/*
* Copyright (c) 2010, 2013, 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
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package jdk.nashorn.internal.runtime;
import static jdk.nashorn.internal.lookup.Lookup.MH;
import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import jdk.nashorn.internal.runtime.linker.LinkerCallSite;
/**
* A container for data needed to instantiate a specific {@link ScriptFunction} at runtime.
* Instances of this class are created during codegen and stored in script classes'
* constants array to reduce function instantiation overhead during runtime.
*/
public abstract class ScriptFunctionData implements Serializable {
static final int MAX_ARITY = LinkerCallSite.ARGLIMIT;
static {
// Assert it fits in a byte, as that's what we store it in. It's just a size optimization though, so if needed
// "byte arity" field can be widened.
assert MAX_ARITY < 256;
}
/** Name of the function or "" for anonymous functions */
protected final String name;
/**
* A list of code versions of a function sorted in ascending order of generic descriptors.
*/
protected transient LinkedList<CompiledFunction> code = new LinkedList<>();
/** Function flags */
protected int flags;
// Parameter arity of the function, corresponding to "f.length". E.g. "function f(a, b, c) { ... }" arity is 3, and
// some built-in ECMAScript functions have their arity declared by the specification. Note that regardless of this
// value, the function might still be capable of receiving variable number of arguments, see isVariableArity.
private int arity;
/**
* A pair of method handles used for generic invoker and constructor. Field is volatile as it can be initialized by
* multiple threads concurrently, but we still tolerate a race condition in it as all values stored into it are
* idempotent.
*/
private volatile transient GenericInvokers genericInvokers;
private static final MethodHandle BIND_VAR_ARGS = findOwnMH("bindVarArgs", Object[].class, Object[].class, Object[].class);
/** Is this a strict mode function? */
public static final int IS_STRICT = 1 << 0;
/** Is this a built-in function? */
public static final int IS_BUILTIN = 1 << 1;
/** Is this a constructor function? */
public static final int IS_CONSTRUCTOR = 1 << 2;
/** Does this function expect a callee argument? */
public static final int NEEDS_CALLEE = 1 << 3;
/** Does this function make use of the this-object argument? */
public static final int USES_THIS = 1 << 4;
/** Is this a variable arity function? */
public static final int IS_VARIABLE_ARITY = 1 << 5;
/** Is this a object literal property getter or setter? */
public static final int IS_PROPERTY_ACCESSOR = 1 << 6;
/** Is this an ES6 method? */
public static final int IS_ES6_METHOD = 1 << 7;
/** Flag for strict or built-in functions */
public static final int IS_STRICT_OR_BUILTIN = IS_STRICT | IS_BUILTIN;
/** Flag for built-in constructors */
public static final int IS_BUILTIN_CONSTRUCTOR = IS_BUILTIN | IS_CONSTRUCTOR;
private static final long serialVersionUID = 4252901245508769114L;
/**
* Constructor
*
* @param name script function name
* @param arity arity
* @param flags the function flags
*/
ScriptFunctionData(final String name, final int arity, final int flags) {
this.name = name;
this.flags = flags;
setArity(arity);
}
final int getArity() {
return arity;
}
String getDocumentation() {
return toSource();
}
String getDocumentationKey() {
return null;
}
final boolean isVariableArity() {
return (flags & IS_VARIABLE_ARITY) != 0;
}
/**
* Used from e.g. Native*$Constructors as an explicit call. TODO - make arity immutable and final
* @param arity new arity
*/
void setArity(final int arity) {
if(arity < 0 || arity > MAX_ARITY) {
throw new IllegalArgumentException(String.valueOf(arity));
}
this.arity = arity;
}
/**
* Used from nasgen generated code.
*
* @param docKey documentation key for this function
*/
void setDocumentationKey(final String docKey) {
}
CompiledFunction bind(final CompiledFunction originalInv, final ScriptFunction fn, final Object self, final Object[] args) {
final MethodHandle boundInvoker = bindInvokeHandle(originalInv.createComposableInvoker(), fn, self, args);
if (isConstructor()) {
return new CompiledFunction(boundInvoker, bindConstructHandle(originalInv.createComposableConstructor(), fn, args), null);
}
return new CompiledFunction(boundInvoker);
}
/**
* Is this a ScriptFunction generated with strict semantics?
