diff options
Diffstat (limited to 'java/lang/invoke/MethodType.java')
| -rw-r--r-- | java/lang/invoke/MethodType.java | 1205 |
1 files changed, 1177 insertions, 28 deletions
diff --git a/java/lang/invoke/MethodType.java b/java/lang/invoke/MethodType.java index 4cb5c226..bfa7ccd5 100644 --- a/java/lang/invoke/MethodType.java +++ b/java/lang/invoke/MethodType.java @@ -25,78 +25,1227 @@ package java.lang.invoke; +import sun.invoke.util.Wrapper; +import java.lang.ref.WeakReference; +import java.lang.ref.Reference; +import java.lang.ref.ReferenceQueue; +import java.util.Arrays; +import java.util.Collections; import java.util.List; +import java.util.Objects; +import java.util.concurrent.ConcurrentMap; +import java.util.concurrent.ConcurrentHashMap; +import sun.invoke.util.BytecodeDescriptor; +import static java.lang.invoke.MethodHandleStatics.*; +/** + * A method type represents the arguments and return type accepted and + * returned by a method handle, or the arguments and return type passed + * and expected by a method handle caller. Method types must be properly + * matched between a method handle and all its callers, + * and the JVM's operations enforce this matching at, specifically + * during calls to {@link MethodHandle#invokeExact MethodHandle.invokeExact} + * and {@link MethodHandle#invoke MethodHandle.invoke}, and during execution + * of {@code invokedynamic} instructions. + * <p> + * The structure is a return type accompanied by any number of parameter types. + * The types (primitive, {@code void}, and reference) are represented by {@link Class} objects. + * (For ease of exposition, we treat {@code void} as if it were a type. + * In fact, it denotes the absence of a return type.) + * <p> + * All instances of {@code MethodType} are immutable. + * Two instances are completely interchangeable if they compare equal. + * Equality depends on pairwise correspondence of the return and parameter types and on nothing else. + * <p> + * This type can be created only by factory methods. + * All factory methods may cache values, though caching is not guaranteed. + * Some factory methods are static, while others are virtual methods which + * modify precursor method types, e.g., by changing a selected parameter. + * <p> + * Factory methods which operate on groups of parameter types + * are systematically presented in two versions, so that both Java arrays and + * Java lists can be used to work with groups of parameter types. + * The query methods {@code parameterArray} and {@code parameterList} + * also provide a choice between arrays and lists. + * <p> + * {@code MethodType} objects are sometimes derived from bytecode instructions + * such as {@code invokedynamic}, specifically from the type descriptor strings associated + * with the instructions in a class file's constant pool. + * <p> + * Like classes and strings, method types can also be represented directly + * in a class file's constant pool as constants. + * A method type may be loaded by an {@code ldc} instruction which refers + * to a suitable {@code CONSTANT_MethodType} constant pool entry. + * The entry refers to a {@code CONSTANT_Utf8} spelling for the descriptor string. + * (For full details on method type constants, + * see sections 4.4.8 and 5.4.3.5 of the Java Virtual Machine Specification.) + * <p> + * When the JVM materializes a {@code MethodType} from a descriptor string, + * all classes named in the descriptor must be accessible, and will be loaded. + * (But the classes need not be initialized, as is the case with a {@code CONSTANT_Class}.) + * This loading may occur at any time before the {@code MethodType} object is first derived. + * @author John Rose, JSR 292 EG + */ public final class MethodType implements java.io.Serializable { + private static final long serialVersionUID = 292L; // {rtype, {ptype...}} + + // The rtype and ptypes fields define the structural identity of the method type: + private final Class<?> rtype; + private final Class<?>[] ptypes; + + // The remaining fields are caches of various sorts: + private @Stable MethodTypeForm form; // erased form, plus cached data about primitives + private @Stable MethodType wrapAlt; // alternative wrapped/unwrapped version + // Android-changed: Remove adapter cache. We're not dynamically generating any + // adapters at this point. + // private @Stable Invokers invokers; // cache of handy higher-order adapters + private @Stable String methodDescriptor; // cache for toMethodDescriptorString + + /** + * Check the given parameters for validity and store them into the final fields. + */ + private MethodType(Class<?> rtype, Class<?>[] ptypes, boolean trusted) { + checkRtype(rtype); + checkPtypes(ptypes); + this.rtype = rtype; + // defensively copy the array passed in by the user + this.ptypes = trusted ? ptypes : Arrays.copyOf(ptypes, ptypes.length); + } + + /** + * Construct a temporary unchecked instance of MethodType for use only as a key to the intern table. + * Does not check the given parameters for validity, and must be discarded after it is used as a searching key. + * The parameters are reversed for this constructor, so that is is not accidentally used. + */ + private MethodType(Class<?>[] ptypes, Class<?> rtype) { + this.rtype = rtype; + this.ptypes = ptypes; + } + + /*trusted*/ MethodTypeForm form() { return form; } + /*trusted*/ /** @hide */ public Class<?> rtype() { return rtype; } + /*trusted*/ /** @hide */ public Class<?