);
m.setAccessible(true);
ClassLoader cl = ClassLoader.getSystemClassLoader();
// maybe we should load the SWT version? (In order for us to work with SWT, BOTH must be the same!!
// SWT is GTK2, but if -DSWT_GTK3=1 is specified, it can be GTK3
isSwtLoaded_ = null != m.invoke(cl, "org.eclipse.swt.widgets.Display");
isSwtLoaded_ = null != Class.forName("org.eclipse.swt.widgets.Display");
if (isSwtLoaded_) {
// Necessary for us to work with SWT based on version info. We can try to set us to be compatible with whatever it is set to
@ -74,125 +61,62 @@ class Swt {
LoggerFactory.getLogger(Swt.class).debug("Error detecting if SWT is loaded", e);
}
isLoaded = isSwtLoaded_;
isGtk3 = isSwtGtk3_;
// we MUST save this now, otherwise it is "null" when methods are run from the swing EDT.
//
// currentDisplay = org.eclipse.swt.widgets.Display.getCurrent();
// currentDisplayThread = currentDisplay.getThread();
// also save the SWT version
Object _currentDisplay = null;
Thread _currentDisplayThread = null;
Method _syncExecMethod = null;
int _version = 0;
if (isSwtLoaded_) {
// we MUST save the currentDisplay now, otherwise it is "null" when methods are run from the swing EDT.
// also save the SWT version
// NOTE: we cannot check if there is a default display, because JUST CHECKING will initialize a new one
Display _currentDisplay = null;
Thread _currentDisplayThread = null;
if (isSwtLoaded_ && SWT.isLoadable()) {
try {
// SWT.getVersion()
Class<?> clazz = Class.forName("org.eclipse.swt.SWT");
Method getVersionMethod = clazz.getMethod("getVersion");
_version = (Integer) getVersionMethod.invoke(null);
_version = SWT.getVersion();
_currentDisplay = Display.getCurrent();
clazz = Class.forName("org.eclipse.swt.widgets.Display");
Method getCurrentMethod = clazz.getMethod("getCurrent");
Method getThreadMethod = clazz.getMethod("getThread");
_syncExecMethod = clazz.getDeclaredMethod("syncExec", Runnable.class);
_currentDisplay = getCurrentMethod.invoke(null);
_currentDisplayThread = (Thread) getThreadMethod.invoke(_currentDisplay);
// re-write the part that is heavily SWT dependent, that cannot be done via reflection.
byte[] bytes;
String body;
CtMethod method;
CtField ctField;
ClassPool pool = ClassPool.getDefault();
CtClass swtOverriedClass = pool.get("dorkbox.util.Swt$SwtOverride");
// the abstractions for listener are REQUIRED by javassist.
{
CtClass listener = pool.makeClass("dorkbox.util.Swt_listener");
listener.addInterface(pool.get("org.eclipse.swt.widgets.Listener"));
ctField = new CtField(pool.get("java.lang.Runnable"), "runnable", listener);
ctField.setModifiers(Modifier.PROTECTED);
listener.addField(ctField);
method = CtNewMethod.make(CtClass.voidType, "handleEvent",
new CtClass[]{pool.get("org.eclipse.swt.widgets.Event")}, null,
"{" +
" this.runnable.run();" +
"}", listener);
listener.addMethod(method);
bytes = listener.toBytecode();
ClassLoaderUtil.defineClass(bytes);
if (_currentDisplay != null) {
_currentDisplayThread = Display.getCurrent().getThread();
}
method = swtOverriedClass.getDeclaredMethod("onShutdown");
body = "{" +
"org.eclipse.swt.widgets.Display currentDisplay = (org.eclipse.swt.widgets.Display)$1;" +
"Runnable runnable = $2;" +
"dorkbox.util.Swt_listener listener = new dorkbox.util.Swt_listener();" +
"listener.runnable = runnable;" +
"org.eclipse.swt.widgets.Shell shell = currentDisplay.getShells()[0];" +
"shell.addListener(org.eclipse.swt.SWT.Close, listener);" +
"}";
method.setBody(body);
bytes = swtOverriedClass.toBytecode();
// define this new class in our current classloader
ClassLoaderUtil.defineClass(bytes);
} catch (Throwable e) {
LoggerFactory.getLogger(Swt.class).error("Cannot initialize SWT", e);
}
}
// if we use SWT incorrectly (ie, it's available on the classpath, but we didn't start the application) then
// '_currentDisplay' will be null. This is a reasonable way to detect if SWT is being used or not.
if (_currentDisplay == null) {
_version = 0;
isSwtLoaded_ = false;
isSwtGtk3_ = false;
}
currentDisplay = _currentDisplay;
currentDisplayThread = _currentDisplayThread;
syncExecMethod = _syncExecMethod;
version = _version;
isLoaded = isSwtLoaded_;
isGtk3 = isSwtGtk3_;
}
// this class is over-written via Javassist, because reflection cannot create anonymous classes. Javassist can, with caveats.
@SuppressWarnings("unused")
public static
class SwtOverride {
static
void onShutdown(final Object currentDisplay, final Runnable runnable) {
// currentDisplay.getShells() must only be called inside the event thread!
private static
void onShutdown(final Display currentDisplay, final Runnable runnable) {
// currentDisplay.getShells() must only be called inside the event thread!
// org.eclipse.swt.widgets.Shell shell = currentDisplay.getShells()[0];
// shell.addListener(org.eclipse.swt.SWT.Close, new org.eclipse.swt.widgets.Listener() {
// @Override
// public
// void handleEvent(final org.eclipse.swt.widgets.Event event) {
// runnable.run();
// }
// });
throw new RuntimeException("This should never happen, as this class is over-written at runtime.");
}
org.eclipse.swt.widgets.Shell shell = currentDisplay.getShells()[0];
shell.addListener(org.eclipse.swt.SWT.Close, new org.eclipse.swt.widgets.Listener() {
@Override
public
void handleEvent(final org.eclipse.swt.widgets.Event event) {
runnable.run();
}
});
}
public static
void dispatch(final Runnable runnable) {
// currentDisplay.syncExec(runnable);
try {
syncExecMethod.invoke(currentDisplay, runnable);
} catch (Throwable e) {
LoggerFactory.getLogger(Swt.class)
.error("Unable to execute JavaFX runLater(). Please create an issue with your OS and Java " +
"version so we may further investigate this issue.");
}
currentDisplay.syncExec(runnable);
}
public static
@ -204,13 +128,13 @@ class Swt {
void onShutdown(final Runnable runnable) {
// currentDisplay.getShells() must only be called inside the event thread!
if (isEventThread()) {
SwtOverride.onShutdown(currentDisplay, runnable);
onShutdown(currentDisplay, runnable);
} else {
dispatch(new Runnable() {
@Override
public
void run() {
SwtOverride.onShutdown(currentDisplay, runnable);
onShutdown(currentDisplay, runnable);
}
});
}