Java example source code file (MethodHandleImpl.java)
The MethodHandleImpl.java Java example source code/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* This code is free software; you can redistribute it and/or modify it
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package java.lang.invoke;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import sun.invoke.empty.Empty;
import sun.invoke.util.ValueConversions;
import sun.invoke.util.VerifyType;
import sun.invoke.util.Wrapper;
import sun.reflect.CallerSensitive;
import sun.reflect.Reflection;
import static java.lang.invoke.LambdaForm.*;
import static java.lang.invoke.MethodHandleStatics.*;
import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
/**
* Trusted implementation code for MethodHandle.
* @author jrose
*/
/*non-public*/ abstract class MethodHandleImpl {
/// Factory methods to create method handles:
static void initStatics() {
// Trigger selected static initializations.
MemberName.Factory.INSTANCE.getClass();
}
static MethodHandle makeArrayElementAccessor(Class<?> arrayClass, boolean isSetter) {
if (!arrayClass.isArray())
throw newIllegalArgumentException("not an array: "+arrayClass);
MethodHandle accessor = ArrayAccessor.getAccessor(arrayClass, isSetter);
MethodType srcType = accessor.type().erase();
MethodType lambdaType = srcType.invokerType();
Name[] names = arguments(1, lambdaType);
Name[] args = Arrays.copyOfRange(names, 1, 1 + srcType.parameterCount());
names[names.length - 1] = new Name(accessor.asType(srcType), (Object[]) args);
LambdaForm form = new LambdaForm("getElement", lambdaType.parameterCount(), names);
MethodHandle mh = SimpleMethodHandle.make(srcType, form);
if (ArrayAccessor.needCast(arrayClass)) {
mh = mh.bindTo(arrayClass);
}
mh = mh.asType(ArrayAccessor.correctType(arrayClass, isSetter));
return mh;
}
static final class ArrayAccessor {
/// Support for array element access
static final HashMap<Class GETTER_CACHE = new HashMap<>(); // TODO use it
static final HashMap<Class SETTER_CACHE = new HashMap<>(); // TODO use it
static int getElementI(int[] a, int i) { return a[i]; }
static long getElementJ(long[] a, int i) { return a[i]; }
static float getElementF(float[] a, int i) { return a[i]; }
static double getElementD(double[] a, int i) { return a[i]; }
static boolean getElementZ(boolean[] a, int i) { return a[i]; }
static byte getElementB(byte[] a, int i) { return a[i]; }
static short getElementS(short[] a, int i) { return a[i]; }
static char getElementC(char[] a, int i) { return a[i]; }
static Object getElementL(Object[] a, int i) { return a[i]; }
static void setElementI(int[] a, int i, int x) { a[i] = x; }
static void setElementJ(long[] a, int i, long x) { a[i] = x; }
static void setElementF(float[] a, int i, float x) { a[i] = x; }
static void setElementD(double[] a, int i, double x) { a[i] = x; }
static void setElementZ(boolean[] a, int i, boolean x) { a[i] = x; }
static void setElementB(byte[] a, int i, byte x) { a[i] = x; }
static void setElementS(short[] a, int i, short x) { a[i] = x; }
static void setElementC(char[] a, int i, char x) { a[i] = x; }
static void setElementL(Object[] a, int i, Object x) { a[i] = x; }
static Object getElementL(Class<?> arrayClass, Object[] a, int i) { arrayClass.cast(a); return a[i]; }
static void setElementL(Class<?> arrayClass, Object[] a, int i, Object x) { arrayClass.cast(a); a[i] = x; }
// Weakly typed wrappers of Object[] accessors:
static Object getElementL(Object a, int i) { return getElementL((Object[])a, i); }
static void setElementL(Object a, int i, Object x) { setElementL((Object[]) a, i, x); }
static Object getElementL(Object arrayClass, Object a, int i) { return getElementL((Class<?>) arrayClass, (Object[])a, i); }
static void setElementL(Object arrayClass, Object a, int i, Object x) { setElementL((Class<?>) arrayClass, (Object[])a, i, x); }
static boolean needCast(Class<?> arrayClass) {
Class<?> elemClass = arrayClass.getComponentType();
return !elemClass.isPrimitive() && elemClass != Object.class;
}
static String name(Class<?> arrayClass, boolean isSetter) {
Class<?> elemClass = arrayClass.getComponentType();
if (elemClass == null) throw new IllegalArgumentException();
return (!isSetter ? "getElement" : "setElement") + Wrapper.basicTypeChar(elemClass);
}
static final boolean USE_WEAKLY_TYPED_ARRAY_ACCESSORS = false; // FIXME: decide
static MethodType type(Class<?> arrayClass, boolean isSetter) {
Class<?> elemClass = arrayClass.getComponentType();
Class<?> arrayArgClass = arrayClass;
if (!elemClass.isPrimitive()) {
arrayArgClass = Object[].class;
if (USE_WEAKLY_TYPED_ARRAY_ACCESSORS)
arrayArgClass = Object.class;
}
if (!needCast(arrayClass)) {
return !isSetter ?
