java.lang.invoke.VarHandles Maven / Gradle / Ivy
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package java.lang.invoke;
import sun.invoke.util.Wrapper;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Parameter;
import java.nio.ByteOrder;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.stream.Stream;
import static java.lang.invoke.MethodHandleStatics.UNSAFE;
import static java.lang.invoke.MethodHandleStatics.VAR_HANDLE_IDENTITY_ADAPT;
import static java.lang.invoke.MethodHandleStatics.newIllegalArgumentException;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;
final class VarHandles {
static ClassValue> ADDRESS_FACTORIES = new ClassValue<>() {
@Override
protected ConcurrentMap computeValue(Class type) {
return new ConcurrentHashMap<>();
}
};
static VarHandle makeFieldHandle(MemberName f, Class refc, Class type, boolean isWriteAllowedOnFinalFields) {
if (!f.isStatic()) {
long foffset = MethodHandleNatives.objectFieldOffset(f);
if (!type.isPrimitive()) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleReferences.FieldInstanceReadOnly(refc, foffset, type)
: new VarHandleReferences.FieldInstanceReadWrite(refc, foffset, type));
}
else if (type == boolean.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleBooleans.FieldInstanceReadOnly(refc, foffset)
: new VarHandleBooleans.FieldInstanceReadWrite(refc, foffset));
}
else if (type == byte.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleBytes.FieldInstanceReadOnly(refc, foffset)
: new VarHandleBytes.FieldInstanceReadWrite(refc, foffset));
}
else if (type == short.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleShorts.FieldInstanceReadOnly(refc, foffset)
: new VarHandleShorts.FieldInstanceReadWrite(refc, foffset));
}
else if (type == char.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleChars.FieldInstanceReadOnly(refc, foffset)
: new VarHandleChars.FieldInstanceReadWrite(refc, foffset));
}
else if (type == int.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleInts.FieldInstanceReadOnly(refc, foffset)
: new VarHandleInts.FieldInstanceReadWrite(refc, foffset));
}
else if (type == long.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleLongs.FieldInstanceReadOnly(refc, foffset)
: new VarHandleLongs.FieldInstanceReadWrite(refc, foffset));
}
else if (type == float.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleFloats.FieldInstanceReadOnly(refc, foffset)
: new VarHandleFloats.FieldInstanceReadWrite(refc, foffset));
}
else if (type == double.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleDoubles.FieldInstanceReadOnly(refc, foffset)
: new VarHandleDoubles.FieldInstanceReadWrite(refc, foffset));
}
else {
throw new UnsupportedOperationException();
}
}
else {
// TODO This is not lazy on first invocation
// and might cause some circular initialization issues
// Replace with something similar to direct method handles
// where a barrier is used then elided after use
if (UNSAFE.shouldBeInitialized(refc))
UNSAFE.ensureClassInitialized(refc);
Object base = MethodHandleNatives.staticFieldBase(f);
long foffset = MethodHandleNatives.staticFieldOffset(f);
if (!type.isPrimitive()) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleReferences.FieldStaticReadOnly(base, foffset, type)
: new VarHandleReferences.FieldStaticReadWrite(base, foffset, type));
}
else if (type == boolean.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleBooleans.FieldStaticReadOnly(base, foffset)
: new VarHandleBooleans.FieldStaticReadWrite(base, foffset));
}
else if (type == byte.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleBytes.FieldStaticReadOnly(base, foffset)
: new VarHandleBytes.FieldStaticReadWrite(base, foffset));
}
else if (type == short.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleShorts.FieldStaticReadOnly(base, foffset)
: new VarHandleShorts.FieldStaticReadWrite(base, foffset));
}
else if (type == char.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleChars.FieldStaticReadOnly(base, foffset)
: new VarHandleChars.FieldStaticReadWrite(base, foffset));
}
else if (type == int.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleInts.FieldStaticReadOnly(base, foffset)
: new VarHandleInts.FieldStaticReadWrite(base, foffset));
}
else if (type == long.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleLongs.FieldStaticReadOnly(base, foffset)
: new VarHandleLongs.FieldStaticReadWrite(base, foffset));
}
else if (type == float.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleFloats.FieldStaticReadOnly(base, foffset)