>[] ptypes() { return ptypes; } + // Android-changed: Removed method setForm. It's unused in the JDK and there's no + // good reason to allow the form to be set externally. + // + // void setForm(MethodTypeForm f) { form = f; } + + /** This number, mandated by the JVM spec as 255, + * is the maximum number of <em>slots</em> + * that any Java method can receive in its argument list. + * It limits both JVM signatures and method type objects. + * The longest possible invocation will look like + * {@code staticMethod(arg1, arg2, ..., arg255)} or + * {@code x.virtualMethod(arg1, arg2, ..., arg254)}. + */ + /*non-public*/ static final int MAX_JVM_ARITY = 255; // this is mandated by the JVM spec. + + /** This number is the maximum arity of a method handle, 254. + * It is derived from the absolute JVM-imposed arity by subtracting one, + * which is the slot occupied by the method handle itself at the + * beginning of the argument list used to invoke the method handle. + * The longest possible invocation will look like + * {@code mh.invoke(arg1, arg2, ..., arg254)}. + */ + // Issue: Should we allow MH.invokeWithArguments to go to the full 255? + /*non-public*/ static final int MAX_MH_ARITY = MAX_JVM_ARITY-1; // deduct one for mh receiver + + /** This number is the maximum arity of a method handle invoker, 253. + * It is derived from the absolute JVM-imposed arity by subtracting two, + * which are the slots occupied by invoke method handle, and the + * target method handle, which are both at the beginning of the argument + * list used to invoke the target method handle. + * The longest possible invocation will look like + * {@code invokermh.invoke(targetmh, arg1, arg2, ..., arg253)}. + */ + /*non-public*/ static final int MAX_MH_INVOKER_ARITY = MAX_MH_ARITY-1; // deduct one more for invoker + + private static void checkRtype(Class<?> rtype) { + Objects.requireNonNull(rtype); + } + private static void checkPtype(Class<?> ptype) { + Objects.requireNonNull(ptype); + if (ptype == void.class) + throw newIllegalArgumentException("parameter type cannot be void"); + } + /** Return number of extra slots (count of long/double args). */ + private static int checkPtypes(Class<?>[] ptypes) { + int slots = 0; + for (Class<?> ptype : ptypes) { + checkPtype(ptype); + if (ptype == double.class || ptype == long.class) { + slots++; + } + } + checkSlotCount(ptypes.length + slots); + return slots; + } + static void checkSlotCount(int count) { + assert((MAX_JVM_ARITY & (MAX_JVM_ARITY+1)) == 0); + // MAX_JVM_ARITY must be power of 2 minus 1 for following code trick to work: + if ((count & MAX_JVM_ARITY) != count) + throw newIllegalArgumentException("bad parameter count "+count); + } + private static IndexOutOfBoundsException newIndexOutOfBoundsException(Object num) { + if (num instanceof Integer) num = "bad index: "+num; + return new IndexOutOfBoundsException(num.toString()); + } + + static final ConcurrentWeakInternSet<MethodType> internTable = new ConcurrentWeakInternSet<>(); + + static final Class<?>[] NO_PTYPES = {}; + + /** + * Finds or creates an instance of the given method type. + * @param rtype the return type + * @param ptypes the parameter types + * @return a method type with the given components + * @throws NullPointerException if {@code rtype} or {@code ptypes} or any element of {@code ptypes} is null + * @throws IllegalArgumentException if any element of {@code ptypes} is {@code void.class} + */ public static MethodType methodType(Class<?> rtype, Class<?>[] ptypes) { - return null; + return makeImpl(rtype, ptypes, false); } + /** + * Finds or creates a method type with the given components. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * @param rtype the return type + * @param ptypes the parameter types + * @return a method type with the given components + * @throws NullPointerException if {@code rtype} or {@code ptypes} or any element of {@code ptypes} is null + * @throws IllegalArgumentException if any element of {@code ptypes} is {@code void.class} + */ public static MethodType methodType(Class<?> rtype, List<Class<?>> ptypes) { - return null; + boolean notrust = false; // random List impl. could return evil ptypes array + return makeImpl(rtype, listToArray(ptypes), notrust); } + private static Class<?>[] listToArray(List<Class<?>> ptypes) { + // sanity check the size before the toArray call, since size might be huge + checkSlotCount(ptypes.size()); + return ptypes.toArray(NO_PTYPES); + } + + /** + * Finds or creates a method type with the given components. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * The leading parameter type is prepended to the remaining array. + * @param rtype the return type + * @param ptype0 the first parameter type + * @param ptypes the remaining parameter types + * @return a method type with the given components + * @throws NullPointerException if {@code rtype} or {@code ptype0} or {@code ptypes} or any element of {@code ptypes} is null + * @throws IllegalArgumentException if {@code ptype0} or {@code ptypes} or any element of {@code ptypes} is {@code void.class} + */ public static - MethodType methodType(Class<?> rtype, Class<?> ptype0, Class<?>... ptypes) { return null; } + MethodType methodType(Class<?> rtype, Class<?> ptype0, Class<?>... ptypes) { + Class<?>[] ptypes1 = new Class<?>[1+ptypes.length]; + ptypes1[0] = ptype0; + System.arraycopy(ptypes, 0, ptypes1, 1, ptypes.length); + return makeImpl(rtype, ptypes1, true); + } + /** + * Finds or creates a method type with the given components. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * The resulting method has no parameter types. + * @param rtype the return type + * @return a method type with the given return value + * @throws NullPointerException if {@code rtype} is null + */ public static - MethodType methodType(Class<?> rtype) { return null; } + MethodType methodType(Class<?> rtype) { + return makeImpl(rtype, NO_PTYPES, true); + } + /** + * Finds or creates a method type with the given components. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * The resulting method has the single given parameter type. + * @param rtype the return type + * @param ptype0 the parameter type + * @return a method type with the given return value and parameter type + * @throws NullPointerException if {@code rtype} or {@code ptype0} is null + * @throws IllegalArgumentException if {@code ptype0} is {@code void.class} + */ public static - MethodType methodType(Class<?> rtype, Class<?> ptype0) { return null; } + MethodType methodType(Class<?> rtype, Class<?> ptype0) { + return makeImpl(rtype, new Class<?>[]{ ptype0 }, true); + } + /** + * Finds or creates a method type with the given components. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * The resulting method has the same parameter types as {@code ptypes}, + * and the specified return type. + * @param rtype the return type + * @param ptypes the method type which supplies the parameter types + * @return a method type with the given components + * @throws NullPointerException if {@code rtype} or {@code ptypes} is null + */ public static - MethodType methodType(Class<?