X-Git-Url: https://gerrit.simantics.org/r/gitweb?a=blobdiff_plain;f=bundles%2Forg.eclipse.swt.win32.win32.x86_64%2Fsrc%2Forg%2Feclipse%2Fswt%2Finternal%2FCallback.java;fp=bundles%2Forg.eclipse.swt.win32.win32.x86_64%2Fsrc%2Forg%2Feclipse%2Fswt%2Finternal%2FCallback.java;h=2248861bae8067dcffd51482fd597ea1d9a2e96d;hb=6b98970d0458754dd67f789afbd0a39e1e7ac6eb;hp=0000000000000000000000000000000000000000;hpb=56a61575ce0d27b340cb12438c8a7f303842095e;p=simantics%2Fplatform.git diff --git a/bundles/org.eclipse.swt.win32.win32.x86_64/src/org/eclipse/swt/internal/Callback.java b/bundles/org.eclipse.swt.win32.win32.x86_64/src/org/eclipse/swt/internal/Callback.java new file mode 100644 index 000000000..2248861ba --- /dev/null +++ b/bundles/org.eclipse.swt.win32.win32.x86_64/src/org/eclipse/swt/internal/Callback.java @@ -0,0 +1,361 @@ +/******************************************************************************* + * Copyright (c) 2000, 2012 IBM Corporation and others. + * + * This program and the accompanying materials + * are made available under the terms of the Eclipse Public License 2.0 + * which accompanies this distribution, and is available at + * https://www.eclipse.org/legal/epl-2.0/ + * + * SPDX-License-Identifier: EPL-2.0 + * + * Contributors: + * IBM Corporation - initial API and implementation + *******************************************************************************/ +package org.eclipse.swt.internal; + +import java.lang.reflect.*; +import java.util.function.*; + +import org.eclipse.swt.*; + +/** + * Instances of this class represent entry points into Java + * which can be invoked from operating system level callback + * routines. + *

+ * IMPORTANT: A callback is only valid when invoked on the + * thread which created it. The results are undefined (and + * typically bad) when a callback is passed out to the + * operating system (or other code) in such a way that the + * callback is called from a different thread. + */ + +public class Callback { + + Object object; + String method, signature; + int argCount; + long address, errorResult; + boolean isStatic, isArrayBased; + + static final boolean is32Bit = C.PTR_SIZEOF == 4 ? true : false; + static final String PTR_SIGNATURE = is32Bit ? "I" : "J"; //$NON-NLS-1$ //$NON-NLS-2$ + static final String SIGNATURE_0 = getSignature(0); + static final String SIGNATURE_1 = getSignature(1); + static final String SIGNATURE_2 = getSignature(2); + static final String SIGNATURE_3 = getSignature(3); + static final String SIGNATURE_4 = getSignature(4); + static final String SIGNATURE_N = "(["+PTR_SIGNATURE+")"+PTR_SIGNATURE; //$NON-NLS-1$ //$NON-NLS-2$ + +/** + * Constructs a new instance of this class given an object + * to send the message to, a string naming the method to + * invoke and an argument count. Note that, if the object + * is an instance of Class it is assumed that + * the method is a static method on that class. + * + *

Note, do not use this if the method arguments have a double, as arguments will be + * shifted/corrupted. See Bug 510538. Instead use the following constructor:
+ * Callback (Object, String, Type, Type [])

+ * + * @param object the object to send the message to + * @param method the name of the method to invoke + * @param argCount the number of arguments that the method takes + */ +public Callback (Object object, String method, int argCount) { + this (object, method, argCount, false); +} + +/** + * Constructs a new instance of this class given an object + * to send the message to, a string naming the method to + * invoke, an argument count and a flag indicating whether + * or not the arguments will be passed in an array. Note + * that, if the object is an instance of Class + * it is assumed that the method is a static method on that + * class. + * + *