: new VarHandleFloats.FieldStaticReadWrite(base, foffset));
}
else if (type == double.class) {
return maybeAdapt(f.isFinal() && !isWriteAllowedOnFinalFields
? new VarHandleDoubles.FieldStaticReadOnly(base, foffset)
: new VarHandleDoubles.FieldStaticReadWrite(base, foffset));
}
else {
throw new UnsupportedOperationException();
}
}
}
// Required by instance field handles
static Field getFieldFromReceiverAndOffset(Class receiverType,
long offset,
Class fieldType) {
for (Field f : receiverType.getDeclaredFields()) {
if (Modifier.isStatic(f.getModifiers())) continue;
if (offset == UNSAFE.objectFieldOffset(f)) {
assert f.getType() == fieldType;
return f;
}
}
throw new InternalError("Field not found at offset");
}
// Required by instance static field handles
static Field getStaticFieldFromBaseAndOffset(Object base,
long offset,
Class fieldType) {
// @@@ This is a little fragile assuming the base is the class
Class receiverType = (Class) base;
for (Field f : receiverType.getDeclaredFields()) {
if (!Modifier.isStatic(f.getModifiers())) continue;
if (offset == UNSAFE.staticFieldOffset(f)) {
assert f.getType() == fieldType;
return f;
}
}
throw new InternalError("Static field not found at offset");
}
static VarHandle makeArrayElementHandle(Class arrayClass) {
if (!arrayClass.isArray())
throw new IllegalArgumentException("not an array: " + arrayClass);
Class componentType = arrayClass.getComponentType();
int aoffset = UNSAFE.arrayBaseOffset(arrayClass);
int ascale = UNSAFE.arrayIndexScale(arrayClass);
int ashift = 31 - Integer.numberOfLeadingZeros(ascale);
if (!componentType.isPrimitive()) {
return maybeAdapt(new VarHandleReferences.Array(aoffset, ashift, arrayClass));
}
else if (componentType == boolean.class) {
return maybeAdapt(new VarHandleBooleans.Array(aoffset, ashift));
}
else if (componentType == byte.class) {
return maybeAdapt(new VarHandleBytes.Array(aoffset, ashift));
}
else if (componentType == short.class) {
return maybeAdapt(new VarHandleShorts.Array(aoffset, ashift));
}
else if (componentType == char.class) {
return maybeAdapt(new VarHandleChars.Array(aoffset, ashift));
}
else if (componentType == int.class) {
return maybeAdapt(new VarHandleInts.Array(aoffset, ashift));
}
else if (componentType == long.class) {
return maybeAdapt(new VarHandleLongs.Array(aoffset, ashift));
}
else if (componentType == float.class) {
return maybeAdapt(new VarHandleFloats.Array(aoffset, ashift));
}
else if (componentType == double.class) {
return maybeAdapt(new VarHandleDoubles.Array(aoffset, ashift));
}
else {
throw new UnsupportedOperationException();
}
}
static VarHandle byteArrayViewHandle(Class viewArrayClass,
boolean be) {
if (!viewArrayClass.isArray())
throw new IllegalArgumentException("not an array: " + viewArrayClass);
Class viewComponentType = viewArrayClass.getComponentType();
if (viewComponentType == long.class) {
return maybeAdapt(new VarHandleByteArrayAsLongs.ArrayHandle(be));
}
else if (viewComponentType == int.class) {
return maybeAdapt(new VarHandleByteArrayAsInts.ArrayHandle(be));
}
else if (viewComponentType == short.class) {
return maybeAdapt(new VarHandleByteArrayAsShorts.ArrayHandle(be));
}
else if (viewComponentType == char.class) {
return maybeAdapt(new VarHandleByteArrayAsChars.ArrayHandle(be));
}
else if (viewComponentType == double.class) {
return maybeAdapt(new VarHandleByteArrayAsDoubles.ArrayHandle(be));
}
else if (viewComponentType == float.class) {
return maybeAdapt(new VarHandleByteArrayAsFloats.ArrayHandle(be));
}
throw new UnsupportedOperationException();
}
static VarHandle makeByteBufferViewHandle(Class viewArrayClass,
boolean be) {
if (!viewArrayClass.isArray())
throw new IllegalArgumentException("not an array: " + viewArrayClass);
Class viewComponentType = viewArrayClass.getComponentType();
if (viewComponentType == long.class) {
return maybeAdapt(new VarHandleByteArrayAsLongs.ByteBufferHandle(be));
}
else if (viewComponentType == int.class) {
return maybeAdapt(new VarHandleByteArrayAsInts.ByteBufferHandle(be));
}
else if (viewComponentType == short.class) {
return maybeAdapt(new VarHandleByteArrayAsShorts.ByteBufferHandle(be));
}
else if (viewComponentType == char.class) {
return maybeAdapt(new VarHandleByteArrayAsChars.ByteBufferHandle(be));
}
else if (viewComponentType == double.class) {
return maybeAdapt(new VarHandleByteArrayAsDoubles.ByteBufferHandle(be));
}
else if (viewComponentType == float.class) {
return maybeAdapt(new VarHandleByteArrayAsFloats.ByteBufferHandle(be));
}
throw new UnsupportedOperationException();
}
/**
* Creates a memory access VarHandle.