> rtype, MethodType ptypes) { return null; } + MethodType methodType(Class<?> rtype, MethodType ptypes) { + return makeImpl(rtype, ptypes.ptypes, true); + } + + /** + * Sole factory method to find or create an interned method type. + * @param rtype desired return type + * @param ptypes desired parameter types + * @param trusted whether the ptypes can be used without cloning + * @return the unique method type of the desired structure + */ + /*trusted*/ static + MethodType makeImpl(Class<?> rtype, Class<?>[] ptypes, boolean trusted) { + MethodType mt = internTable.get(new MethodType(ptypes, rtype)); + if (mt != null) + return mt; + if (ptypes.length == 0) { + ptypes = NO_PTYPES; trusted = true; + } + mt = new MethodType(rtype, ptypes, trusted); + // promote the object to the Real Thing, and reprobe + mt.form = MethodTypeForm.findForm(mt); + return internTable.add(mt); + } + private static final MethodType[] objectOnlyTypes = new MethodType[20]; + /** + * Finds or creates a method type whose components are {@code Object} with an optional trailing {@code Object[]} array. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * All parameters and the return type will be {@code Object}, + * except the final array parameter if any, which will be {@code Object[]}. + * @param objectArgCount number of parameters (excluding the final array parameter if any) + * @param finalArray whether there will be a trailing array parameter, of type {@code Object[]} + * @return a generally applicable method type, for all calls of the given fixed argument count and a collected array of further arguments + * @throws IllegalArgumentException if {@code objectArgCount} is negative or greater than 255 (or 254, if {@code finalArray} is true) + * @see #genericMethodType(int) + */ public static - MethodType genericMethodType(int objectArgCount, boolean finalArray) { return null; } + MethodType genericMethodType(int objectArgCount, boolean finalArray) { + MethodType mt; + checkSlotCount(objectArgCount); + int ivarargs = (!finalArray ? 0 : 1); + int ootIndex = objectArgCount*2 + ivarargs; + if (ootIndex < objectOnlyTypes.length) { + mt = objectOnlyTypes[ootIndex]; + if (mt != null) return mt; + } + Class<?>[] ptypes = new Class<?>[objectArgCount + ivarargs]; + Arrays.fill(ptypes, Object.class); + if (ivarargs != 0) ptypes[objectArgCount] = Object[].class; + mt = makeImpl(Object.class, ptypes, true); + if (ootIndex < objectOnlyTypes.length) { + objectOnlyTypes[ootIndex] = mt; // cache it here also! + } + return mt; + } + /** + * Finds or creates a method type whose components are all {@code Object}. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * All parameters and the return type will be Object. + * @param objectArgCount number of parameters + * @return a generally applicable method type, for all calls of the given argument count + * @throws IllegalArgumentException if {@code objectArgCount} is negative or greater than 255 + * @see #genericMethodType(int, boolean) + */ public static - MethodType genericMethodType(int objectArgCount) { return null; } + MethodType genericMethodType(int objectArgCount) { + return genericMethodType(objectArgCount, false); + } + + /** + * Finds or creates a method type with a single different parameter type. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * @param num the index (zero-based) of the parameter type to change + * @param nptype a new parameter type to replace the old one with + * @return the same type, except with the selected parameter changed + * @throws IndexOutOfBoundsException if {@code num} is not a valid index into {@code parameterArray()} + * @throws IllegalArgumentException if {@code nptype} is {@code void.class} + * @throws NullPointerException if {@code nptype} is null + */ + public MethodType changeParameterType(int num, Class<?> nptype) { + if (parameterType(num) == nptype) return this; + checkPtype(nptype); + Class<?>[] nptypes = ptypes.clone(); + nptypes[num] = nptype; + return makeImpl(rtype, nptypes, true); + } + + /** + * Finds or creates a method type with additional parameter types. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * @param num the position (zero-based) of the inserted parameter type(s) + * @param ptypesToInsert zero or more new parameter types to insert into the parameter list + * @return the same type, except with the selected parameter(s) inserted + * @throws IndexOutOfBoundsException if {@code num} is negative or greater than {@code parameterCount()} + * @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class} + * or if the resulting method type would have more than 255 parameter slots + * @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null + */ + public MethodType insertParameterTypes(int num, Class<?>... ptypesToInsert) { + int len = ptypes.length; + if (num < 0 || num > len) + throw newIndexOutOfBoundsException(num); + int ins = checkPtypes(ptypesToInsert); + checkSlotCount(parameterSlotCount() + ptypesToInsert.length + ins); + int ilen = ptypesToInsert.length; + if (ilen == 0) return this; + Class<?>[] nptypes = Arrays.copyOfRange(ptypes, 0, len+ilen); + System.arraycopy(nptypes, num, nptypes, num+ilen, len-num); + System.arraycopy(ptypesToInsert, 0, nptypes, num, ilen); + return makeImpl(rtype, nptypes, true); + } + + /** + * Finds or creates a method type with additional parameter types. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * @param ptypesToInsert zero or more new parameter types to insert after the end of the parameter list + * @return the same type, except with the selected parameter(s) appended + * @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class} + * or if the resulting method type would have more than 255 parameter slots + * @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null + */ + public MethodType appendParameterTypes(Class<?>... ptypesToInsert) { + return insertParameterTypes(parameterCount(), ptypesToInsert); + } + + /** + * Finds or creates a method type with additional parameter types. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * @param num the position (zero-based) of the inserted parameter type(s) + * @param ptypesToInsert zero or more new parameter types to insert into the parameter list + * @return the same type, except with the selected parameter(s) inserted + * @throws IndexOutOfBoundsException if {@code num} is negative or greater than {@code parameterCount()} + * @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class} + * or if the resulting method type would have more than 255 parameter slots + * @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null + */ + public MethodType insertParameterTypes(int num, List<Class<?>> ptypesToInsert) { + return insertParameterTypes(num, listToArray(ptypesToInsert)); + } + + /** + * Finds or creates a method type with additional parameter types. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * @param ptypesToInsert zero or more new parameter types to insert after the end of the parameter list + * @return the same type, except with the selected parameter(s) appended + * @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class} + * or if the resulting method type would have more than 255 parameter slots + * @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null + */ + public MethodType appendParameterTypes(List<Class<?>> ptypesToInsert) { + return insertParameterTypes(parameterCount(), ptypesToInsert); + } + + /** + * Finds or creates a method type with modified parameter types. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * @param start the position (zero-based) of the first replaced parameter type(s) + * @param end the position (zero-based) after the last replaced parameter type(s) + * @param ptypesToInsert zero or more new parameter types to insert into the parameter list + * @return the same type, except with the selected parameter(s) replaced + * @throws IndexOutOfBoundsException if {@code start} is negative or greater than {@code parameterCount()} + * or if {@code end} is negative or greater than {@code parameterCount()} + * or if {@code start} is greater than {@code end} + * @throws IllegalArgumentException if any element of {@code ptypesToInsert} is {@code void.class} + * or if the resulting method type would have more than 255 parameter slots + * @throws NullPointerException if {@code ptypesToInsert} or any of its elements is null + */ + /*non-public*/ MethodType replaceParameterTypes(int start, int end, Class<?>... ptypesToInsert) { + if (start == end) + return insertParameterTypes(start, ptypesToInsert); + int len = ptypes.length; + if (!(0 <= start && start <= end && end <= len)) + throw newIndexOutOfBoundsException("start="+start+" end="+end); + int ilen = ptypesToInsert.length; + if (ilen == 0) + return dropParameterTypes(start, end); + return dropParameterTypes(start, end).insertParameterTypes(start, ptypesToInsert); + } + + /** Replace the last arrayLength parameter types with the component type of arrayType. + * @param arrayType any array type + * @param arrayLength the number of parameter types to change + * @return the resulting type + */ + /*non-public*/ MethodType asSpreaderType(Class<?> arrayType, int arrayLength) { + assert(parameterCount() >= arrayLength); + int spreadPos = ptypes.length - arrayLength; + if (arrayLength == 0) return this; // nothing to change + if (arrayType == Object[].class) { + if (isGeneric()) return this; // nothing to change + if (spreadPos == 0) { + // no leading arguments to preserve; go generic + MethodType res = genericMethodType(arrayLength); + if (rtype != Object.class) { + res = res.changeReturnType(rtype); + } + return res; + } + } + Class<?> elemType = arrayType.getComponentType(); + assert(elemType != null); + for (int i = spreadPos; i < ptypes.length; i++) { + if (ptypes[i] != elemType) { + Class<?>[] fixedPtypes = ptypes.clone(); + Arrays.fill(fixedPtypes, i, ptypes.length, elemType); + return methodType(rtype, fixedPtypes); + } + } + return this; // arguments check out; no change + } + + /** Return the leading parameter type, which must exist and be a reference. + * @return the leading parameter type, after error checks + */ + /*non-public*/ Class<?> leadingReferenceParameter() { + Class<?> ptype; + if (ptypes.length == 0 || + (ptype = ptypes[0]).isPrimitive()) + throw newIllegalArgumentException("no leading reference parameter"); + return ptype; + } + + /** Delete the last parameter type and replace it with arrayLength copies of the component type of arrayType. + * @param arrayType any array type + * @param arrayLength the number of parameter types to insert + * @return the resulting type + */ + /*non-public*/ MethodType asCollectorType(Class<?> arrayType, int arrayLength) { + assert(parameterCount() >= 1); + assert(lastParameterType().isAssignableFrom(arrayType)); + MethodType res; + if (arrayType == Object[].class) { + res = genericMethodType(arrayLength); + if (rtype != Object.class) { + res = res.changeReturnType(rtype); + } + } else { + Class<?> elemType = arrayType.getComponentType(); + assert(elemType != null); + res = methodType(rtype, Collections.nCopies(arrayLength, elemType)); + } + if (ptypes.length == 1) { + return res; + } else { + return res.insertParameterTypes(0, parameterList().subList(0, ptypes.length-1)); + } + } + + /** + * Finds or creates a method type with some parameter types omitted. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * @param start the index (zero-based) of the first parameter type to remove + * @param end the index (greater than {@code start}) of the first parameter type after not to remove + * @return the same type, except with the selected parameter(s) removed + * @throws IndexOutOfBoundsException if {@code start} is negative or greater than {@code parameterCount()} + * or if {@code end} is negative or greater than {@code parameterCount()} + * or if {@code start} is greater than {@code end} + */ + public MethodType dropParameterTypes(int start, int end) { + int len = ptypes.length; + if (!(0 <= start && start <= end && end <= len)) + throw newIndexOutOfBoundsException("start="+start+" end="+end); + if (start == end) return this; + Class<?