MethodType.methodType(elemClass, arrayArgClass, int.class) :
MethodType.methodType(void.class, arrayArgClass, int.class, elemClass);
} else {
Class<?> classArgClass = Class.class;
if (USE_WEAKLY_TYPED_ARRAY_ACCESSORS)
classArgClass = Object.class;
return !isSetter ?
MethodType.methodType(Object.class, classArgClass, arrayArgClass, int.class) :
MethodType.methodType(void.class, classArgClass, arrayArgClass, int.class, Object.class);
}
}
static MethodType correctType(Class<?> arrayClass, boolean isSetter) {
Class<?> elemClass = arrayClass.getComponentType();
return !isSetter ?
MethodType.methodType(elemClass, arrayClass, int.class) :
MethodType.methodType(void.class, arrayClass, int.class, elemClass);
}
static MethodHandle getAccessor(Class<?> arrayClass, boolean isSetter) {
String name = name(arrayClass, isSetter);
MethodType type = type(arrayClass, isSetter);
try {
return IMPL_LOOKUP.findStatic(ArrayAccessor.class, name, type);
} catch (ReflectiveOperationException ex) {
throw uncaughtException(ex);
}
}
}
/**
* Create a JVM-level adapter method handle to conform the given method
* handle to the similar newType, using only pairwise argument conversions.
* For each argument, convert incoming argument to the exact type needed.
* The argument conversions allowed are casting, boxing and unboxing,
* integral widening or narrowing, and floating point widening or narrowing.
* @param srcType required call type
* @param target original method handle
* @param level which strength of conversion is allowed
* @return an adapter to the original handle with the desired new type,
* or the original target if the types are already identical
* or null if the adaptation cannot be made
*/
static MethodHandle makePairwiseConvert(MethodHandle target, MethodType srcType, int level) {
assert(level >= 0 && level <= 2);
MethodType dstType = target.type();
assert(dstType.parameterCount() == target.type().parameterCount());
if (srcType == dstType)
return target;
// Calculate extra arguments (temporaries) required in the names array.
// FIXME: Use an ArrayList<Name>. Some arguments require more than one conversion step.
final int INARG_COUNT = srcType.parameterCount();
int conversions = 0;
boolean[] needConv = new boolean[1+INARG_COUNT];
for (int i = 0; i <= INARG_COUNT; i++) {
Class<?> src = (i == INARG_COUNT) ? dstType.returnType() : srcType.parameterType(i);
Class<?> dst = (i == INARG_COUNT) ? srcType.returnType() : dstType.parameterType(i);
if (!VerifyType.isNullConversion(src, dst) ||
level <= 1 && dst.isInterface() && !dst.isAssignableFrom(src)) {
needConv[i] = true;
conversions++;
}
}
boolean retConv = needConv[INARG_COUNT];
final int IN_MH = 0;
final int INARG_BASE = 1;
final int INARG_LIMIT = INARG_BASE + INARG_COUNT;
final int NAME_LIMIT = INARG_LIMIT + conversions + 1;
final int RETURN_CONV = (!retConv ? -1 : NAME_LIMIT - 1);
final int OUT_CALL = (!retConv ? NAME_LIMIT : RETURN_CONV) - 1;
// Now build a LambdaForm.