* @return true if strict, false otherwise
*/
public final boolean isStrict() {
return (flags & IS_STRICT) != 0;
}
/**
* Return the complete internal function name for this
* data, not anonymous or similar. May be identical
* @return internal function name
*/
protected String getFunctionName() {
return getName();
}
final boolean isBuiltin() {
return (flags & IS_BUILTIN) != 0;
}
final boolean isConstructor() {
return (flags & IS_CONSTRUCTOR) != 0;
}
abstract boolean needsCallee();
/**
* Returns true if this is a non-strict, non-built-in function that requires non-primitive this argument
* according to ECMA 10.4.3.
* @return true if this argument must be an object
*/
final boolean needsWrappedThis() {
return (flags & USES_THIS) != 0 && (flags & IS_STRICT_OR_BUILTIN) == 0;
}
String toSource() {
return "function " + (name == null ? "" : name) + "() { [native code] }";
}
String getName() {
return name;
}
/**
* Get this function as a String containing its source code. If no source code
* exists in this ScriptFunction, its contents will be displayed as {@code [native code]}
*
* @return string representation of this function
*/
@Override
public String toString() {
return name.isEmpty() ? "<anonymous>" : name;
}
/**
* Verbose description of data
* @return verbose description
*/
public String toStringVerbose() {
final StringBuilder sb = new StringBuilder();
sb.append("name='").
append(name.isEmpty() ? "<anonymous>" : name).
append("' ").
append(code.size()).
append(" invokers=").
append(code);
return sb.toString();
}
/**
* Pick the best invoker, i.e. the one version of this method with as narrow and specific
* types as possible. If the call site arguments are objects, but boxed primitives we can
* also try to get a primitive version of the method and do an unboxing filter, but then
* we need to insert a guard that checks the argument is really always a boxed primitive
* and not suddenly a "real" object
*
* @param callSiteType callsite type
* @return compiled function object representing the best invoker.
*/
final CompiledFunction getBestInvoker(final MethodType callSiteType, final ScriptObject runtimeScope) {
return getBestInvoker(callSiteType, runtimeScope, CompiledFunction.NO_FUNCTIONS);
}
final CompiledFunction getBestInvoker(final MethodType callSiteType, final ScriptObject runtimeScope, final Collection<CompiledFunction> forbidden) {
final CompiledFunction cf = getBest(callSiteType, runtimeScope, forbidden);
assert cf != null;
return cf;
}
final CompiledFunction getBestConstructor(final MethodType callSiteType, final ScriptObject runtimeScope, final Collection<CompiledFunction> forbidden) {
if (!isConstructor()) {
throw typeError("not.a.constructor", toSource());
}
// Constructor call sites don't have a "this", but getBest is meant to operate on "callee, this, ..." style
final CompiledFunction cf = getBest(callSiteType.insertParameterTypes(1, Object.class), runtimeScope, forbidden);
return cf;
}
/**
* If we can have lazy code generation, this is a hook to ensure that the code has been compiled.
* This does not guarantee the code been installed in this {@code ScriptFunctionData} instance
*/
protected void ensureCompiled() {
//empty
}
/**
* Return a generic Object/Object invoker for this method. It will ensure code
* is generated, get the most generic of all versions of this function and adapt it
* to Objects.
*
* @param runtimeScope the runtime scope. It can be used to evaluate types of scoped variables to guide the
* optimistic compilation, should the call to this method trigger code compilation. Can be null if current runtime
* scope is not known, but that might cause compilation of code that will need more deoptimization passes.