>[] nptypes; + if (start == 0) { + if (end == len) { + // drop all parameters + nptypes = NO_PTYPES; + } else { + // drop initial parameter(s) + nptypes = Arrays.copyOfRange(ptypes, end, len); + } + } else { + if (end == len) { + // drop trailing parameter(s) + nptypes = Arrays.copyOfRange(ptypes, 0, start); + } else { + int tail = len - end; + nptypes = Arrays.copyOfRange(ptypes, 0, start + tail); + System.arraycopy(ptypes, end, nptypes, start, tail); + } + } + return makeImpl(rtype, nptypes, true); + } + + /** + * Finds or creates a method type with a different return type. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * @param nrtype a return parameter type to replace the old one with + * @return the same type, except with the return type change + * @throws NullPointerException if {@code nrtype} is null + */ + public MethodType changeReturnType(Class<?> nrtype) { + if (returnType() == nrtype) return this; + return makeImpl(nrtype, ptypes, true); + } + + /** + * Reports if this type contains a primitive argument or return value. + * The return type {@code void} counts as a primitive. + * @return true if any of the types are primitives + */ + public boolean hasPrimitives() { + return form.hasPrimitives(); + } + + /** + * Reports if this type contains a wrapper argument or return value. + * Wrappers are types which box primitive values, such as {@link Integer}. + * The reference type {@code java.lang.Void} counts as a wrapper, + * if it occurs as a return type. + * @return true if any of the types are wrappers + */ + public boolean hasWrappers() { + return unwrap() != this; + } + + /** + * Erases all reference types to {@code Object}. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * All primitive types (including {@code void}) will remain unchanged. + * @return a version of the original type with all reference types replaced + */ + public MethodType erase() { + return form.erasedType(); + } + + /** + * Erases all reference types to {@code Object}, and all subword types to {@code int}. + * This is the reduced type polymorphism used by private methods + * such as {@link MethodHandle#invokeBasic invokeBasic}. + * @return a version of the original type with all reference and subword types replaced + */ + /*non-public*/ MethodType basicType() { + return form.basicType(); + } + + /** + * @return a version of the original type with MethodHandle prepended as the first argument + */ + /*non-public*/ MethodType invokerType() { + return insertParameterTypes(0, MethodHandle.class); + } - public MethodType changeParameterType(int num, Class<?> nptype) { return null; } + /** + * Converts all types, both reference and primitive, to {@code Object}. + * Convenience method for {@link #genericMethodType(int) genericMethodType}. + * The expression {@code type.wrap().erase()} produces the same value + * as {@code type.generic()}. + * @return a version of the original type with all types replaced + */ + public MethodType generic() { + return genericMethodType(parameterCount()); + } - public MethodType insertParameterTypes(int num, Class<?>... ptypesToInsert) { return null; } + /*non-public*/ boolean isGeneric() { + return this == erase() && !hasPrimitives(); + } - public MethodType appendParameterTypes(Class<?>... ptypesToInsert) { return null; } + /** + * Converts all primitive types to their corresponding wrapper types. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * All reference types (including wrapper types) will remain unchanged. + * A {@code void} return type is changed to the type {@code java.lang.Void}. + * The expression {@code type.wrap().erase()} produces the same value + * as {@code type.generic()}. + * @return a version of the original type with all primitive types replaced + */ + public MethodType wrap() { + return hasPrimitives() ? wrapWithPrims(this) : this; + } - public MethodType insertParameterTypes(int num, List<Class<?>> ptypesToInsert) { return null; } + /** + * Converts all wrapper types to their corresponding primitive types. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * All primitive types (including {@code void}) will remain unchanged. + * A return type of {@code java.lang.Void} is changed to {@code void}. + * @return a version of the original type with all wrapper types replaced + */ + public MethodType unwrap() { + MethodType noprims = !hasPrimitives() ? this : wrapWithPrims(this); + return unwrapWithNoPrims(noprims); + } - public MethodType appendParameterTypes(List<Class<?>> ptypesToInsert) { return null; } + private static MethodType wrapWithPrims(MethodType pt) { + assert(pt.hasPrimitives()); + MethodType wt = pt.wrapAlt; + if (wt == null) { + // fill in lazily + wt = MethodTypeForm.canonicalize(pt, MethodTypeForm.WRAP, MethodTypeForm.WRAP); + assert(wt != null); + pt.wrapAlt = wt; + } + return wt; + } - public MethodType dropParameterTypes(int start, int end) { return null; } + private static MethodType unwrapWithNoPrims(MethodType wt) { + assert(!wt.hasPrimitives()); + MethodType uwt = wt.wrapAlt; + if (uwt == null) { + // fill in lazily + uwt = MethodTypeForm.canonicalize(wt, MethodTypeForm.UNWRAP, MethodTypeForm.UNWRAP); + if (uwt == null) + uwt = wt; // type has no wrappers or prims at all + wt.wrapAlt = uwt; + } + return uwt; + } - public MethodType changeReturnType(Class<?> nrtype) { return null; } + /** + * Returns the parameter type at the specified index, within this method type. + * @param num the index (zero-based) of the desired parameter type + * @return the selected parameter type + * @throws IndexOutOfBoundsException if {@code num} is not a valid index into {@code parameterArray()} + */ + public Class<?> parameterType(int num) { + return ptypes[num]; + } + /** + * Returns the number of parameter types in this method type. + * @return the number of parameter types + */ + public int parameterCount() { + return ptypes.length; + } + /** + * Returns the return type of this method type. + * @return the return type + */ + public Class<?> returnType() { + return rtype; + } - public boolean hasPrimitives() { return false; } + /** + * Presents the parameter types as a list (a convenience method). + * The list will be immutable. + * @return the parameter types (as an immutable list) + */ + public List<Class<?>> parameterList() { + return Collections.unmodifiableList(Arrays.asList(ptypes.clone())); + } - public boolean hasWrappers() { return false; } + /*non-public*/ Class<?