MethodType lambdaType = srcType.basicType().invokerType();
Name[] names = arguments(NAME_LIMIT - INARG_LIMIT, lambdaType);
// Collect the arguments to the outgoing call, maybe with conversions:
final int OUTARG_BASE = 0; // target MH is Name.function, name Name.arguments[0]
Object[] outArgs = new Object[OUTARG_BASE + INARG_COUNT];
int nameCursor = INARG_LIMIT;
for (int i = 0; i < INARG_COUNT; i++) {
Class<?> src = srcType.parameterType(i);
Class<?> dst = dstType.parameterType(i);
if (!needConv[i]) {
// do nothing: difference is trivial
outArgs[OUTARG_BASE + i] = names[INARG_BASE + i];
continue;
}
// Tricky case analysis follows.
MethodHandle fn = null;
if (src.isPrimitive()) {
if (dst.isPrimitive()) {
fn = ValueConversions.convertPrimitive(src, dst);
} else {
Wrapper w = Wrapper.forPrimitiveType(src);
MethodHandle boxMethod = ValueConversions.box(w);
if (dst == w.wrapperType())
fn = boxMethod;
else
fn = boxMethod.asType(MethodType.methodType(dst, src));
}
} else {
if (dst.isPrimitive()) {
// Caller has boxed a primitive. Unbox it for the target.
Wrapper w = Wrapper.forPrimitiveType(dst);
if (level == 0 || VerifyType.isNullConversion(src, w.wrapperType())) {
fn = ValueConversions.unbox(dst);
} else if (src == Object.class || !Wrapper.isWrapperType(src)) {
// Examples: Object->int, Number->int, Comparable->int; Byte->int, Character->int
// must include additional conversions
// src must be examined at runtime, to detect Byte, Character, etc.
MethodHandle unboxMethod = (level == 1
? ValueConversions.unbox(dst)
: ValueConversions.unboxCast(dst));
fn = unboxMethod;
} else {
// Example: Byte->int
// Do this by reformulating the problem to Byte->byte.
Class<?> srcPrim = Wrapper.forWrapperType(src).primitiveType();
MethodHandle unbox = ValueConversions.unbox(srcPrim);
// Compose the two conversions. FIXME: should make two Names for this job
fn = unbox.asType(MethodType.methodType(dst, src));
}
} else {
// Simple reference conversion.
// Note: Do not check for a class hierarchy relation
// between src and dst. In all cases a 'null' argument
// will pass the cast conversion.
fn = ValueConversions.cast(dst);
}
}
Name conv = new Name(fn, names[INARG_BASE + i]);
assert(names[nameCursor] == null);
names[nameCursor++] = conv;
assert(outArgs[OUTARG_BASE + i] == null);
outArgs[OUTARG_BASE + i] = conv;
}
// Build argument array for the call.
assert(nameCursor == OUT_CALL);
names[OUT_CALL] = new Name(target, outArgs);
if (RETURN_CONV < 0) {
assert(OUT_CALL == names.length-1);
} else {
Class<?> needReturn = srcType.returnType();
Class<?> haveReturn = dstType.returnType();
MethodHandle fn;
Object[] arg = { names[OUT_CALL] };
if (haveReturn == void.class) {
// synthesize a zero value for the given void
Object zero = Wrapper.forBasicType(needReturn).zero();
fn = MethodHandles.constant(needReturn, zero);
arg = new Object[0]; // don't pass names[OUT_CALL] to conversion
} else {
MethodHandle identity = MethodHandles.identity(needReturn);
MethodType needConversion = identity.type().changeParameterType(0, haveReturn);
fn = makePairwiseConvert(identity, needConversion, level);
}
assert(names[RETURN_CONV] == null);
names[RETURN_CONV] = new Name(fn, arg);
assert(RETURN_CONV == names.length-1);
}
LambdaForm form = new LambdaForm("convert", lambdaType.parameterCount(), names);
return SimpleMethodHandle.make(srcType, form);
}
static MethodHandle makeReferenceIdentity(Class<?> refType) {
MethodType lambdaType = MethodType.genericMethodType(1).invokerType();
Name[] names = arguments(1, lambdaType);
names[names.length - 1] = new Name(ValueConversions.identity(), names[1]);
LambdaForm form = new LambdaForm("identity", lambdaType.parameterCount(), names);
return SimpleMethodHandle.make(MethodType.methodType(refType, refType), form);
}
static MethodHandle makeVarargsCollector(MethodHandle target, Class<?> arrayType) {
MethodType type = target.type();
int last = type.parameterCount() - 1;
if (type.parameterType(last) != arrayType)
target = target.asType(type.changeParameterType(last, arrayType));