* @return generic invoker of this script function
*/
final MethodHandle getGenericInvoker(final ScriptObject runtimeScope) {
// This method has race conditions both on genericsInvoker and genericsInvoker.invoker, but even if invoked
// concurrently, they'll create idempotent results, so it doesn't matter. We could alternatively implement this
// using java.util.concurrent.AtomicReferenceFieldUpdater, but it's hardly worth it.
final GenericInvokers lgenericInvokers = ensureGenericInvokers();
MethodHandle invoker = lgenericInvokers.invoker;
if(invoker == null) {
lgenericInvokers.invoker = invoker = createGenericInvoker(runtimeScope);
}
return invoker;
}
private MethodHandle createGenericInvoker(final ScriptObject runtimeScope) {
return makeGenericMethod(getGeneric(runtimeScope).createComposableInvoker());
}
final MethodHandle getGenericConstructor(final ScriptObject runtimeScope) {
// This method has race conditions both on genericsInvoker and genericsInvoker.constructor, but even if invoked
// concurrently, they'll create idempotent results, so it doesn't matter. We could alternatively implement this
// using java.util.concurrent.AtomicReferenceFieldUpdater, but it's hardly worth it.
final GenericInvokers lgenericInvokers = ensureGenericInvokers();
MethodHandle constructor = lgenericInvokers.constructor;
if(constructor == null) {
lgenericInvokers.constructor = constructor = createGenericConstructor(runtimeScope);
}
return constructor;
}
private MethodHandle createGenericConstructor(final ScriptObject runtimeScope) {
return makeGenericMethod(getGeneric(runtimeScope).createComposableConstructor());
}
private GenericInvokers ensureGenericInvokers() {
GenericInvokers lgenericInvokers = genericInvokers;
if(lgenericInvokers == null) {
genericInvokers = lgenericInvokers = new GenericInvokers();
}
return lgenericInvokers;
}
private static MethodType widen(final MethodType cftype) {
final Class<?>[] paramTypes = new Class<?>[cftype.parameterCount()];
for (int i = 0; i < cftype.parameterCount(); i++) {
paramTypes[i] = cftype.parameterType(i).isPrimitive() ? cftype.parameterType(i) : Object.class;
}
return MH.type(cftype.returnType(), paramTypes);
}
/**
* Used to find an apply to call version that fits this callsite.
* We cannot just, as in the normal matcher case, return e.g. (Object, Object, int)
* for (Object, Object, int, int, int) or we will destroy the semantics and get
* a function that, when padded with undefined values, behaves differently
* @param type actual call site type
* @return apply to call that perfectly fits this callsite or null if none found
*/
CompiledFunction lookupExactApplyToCall(final MethodType type) {
for (final CompiledFunction cf : code) {
if (!cf.isApplyToCall()) {
continue;
}
final MethodType cftype = cf.type();
if (cftype.parameterCount() != type.parameterCount()) {
continue;
}
if (widen(cftype).equals(widen(type))) {
return cf;
}
}
return null;
}
CompiledFunction pickFunction(final MethodType callSiteType, final boolean canPickVarArg) {
for (final CompiledFunction candidate : code) {
if (candidate.matchesCallSite(callSiteType, canPickVarArg)) {
return candidate;
}
}
return null;
}
/**
* Returns the best function for the specified call site type.
* @param callSiteType The call site type. Call site types are expected to have the form
* {@code (callee, this[, args...])}.
* @param runtimeScope the runtime scope. It can be used to evaluate types of scoped variables to guide the
* optimistic compilation, should the call to this method trigger code compilation. Can be null if current runtime
* scope is not known, but that might cause compilation of code that will need more deoptimization passes.
* @param linkLogicOkay is a CompiledFunction with a LinkLogic acceptable?
* @return the best function for the specified call site type.
*/
abstract CompiledFunction getBest(final MethodType callSiteType, final ScriptObject runtimeScope, final Collection<CompiledFunction> forbidden, final boolean linkLogicOkay);
/**
* Returns the best function for the specified call site type.
* @param callSiteType The call site type. Call site types are expected to have the form
* {@code (callee, this[, args...])}.
* @param runtimeScope the runtime scope. It can be used to evaluate types of scoped variables to guide the
* optimistic compilation, should the call to this method trigger code compilation. Can be null if current runtime
* scope is not known, but that might cause compilation of code that will need more deoptimization passes.
* @return the best function for the specified call site type.
*/
final CompiledFunction getBest(final MethodType callSiteType, final ScriptObject runtimeScope, final Collection<CompiledFunction> forbidden) {
return getBest(callSiteType, runtimeScope, forbidden, true);
}
boolean isValidCallSite(final MethodType callSiteType) {
return callSiteType.parameterCount() >= 2 && // Must have at least (callee, this)
callSiteType.parameterType(0).isAssignableFrom(ScriptFunction.class); // Callee must be assignable from script function
}
CompiledFunction getGeneric(final ScriptObject runtimeScope) {
return getBest(getGenericType(), runtimeScope, CompiledFunction.NO_FUNCTIONS, false);
}
/**
* Get a method type for a generic invoker.