> lastParameterType() { + int len = ptypes.length; + return len == 0 ? void.class : ptypes[len-1]; + } - public MethodType erase() { return null; } + /** + * Presents the parameter types as an array (a convenience method). + * Changes to the array will not result in changes to the type. + * @return the parameter types (as a fresh copy if necessary) + */ + public Class<?>[] parameterArray() { + return ptypes.clone(); + } - public MethodType generic() { return null; } + /** + * Compares the specified object with this type for equality. + * That is, it returns <tt>true</tt> if and only if the specified object + * is also a method type with exactly the same parameters and return type. + * @param x object to compare + * @see Object#equals(Object) + */ + @Override + public boolean equals(Object x) { + return this == x || x instanceof MethodType && equals((MethodType)x); + } - public MethodType wrap() { return null; } + private boolean equals(MethodType that) { + return this.rtype == that.rtype + && Arrays.equals(this.ptypes, that.ptypes); + } - public MethodType unwrap() { return null; } + /** + * Returns the hash code value for this method type. + * It is defined to be the same as the hashcode of a List + * whose elements are the return type followed by the + * parameter types. + * @return the hash code value for this method type + * @see Object#hashCode() + * @see #equals(Object) + * @see List#hashCode() + */ + @Override + public int hashCode() { + int hashCode = 31 + rtype.hashCode(); + for (Class<?> ptype : ptypes) + hashCode = 31*hashCode + ptype.hashCode(); + return hashCode; + } - public Class<?> parameterType(int num) { return null; } + /** + * Returns a string representation of the method type, + * of the form {@code "(PT0,PT1...)RT"}. + * The string representation of a method type is a + * parenthesis enclosed, comma separated list of type names, + * followed immediately by the return type. + * <p> + * Each type is represented by its + * {@link java.lang.Class#getSimpleName simple name}. + */ + @Override + public String toString() { + StringBuilder sb = new StringBuilder(); + sb.append("("); + for (int i = 0; i < ptypes.length; i++) { + if (i > 0) sb.append(","); + sb.append(ptypes[i].getSimpleName()); + } + sb.append(")"); + sb.append(rtype.getSimpleName()); + return sb.toString(); + } - public int parameterCount() { return 0; } + /** True if the old return type can always be viewed (w/o casting) under new return type, + * and the new parameters can be viewed (w/o casting) under the old parameter types. + */ + // Android-changed: Removed implementation details. + // boolean isViewableAs(MethodType newType, boolean keepInterfaces); + // boolean parametersAreViewableAs(MethodType newType, boolean keepInterfaces); + /*non-public*/ + boolean isConvertibleTo(MethodType newType) { + MethodTypeForm oldForm = this.form(); + MethodTypeForm newForm = newType.form(); + if (oldForm == newForm) + // same parameter count, same primitive/object mix + return true; + if (!canConvert(returnType(), newType.returnType())) + return false; + Class<?>[] srcTypes = newType.ptypes; + Class<?>[] dstTypes = ptypes; + if (srcTypes == dstTypes) + return true; + int argc; + if ((argc = srcTypes.length) != dstTypes.length) + return false; + if (argc <= 1) { + if (argc == 1 && !canConvert(srcTypes[0], dstTypes[0])) + return false; + return true; + } + if ((oldForm.primitiveParameterCount() == 0 && oldForm.erasedType == this) || + (newForm.primitiveParameterCount() == 0 && newForm.erasedType == newType)) { + // Somewhat complicated test to avoid a loop of 2 or more trips. + // If either type has only Object parameters, we know we can convert. + assert(canConvertParameters(srcTypes, dstTypes)); + return true; + } + return canConvertParameters(srcTypes, dstTypes); + } + + /** Returns true if MHs.explicitCastArguments produces the same result as MH.asType. + * If the type conversion is impossible for either, the result should be false. + */ + /*non-public*/ + boolean explicitCastEquivalentToAsType(MethodType newType) { + if (this == newType) return true; + if (!explicitCastEquivalentToAsType(rtype, newType.rtype)) { + return false; + } + Class<?>[] srcTypes = newType.ptypes; + Class<?>[] dstTypes = ptypes; + if (dstTypes == srcTypes) { + return true; + } + assert(dstTypes.length == srcTypes.length); + for (int i = 0; i < dstTypes.length; i++) { + if (!explicitCastEquivalentToAsType(srcTypes[i], dstTypes[i])) { + return false; + } + } + return true; + } + + /** Reports true if the src can be converted to the dst, by both asType and MHs.eCE, + * and with the same effect. + * MHs.eCA has the following "upgrades" to MH.asType: + * 1. interfaces are unchecked (that is, treated as if aliased to Object) + * Therefore, {@code Object->CharSequence} is possible in both cases but has different semantics + * 2a. the full matrix of primitive-to-primitive conversions is supported + * Narrowing like {@code long->byte} and basic-typing like {@code boolean->int} + * are not supported by asType, but anything supported by asType is equivalent + * with MHs.eCE. + * 2b. conversion of void->primitive means explicit cast has to insert zero/false/null. + * 3a. unboxing conversions can be followed by the full matrix of primitive conversions + * 3b. unboxing of null is permitted (creates a zero primitive value) + * Other than interfaces, reference-to-reference conversions are the same. + * Boxing primitives to references is the same for both operators. + */ + private static boolean explicitCastEquivalentToAsType(Class<?> src, Class<?> dst) { + if (src == dst || dst == Object.class || dst == void.class) { + return true; + } else if (src.isPrimitive() && src != void.class) { + // Could be a prim/prim conversion, where casting is a strict superset. + // Or a boxing conversion, which is always to an exact wrapper class. + return canConvert(src, dst); + } else if (dst.isPrimitive()) { + // Unboxing behavior is different between MHs.eCA & MH.asType (see 3b). + return false; + } else { + // R->R always works, but we have to avoid a check-cast to an interface. + return !dst.isInterface() || dst.isAssignableFrom(src); + } + } - public Class<?> returnType() { return null; } + private boolean canConvertParameters(Class<?>[] srcTypes, Class<?