target = target.asFixedArity(); // make sure this attribute is turned off
return new AsVarargsCollector(target, target.type(), arrayType);
}
static class AsVarargsCollector extends MethodHandle {
private final MethodHandle target;
private final Class<?> arrayType;
private /*@Stable*/ MethodHandle asCollectorCache;
AsVarargsCollector(MethodHandle target, MethodType type, Class<?> arrayType) {
super(type, reinvokerForm(target));
this.target = target;
this.arrayType = arrayType;
this.asCollectorCache = target.asCollector(arrayType, 0);
}
@Override MethodHandle reinvokerTarget() { return target; }
@Override
public boolean isVarargsCollector() {
return true;
}
@Override
public MethodHandle asFixedArity() {
return target;
}
@Override
public MethodHandle asTypeUncached(MethodType newType) {
MethodType type = this.type();
int collectArg = type.parameterCount() - 1;
int newArity = newType.parameterCount();
if (newArity == collectArg+1 &&
type.parameterType(collectArg).isAssignableFrom(newType.parameterType(collectArg))) {
// if arity and trailing parameter are compatible, do normal thing
return asTypeCache = asFixedArity().asType(newType);
}
// check cache
MethodHandle acc = asCollectorCache;
if (acc != null && acc.type().parameterCount() == newArity)
return asTypeCache = acc.asType(newType);
// build and cache a collector
int arrayLength = newArity - collectArg;
MethodHandle collector;
try {
collector = asFixedArity().asCollector(arrayType, arrayLength);
assert(collector.type().parameterCount() == newArity) : "newArity="+newArity+" but collector="+collector;
} catch (IllegalArgumentException ex) {
throw new WrongMethodTypeException("cannot build collector", ex);
}
asCollectorCache = collector;
return asTypeCache = collector.asType(newType);
}
@Override
MethodHandle setVarargs(MemberName member) {
if (member.isVarargs()) return this;
return asFixedArity();
}
@Override
MethodHandle viewAsType(MethodType newType) {
if (newType.lastParameterType() != type().lastParameterType())
throw new InternalError();
MethodHandle newTarget = asFixedArity().viewAsType(newType);
// put back the varargs bit:
return new AsVarargsCollector(newTarget, newType, arrayType);
}
@Override
MemberName internalMemberName() {
return asFixedArity().internalMemberName();
}
@Override
Class<?> internalCallerClass() {
return asFixedArity().internalCallerClass();
}
/*non-public*/
@Override
boolean isInvokeSpecial() {
return asFixedArity().isInvokeSpecial();
}
@Override
MethodHandle bindArgument(int pos, char basicType, Object value) {
return asFixedArity().bindArgument(pos, basicType, value);
}
@Override
MethodHandle bindReceiver(Object receiver) {
return asFixedArity().bindReceiver(receiver);
}
@Override
MethodHandle dropArguments(MethodType srcType, int pos, int drops) {
return asFixedArity().dropArguments(srcType, pos, drops);
}
@Override
MethodHandle permuteArguments(MethodType newType, int[] reorder) {
return asFixedArity().permuteArguments(newType, reorder);
}
}
/** Factory method: Spread selected argument. */
static MethodHandle makeSpreadArguments(MethodHandle target,
Class<?> spreadArgType, int spreadArgPos, int spreadArgCount) {
MethodType targetType = target.type();
for (int i = 0; i < spreadArgCount; i++) {
Class<?> arg = VerifyType.spreadArgElementType(spreadArgType, i);
if (arg == null) arg = Object.class;
targetType = targetType.changeParameterType(spreadArgPos + i, arg);
}
target = target.asType(targetType);
MethodType srcType = targetType
.replaceParameterTypes(spreadArgPos, spreadArgPos + spreadArgCount, spreadArgType);
// Now build a LambdaForm.
MethodType lambdaType = srcType.invokerType();
Name[] names = arguments(spreadArgCount + 2, lambdaType);
int nameCursor = lambdaType.parameterCount();
int[] indexes = new int[targetType.parameterCount()];
for (int i = 0, argIndex = 1; i < targetType.parameterCount() + 1; i++, argIndex++) {
Class<?> src = lambdaType.parameterType(i);
if (i == spreadArgPos) {
// Spread the array.