* @return the method type for the generic invoker
*/
abstract MethodType getGenericType();
/**
* Allocates an object using this function's allocator.
*
* @param map the property map for the allocated object.
* @return the object allocated using this function's allocator, or null if the function doesn't have an allocator.
*/
ScriptObject allocate(final PropertyMap map) {
return null;
}
/**
* Get the property map to use for objects allocated by this function.
*
* @param prototype the prototype of the allocated object
* @return the property map for allocated objects.
*/
PropertyMap getAllocatorMap(final ScriptObject prototype) {
return null;
}
/**
* This method is used to create the immutable portion of a bound function.
* See {@link ScriptFunction#createBound(Object, Object[])}
*
* @param fn the original function being bound
* @param self this reference to bind. Can be null.
* @param args additional arguments to bind. Can be null.
*/
ScriptFunctionData makeBoundFunctionData(final ScriptFunction fn, final Object self, final Object[] args) {
final Object[] allArgs = args == null ? ScriptRuntime.EMPTY_ARRAY : args;
final int length = args == null ? 0 : args.length;
// Clear the callee and this flags
final int boundFlags = flags & ~NEEDS_CALLEE & ~USES_THIS;
final List<CompiledFunction> boundList = new LinkedList<>();
final ScriptObject runtimeScope = fn.getScope();
final CompiledFunction bindTarget = new CompiledFunction(getGenericInvoker(runtimeScope), getGenericConstructor(runtimeScope), null);
boundList.add(bind(bindTarget, fn, self, allArgs));
return new FinalScriptFunctionData(name, Math.max(0, getArity() - length), boundList, boundFlags);
}
/**
* Convert this argument for non-strict functions according to ES 10.4.3
*
* @param thiz the this argument
*
* @return the converted this object
*/
private Object convertThisObject(final Object thiz) {
return needsWrappedThis() ? wrapThis(thiz) : thiz;
}
static Object wrapThis(final Object thiz) {
if (!(thiz instanceof ScriptObject)) {
if (JSType.nullOrUndefined(thiz)) {
return Context.getGlobal();
}
if (isPrimitiveThis(thiz)) {
return Context.getGlobal().wrapAsObject(thiz);
}
}
return thiz;
}
static boolean isPrimitiveThis(final Object obj) {
return JSType.isString(obj) || obj instanceof Number || obj instanceof Boolean;
}
/**
* Creates an invoker method handle for a bound function.
*
* @param targetFn the function being bound
* @param originalInvoker an original invoker method handle for the function. This can be its generic invoker or
* any of its specializations.
* @param self the "this" value being bound
* @param args additional arguments being bound
*
* @return a bound invoker method handle that will bind the self value and the specified arguments. The resulting
* invoker never needs a callee; if the original invoker needed it, it will be bound to {@code fn}. The resulting
* invoker still takes an initial {@code this} parameter, but it is always dropped and the bound {@code self} passed
* to the original invoker on invocation.
*/
private MethodHandle bindInvokeHandle(final MethodHandle originalInvoker, final ScriptFunction targetFn, final Object self, final Object[] args) {
// Is the target already bound? If it is, we won't bother binding either callee or self as they're already bound
// in the target and will be ignored anyway.
final boolean isTargetBound = targetFn.isBoundFunction();
final boolean needsCallee = needsCallee(originalInvoker);
assert needsCallee == needsCallee() : "callee contract violation 2";
assert !(isTargetBound && needsCallee); // already bound functions don't need a callee
final Object boundSelf = isTargetBound ? null : convertThisObject(self);
final MethodHandle boundInvoker;
if (isVarArg(originalInvoker)) {
// First, bind callee and this without arguments
final MethodHandle noArgBoundInvoker;
if (isTargetBound) {
// Don't bind either callee or this
noArgBoundInvoker = originalInvoker;
} else if (needsCallee) {
// Bind callee and this
noArgBoundInvoker = MH.insertArguments(originalInvoker, 0, targetFn, boundSelf);
} else {
// Only bind this
noArgBoundInvoker = MH.bindTo(originalInvoker, boundSelf);
}
// Now bind arguments
if (args.length > 0) {
boundInvoker = varArgBinder(noArgBoundInvoker, args);
} else {
boundInvoker = noArgBoundInvoker;
}
} else {
// If target is already bound, insert additional bound arguments after "this" argument, at position 1.