*
* Resulting VarHandle will take a memory address as first argument,
* and a certain number of coordinate {@code long} parameters, depending on the length
* of the {@code strides} argument array.
*
* Coordinates are multiplied with corresponding scale factors ({@code strides}) and added
* to a single fixed offset to compute an effective offset from the given MemoryAddress for the access.
*
* @param carrier the Java carrier type.
* @param skipAlignmentMaskCheck if true, only the base part of the address will be checked for alignment.
* @param alignmentMask alignment requirement to be checked upon access. In bytes. Expressed as a mask.
* @param byteOrder the byte order.
* @return the created VarHandle.
*/
static VarHandle makeMemoryAddressViewHandle(Class carrier, boolean skipAlignmentMaskCheck, long alignmentMask,
ByteOrder byteOrder) {
if (!carrier.isPrimitive() || carrier == void.class || carrier == boolean.class) {
throw new IllegalArgumentException("Invalid carrier: " + carrier.getName());
}
long size = Wrapper.forPrimitiveType(carrier).bitWidth() / 8;
boolean be = byteOrder == ByteOrder.BIG_ENDIAN;
boolean exact = false;
if (carrier == byte.class) {
return maybeAdapt(new MemoryAccessVarHandleByteHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
} else if (carrier == char.class) {
return maybeAdapt(new MemoryAccessVarHandleCharHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
} else if (carrier == short.class) {
return maybeAdapt(new MemoryAccessVarHandleShortHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
} else if (carrier == int.class) {
return maybeAdapt(new MemoryAccessVarHandleIntHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
} else if (carrier == float.class) {
return maybeAdapt(new MemoryAccessVarHandleFloatHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
} else if (carrier == long.class) {
return maybeAdapt(new MemoryAccessVarHandleLongHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
} else if (carrier == double.class) {
return maybeAdapt(new MemoryAccessVarHandleDoubleHelper(skipAlignmentMaskCheck, be, size, alignmentMask, exact));
} else {
throw new IllegalStateException("Cannot get here");
}
}
private static VarHandle maybeAdapt(VarHandle target) {
if (!VAR_HANDLE_IDENTITY_ADAPT) return target;
target = filterValue(target,
MethodHandles.identity(target.varType()), MethodHandles.identity(target.varType()));
MethodType mtype = target.accessModeType(VarHandle.AccessMode.GET);
for (int i = 0 ; i < mtype.parameterCount() ; i++) {
target = filterCoordinates(target, i, MethodHandles.identity(mtype.parameterType(i)));
}
return target;
}
public static VarHandle filterValue(VarHandle target, MethodHandle filterToTarget, MethodHandle filterFromTarget) {
Objects.requireNonNull(target);
Objects.requireNonNull(filterToTarget);
Objects.requireNonNull(filterFromTarget);
//check that from/to filters do not throw checked exceptions
noCheckedExceptions(filterToTarget);
noCheckedExceptions(filterFromTarget);
List> newCoordinates = new ArrayList<>();
List> additionalCoordinates = new ArrayList<>();
newCoordinates.addAll(target.coordinateTypes());
//check that from/to filters have right signatures
if (filterFromTarget.type().parameterCount() != filterToTarget.type().parameterCount()) {
throw newIllegalArgumentException("filterFromTarget and filterToTarget have different arity", filterFromTarget.type(), filterToTarget.type());
} else if (filterFromTarget.type().parameterCount() < 1) {
throw newIllegalArgumentException("filterFromTarget filter type has wrong arity", filterFromTarget.type());
} else if (filterToTarget.type().parameterCount() < 1) {
throw newIllegalArgumentException("filterToTarget filter type has wrong arity", filterFromTarget.type());
} else if (filterFromTarget.type().lastParameterType() != filterToTarget.type().returnType() ||
filterToTarget.type().lastParameterType() != filterFromTarget.type().returnType()) {
