--- /dev/null
+/*******************************************************************************
+ * 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.
+ * <p>
+ * 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 <code>Class</code> it is assumed that
+ * the method is a static method on that class.
+ *
+ * <p>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: <br>
+ * <code> Callback (Object, String, Type, Type [])</code></p>
+ *
+ * @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 <code>Class</code>
+ * it is assumed that the method is a static method on that
+ * class.
+ *
+ * <p>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: <br>
+ * <code> Callback (Object, String, Type, Type [])</code></p>
+ *
+ * @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 <code>true</code> 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 <code>Class</code>
+ * it is assumed that the method is a static method on that
+ * class.
+ *
+ * <p>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: <br>
+ * <code> Callback (Object, String, Type, Type [])</code></p>
+ *
+ * @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 <code>true</code> 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);
+}
+
+
+/**
+ * <p>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)</p>
+ *
+ * <p>The other constructors hard-code int/long into the method signature:<br>
+ * <code> long method (long ...) </code><br>
+ * Which is suitable for int/long and pointers.<br>
+ * This constructor is used if you need to use a different return/argument type, e.g double. See Bug 510538 </p>
+ *
+ * <p> Note:
+ * <ul>
+ * <li> Array support is not implemented/supported by this constructor. Use other constructors.</li>
+ * <li> If the object is an instance of <code>Class</code> it is assumed that
+ * the method is a static method on that class. </li>
+ * <li> Note, long types are converted to ints on 32 bit system automatically to account for smaller pointers.
+ * This means if you use 'long', you need to cast int next to it. like: <code> long /*int*/</code> </li>
+ * </ul></p>
+ *
+ * <p>The following types are supported: <br>
+ * <ul>
+ * <li>void (for return values only) </li>
+ * <li>int</li>
+ * <li>long</li>
+ * <li>byte</li>
+ * <li>char</li>
+ * <li>double</li>
+ * <li>float</li>
+ * <li>short</li>
+ * <li>boolean</li>
+ * </ul>
+ *
+ * <p> For example if you want to link the following method: <br>
+ * <code> void myMethod(long /*int*/ arg1, double arg2) </code> <br>
+ * Then you would call this callback like:<br>
+ * <code> Callback (this, "myMethod", void.class, new Type []{long.class, double.class}); </code>
+ * </p>
+ *
+ * @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 <code>void.class, long.class, double.class </code>
+ * @param arguments specify the list of arguments like <code> new Type [] {long.class, double.class } </code>
+ */
+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 <Type, String> 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.
+ * <p>
+ * Note: This should not be called by application code.
+ * </p>
+ *
+ * @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
+ * <code>Callback</code> objects to be invoked. This method is used
+ * to safely shut down SWT when it is run within environments
+ * which can generate spurious events.
+ * <p>
+ * Note: This should not be called by application code.
+ * </p>
+ *
+ * @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
+ * <code>Callback</code> objects to be invoked. This method is used
+ * to safely shut down SWT when it is run within environments
+ * which can generate spurious events.
+ * <p>
+ * Note: This should not be called by application code.
+ * </p>
+ *
+ * @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 <em>all</em> callbacks.
+ * <p>
+ * <b>WARNING:</b> This operation is <em>extremely</em> dangerous,
+ * and should never be performed by application code.
+ * </p>
+ */
+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);
+
+}
Code Review / simantics / platform.git / blobdiff