MethodHandle aload = MethodHandles.arrayElementGetter(spreadArgType);
Name array = names[argIndex];
names[nameCursor++] = new Name(Lazy.NF_checkSpreadArgument, array, spreadArgCount);
for (int j = 0; j < spreadArgCount; i++, j++) {
indexes[i] = nameCursor;
names[nameCursor++] = new Name(aload, array, j);
}
} else if (i < indexes.length) {
indexes[i] = argIndex;
}
}
assert(nameCursor == names.length-1); // leave room for the final call
// Build argument array for the call.
Name[] targetArgs = new Name[targetType.parameterCount()];
for (int i = 0; i < targetType.parameterCount(); i++) {
int idx = indexes[i];
targetArgs[i] = names[idx];
}
names[names.length - 1] = new Name(target, (Object[]) targetArgs);
LambdaForm form = new LambdaForm("spread", lambdaType.parameterCount(), names);
return SimpleMethodHandle.make(srcType, form);
}
static void checkSpreadArgument(Object av, int n) {
if (av == null) {
if (n == 0) return;
} else if (av instanceof Object[]) {
int len = ((Object[])av).length;
if (len == n) return;
} else {
int len = java.lang.reflect.Array.getLength(av);
if (len == n) return;
}
// fall through to error:
throw newIllegalArgumentException("array is not of length "+n);
}
/**
* Pre-initialized NamedFunctions for bootstrapping purposes.
* Factored in an inner class to delay initialization until first usage.
*/
private static class Lazy {
static final NamedFunction NF_checkSpreadArgument;
static {
try {
NF_checkSpreadArgument = new NamedFunction(MethodHandleImpl.class
.getDeclaredMethod("checkSpreadArgument", Object.class, int.class));
NF_checkSpreadArgument.resolve();
} catch (ReflectiveOperationException ex) {
throw newInternalError(ex);
}
}
}
/** Factory method: Collect or filter selected argument(s). */
static MethodHandle makeCollectArguments(MethodHandle target,
MethodHandle collector, int collectArgPos, boolean retainOriginalArgs) {
MethodType targetType = target.type(); // (a..., c, [b...])=>r
MethodType collectorType = collector.type(); // (b...)=>c
int collectArgCount = collectorType.parameterCount();
Class<?> collectValType = collectorType.returnType();
int collectValCount = (collectValType == void.class ? 0 : 1);
MethodType srcType = targetType // (a..., [b...])=>r
.dropParameterTypes(collectArgPos, collectArgPos+collectValCount);
if (!retainOriginalArgs) { // (a..., b...)=>r
srcType = srcType.insertParameterTypes(collectArgPos, collectorType.parameterList());
}
// in arglist: [0: ...keep1 | cpos: collect... | cpos+cacount: keep2... ]
// out arglist: [0: ...keep1 | cpos: collectVal? | cpos+cvcount: keep2... ]
// out(retain): [0: ...keep1 | cpos: cV? coll... | cpos+cvc+cac: keep2... ]
// Now build a LambdaForm.
MethodType lambdaType = srcType.invokerType();
Name[] names = arguments(2, lambdaType);
final int collectNamePos = names.length - 2;
final int targetNamePos = names.length - 1;
Name[] collectorArgs = Arrays.copyOfRange(names, 1 + collectArgPos, 1 + collectArgPos + collectArgCount);
names[collectNamePos] = new Name(collector, (Object[]) collectorArgs);
// Build argument array for the target.
// Incoming LF args to copy are: [ (mh) headArgs collectArgs tailArgs ].
// Output argument array is [ headArgs (collectVal)? (collectArgs)? tailArgs ].