throw newIllegalArgumentException("filterFromTarget and filterToTarget filter types do not match", filterFromTarget.type(), filterToTarget.type());
} else if (target.varType() != filterFromTarget.type().lastParameterType()) {
throw newIllegalArgumentException("filterFromTarget filter type does not match target var handle type", filterFromTarget.type(), target.varType());
} else if (target.varType() != filterToTarget.type().returnType()) {
throw newIllegalArgumentException("filterFromTarget filter type does not match target var handle type", filterToTarget.type(), target.varType());
} else if (filterFromTarget.type().parameterCount() > 1) {
for (int i = 0 ; i < filterFromTarget.type().parameterCount() - 1 ; i++) {
if (filterFromTarget.type().parameterType(i) != filterToTarget.type().parameterType(i)) {
throw newIllegalArgumentException("filterFromTarget and filterToTarget filter types do not match", filterFromTarget.type(), filterToTarget.type());
} else {
newCoordinates.add(filterFromTarget.type().parameterType(i));
additionalCoordinates.add((filterFromTarget.type().parameterType(i)));
}
}
}
return new IndirectVarHandle(target, filterFromTarget.type().returnType(), newCoordinates.toArray(new Class[0]),
(mode, modeHandle) -> {
int lastParameterPos = modeHandle.type().parameterCount() - 1;
return switch (mode.at) {
case GET -> MethodHandles.collectReturnValue(modeHandle, filterFromTarget);
case SET -> MethodHandles.collectArguments(modeHandle, lastParameterPos, filterToTarget);
case GET_AND_UPDATE -> {
MethodHandle adapter = MethodHandles.collectReturnValue(modeHandle, filterFromTarget);
MethodHandle res = MethodHandles.collectArguments(adapter, lastParameterPos, filterToTarget);
if (additionalCoordinates.size() > 0) {
res = joinDuplicateArgs(res, lastParameterPos,
lastParameterPos + additionalCoordinates.size() + 1,
additionalCoordinates.size());
}
yield res;
}
case COMPARE_AND_EXCHANGE -> {
MethodHandle adapter = MethodHandles.collectReturnValue(modeHandle, filterFromTarget);
adapter = MethodHandles.collectArguments(adapter, lastParameterPos, filterToTarget);
if (additionalCoordinates.size() > 0) {
adapter = joinDuplicateArgs(adapter, lastParameterPos,
lastParameterPos + additionalCoordinates.size() + 1,
additionalCoordinates.size());
}
MethodHandle res = MethodHandles.collectArguments(adapter, lastParameterPos - 1, filterToTarget);
if (additionalCoordinates.size() > 0) {
res = joinDuplicateArgs(res, lastParameterPos - 1,
lastParameterPos + additionalCoordinates.size(),
additionalCoordinates.size());
}
yield res;
}
case COMPARE_AND_SET -> {
MethodHandle adapter = MethodHandles.collectArguments(modeHandle, lastParameterPos, filterToTarget);
MethodHandle res = MethodHandles.collectArguments(adapter, lastParameterPos - 1, filterToTarget);
if (additionalCoordinates.size() > 0) {
res = joinDuplicateArgs(res, lastParameterPos - 1,
lastParameterPos + additionalCoordinates.size(),
additionalCoordinates.size());
}
yield res;
}
};
});
}
private static MethodHandle joinDuplicateArgs(MethodHandle handle, int originalStart, int dropStart, int length) {
int[] perms = new int[handle.type().parameterCount()];
for (int i = 0 ; i < dropStart; i++) {
perms[i] = i;
}
for (int i = 0 ; i < length ; i++) {
perms[dropStart + i] = originalStart + i;
}
for (int i = dropStart + length ; i < perms.length ; i++) {
perms[i] = i - length;
}
return MethodHandles.permuteArguments(handle,
handle.type().dropParameterTypes(dropStart, dropStart + length),
perms);
}
public static VarHandle filterCoordinates(VarHandle target, int pos, MethodHandle... filters) {
Objects.requireNonNull(target);
Objects.requireNonNull(filters);
List> targetCoordinates = target.coordinateTypes();
if (pos < 0 || pos >= targetCoordinates.size()) {
throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
} else if (pos + filters.length > targetCoordinates.size()) {
throw new IllegalArgumentException("Too many filters");
}
if (filters.length == 0) return target;
List> newCoordinates = new ArrayList<>(targetCoordinates);