>[] dstTypes) { + for (int i = 0; i < srcTypes.length; i++) { + if (!canConvert(srcTypes[i], dstTypes[i])) { + return false; + } + } + return true; + } - public List<Class<?>> parameterList() { return null; } + /*non-public*/ + static boolean canConvert(Class<?> src, Class<?> dst) { + // short-circuit a few cases: + if (src == dst || src == Object.class || dst == Object.class) return true; + // the remainder of this logic is documented in MethodHandle.asType + if (src.isPrimitive()) { + // can force void to an explicit null, a la reflect.Method.invoke + // can also force void to a primitive zero, by analogy + if (src == void.class) return true; //or !dst.isPrimitive()? + Wrapper sw = Wrapper.forPrimitiveType(src); + if (dst.isPrimitive()) { + // P->P must widen + return Wrapper.forPrimitiveType(dst).isConvertibleFrom(sw); + } else { + // P->R must box and widen + return dst.isAssignableFrom(sw.wrapperType()); + } + } else if (dst.isPrimitive()) { + // any value can be dropped + if (dst == void.class) return true; + Wrapper dw = Wrapper.forPrimitiveType(dst); + // R->P must be able to unbox (from a dynamically chosen type) and widen + // For example: + // Byte/Number/Comparable/Object -> dw:Byte -> byte. + // Character/Comparable/Object -> dw:Character -> char + // Boolean/Comparable/Object -> dw:Boolean -> boolean + // This means that dw must be cast-compatible with src. + if (src.isAssignableFrom(dw.wrapperType())) { + return true; + } + // The above does not work if the source reference is strongly typed + // to a wrapper whose primitive must be widened. For example: + // Byte -> unbox:byte -> short/int/long/float/double + // Character -> unbox:char -> int/long/float/double + if (Wrapper.isWrapperType(src) && + dw.isConvertibleFrom(Wrapper.forWrapperType(src))) { + // can unbox from src and then widen to dst + return true; + } + // We have already covered cases which arise due to runtime unboxing + // of a reference type which covers several wrapper types: + // Object -> cast:Integer -> unbox:int -> long/float/double + // Serializable -> cast:Byte -> unbox:byte -> byte/short/int/long/float/double + // An marginal case is Number -> dw:Character -> char, which would be OK if there were a + // subclass of Number which wraps a value that can convert to char. + // Since there is none, we don't need an extra check here to cover char or boolean. + return false; + } else { + // R->R always works, since null is always valid dynamically + return true; + } + } - public Class<?>[] parameterArray() { return null; } + /** Reports the number of JVM stack slots required to invoke a method + * of this type. Note that (for historical reasons) the JVM requires + * a second stack slot to pass long and double arguments. + * So this method returns {@link #parameterCount() parameterCount} plus the + * number of long and double parameters (if any). + * <p> + * This method is included for the benefit of applications that must + * generate bytecodes that process method handles and invokedynamic. + * @return the number of JVM stack slots for this type's parameters + */ + /*non-public*/ int parameterSlotCount() { + return form.parameterSlotCount(); + } + /// Queries which have to do with the bytecode architecture + + // Android-changed: These methods aren't needed on Android and are unused within the JDK. + // + // int parameterSlotDepth(int num); + // int returnSlotCount(); + // + // Android-changed: Removed cache of higher order adapters. + // + // Invokers invokers(); + + /** + * Finds or creates an instance of a method type, given the spelling of its bytecode descriptor. + * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}. + * Any class or interface name embedded in the descriptor string + * will be resolved by calling {@link ClassLoader#loadClass(java.lang.String)} + * on the given loader (or if it is null, on the system class loader). + * <p> + * Note that it is possible to encounter method types which cannot be + * constructed by this method, because their component types are + * not all reachable from a common class loader. + * <p> + * This method is included for the benefit of applications that must + * generate bytecodes that process method handles and {@code invokedynamic}. + * @param descriptor a bytecode-level type descriptor string "(T...)T" + * @param loader the class loader in which to look up the types + * @return a method type matching the bytecode-level type descriptor + * @throws NullPointerException if the string is null + * @throws IllegalArgumentException if the string is not well-formed + * @throws TypeNotPresentException if a named type cannot be found + */ public static MethodType fromMethodDescriptorString(String descriptor, ClassLoader loader) - throws IllegalArgumentException, TypeNotPresentException { return null; } + throws IllegalArgumentException, TypeNotPresentException + { + if (!descriptor.startsWith("(") || // also generates NPE if needed + descriptor.indexOf(')') < 0 || + descriptor.indexOf('.') >= 0) + throw newIllegalArgumentException("not a method descriptor: "+descriptor); + List<Class<?>> types = BytecodeDescriptor.parseMethod(descriptor, loader); + Class<?> rtype = types.remove(types.size() - 1); + checkSlotCount(types.size()); + Class<?>[] ptypes = listToArray(types); + return makeImpl(rtype, ptypes, true); + } + + /** + * Produces a bytecode descriptor representation of the method type. + * <p> + * Note that this is not a strict inverse of {@link #fromMethodDescriptorString fromMethodDescriptorString}. + * Two distinct classes which share a common name but have different class loaders + * will appear identical when viewed within descriptor strings. + * <p> + * This method is included for the benefit of applications that must + * generate bytecodes that process method handles and {@code invokedynamic}. + * {@link #fromMethodDescriptorString(java.lang.String, java.lang.ClassLoader) fromMethodDescriptorString}, + * because the latter requires a suitable class loader argument. + * @return the bytecode type descriptor representation + */ + public String toMethodDescriptorString() { + String desc = methodDescriptor; + if (desc == null) { + desc = BytecodeDescriptor.unparse(this); + methodDescriptor = desc; + } + return desc; + } + + /*non-public*/ static String toFieldDescriptorString(Class<?