Name[] targetArgs = new Name[targetType.parameterCount()];
int inputArgPos = 1; // incoming LF args to copy to target
int targetArgPos = 0; // fill pointer for targetArgs
int chunk = collectArgPos; // |headArgs|
System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
inputArgPos += chunk;
targetArgPos += chunk;
if (collectValType != void.class) {
targetArgs[targetArgPos++] = names[collectNamePos];
}
chunk = collectArgCount;
if (retainOriginalArgs) {
System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
targetArgPos += chunk; // optionally pass on the collected chunk
}
inputArgPos += chunk;
chunk = targetArgs.length - targetArgPos; // all the rest
System.arraycopy(names, inputArgPos, targetArgs, targetArgPos, chunk);
assert(inputArgPos + chunk == collectNamePos); // use of rest of input args also
names[targetNamePos] = new Name(target, (Object[]) targetArgs);
LambdaForm form = new LambdaForm("collect", lambdaType.parameterCount(), names);
return SimpleMethodHandle.make(srcType, form);
}
static
MethodHandle selectAlternative(boolean testResult, MethodHandle target, MethodHandle fallback) {
return testResult ? target : fallback;
}
static MethodHandle SELECT_ALTERNATIVE;
static MethodHandle selectAlternative() {
if (SELECT_ALTERNATIVE != null) return SELECT_ALTERNATIVE;
try {
SELECT_ALTERNATIVE
= IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "selectAlternative",
MethodType.methodType(MethodHandle.class, boolean.class, MethodHandle.class, MethodHandle.class));
} catch (ReflectiveOperationException ex) {
throw new RuntimeException(ex);
}
return SELECT_ALTERNATIVE;
}
static
MethodHandle makeGuardWithTest(MethodHandle test,
MethodHandle target,
MethodHandle fallback) {
MethodType basicType = target.type().basicType();
MethodHandle invokeBasic = MethodHandles.basicInvoker(basicType);
int arity = basicType.parameterCount();
int extraNames = 3;
MethodType lambdaType = basicType.invokerType();
Name[] names = arguments(extraNames, lambdaType);
Object[] testArgs = Arrays.copyOfRange(names, 1, 1 + arity, Object[].class);
Object[] targetArgs = Arrays.copyOfRange(names, 0, 1 + arity, Object[].class);
// call test
names[arity + 1] = new Name(test, testArgs);
// call selectAlternative
Object[] selectArgs = { names[arity + 1], target, fallback };
names[arity + 2] = new Name(MethodHandleImpl.selectAlternative(), selectArgs);
targetArgs[0] = names[arity + 2];
// call target or fallback
names[arity + 3] = new Name(new NamedFunction(invokeBasic), targetArgs);
LambdaForm form = new LambdaForm("guard", lambdaType.parameterCount(), names);
return SimpleMethodHandle.make(target.type(), form);
}
private static class GuardWithCatch {
private final MethodHandle target;
private final Class<? extends Throwable> exType;
private final MethodHandle catcher;
// FIXME: Build the control flow out of foldArguments.
GuardWithCatch(MethodHandle target, Class<? extends Throwable> exType, MethodHandle catcher) {
this.target = target;
this.exType = exType;
this.catcher = catcher;
}
@LambdaForm.Hidden
private Object invoke_V(Object... av) throws Throwable {
try {
return target.invokeExact(av);
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.invokeExact(t, av);
}
}
@LambdaForm.Hidden
private Object invoke_L0() throws Throwable {
try {
return target.invokeExact();
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.invokeExact(t);
}
}
@LambdaForm.Hidden
private Object invoke_L1(Object a0) throws Throwable {
try {
return target.invokeExact(a0);
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.invokeExact(t, a0);
}
}
@LambdaForm.Hidden
private Object invoke_L2(Object a0, Object a1) throws Throwable {
try {
return target.invokeExact(a0, a1);
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.invokeExact(t, a0, a1);
}
}
@LambdaForm.Hidden
private Object invoke_L3(Object a0, Object a1, Object a2) throws Throwable {
try {
return target.invokeExact(a0, a1, a2);
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.invokeExact(t, a0, a1, a2);
}
}
@LambdaForm.Hidden
private Object invoke_L4(Object a0, Object a1, Object a2, Object a3) throws Throwable {
try {