final int argInsertPos = isTargetBound ? 1 : 0;
final Object[] boundArgs = new Object[Math.min(originalInvoker.type().parameterCount() - argInsertPos, args.length + (isTargetBound ? 0 : needsCallee ? 2 : 1))];
int next = 0;
if (!isTargetBound) {
if (needsCallee) {
boundArgs[next++] = targetFn;
}
boundArgs[next++] = boundSelf;
}
// If more bound args were specified than the function can take, we'll just drop those.
System.arraycopy(args, 0, boundArgs, next, boundArgs.length - next);
// If target is already bound, insert additional bound arguments after "this" argument, at position 1;
// "this" will get dropped anyway by the target invoker. We previously asserted that already bound functions
// don't take a callee parameter, so we can know that the signature is (this[, args...]) therefore args
// start at position 1. If the function is not bound, we start inserting arguments at position 0.
boundInvoker = MH.insertArguments(originalInvoker, argInsertPos, boundArgs);
}
if (isTargetBound) {
return boundInvoker;
}
// If the target is not already bound, add a dropArguments that'll throw away the passed this
return MH.dropArguments(boundInvoker, 0, Object.class);
}
/**
* Creates a constructor method handle for a bound function using the passed constructor handle.
*
* @param originalConstructor the constructor handle to bind. It must be a composed constructor.
* @param fn the function being bound
* @param args arguments being bound
*
* @return a bound constructor method handle that will bind the specified arguments. The resulting constructor never
* needs a callee; if the original constructor needed it, it will be bound to {@code fn}. The resulting constructor
* still takes an initial {@code this} parameter and passes it to the underlying original constructor. Finally, if
* this script function data object has no constructor handle, null is returned.
*/
private static MethodHandle bindConstructHandle(final MethodHandle originalConstructor, final ScriptFunction fn, final Object[] args) {
assert originalConstructor != null;
// If target function is already bound, don't bother binding the callee.
final MethodHandle calleeBoundConstructor = fn.isBoundFunction() ? originalConstructor :
MH.dropArguments(MH.bindTo(originalConstructor, fn), 0, ScriptFunction.class);
if (args.length == 0) {
return calleeBoundConstructor;
}
if (isVarArg(calleeBoundConstructor)) {
return varArgBinder(calleeBoundConstructor, args);
}
final Object[] boundArgs;
final int maxArgCount = calleeBoundConstructor.type().parameterCount() - 1;
if (args.length <= maxArgCount) {
boundArgs = args;
} else {
boundArgs = new Object[maxArgCount];
System.arraycopy(args, 0, boundArgs, 0, maxArgCount);
}
return MH.insertArguments(calleeBoundConstructor, 1, boundArgs);
}
/**
* Takes a method handle, and returns a potentially different method handle that can be used in
* {@code ScriptFunction#invoke(Object, Object...)} or {code ScriptFunction#construct(Object, Object...)}.
* The returned method handle will be sure to return {@code Object}, and will have all its parameters turned into
* {@code Object} as well, except for the following ones:
* <ul>
* <li>a last parameter of type {@code Object[]} which is used for vararg functions,</li>
* <li>the first argument, which is forced to be {@link ScriptFunction}, in case the function receives itself
* (callee) as an argument.</li>
* </ul>
*
* @param mh the original method handle
*
* @return the new handle, conforming to the rules above.
*/
private static MethodHandle makeGenericMethod(final MethodHandle mh) {
final MethodType type = mh.type();
final MethodType newType = makeGenericType(type);
return type.equals(newType) ? mh : mh.asType(newType);
}
private static MethodType makeGenericType(final MethodType type) {
MethodType newType = type.generic();
if (isVarArg(type)) {
newType = newType.changeParameterType(type.parameterCount() - 1, Object[].class);
}
if (needsCallee(type)) {
newType = newType.changeParameterType(0, ScriptFunction.class);
}
return newType;
}
/**
* Execute this script function.