> cls) { + return BytecodeDescriptor.unparse(cls); + } - public String toMethodDescriptorString() { return null; } + /// Serialization. + + /** + * There are no serializable fields for {@code MethodType}. + */ + private static final java.io.ObjectStreamField[] serialPersistentFields = { }; + + /** + * Save the {@code MethodType} instance to a stream. + * + * @serialData + * For portability, the serialized format does not refer to named fields. + * Instead, the return type and parameter type arrays are written directly + * from the {@code writeObject} method, using two calls to {@code s.writeObject} + * as follows: + * <blockquote><pre>{@code +s.writeObject(this.returnType()); +s.writeObject(this.parameterArray()); + * }</pre></blockquote> + * <p> + * The deserialized field values are checked as if they were + * provided to the factory method {@link #methodType(Class,Class[]) methodType}. + * For example, null values, or {@code void} parameter types, + * will lead to exceptions during deserialization. + * @param s the stream to write the object to + * @throws java.io.IOException if there is a problem writing the object + */ + private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException { + s.defaultWriteObject(); // requires serialPersistentFields to be an empty array + s.writeObject(returnType()); + s.writeObject(parameterArray()); + } + + /** + * Reconstitute the {@code MethodType} instance from a stream (that is, + * deserialize it). + * This instance is a scratch object with bogus final fields. + * It provides the parameters to the factory method called by + * {@link #readResolve readResolve}. + * After that call it is discarded. + * @param s the stream to read the object from + * @throws java.io.IOException if there is a problem reading the object + * @throws ClassNotFoundException if one of the component classes cannot be resolved + * @see #MethodType() + * @see #readResolve + * @see #writeObject + */ + private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException { + s.defaultReadObject(); // requires serialPersistentFields to be an empty array + + Class<?> returnType = (Class<?>) s.readObject(); + Class<?>[] parameterArray = (Class<?>[]) s.readObject(); + + // Probably this object will never escape, but let's check + // the field values now, just to be sure. + checkRtype(returnType); + checkPtypes(parameterArray); + + parameterArray = parameterArray.clone(); // make sure it is unshared + MethodType_init(returnType, parameterArray); + } + + /** + * For serialization only. + * Sets the final fields to null, pending {@code Unsafe.putObject}. + */ + private MethodType() { + this.rtype = null; + this.ptypes = null; + } + private void MethodType_init(Class<?> rtype, Class<?>[] ptypes) { + // In order to communicate these values to readResolve, we must + // store them into the implementation-specific final fields. + checkRtype(rtype); + checkPtypes(ptypes); + UNSAFE.putObject(this, rtypeOffset, rtype); + UNSAFE.putObject(this, ptypesOffset, ptypes); + } + + // Support for resetting final fields while deserializing + private static final long rtypeOffset, ptypesOffset; + static { + try { + rtypeOffset = UNSAFE.objectFieldOffset + (MethodType.class.getDeclaredField("rtype")); + ptypesOffset = UNSAFE.objectFieldOffset + (MethodType.class.getDeclaredField("ptypes")); + } catch (Exception ex) { + throw new Error(ex); + } + } + + /** + * Resolves and initializes a {@code MethodType} object + * after serialization. + * @return the fully initialized {@code MethodType} object + */ + private Object readResolve() { + // Do not use a trusted path for deserialization: + //return makeImpl(rtype, ptypes, true); + // Verify all operands, and make sure ptypes is unshared: + return methodType(rtype, ptypes); + } + + /** + * Simple implementation of weak concurrent intern set. + * + * @param <T> interned type + */ + private static class ConcurrentWeakInternSet<T> { + + private final ConcurrentMap<WeakEntry<T>, WeakEntry<T>> map; + private final ReferenceQueue<T> stale; + + public ConcurrentWeakInternSet() { + this.map = new ConcurrentHashMap<>(); + this.stale = new ReferenceQueue<>(); + } + + /** + * Get the existing interned element. + * This method returns null if no element is interned. + * + * @param elem element to look up + * @return the interned element + */ + public T get(T elem) { + if (elem == null) throw new NullPointerException(); + expungeStaleElements(); + + WeakEntry<T> value = map.get(new WeakEntry<>(elem)); + if (value != null) { + T res = value.get(); + if (res != null) { + return res; + } + } + return null; + } + + /** + * Interns the element. + * Always returns non-null element, matching the one in the intern set. + * Under the race against another add(), it can return <i>different</i> + * element, if another thread beats us to interning it. + * + * @param elem element to add + * @return element that was actually added + */ + public T add(T elem) { + if (elem == null) throw new NullPointerException(); + + // Playing double race here, and so spinloop is required. + // First race is with two concurrent updaters. + // Second race is with GC purging weak ref under our feet. + // Hopefully, we almost always end up with a single pass. + T interned; + WeakEntry<T> e = new WeakEntry<>(elem, stale); + do { + expungeStaleElements(); + WeakEntry<T> exist = map.putIfAbsent(e, e); + interned = (exist == null) ? elem : exist.get(); + } while (interned == null); + return interned; + } + + private void expungeStaleElements() { + Reference<? extends T> reference; + while ((reference = stale.poll()) != null) { + map.remove(reference); + } + } + + private static class WeakEntry<T> extends WeakReference<T> { + + public final int hashcode; + + public WeakEntry(T key, ReferenceQueue<T> queue) { + super(key, queue); + hashcode = key.hashCode(); + } + + public WeakEntry(T key) { + super(key); + hashcode = key.hashCode(); + } + + @Override + public boolean equals(Object obj) { + if (obj instanceof WeakEntry) { + Object that = ((WeakEntry) obj).get(); + Object mine = get(); + return (that == null || mine == null) ? (this == obj) : mine.equals(that); + } + return false; + } + + @Override + public int hashCode() { + return hashcode; + } + + } + } } |