for (int i = 0 ; i < filters.length ; i++) {
noCheckedExceptions(filters[i]);
MethodType filterType = filters[i].type();
if (filterType.parameterCount() != 1) {
throw newIllegalArgumentException("Invalid filter type " + filterType);
} else if (newCoordinates.get(pos + i) != filterType.returnType()) {
throw newIllegalArgumentException("Invalid filter type " + filterType + " for coordinate type " + newCoordinates.get(i));
}
newCoordinates.set(pos + i, filters[i].type().parameterType(0));
}
return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class[0]),
(mode, modeHandle) -> MethodHandles.filterArguments(modeHandle, 1 + pos, filters));
}
public static VarHandle insertCoordinates(VarHandle target, int pos, Object... values) {
Objects.requireNonNull(target);
Objects.requireNonNull(values);
List> targetCoordinates = target.coordinateTypes();
if (pos < 0 || pos >= targetCoordinates.size()) {
throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
} else if (pos + values.length > targetCoordinates.size()) {
throw new IllegalArgumentException("Too many values");
}
if (values.length == 0) return target;
List> newCoordinates = new ArrayList<>(targetCoordinates);
for (int i = 0 ; i < values.length ; i++) {
Class pt = newCoordinates.get(pos);
if (pt.isPrimitive()) {
Wrapper w = Wrapper.forPrimitiveType(pt);
w.convert(values[i], pt);
} else {
pt.cast(values[i]);
}
newCoordinates.remove(pos);
}
return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class[0]),
(mode, modeHandle) -> MethodHandles.insertArguments(modeHandle, 1 + pos, values));
}
public static VarHandle permuteCoordinates(VarHandle target, List> newCoordinates, int... reorder) {
Objects.requireNonNull(target);
Objects.requireNonNull(newCoordinates);
Objects.requireNonNull(reorder);
List> targetCoordinates = target.coordinateTypes();
MethodHandles.permuteArgumentChecks(reorder,
MethodType.methodType(void.class, newCoordinates),
MethodType.methodType(void.class, targetCoordinates));
return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class[0]),
(mode, modeHandle) ->
MethodHandles.permuteArguments(modeHandle,
methodTypeFor(mode.at, modeHandle.type(), targetCoordinates, newCoordinates),
reorderArrayFor(mode.at, newCoordinates, reorder)));
}
private static int numTrailingArgs(VarHandle.AccessType at) {
return switch (at) {
case GET -> 0;
case GET_AND_UPDATE, SET -> 1;
case COMPARE_AND_SET, COMPARE_AND_EXCHANGE -> 2;
};
}
private static int[] reorderArrayFor(VarHandle.AccessType at, List> newCoordinates, int[] reorder) {
int numTrailingArgs = numTrailingArgs(at);
int[] adjustedReorder = new int[reorder.length + 1 + numTrailingArgs];
adjustedReorder[0] = 0;
for (int i = 0 ; i < reorder.length ; i++) {
adjustedReorder[i + 1] = reorder[i] + 1;
}
for (int i = 0 ; i < numTrailingArgs ; i++) {
adjustedReorder[i + reorder.length + 1] = i + newCoordinates.size() + 1;
}
return adjustedReorder;
}
private static MethodType methodTypeFor(VarHandle.AccessType at, MethodType oldType, List> oldCoordinates, List> newCoordinates) {
int numTrailingArgs = numTrailingArgs(at);
MethodType adjustedType = MethodType.methodType(oldType.returnType(), oldType.parameterType(0));
adjustedType = adjustedType.appendParameterTypes(newCoordinates);
for (int i = 0 ; i < numTrailingArgs ; i++) {
adjustedType = adjustedType.appendParameterTypes(oldType.parameterType(1 + oldCoordinates.size() + i));
}
return adjustedType;
}
public static VarHandle collectCoordinates(VarHandle target, int pos, MethodHandle filter) {
Objects.requireNonNull(target);
Objects.requireNonNull(filter);
noCheckedExceptions(filter);
List> targetCoordinates = target.coordinateTypes();
if (pos < 0 || pos >= targetCoordinates.size()) {
throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
} else if (filter.type().returnType() == void.class) {
throw newIllegalArgumentException("Invalid filter type " + filter.type() + " ; filter cannot be void");