Note, do not use this if the method arguments have a double, as arguments will be + * shifted/corrupted. See Bug 510538. Instead use the following constructor:
+ * Callback (Object, String, Type, Type [])

+ * + * @param object the object to send the message to + * @param method the name of the method to invoke + * @param argCount the number of arguments that the method takes + * @param isArrayBased true if the arguments should be passed in an array and false otherwise + */ +public Callback (Object object, String method, int argCount, boolean isArrayBased) { + this (object, method, argCount, isArrayBased, 0); +} + +/** + * Constructs a new instance of this class given an object + * to send the message to, a string naming the method to + * invoke, an argument count, a flag indicating whether + * or not the arguments will be passed in an array and a value + * to return when an exception happens. Note that, if + * the object is an instance of Class + * it is assumed that the method is a static method on that + * class. + * + *

Note, do not use this if the method arguments have a double, as arguments will be + * shifted/corrupted. See Bug 510538. Instead use the following constructor:
+ * Callback (Object, String, Type, Type [])

+ * + * @param object the object to send the message to + * @param method the name of the method to invoke + * @param argCount the number of arguments that the method takes + * @param isArrayBased true if the arguments should be passed in an array and false otherwise + * @param errorResult the return value if the java code throws an exception + */ +public Callback (Object object, String method, int argCount, boolean isArrayBased, long errorResult) { + + /* Set the callback fields */ + this.object = object; + this.method = method; + this.argCount = argCount; + this.isStatic = object instanceof Class; + this.isArrayBased = isArrayBased; + this.errorResult = errorResult; + + /* Inline the common cases */ + if (isArrayBased) { + signature = SIGNATURE_N; + } else { + switch (argCount) { + case 0: signature = SIGNATURE_0; break; //$NON-NLS-1$ + case 1: signature = SIGNATURE_1; break; //$NON-NLS-1$ + case 2: signature = SIGNATURE_2; break; //$NON-NLS-1$ + case 3: signature = SIGNATURE_3; break; //$NON-NLS-1$ + case 4: signature = SIGNATURE_4; break; //$NON-NLS-1$ + default: + signature = getSignature(argCount); + } + } + + /* Bind the address */ + address = bind (this, object, method, signature, argCount, isStatic, isArrayBased, errorResult); +} + + +/** + *

Register the java method to be a C callback. + * I.e, C will be able to make a call to this java method directly (through callback.c)

+ * + *

The other constructors hard-code int/long into the method signature:
+ * long method (long ...)
+ * Which is suitable for int/long and pointers.
+ * This constructor is used if you need to use a different return/argument type, e.g double. See Bug 510538

+ * + *

Note: + *

+ * + *

The following types are supported:
+ *

+ * + *

For example if you want to link the following method:
+ * void myMethod(long /*int*/ arg1, double arg2)
+ * Then you would call this callback like:
+ * Callback (this, "myMethod", void.class, new Type []{long.class, double.class}); + *