*
* @param self Target object.
* @param arguments Call arguments.
* @return ScriptFunction result.
*
* @throws Throwable if there is an exception/error with the invocation or thrown from it
*/
Object invoke(final ScriptFunction fn, final Object self, final Object... arguments) throws Throwable {
final MethodHandle mh = getGenericInvoker(fn.getScope());
final Object selfObj = convertThisObject(self);
final Object[] args = arguments == null ? ScriptRuntime.EMPTY_ARRAY : arguments;
DebuggerSupport.notifyInvoke(mh);
if (isVarArg(mh)) {
if (needsCallee(mh)) {
return mh.invokeExact(fn, selfObj, args);
}
return mh.invokeExact(selfObj, args);
}
final int paramCount = mh.type().parameterCount();
if (needsCallee(mh)) {
switch (paramCount) {
case 2:
return mh.invokeExact(fn, selfObj);
case 3:
return mh.invokeExact(fn, selfObj, getArg(args, 0));
case 4:
return mh.invokeExact(fn, selfObj, getArg(args, 0), getArg(args, 1));
case 5:
return mh.invokeExact(fn, selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2));
case 6:
return mh.invokeExact(fn, selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3));
case 7:
return mh.invokeExact(fn, selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4));
case 8:
return mh.invokeExact(fn, selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4), getArg(args, 5));
default:
return mh.invokeWithArguments(withArguments(fn, selfObj, paramCount, args));
}
}
switch (paramCount) {
case 1:
return mh.invokeExact(selfObj);
case 2:
return mh.invokeExact(selfObj, getArg(args, 0));
case 3:
return mh.invokeExact(selfObj, getArg(args, 0), getArg(args, 1));
case 4:
return mh.invokeExact(selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2));
case 5:
return mh.invokeExact(selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3));
case 6:
return mh.invokeExact(selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4));
case 7:
return mh.invokeExact(selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4), getArg(args, 5));
default:
return mh.invokeWithArguments(withArguments(null, selfObj, paramCount, args));
}
}
Object construct(final ScriptFunction fn, final Object... arguments) throws Throwable {
final MethodHandle mh = getGenericConstructor(fn.getScope());
final Object[] args = arguments == null ? ScriptRuntime.EMPTY_ARRAY : arguments;
DebuggerSupport.notifyInvoke(mh);
if (isVarArg(mh)) {
if (needsCallee(mh)) {
return mh.invokeExact(fn, args);
}
return mh.invokeExact(args);
}
final int paramCount = mh.type().parameterCount();
if (needsCallee(mh)) {
switch (paramCount) {
case 1:
return mh.invokeExact(fn);
case 2:
return mh.invokeExact(fn, getArg(args, 0));
case 3:
return mh.invokeExact(fn, getArg(args, 0), getArg(args, 1));
case 4:
return mh.invokeExact(fn, getArg(args, 0), getArg(args, 1), getArg(args, 2));
case 5:
return mh.invokeExact(fn, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3));
case 6:
return mh.invokeExact(fn, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4));
case 7:
return mh.invokeExact(fn, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4), getArg(args, 5));
default:
return mh.invokeWithArguments(withArguments(fn, paramCount, args));
}
}
switch (paramCount) {
case 0:
return mh.invokeExact();
case 1:
return mh.invokeExact(getArg(args, 0));
case 2:
return mh.invokeExact(getArg(args, 0), getArg(args, 1));
case 3:
return mh.invokeExact(getArg(args, 0), getArg(args, 1), getArg(args, 2));
case 4:
return mh.invokeExact(getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3));
case 5:
return mh.invokeExact(getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4));
case 6:
return mh.invokeExact(getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4), getArg(args, 5));
default:
return mh.invokeWithArguments(withArguments(null, paramCount, args));
}
}
private static Object getArg(final Object[] args, final int i) {
return i < args.length ? args[i] : UNDEFINED;
}
private static Object[] withArguments(final ScriptFunction fn, final int argCount, final Object[] args) {
final Object[] finalArgs = new Object[argCount];
int nextArg = 0;
if (fn != null) {
//needs callee
finalArgs[nextArg++] = fn;
}
// Don't add more args that there is argCount in the handle (including self and callee).