} else if (filter.type().returnType() != targetCoordinates.get(pos)) {
throw newIllegalArgumentException("Invalid filter type " + filter.type() + " for coordinate type " + targetCoordinates.get(pos));
}
List> newCoordinates = new ArrayList<>(targetCoordinates);
newCoordinates.remove(pos);
newCoordinates.addAll(pos, filter.type().parameterList());
return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class[0]),
(mode, modeHandle) -> MethodHandles.collectArguments(modeHandle, 1 + pos, filter));
}
public static VarHandle dropCoordinates(VarHandle target, int pos, Class... valueTypes) {
Objects.requireNonNull(target);
Objects.requireNonNull(valueTypes);
List> targetCoordinates = target.coordinateTypes();
if (pos < 0 || pos > targetCoordinates.size()) {
throw newIllegalArgumentException("Invalid position " + pos + " for coordinate types", targetCoordinates);
}
if (valueTypes.length == 0) return target;
List> newCoordinates = new ArrayList<>(targetCoordinates);
newCoordinates.addAll(pos, List.of(valueTypes));
return new IndirectVarHandle(target, target.varType(), newCoordinates.toArray(new Class[0]),
(mode, modeHandle) -> MethodHandles.dropArguments(modeHandle, 1 + pos, valueTypes));
}
private static void noCheckedExceptions(MethodHandle handle) {
if (handle instanceof DirectMethodHandle directHandle) {
byte refKind = directHandle.member.getReferenceKind();
MethodHandleInfo info = new InfoFromMemberName(
MethodHandles.Lookup.IMPL_LOOKUP,
directHandle.member,
refKind);
final Class[] exceptionTypes;
if (MethodHandleNatives.refKindIsMethod(refKind)) {
exceptionTypes = info.reflectAs(Method.class, MethodHandles.Lookup.IMPL_LOOKUP)
.getExceptionTypes();
} else if (MethodHandleNatives.refKindIsField(refKind)) {
exceptionTypes = null;
} else if (MethodHandleNatives.refKindIsConstructor(refKind)) {
exceptionTypes = info.reflectAs(Constructor.class, MethodHandles.Lookup.IMPL_LOOKUP)
.getExceptionTypes();
} else {
throw new AssertionError("Cannot get here");
}
if (exceptionTypes != null) {
if (Stream.of(exceptionTypes).anyMatch(VarHandles::isCheckedException)) {
throw newIllegalArgumentException("Cannot adapt a var handle with a method handle which throws checked exceptions");
}
}
} else if (handle instanceof DelegatingMethodHandle) {
noCheckedExceptions(((DelegatingMethodHandle)handle).getTarget());
} else {
//bound
BoundMethodHandle boundHandle = (BoundMethodHandle)handle;
for (int i = 0 ; i < boundHandle.fieldCount() ; i++) {
Object arg = boundHandle.arg(i);
if (arg instanceof MethodHandle){
noCheckedExceptions((MethodHandle) arg);
}
}
}
}
private static boolean isCheckedException(Class clazz) {
return Throwable.class.isAssignableFrom(clazz) &&
!RuntimeException.class.isAssignableFrom(clazz) &&
!Error.class.isAssignableFrom(clazz);
}
// /**
// * A helper program to generate the VarHandleGuards class with a set of
// * static guard methods each of which corresponds to a particular shape and
// * performs a type check of the symbolic type descriptor with the VarHandle
// * type descriptor before linking/invoking to the underlying operation as
// * characterized by the operation member name on the VarForm of the
// * VarHandle.
// *
// * The generated class essentially encapsulates pre-compiled LambdaForms,
// * one for each method, for the most set of common method signatures.
// * This reduces static initialization costs, footprint costs, and circular
// * dependencies that may arise if a class is generated per LambdaForm.
// *
// * A maximum of L*T*S methods will be generated where L is the number of
// * access modes kinds (or unique operation signatures) and T is the number
// * of variable types and S is the number of shapes (such as instance field,
// * static field, or array access).
// * If there are 4 unique operation signatures, 5 basic types (Object, int,
// * long, float, double), and 3 shapes then a maximum of 60 methods will be
// * generated. However, the number is likely to be less since there
// * be duplicate signatures.
