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/*
* Copyright (C) 2018-20199 The Project Lombok Authors.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package lombok.permit;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import com.sun.tools.javac.tree.JCTree.JCExpression;
import com.sun.tools.javac.util.List;
// sunapi suppresses javac's warning about using Unsafe; 'all' suppresses eclipse's warning about the unspecified 'sunapi' key. Leave them both.
// Yes, javac's definition of the word 'all' is quite contrary to what the dictionary says it means. 'all' does NOT include 'sunapi' according to javac.
@SuppressWarnings({"sunapi", "all"})
public class Permit {
private Permit() {}
private static final long ACCESSIBLE_OVERRIDE_FIELD_OFFSET;
private static final IllegalAccessException INIT_ERROR;
private static final sun.misc.Unsafe UNSAFE = (sun.misc.Unsafe) reflectiveStaticFieldAccess(sun.misc.Unsafe.class, "theUnsafe");
static {
Field f;
long g;
Throwable ex;
try {
g = getOverrideFieldOffset();
ex = null;
} catch (Throwable t) {
f = null;
g = -1L;
ex = t;
}
ACCESSIBLE_OVERRIDE_FIELD_OFFSET = g;
if (ex == null) INIT_ERROR = null;
else if (ex instanceof IllegalAccessException) INIT_ERROR = (IllegalAccessException) ex;
else {
INIT_ERROR = new IllegalAccessException("Cannot initialize Unsafe-based permit");
INIT_ERROR.initCause(ex);
}
}
public static <T extends AccessibleObject> T setAccessible(T accessor) {
if (INIT_ERROR == null) {
UNSAFE.putBoolean(accessor, ACCESSIBLE_OVERRIDE_FIELD_OFFSET, true);
} else {
accessor.setAccessible(true);
}
return accessor;
}
private static long getOverrideFieldOffset() throws Throwable {
Field f = null;
Throwable saved = null;
try {
f = AccessibleObject.class.getDeclaredField("override");
} catch (Throwable t) {
saved = t;
}
if (f != null) {
return UNSAFE.objectFieldOffset(f);
}
// The below seems very risky, but for all AccessibleObjects in java today it does work, and starting with JDK12, making the field accessible is no longer possible.
try {
return UNSAFE.objectFieldOffset(Fake.class.getDeclaredField("override"));
} catch (Throwable t) {
throw saved;
}
}
static class Fake {
boolean override;
Object accessCheckCache;
}
public static Method getMethod(Class<?> c, String mName, Class<?>... parameterTypes) throws NoSuchMethodException {
Method m = null;
Class<?> oc = c;
while (c != null) {
try {
m = c.getDeclaredMethod(mName, parameterTypes);
break;
} catch (NoSuchMethodException e) {}
c = c.getSuperclass();
}
if (m == null) throw new NoSuchMethodException(oc.getName() + " :: " + mName + "(args)");
return setAccessible(m);
}
public static Field getField(Class<?> c, String fName) throws NoSuchFieldException {
Field f = null;
Class<?> oc = c;
while (c != null) {
try {
f = c.getDeclaredField(fName);
break;
} catch (NoSuchFieldException e) {}
c = c.getSuperclass();
}
if (f == null) throw new NoSuchFieldException(oc.getName() + " :: " + fName);
return setAccessible(f);
}
public static Field permissiveGetField(Class<?> c, String fName) {
try {
return getField(c, fName);
} catch (Exception ignore) {
return null;
}
}
public static <T> T permissiveReadField(Class<T> type, Field f, Object instance) {
try {
return type.cast(f.get(instance));
} catch (Exception ignore) {
return null;
}
}
public static <T> Constructor<T> getConstructor(Class<T> c, Class<?>... parameterTypes) throws NoSuchMethodException {
return setAccessible(c.getDeclaredConstructor(parameterTypes));
}
private static Object reflectiveStaticFieldAccess(Class<?> c, String fName) {
try {
Field f = c.getDeclaredField(fName);
f.setAccessible(true);
return f.get(null);
} catch (Exception e) {
return null;
}
}
}
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