for (int i = 0; i < args.length && nextArg < argCount;) {
finalArgs[nextArg++] = args[i++];
}
// If we have fewer args than argCount, pad with undefined.
while (nextArg < argCount) {
finalArgs[nextArg++] = UNDEFINED;
}
return finalArgs;
}
private static Object[] withArguments(final ScriptFunction fn, final Object self, final int argCount, final Object[] args) {
final Object[] finalArgs = new Object[argCount];
int nextArg = 0;
if (fn != null) {
//needs callee
finalArgs[nextArg++] = fn;
}
finalArgs[nextArg++] = self;
// Don't add more args that there is argCount in the handle (including self and callee).
for (int i = 0; i < args.length && nextArg < argCount;) {
finalArgs[nextArg++] = args[i++];
}
// If we have fewer args than argCount, pad with undefined.
while (nextArg < argCount) {
finalArgs[nextArg++] = UNDEFINED;
}
return finalArgs;
}
/**
* Takes a variable-arity method and binds a variable number of arguments in it. The returned method will filter the
* vararg array and pass a different array that prepends the bound arguments in front of the arguments passed on
* invocation
*
* @param mh the handle
* @param args the bound arguments
*
* @return the bound method handle
*/
private static MethodHandle varArgBinder(final MethodHandle mh, final Object[] args) {
assert args != null;
assert args.length > 0;
return MH.filterArguments(mh, mh.type().parameterCount() - 1, MH.bindTo(BIND_VAR_ARGS, args));
}
/**
* Heuristic to figure out if the method handle has a callee argument. If it's type is
* {@code (ScriptFunction, ...)}, then we'll assume it has a callee argument. We need this as
* the constructor above is not passed this information, and can't just blindly assume it's false
* (notably, it's being invoked for creation of new scripts, and scripts have scopes, therefore
* they also always receive a callee).
*
* @param mh the examined method handle
*
* @return true if the method handle expects a callee, false otherwise
*/
protected static boolean needsCallee(final MethodHandle mh) {
return needsCallee(mh.type());
}
static boolean needsCallee(final MethodType type) {
final int length = type.parameterCount();
if (length == 0) {
return false;
}
final Class<?> param0 = type.parameterType(0);
return param0 == ScriptFunction.class || param0 == boolean.class && length > 1 && type.parameterType(1) == ScriptFunction.class;
}
/**
* Check if a javascript function methodhandle is a vararg handle
*
* @param mh method handle to check
*
* @return true if vararg
*/
protected static boolean isVarArg(final MethodHandle mh) {
return isVarArg(mh.type());
}
static boolean isVarArg(final MethodType type) {
return type.parameterType(type.parameterCount() - 1).isArray();
}
/**
* Is this ScriptFunction declared in a dynamic context
* @return true if in dynamic context, false if not or irrelevant
*/
public boolean inDynamicContext() {
return false;
}
@SuppressWarnings("unused")
private static Object[] bindVarArgs(final Object[] array1, final Object[] array2) {
if (array2 == null) {
// Must clone it, as we can't allow the receiving method to alter the array
return array1.clone();
}
final int l2 = array2.length;
if (l2 == 0) {
return array1.clone();
}
final int l1 = array1.length;
final Object[] concat = new Object[l1 + l2];
System.arraycopy(array1, 0, concat, 0, l1);
System.arraycopy(array2, 0, concat, l1, l2);
return concat;
}
private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {
return MH.findStatic(MethodHandles.lookup(), ScriptFunctionData.class, name, MH.type(rtype, types));
}
/**
* This class is used to hold the generic invoker and generic constructor pair. It is structured in this way since
* most functions will never use them, so this way ScriptFunctionData only pays storage cost for one null reference
* to the GenericInvokers object, instead of two null references for the two method handles.
*/
private static final class GenericInvokers {
volatile MethodHandle invoker;
volatile MethodHandle constructor;
}
private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
in.defaultReadObject();
code = new LinkedList<>();
}
}