// *
// * Each method is annotated with @LambdaForm.Compiled to inform the runtime
// * that such methods should be treated as if a method of a class that is the
// * result of compiling a LambdaForm. Annotation of such methods is
// * important for correct evaluation of certain assertions and method return
// * type profiling in HotSpot.
// */
// public static class GuardMethodGenerator {
//
// static final String GUARD_METHOD_SIG_TEMPLATE = " _()";
//
// static final String GUARD_METHOD_TEMPLATE =
// """
// @ForceInline
// @LambdaForm.Compiled
// @Hidden
// static final throws Throwable {
// handle.checkExactAccessMode(ad);
// if (handle.isDirect() && handle.vform.methodType_table[ad.type] == ad.symbolicMethodTypeErased) {
// MethodHandle.linkToStatic();
// } else {
// MethodHandle mh = handle.getMethodHandle(ad.mode);
// mh.asType(ad.symbolicMethodTypeInvoker).invokeBasic();
// }
// }""";
//
// static final String GUARD_METHOD_TEMPLATE_V =
// """
// @ForceInline
// @LambdaForm.Compiled
// @Hidden
// static final throws Throwable {
// handle.checkExactAccessMode(ad);
// if (handle.isDirect() && handle.vform.methodType_table[ad.type] == ad.symbolicMethodTypeErased) {
// MethodHandle.linkToStatic();
// } else if (handle.isDirect() && handle.vform.getMethodType_V(ad.type) == ad.symbolicMethodTypeErased) {
// MethodHandle.linkToStatic();
// } else {
// MethodHandle mh = handle.getMethodHandle(ad.mode);
// mh.asType(ad.symbolicMethodTypeInvoker).invokeBasic();
// }
// }""";
//
// // A template for deriving the operations
// // could be supported by annotating VarHandle directly with the
// // operation kind and shape
// interface VarHandleTemplate {
// Object get();
//
// void set(Object value);
//
// boolean compareAndSet(Object actualValue, Object expectedValue);
//
// Object compareAndExchange(Object actualValue, Object expectedValue);
//
// Object getAndUpdate(Object value);
// }
//
// static class HandleType {
// final Class receiver;
// final Class[] intermediates;
// final Class value;
//
// HandleType(Class receiver, Class value, Class... intermediates) {
// this.receiver = receiver;
// this.intermediates = intermediates;
// this.value = value;
// }
// }
//
// /**
// * @param args parameters
// */
// public static void main(String[] args) {
// System.out.println("package java.lang.invoke;");
// System.out.println();
// System.out.println("import jdk.internal.vm.annotation.ForceInline;");
// System.out.println("import jdk.internal.vm.annotation.Hidden;");
// System.out.println();
// System.out.println("// This class is auto-generated by " +
// GuardMethodGenerator.class.getName() +
// ". Do not edit.");
// System.out.println("final class VarHandleGuards {");
//
// System.out.println();
//
// // Declare the stream of shapes
// Stream hts = Stream.of(
// // Object->Object
// new HandleType(Object.class, Object.class),
// // Object->int
// new HandleType(Object.class, int.class),
// // Object->long
// new HandleType(Object.class, long.class),
// // Object->float
// new HandleType(Object.class, float.class),
// // Object->double
// new HandleType(Object.class, double.class),
//
// // ->Object
// new HandleType(null, Object.class),
// // ->int
// new HandleType(null, int.class),
// // ->long
// new HandleType(null, long.class),
// // ->float
// new HandleType(null, float.class),
// // ->double
// new HandleType(null, double.class),
//
// // Array[int]->Object
// new HandleType(Object.class, Object.class, int.class),
// // Array[int]->int
// new HandleType(Object.class, int.class, int.class),
// // Array[int]->long
// new HandleType(Object.class, long.class, int.class),
// // Array[int]->float
// new HandleType(Object.class, float.class, int.class),
// // Array[int]->double
// new HandleType(Object.class, double.class, int.class),
//
// // Array[long]->int
// new HandleType(Object.class, int.class, long.class),
// // Array[long]->long
// new HandleType(Object.class, long.class, long.class)
// );
//
// hts.flatMap(ht -> Stream.of(VarHandleTemplate.class.getMethods()).
// map(m -> generateMethodType(m, ht.receiver, ht.value, ht.intermediates))).
// distinct().
// map(GuardMethodGenerator::generateMethod).