return target.invokeExact(a0, a1, a2, a3);
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.invokeExact(t, a0, a1, a2, a3);
}
}
@LambdaForm.Hidden
private Object invoke_L5(Object a0, Object a1, Object a2, Object a3, Object a4) throws Throwable {
try {
return target.invokeExact(a0, a1, a2, a3, a4);
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.invokeExact(t, a0, a1, a2, a3, a4);
}
}
@LambdaForm.Hidden
private Object invoke_L6(Object a0, Object a1, Object a2, Object a3, Object a4, Object a5) throws Throwable {
try {
return target.invokeExact(a0, a1, a2, a3, a4, a5);
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.invokeExact(t, a0, a1, a2, a3, a4, a5);
}
}
@LambdaForm.Hidden
private Object invoke_L7(Object a0, Object a1, Object a2, Object a3, Object a4, Object a5, Object a6) throws Throwable {
try {
return target.invokeExact(a0, a1, a2, a3, a4, a5, a6);
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.invokeExact(t, a0, a1, a2, a3, a4, a5, a6);
}
}
@LambdaForm.Hidden
private Object invoke_L8(Object a0, Object a1, Object a2, Object a3, Object a4, Object a5, Object a6, Object a7) throws Throwable {
try {
return target.invokeExact(a0, a1, a2, a3, a4, a5, a6, a7);
} catch (Throwable t) {
if (!exType.isInstance(t)) throw t;
return catcher.invokeExact(t, a0, a1, a2, a3, a4, a5, a6, a7);
}
}
static MethodHandle[] makeInvokes() {
ArrayList<MethodHandle> invokes = new ArrayList<>();
MethodHandles.Lookup lookup = IMPL_LOOKUP;
for (;;) {
int nargs = invokes.size();
String name = "invoke_L"+nargs;
MethodHandle invoke = null;
try {
invoke = lookup.findVirtual(GuardWithCatch.class, name, MethodType.genericMethodType(nargs));
} catch (ReflectiveOperationException ex) {
}
if (invoke == null) break;
invokes.add(invoke);
}
assert(invokes.size() == 9); // current number of methods
return invokes.toArray(new MethodHandle[0]);
};
static final MethodHandle[] INVOKES = makeInvokes();
// For testing use this:
//static final MethodHandle[] INVOKES = Arrays.copyOf(makeInvokes(), 2);
static final MethodHandle VARARGS_INVOKE;
static {
try {
VARARGS_INVOKE = IMPL_LOOKUP.findVirtual(GuardWithCatch.class, "invoke_V", MethodType.genericMethodType(0, true));
} catch (ReflectiveOperationException ex) {
throw uncaughtException(ex);
}
}
}
static
MethodHandle makeGuardWithCatch(MethodHandle target,
Class<? extends Throwable> exType,
MethodHandle catcher) {
MethodType type = target.type();
MethodType ctype = catcher.type();
int nargs = type.parameterCount();
if (nargs < GuardWithCatch.INVOKES.length) {
MethodType gtype = type.generic();
MethodType gcatchType = gtype.insertParameterTypes(0, Throwable.class);
// Note: convertArguments(...2) avoids interface casts present in convertArguments(...0)
MethodHandle gtarget = makePairwiseConvert(target, gtype, 2);
MethodHandle gcatcher = makePairwiseConvert(catcher, gcatchType, 2);
GuardWithCatch gguard = new GuardWithCatch(gtarget, exType, gcatcher);
if (gtarget == null || gcatcher == null) throw new InternalError();
MethodHandle ginvoker = GuardWithCatch.INVOKES[nargs].bindReceiver(gguard);
return makePairwiseConvert(ginvoker, type, 2);
} else {
target = target.asType(type.changeReturnType(Object.class));
MethodHandle gtarget = makeSpreadArguments(target, Object[].class, 0, nargs);
MethodType catcherType = ctype.changeParameterType(0, Throwable.class)
.changeReturnType(Object.class);
catcher = catcher.asType(catcherType);
MethodHandle gcatcher = makeSpreadArguments(catcher, Object[].class, 1, nargs);
GuardWithCatch gguard = new GuardWithCatch(gtarget, exType, gcatcher);
if (gtarget == null || gcatcher == null) throw new InternalError();
MethodHandle ginvoker = GuardWithCatch.VARARGS_INVOKE.bindReceiver(gguard);
MethodHandle gcollect = makeCollectArguments(ginvoker, ValueConversions.varargsArray(nargs), 0, false);
return makePairwiseConvert(gcollect, type, 2);
}
}
static
MethodHandle throwException(MethodType type) {
assert(Throwable.class.isAssignableFrom(type.parameterType(0)));
int arity = type.parameterCount();
if (arity > 1) {
return throwException(type.dropParameterTypes(1, arity)).dropArguments(type, 1, arity-1);
}
