8187443: Forest Consolidation: Move files to unified layout

Reviewed-by: darcy, ihse

src/java.base/share/classes/java/lang/invoke/DelegatingMethodHandle.java

@@ -0,0 +1,175 @@
+/*
+ * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * 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.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package java.lang.invoke;
+
+import java.util.Arrays;
+import static java.lang.invoke.LambdaForm.*;
+import static java.lang.invoke.LambdaForm.Kind.*;
+import static java.lang.invoke.MethodHandleStatics.*;
+
+/**
+ * A method handle whose invocation behavior is determined by a target.
+ * The delegating MH itself can hold extra "intentions" beyond the simple behavior.
+ * @author jrose
+ */
+/*non-public*/
+abstract class DelegatingMethodHandle extends MethodHandle {
+    protected DelegatingMethodHandle(MethodHandle target) {
+        this(target.type(), target);
+    }
+
+    protected DelegatingMethodHandle(MethodType type, MethodHandle target) {
+        super(type, chooseDelegatingForm(target));
+    }
+
+    protected DelegatingMethodHandle(MethodType type, LambdaForm form) {
+        super(type, form);
+    }
+
+    /** Define this to extract the delegated target which supplies the invocation behavior. */
+    protected abstract MethodHandle getTarget();
+
+    @Override
+    abstract MethodHandle asTypeUncached(MethodType newType);
+
+    @Override
+    MemberName internalMemberName() {
+        return getTarget().internalMemberName();
+    }
+
+    @Override
+    boolean isInvokeSpecial() {
+        return getTarget().isInvokeSpecial();
+    }
+
+    @Override
+    Class<?> internalCallerClass() {
+        return getTarget().internalCallerClass();
+    }
+
+    @Override
+    MethodHandle copyWith(MethodType mt, LambdaForm lf) {
+        // FIXME: rethink 'copyWith' protocol; it is too low-level for use on all MHs
+        throw newIllegalArgumentException("do not use this");
+    }
+
+    @Override
+    String internalProperties() {
+        return "\n& Class="+getClass().getSimpleName()+
+               "\n& Target="+getTarget().debugString();
+    }
+
+    @Override
+    BoundMethodHandle rebind() {
+        return getTarget().rebind();
+    }
+
+    private static LambdaForm chooseDelegatingForm(MethodHandle target) {
+        if (target instanceof SimpleMethodHandle)
+            return target.internalForm();  // no need for an indirection
+        return makeReinvokerForm(target, MethodTypeForm.LF_DELEGATE, DelegatingMethodHandle.class, NF_getTarget);
+    }
+
+    static LambdaForm makeReinvokerForm(MethodHandle target,
+                                        int whichCache,
+                                        Object constraint,
+                                        NamedFunction getTargetFn) {
+        // No pre-action needed.
+        return makeReinvokerForm(target, whichCache, constraint, true, getTargetFn, null);
+    }
+    /** Create a LF which simply reinvokes a target of the given basic type. */
+    static LambdaForm makeReinvokerForm(MethodHandle target,
+                                        int whichCache,
+                                        Object constraint,
+                                        boolean forceInline,
+                                        NamedFunction getTargetFn,
+                                        NamedFunction preActionFn) {
+        MethodType mtype = target.type().basicType();
+        Kind kind = whichKind(whichCache);
+        boolean customized = (whichCache < 0 ||
+                mtype.parameterSlotCount() > MethodType.MAX_MH_INVOKER_ARITY);
+        boolean hasPreAction = (preActionFn != null);
+        LambdaForm form;
+        if (!customized) {
+            form = mtype.form().cachedLambdaForm(whichCache);
+            if (form != null)  return form;
+        }
+        final int THIS_DMH    = 0;
+        final int ARG_BASE    = 1;
+        final int ARG_LIMIT   = ARG_BASE + mtype.parameterCount();
+        int nameCursor = ARG_LIMIT;
+        final int PRE_ACTION   = hasPreAction ? nameCursor++ : -1;
+        final int NEXT_MH     = customized ? -1 : nameCursor++;
+        final int REINVOKE    = nameCursor++;
+        LambdaForm.Name[] names = LambdaForm.arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
+        assert(names.length == nameCursor);
+        names[THIS_DMH] = names[THIS_DMH].withConstraint(constraint);
+        Object[] targetArgs;
+        if (hasPreAction) {
+            names[PRE_ACTION] = new LambdaForm.Name(preActionFn, names[THIS_DMH]);
+        }
+        if (customized) {
+            targetArgs = Arrays.copyOfRange(names, ARG_BASE, ARG_LIMIT, Object[].class);
+            names[REINVOKE] = new LambdaForm.Name(target, targetArgs);  // the invoker is the target itself
+        } else {
+            names[NEXT_MH] = new LambdaForm.Name(getTargetFn, names[THIS_DMH]);
+            targetArgs = Arrays.copyOfRange(names, THIS_DMH, ARG_LIMIT, Object[].class);
+            targetArgs[0] = names[NEXT_MH];  // overwrite this MH with next MH
+            names[REINVOKE] = new LambdaForm.Name(mtype, targetArgs);
+        }
+        form = new LambdaForm(ARG_LIMIT, names, forceInline, kind);
+        if (!customized) {
+            form = mtype.form().setCachedLambdaForm(whichCache, form);
+        }
+        return form;
+    }
+
+    private static Kind whichKind(int whichCache) {
+        switch(whichCache) {
+            case MethodTypeForm.LF_REBIND:   return BOUND_REINVOKER;
+            case MethodTypeForm.LF_DELEGATE: return DELEGATE;
+            default:                         return REINVOKER;
+        }
+    }
+
+    static final NamedFunction NF_getTarget;
+    static {
+        try {
+            NF_getTarget = new NamedFunction(DelegatingMethodHandle.class
+                                             .getDeclaredMethod("getTarget"));
+        } catch (ReflectiveOperationException ex) {
+            throw newInternalError(ex);
+        }
+        // The Holder class will contain pre-generated DelegatingMethodHandles resolved
+        // speculatively using MemberName.getFactory().resolveOrNull. However, that
+        // doesn't initialize the class, which subtly breaks inlining etc. By forcing
+        // initialization of the Holder class we avoid these issues.
+        UNSAFE.ensureClassInitialized(Holder.class);
+    }
+
+    /* Placeholder class for DelegatingMethodHandles generated ahead of time */
+    final class Holder {}
+}