// forEach(System.out::println);
//
// System.out.println("}");
// }
//
// static MethodType generateMethodType(Method m, Class receiver, Class value, Class... intermediates) {
// Class returnType = m.getReturnType() == Object.class
// ? value : m.getReturnType();
//
// List> params = new ArrayList<>();
// if (receiver != null)
// params.add(receiver);
// for (int i = 0; i < intermediates.length; i++) {
// params.add(intermediates[i]);
// }
// for (Parameter p : m.getParameters()) {
// params.add(value);
// }
// return MethodType.methodType(returnType, params);
// }
//
// static String generateMethod(MethodType mt) {
// Class returnType = mt.returnType();
//
// LinkedHashMap> params = new LinkedHashMap<>();
// params.put("handle", VarHandle.class);
// for (int i = 0; i < mt.parameterCount(); i++) {
// params.put("arg" + i, mt.parameterType(i));
// }
// params.put("ad", VarHandle.AccessDescriptor.class);
//
// // Generate method signature line
// String RETURN = className(returnType);
// String NAME = "guard";
// String SIGNATURE = getSignature(mt);
// String PARAMS = params.entrySet().stream().
// map(e -> className(e.getValue()) + " " + e.getKey()).
// collect(joining(", "));
// String METHOD = GUARD_METHOD_SIG_TEMPLATE.
// replace("", RETURN).
// replace("", NAME).
// replace("", SIGNATURE).
// replace("", PARAMS);
//
// // Generate method
// params.remove("ad");
//
// List LINK_TO_STATIC_ARGS = params.keySet().stream().
// collect(toList());
// LINK_TO_STATIC_ARGS.add("handle.vform.getMemberName(ad.mode)");
// List LINK_TO_STATIC_ARGS_V = params.keySet().stream().
// collect(toList());
// LINK_TO_STATIC_ARGS_V.add("handle.vform.getMemberName_V(ad.mode)");
//
// List LINK_TO_INVOKER_ARGS = params.keySet().stream().
// collect(toList());
// LINK_TO_INVOKER_ARGS.set(0, LINK_TO_INVOKER_ARGS.get(0) + ".asDirect()");
//
// RETURN = returnType == void.class
// ? ""
// : returnType == Object.class
// ? "return "
// : "return (" + returnType.getName() + ") ";
//
// String RESULT_ERASED = returnType == void.class
// ? ""
// : returnType != Object.class
// ? "return (" + returnType.getName() + ") "
// : "Object r = ";
//
// String RETURN_ERASED = returnType != Object.class
// ? ""
// : "\n return ad.returnType.cast(r);";
//
// String template = returnType == void.class
// ? GUARD_METHOD_TEMPLATE_V
// : GUARD_METHOD_TEMPLATE;
// return template.
// replace("", METHOD).
// replace("", NAME).
// replaceAll("", RETURN).
// replace("", RESULT_ERASED).
// replace("", RETURN_ERASED).
// replaceAll("", LINK_TO_STATIC_ARGS.stream().
// collect(joining(", "))).
// replaceAll("", LINK_TO_STATIC_ARGS_V.stream().
// collect(joining(", "))).
// replace("", LINK_TO_INVOKER_ARGS.stream().
// collect(joining(", ")))
// .indent(4);
// }
//
// static String className(Class c) {
// String n = c.getName();
// if (n.startsWith("java.lang.")) {
// n = n.replace("java.lang.", "");
// if (n.startsWith("invoke.")) {
// n = n.replace("invoke.", "");
// }
// }
// return n.replace('$', '.');
// }
//
// static String getSignature(MethodType m) {
// StringBuilder sb = new StringBuilder(m.parameterCount() + 1);
//
// for (int i = 0; i < m.parameterCount(); i++) {
// Class pt = m.parameterType(i);
// sb.append(getCharType(pt));
// }
//
// sb.append('_').append(getCharType(m.returnType()));
//
// return sb.toString();
// }
//
// static char getCharType(Class pt) {
// if (pt == void.class) {
// return 'V';
// }
// else if (!pt.isPrimitive()) {
// return 'L';
// }
// else if (pt == boolean.class) {
// return 'Z';
// }
// else if (pt == int.class) {
// return 'I';
// }
// else if (pt == long.class) {
// return 'J';
// }
// else if (pt == float.class) {
// return 'F';
// }
// else if (pt == double.class) {
// return 'D';
// }
// else {
// throw new IllegalStateException(pt.getName());
// }
// }
// }
}