org.mozilla.javascript.Kit Maven / Gradle / Ivy
/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.javascript;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.lang.reflect.Method;
import java.util.Map;
/**
* Collection of utilities
*/
public class Kit
{
/**
* Reflection of Throwable.initCause(Throwable) from JDK 1.4
* or nul if it is not available.
*/
private static Method Throwable_initCause = null;
static {
// Are we running on a JDK 1.4 or later system?
try {
Class ThrowableClass = Kit.classOrNull("java.lang.Throwable");
Class[] signature = { ThrowableClass };
Throwable_initCause
= ThrowableClass.getMethod("initCause", signature);
} catch (Exception ex) {
// Assume any exceptions means the method does not exist.
}
}
public static Class classOrNull(String className)
{
try {
return Class.forName(className);
} catch (ClassNotFoundException ex) {
} catch (SecurityException ex) {
} catch (LinkageError ex) {
} catch (IllegalArgumentException e) {
// Can be thrown if name has characters that a class name
// can not contain
}
return null;
}
/**
* Attempt to load the class of the given name. Note that the type parameter
* isn't checked.
*/
public static Class classOrNull(ClassLoader loader, String className)
{
try {
return loader.loadClass(className);
} catch (ClassNotFoundException ex) {
} catch (SecurityException ex) {
} catch (LinkageError ex) {
} catch (IllegalArgumentException e) {
// Can be thrown if name has characters that a class name
// can not contain
}
return null;
}
static Object newInstanceOrNull(Class cl)
{
try {
return cl.newInstance();
} catch (SecurityException x) {
} catch (LinkageError ex) {
} catch (InstantiationException x) {
} catch (IllegalAccessException x) {
}
return null;
}
/**
* Check that testClass is accessible from the given loader.
*/
static boolean testIfCanLoadRhinoClasses(ClassLoader loader)
{
Class testClass = ScriptRuntime.ContextFactoryClass;
Class x = Kit.classOrNull(loader, testClass.getName());
if (x != testClass) {
// The check covers the case when x == null =>
// loader does not know about testClass or the case
// when x != null && x != testClass =>
// loader loads a class unrelated to testClass
return false;
}
return true;
}
/**
* If initCause methods exists in Throwable, call
* ex.initCause(cause) or otherwise do nothing.
* @return The ex argument.
*/
public static RuntimeException initCause(RuntimeException ex,
Throwable cause)
{
if (Throwable_initCause != null) {
Object[] args = { cause };
try {
Throwable_initCause.invoke(ex, args);
} catch (Exception e) {
// Ignore any exceptions
}
}
return ex;
}
/**
* If character c is a hexadecimal digit, return
* accumulator * 16 plus corresponding
* number. Otherise return -1.
*/
public static int xDigitToInt(int c, int accumulator)
{
check: {
// Use 0..9 < A..Z < a..z
if (c <= '9') {
c -= '0';
if (0 <= c) { break check; }
} else if (c <= 'F') {
if ('A' <= c) {
c -= ('A' - 10);
break check;
}
} else if (c <= 'f') {
if ('a' <= c) {
c -= ('a' - 10);
break check;
}
}
return -1;
}
return (accumulator << 4) | c;
}
/**
* Add listener to bag of listeners.
* The function does not modify bag and return a new collection
* containing listener and all listeners from bag.
* Bag without listeners always represented as the null value.
*
* Usage example:
*
* private volatile Object changeListeners;
*
* public void addMyListener(PropertyChangeListener l)
* {
* synchronized (this) {
* changeListeners = Kit.addListener(changeListeners, l);
* }
* }
*
* public void removeTextListener(PropertyChangeListener l)
* {
* synchronized (this) {
* changeListeners = Kit.removeListener(changeListeners, l);
* }
* }
*
* public void fireChangeEvent(Object oldValue, Object newValue)
* {
* // Get immune local copy
* Object listeners = changeListeners;
* if (listeners != null) {
* PropertyChangeEvent e = new PropertyChangeEvent(
* this, "someProperty" oldValue, newValue);
* for (int i = 0; ; ++i) {
* Object l = Kit.getListener(listeners, i);
* if (l == null)
* break;
* ((PropertyChangeListener)l).propertyChange(e);
* }
* }
* }
*
*
* @param listener Listener to add to bag
* @param bag Current collection of listeners.
* @return A new bag containing all listeners from bag and
* listener.
* @see #removeListener(Object bag, Object listener)
* @see #getListener(Object bag, int index)
*/
public static Object addListener(Object bag, Object listener)
{
if (listener == null) throw new IllegalArgumentException();
if (listener instanceof Object[]) throw new IllegalArgumentException();
if (bag == null) {
bag = listener;
} else if (!(bag instanceof Object[])) {
bag = new Object[] { bag, listener };
} else {
Object[] array = (Object[])bag;
int L = array.length;
// bag has at least 2 elements if it is array
if (L < 2) throw new IllegalArgumentException();
Object[] tmp = new Object[L + 1];
System.arraycopy(array, 0, tmp, 0, L);
tmp[L] = listener;
bag = tmp;
}
return bag;
}
/**
* Remove listener from bag of listeners.
* The function does not modify bag and return a new collection
* containing all listeners from bag except listener.
* If bag does not contain listener, the function returns
* bag.
*
* For usage example, see {@link #addListener(Object bag, Object listener)}.
*
* @param listener Listener to remove from bag
* @param bag Current collection of listeners.