return makePairwiseConvert(throwException(), type, 2);
}
static MethodHandle THROW_EXCEPTION;
static MethodHandle throwException() {
MethodHandle mh = THROW_EXCEPTION;
if (mh != null) return mh;
try {
mh
= IMPL_LOOKUP.findStatic(MethodHandleImpl.class, "throwException",
MethodType.methodType(Empty.class, Throwable.class));
} catch (ReflectiveOperationException ex) {
throw new RuntimeException(ex);
}
THROW_EXCEPTION = mh;
return mh;
}
static <T extends Throwable> Empty throwException(T t) throws T { throw t; }
static MethodHandle[] FAKE_METHOD_HANDLE_INVOKE = new MethodHandle[2];
static MethodHandle fakeMethodHandleInvoke(MemberName method) {
int idx;
assert(method.isMethodHandleInvoke());
switch (method.getName()) {
case "invoke": idx = 0; break;
case "invokeExact": idx = 1; break;
default: throw new InternalError(method.getName());
}
MethodHandle mh = FAKE_METHOD_HANDLE_INVOKE[idx];
if (mh != null) return mh;
MethodType type = MethodType.methodType(Object.class, UnsupportedOperationException.class,
MethodHandle.class, Object[].class);
mh = throwException(type);
mh = mh.bindTo(new UnsupportedOperationException("cannot reflectively invoke MethodHandle"));
if (!method.getInvocationType().equals(mh.type()))
throw new InternalError(method.toString());
mh = mh.withInternalMemberName(method);
mh = mh.asVarargsCollector(Object[].class);
assert(method.isVarargs());
FAKE_METHOD_HANDLE_INVOKE[idx] = mh;
return mh;
}
/**
* Create an alias for the method handle which, when called,
* appears to be called from the same class loader and protection domain
* as hostClass.
* This is an expensive no-op unless the method which is called
* is sensitive to its caller. A small number of system methods
* are in this category, including Class.forName and Method.invoke.
*/
static
MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
return BindCaller.bindCaller(mh, hostClass);
}
// Put the whole mess into its own nested class.
// That way we can lazily load the code and set up the constants.
private static class BindCaller {
static
MethodHandle bindCaller(MethodHandle mh, Class<?> hostClass) {
// Do not use this function to inject calls into system classes.
if (hostClass == null
|| (hostClass.isArray() ||
hostClass.isPrimitive() ||
hostClass.getName().startsWith("java.") ||
hostClass.getName().startsWith("sun."))) {
throw new InternalError(); // does not happen, and should not anyway
}
// For simplicity, convert mh to a varargs-like method.
MethodHandle vamh = prepareForInvoker(mh);
// Cache the result of makeInjectedInvoker once per argument class.
MethodHandle bccInvoker = CV_makeInjectedInvoker.get(hostClass);
return restoreToType(bccInvoker.bindTo(vamh), mh.type(), mh.internalMemberName(), hostClass);
}
private static MethodHandle makeInjectedInvoker(Class<?> hostClass) {
Class<?> bcc = UNSAFE.defineAnonymousClass(hostClass, T_BYTES, null);
if (hostClass.getClassLoader() != bcc.getClassLoader())
throw new InternalError(hostClass.getName()+" (CL)");
try {
if (hostClass.getProtectionDomain() != bcc.getProtectionDomain())
throw new InternalError(hostClass.getName()+" (PD)");
} catch (SecurityException ex) {
// Self-check was blocked by security manager. This is OK.
// In fact the whole try body could be turned into an assertion.
}
try {
MethodHandle init = IMPL_LOOKUP.findStatic(bcc, "init", MethodType.methodType(void.class));
init.invokeExact(); // force initialization of the class
} catch (Throwable ex) {
throw uncaughtException(ex);
}
MethodHandle bccInvoker;
try {
MethodType invokerMT = MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
bccInvoker = IMPL_LOOKUP.findStatic(bcc, "invoke_V", invokerMT);
} catch (ReflectiveOperationException ex) {
throw uncaughtException(ex);
}
// Test the invoker, to ensure that it really injects into the right place.
try {
MethodHandle vamh = prepareForInvoker(MH_checkCallerClass);
Object ok = bccInvoker.invokeExact(vamh, new Object[]{hostClass, bcc});
} catch (Throwable ex) {
throw new InternalError(ex);
}
return bccInvoker;
}
private static ClassValue<MethodHandle> CV_makeInjectedInvoker = new ClassValue
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