import jdk.nashorn.internal.runtime.arrays.ContinuousArrayData; //导入依赖的package包/类
/**
 * ECMA 15.4.4.4 Array.prototype.concat ( [ item1 [ , item2 [ , ... ] ] ] )
 *
 * @param self self reference
 * @param arg argument
 * @return resulting NativeArray
 */
@SpecializedFunction(linkLogic=ConcatLinkLogic.class)
public static NativeArray concat(final Object self, final Object arg) {
    //arg is [NativeArray] of same type.
    final ContinuousArrayData selfData = getContinuousArrayDataCCE(self);
    final ContinuousArrayData newData;

    if (arg instanceof NativeArray) {
        final ContinuousArrayData argData = (ContinuousArrayData)((NativeArray)arg).getArray();
        if (argData.isEmpty()) {
            newData = selfData.copy();
        } else if (selfData.isEmpty()) {
            newData = argData.copy();
        } else {
            final Class<?> widestElementType = selfData.widest(argData).getBoxedElementType();
            newData = ((ContinuousArrayData)selfData.convert(widestElementType)).fastConcat((ContinuousArrayData)argData.convert(widestElementType));
        }
    } else {
        newData = getContinuousArrayDataCCE(self, Object.class).copy();
        newData.fastPush(arg);
    }

    return new NativeArray(newData);
}
 

import jdk.nashorn.internal.runtime.arrays.ContinuousArrayData; //导入依赖的package包/类
@Override
public boolean canLink(final Object self, final CallSiteDescriptor desc, final LinkRequest request) {
    final Object[] args = request.getArguments();

    if (args.length != 3) { //single argument check
        return false;
    }

    final ContinuousArrayData selfData = getContinuousArrayData(self);
    if (selfData == null) {
        return false;
    }

    final Object arg = args[2];
    //args[2] continuousarray or non arraydata, let past non array datas
    if (arg instanceof NativeArray) {
        final ContinuousArrayData argData = getContinuousArrayData(arg);
        if (argData == null) {
            return false;
        }
    }

    return true;
}
 

import jdk.nashorn.internal.runtime.arrays.ContinuousArrayData; //导入依赖的package包/类
@Override
public boolean canLink(final Object self, final CallSiteDescriptor desc, final LinkRequest request) {
    final Object[] args = request.getArguments();

    if (args.length != 3) { //single argument check
        return false;
    }

    final ContinuousArrayData selfData = getContinuousArrayData(self);
    if (selfData == null) {
        return false;
    }

    final Object arg = args[2];
    // The generic version uses its own logic and ArrayLikeIterator to decide if an object should
    // be iterated over or added as single element. To avoid duplication of code and err on the safe side
    // we only use the specialized version if arg is either a continuous array or a JS primitive.
    if (arg instanceof NativeArray) {
        return (getContinuousArrayData(arg) != null);
    }

    return JSType.isPrimitive(arg);
}
 

import jdk.nashorn.internal.runtime.arrays.ContinuousArrayData; //导入依赖的package包/类
protected static ContinuousArrayData getContinuousArrayData(final Object self) {
    try {
        //cast to NativeArray, to avoid cases like x = {0:0, 1:1}, x.length = 2, where we can't use the array push/pop
        return (ContinuousArrayData)((NativeArray)self).getArray();
    } catch (final Exception e) {
        return null;
    }
}
 

import jdk.nashorn.internal.runtime.arrays.ContinuousArrayData; //导入依赖的package包/类
private static ContinuousArrayData getContinuousNonEmptyArrayData(final Object self) {
    final ContinuousArrayData data = getContinuousArrayData(self);
    if (data != null) {
        return data.length() == 0 ? null : data;
    }
    return null;
}
 

import jdk.nashorn.internal.runtime.arrays.ContinuousArrayData; //导入依赖的package包/类
private static final <T> ContinuousArrayData getContinuousNonEmptyArrayDataCCE(final Object self, final Class<T> clazz) {
    try {
        @SuppressWarnings("unchecked")
        final ContinuousArrayData data = (ContinuousArrayData)(T)((NativeArray)self).getArray();
        if (data.length() != 0L) {
            return data; //if length is 0 we cannot pop and have to relink, because then we'd have to return an undefined, which is a wider type than e.g. int
       }
    } catch (final NullPointerException e) {
        //fallthru
    }
    throw new ClassCastException();
}
 

import jdk.nashorn.internal.runtime.arrays.ContinuousArrayData; //导入依赖的package包/类
private static final ContinuousArrayData getContinuousArrayDataCCE(final Object self) {
    try {
        return (ContinuousArrayData)((NativeArray)self).getArray();
     } catch (final NullPointerException e) {
         throw new ClassCastException();
     }
}
 

import jdk.nashorn.internal.runtime.arrays.ContinuousArrayData; //导入依赖的package包/类
private static <T> ContinuousArrayData getContinuousNonEmptyArrayDataCCE(final Object self, final Class<T> clazz) {
    try {
        @SuppressWarnings("unchecked")
        final ContinuousArrayData data = (ContinuousArrayData)(T)((NativeArray)self).getArray();
        if (data.length() != 0L) {
            return data; //if length is 0 we cannot pop and have to relink, because then we'd have to return an undefined, which is a wider type than e.g. int
       }
    } catch (final NullPointerException e) {
        //fallthru
    }
    throw new ClassCastException();
}
 

import jdk.nashorn.internal.runtime.arrays.ContinuousArrayData; //导入依赖的package包/类
private static ContinuousArrayData getContinuousArrayDataCCE(final Object self) {
    try {
        return (ContinuousArrayData)((NativeArray)self).getArray();
     } catch (final NullPointerException e) {
         throw new ClassCastException();
     }
}