+ * + * @param object the object to send the message to + * @param method method the name of the method to invoke + * @param returnType specify the type like void.class, long.class, double.class + * @param arguments specify the list of arguments like new Type [] {long.class, double.class } + */ +public Callback (Object object, String method, Type returnType, Type [] arguments) { + /* Set the callback fields */ + this.object = object; + this.method = method; + this.argCount = arguments != null ? arguments.length : 0; + this.isStatic = object instanceof Class; + this.isArrayBased = false; + this.errorResult = 0; + + Function getTypeLetter = type -> { + // https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html#jvms-4.3.2 + if (int.class.equals(type)) { + return "I"; + } else if (long.class.equals(type)) { + return "J"; + } else if (void.class.equals(type)) { // for return type. + return "V"; + } else if (byte.class.equals(type)) { + return "B"; + } else if (char.class.equals(type)) { + return "C"; + } else if (double.class.equals(type)) { + return "D"; + } else if (float.class.equals(type)) { + return "F"; + } else if (short.class.equals(type)) { + return "S"; + } else if (boolean.class.equals(type)) { + return "Z"; + } + SWT.error(SWT.ERROR_INVALID_ARGUMENT, null, type.toString() + "Not supported"); + return null; // not reachable. Suppress warning. + }; + + StringBuilder signature = new StringBuilder("("); + for (Type t : arguments) { + if (t.equals(void.class)) { + SWT.error(SWT.ERROR_INVALID_ARGUMENT, null, "void is not a valid argument"); + } + signature.append(getTypeLetter.apply(t)); + } + signature.append(")"); + signature.append(getTypeLetter.apply(returnType)); + this.signature = signature.toString(); + if (is32Bit) { + this.signature = this.signature.replace("J", "I"); + } + + /* Bind the address */ + address = bind (this, this.object, this.method, this.signature, this.argCount, this.isStatic, this.isArrayBased, this.errorResult); +} + + + +/** + * Allocates the native level resources associated with the + * callback. This method is only invoked from within the + * constructor for the argument. + * + * @param callback the callback to bind + * @param object the callback's object + * @param method the callback's method + * @param signature the callback's method signature + * @param argCount the callback's method argument count + * @param isStatic whether the callback's method is static + * @param isArrayBased whether the callback's method is array based + * @param errorResult the callback's error result + */ +static native synchronized long bind (Callback callback, Object object, String method, String signature, int argCount, boolean isStatic, boolean isArrayBased, long errorResult); + +/** + * Releases the native level resources associated with the callback, + * and removes all references between the callback and + * other objects. This helps to prevent (bad) application code + * from accidentally holding onto extraneous garbage. + */ +public void dispose () { + if (object == null) return; + unbind (this); + object = method = signature = null; + address = 0; +} + +/** + * Returns the address of a block of machine code which will + * invoke the callback represented by the receiver. + * + * @return the callback address + */ +public long getAddress () { + return address; +} + +/** + * Returns the SWT platform name. + * + * @return the platform name of the currently running SWT + */ +public static native String getPlatform (); + +/** + * Returns the number of times the system has been recursively entered + * through a callback. + *

+ * Note: This should not be called by application code. + *

+ * + * @return the entry count + * + * @since 2.1 + */ +public static native int getEntryCount (); + +static String getSignature(int argCount) { + String signature = "("; //$NON-NLS-1$ + for (int i = 0; i < argCount; i++) signature += PTR_SIGNATURE; + signature += ")" + PTR_SIGNATURE; //$NON-NLS-1$ + return signature; +} + +/** + * Indicates whether or not callbacks which are triggered at the + * native level should cause the messages described by the matching + * Callback objects to be invoked. This method is used + * to safely shut down SWT when it is run within environments + * which can generate spurious events. + *

+ * Note: This should not be called by application code. + *

+ * + * @param enable true if callbacks should be invoked + */ +public static final native synchronized void setEnabled (boolean enable); + +/** + * Returns whether or not callbacks which are triggered at the + * native level should cause the messages described by the matching + * Callback objects to be invoked. This method is used + * to safely shut down SWT when it is run within environments + * which can generate spurious events. + *

+ * Note: This should not be called by application code. + *

+ * + * @return true if callbacks should not be invoked + */ +public static final native synchronized boolean getEnabled (); + +/** + * This might be called directly from native code in environments + * which can generate spurious events. Check before removing it. + * + * @deprecated + * + * @param ignore true if callbacks should not be invoked + */ +@Deprecated +static final void ignoreCallbacks (boolean ignore) { + setEnabled (!ignore); +} + +/** + * Immediately wipes out all native level state associated + * with all callbacks. + *

+ * WARNING: This operation is extremely dangerous, + * and should never be performed by application code. + *

+ */ +public static final native synchronized void reset (); + +/** + * Releases the native level resources associated with the callback. + * + * @see #dispose + */ +static final native synchronized void unbind (Callback callback); + +}