* @return A new bag containing all listeners from bag except
* listener.
* @see #addListener(Object bag, Object listener)
* @see #getListener(Object bag, int index)
*/
public static Object removeListener(Object bag, Object listener)
{
if (listener == null) throw new IllegalArgumentException();
if (listener instanceof Object[]) throw new IllegalArgumentException();
if (bag == listener) {
bag = null;
} else if (bag instanceof Object[]) {
Object[] array = (Object[])bag;
int L = array.length;
// bag has at least 2 elements if it is array
if (L < 2) throw new IllegalArgumentException();
if (L == 2) {
if (array[1] == listener) {
bag = array[0];
} else if (array[0] == listener) {
bag = array[1];
}
} else {
int i = L;
do {
--i;
if (array[i] == listener) {
Object[] tmp = new Object[L - 1];
System.arraycopy(array, 0, tmp, 0, i);
System.arraycopy(array, i + 1, tmp, i, L - (i + 1));
bag = tmp;
break;
}
} while (i != 0);
}
}
return bag;
}
/**
* Get listener at index position in bag or null if
* index equals to number of listeners in bag.
*
* For usage example, see {@link #addListener(Object bag, Object listener)}.
*
* @param bag Current collection of listeners.
* @param index Index of the listener to access.
* @return Listener at the given index or null.
* @see #addListener(Object bag, Object listener)
* @see #removeListener(Object bag, Object listener)
*/
public static Object getListener(Object bag, int index)
{
if (index == 0) {
if (bag == null)
return null;
if (!(bag instanceof Object[]))
return bag;
Object[] array = (Object[])bag;
// bag has at least 2 elements if it is array
if (array.length < 2) throw new IllegalArgumentException();
return array[0];
} else if (index == 1) {
if (!(bag instanceof Object[])) {
if (bag == null) throw new IllegalArgumentException();
return null;
}
Object[] array = (Object[])bag;
// the array access will check for index on its own
return array[1];
} else {
// bag has to array
Object[] array = (Object[])bag;
int L = array.length;
if (L < 2) throw new IllegalArgumentException();
if (index == L)
return null;
return array[index];
}
}
static Object initHash(Map h, Object key, Object initialValue)
{
synchronized (h) {
Object current = h.get(key);
if (current == null) {
h.put(key, initialValue);
} else {
initialValue = current;
}
}
return initialValue;
}
private final static class ComplexKey
{
private Object key1;
private Object key2;
private int hash;
ComplexKey(Object key1, Object key2)
{
this.key1 = key1;
this.key2 = key2;
}
@Override
public boolean equals(Object anotherObj)
{
if (!(anotherObj instanceof ComplexKey))
return false;
ComplexKey another = (ComplexKey)anotherObj;
return key1.equals(another.key1) && key2.equals(another.key2);
}
@Override
public int hashCode()
{
if (hash == 0) {
hash = key1.hashCode() ^ key2.hashCode();
}
return hash;
}
}
public static Object makeHashKeyFromPair(Object key1, Object key2)
{
if (key1 == null) throw new IllegalArgumentException();
if (key2 == null) throw new IllegalArgumentException();
return new ComplexKey(key1, key2);
}
public static String readReader(Reader r)
throws IOException
{
char[] buffer = new char[512];
int cursor = 0;
for (;;) {
int n = r.read(buffer, cursor, buffer.length - cursor);
if (n < 0) { break; }
cursor += n;
if (cursor == buffer.length) {
char[] tmp = new char[buffer.length * 2];
System.arraycopy(buffer, 0, tmp, 0, cursor);
buffer = tmp;
}
}
return new String(buffer, 0, cursor);
}
public static byte[] readStream(InputStream is, int initialBufferCapacity)
throws IOException
{
if (initialBufferCapacity <= 0) {
throw new IllegalArgumentException(
"Bad initialBufferCapacity: "+initialBufferCapacity);
}
byte[] buffer = new byte[initialBufferCapacity];
int cursor = 0;
for (;;) {
int n = is.read(buffer, cursor, buffer.length - cursor);
if (n < 0) { break; }
cursor += n;
if (cursor == buffer.length) {
byte[] tmp = new byte[buffer.length * 2];
System.arraycopy(buffer, 0, tmp, 0, cursor);
buffer = tmp;
}
}
if (cursor != buffer.length) {
byte[] tmp = new byte[cursor];
System.arraycopy(buffer, 0, tmp, 0, cursor);
buffer = tmp;
}
return buffer;
}
/**
* Throws RuntimeException to indicate failed assertion.
* The function never returns and its return type is RuntimeException
* only to be able to write throw Kit.codeBug() if plain
* Kit.codeBug() triggers unreachable code error.
*/
public static RuntimeException codeBug()
throws RuntimeException
{
RuntimeException ex = new IllegalStateException("FAILED ASSERTION");
// Print stack trace ASAP
ex.printStackTrace(System.err);
throw ex;
}
/**
* Throws RuntimeException to indicate failed assertion.
* The function never returns and its return type is RuntimeException
* only to be able to write throw Kit.codeBug() if plain
* Kit.codeBug() triggers unreachable code error.
*/
public static RuntimeException codeBug(String msg)
throws RuntimeException
{
msg = "FAILED ASSERTION: " + msg;
RuntimeException ex = new IllegalStateException(msg);
// Print stack trace ASAP
ex.printStackTrace(System.err);
throw ex;
}
}