// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
// All rights reserved.
//
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package net.hasor.utils.asm;
/**
 * A {@link FieldVisitor} that generates a corresponding 'field_info' structure, as defined in the
 * Java Virtual Machine Specification (JVMS).
 *
 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.5">JVMS 4.5</a>
 * @author Eric Bruneton
 */
final class FieldWriter extends FieldVisitor {
    /** Where the constants used in this FieldWriter must be stored. */
    private final SymbolTable      symbolTable;
    // Note: fields are ordered as in the field_info structure, and those related to attributes are
    // ordered as in Section 4.7 of the JVMS.
    /**
     * The access_flags field of the field_info JVMS structure. This field can contain ASM specific
     * access flags, such as {@link Opcodes#ACC_DEPRECATED}, which are removed when generating the
     * ClassFile structure.
     */
    private final int              accessFlags;
    /** The name_index field of the field_info JVMS structure. */
    private final int              nameIndex;
    /** The descriptor_index field of the field_info JVMS structure. */
    private final int              descriptorIndex;
    /**
     * The signature_index field of the Signature attribute of this field_info, or 0 if there is no
     * Signature attribute.
     */
    private       int              signatureIndex;
    /**
     * The constantvalue_index field of the ConstantValue attribute of this field_info, or 0 if there
     * is no ConstantValue attribute.
     */
    private       int              constantValueIndex;
    /**
     * The last runtime visible annotation of this field. The previous ones can be accessed with the
     * {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
     */
    private       AnnotationWriter lastRuntimeVisibleAnnotation;
    /**
     * The last runtime invisible annotation of this field. The previous ones can be accessed with the
     * {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
     */
    private       AnnotationWriter lastRuntimeInvisibleAnnotation;
    /**
     * The last runtime visible type annotation of this field. The previous ones can be accessed with
     * the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
     */
    private       AnnotationWriter lastRuntimeVisibleTypeAnnotation;
    /**
     * The last runtime invisible type annotation of this field. The previous ones can be accessed
     * with the {@link AnnotationWriter#previousAnnotation} field. May be {@literal null}.
     */
    private       AnnotationWriter lastRuntimeInvisibleTypeAnnotation;
    /**
     * The first non standard attribute of this field. The next ones can be accessed with the {@link
     * Attribute#nextAttribute} field. May be {@literal null}.
     *
     * <p><b>WARNING</b>: this list stores the attributes in the <i>reverse</i> order of their visit.
     * firstAttribute is actually the last attribute visited in {@link #visitAttribute}. The {@link
     * #putFieldInfo} method writes the attributes in the order defined by this list, i.e. in the
     * reverse order specified by the user.
     */
    private       Attribute        firstAttribute;
    // -----------------------------------------------------------------------------------------------
    // Constructor
    // -----------------------------------------------------------------------------------------------

    /**
     * Constructs a new {@link FieldWriter}.
     *
     * @param symbolTable where the constants used in this FieldWriter must be stored.
     * @param access the field's access flags (see {@link Opcodes}).
     * @param name the field's name.
     * @param descriptor the field's descriptor (see {@link Type}).
     * @param signature the field's signature. May be {@literal null}.
     * @param constantValue the field's constant value. May be {@literal null}.
     */
    FieldWriter(final SymbolTable symbolTable, final int access, final String name, final String descriptor, final String signature, final Object constantValue) {
        super(/* latest api = */ Opcodes.ASM7);
        this.symbolTable = symbolTable;
        this.accessFlags = access;
        this.nameIndex = symbolTable.addConstantUtf8(name);
        this.descriptorIndex = symbolTable.addConstantUtf8(descriptor);
        if (signature != null) {
            this.signatureIndex = symbolTable.addConstantUtf8(signature);
        }
        if (constantValue != null) {
            this.constantValueIndex = symbolTable.addConstant(constantValue).index;
        }
    }
    // -----------------------------------------------------------------------------------------------
    // Implementation of the FieldVisitor abstract class
    // -----------------------------------------------------------------------------------------------

    @Override
    public AnnotationVisitor visitAnnotation(final String descriptor, final boolean visible) {
        if (visible) {
            return lastRuntimeVisibleAnnotation = AnnotationWriter.create(symbolTable, descriptor, lastRuntimeVisibleAnnotation);
        } else {
            return lastRuntimeInvisibleAnnotation = AnnotationWriter.create(symbolTable, descriptor, lastRuntimeInvisibleAnnotation);
        }
    }

    @Override
    public AnnotationVisitor visitTypeAnnotation(final int typeRef, final TypePath typePath, final String descriptor, final boolean visible) {
        if (visible) {
            return lastRuntimeVisibleTypeAnnotation = AnnotationWriter.create(symbolTable, typeRef, typePath, descriptor, lastRuntimeVisibleTypeAnnotation);
        } else {
            return lastRuntimeInvisibleTypeAnnotation = AnnotationWriter.create(symbolTable, typeRef, typePath, descriptor, lastRuntimeInvisibleTypeAnnotation);
        }
    }

    @Override
    public void visitAttribute(final Attribute attribute) {
        // Store the attributes in the <i>reverse</i> order of their visit by this method.
        attribute.nextAttribute = firstAttribute;
        firstAttribute = attribute;
    }

    @Override
    public void visitEnd() {
        // Nothing to do.
    }
    // -----------------------------------------------------------------------------------------------
    // Utility methods
    // -----------------------------------------------------------------------------------------------

    /**
     * Returns the size of the field_info JVMS structure generated by this FieldWriter. Also adds the
     * names of the attributes of this field in the constant pool.
     *
     * @return the size in bytes of the field_info JVMS structure.
     */
    int computeFieldInfoSize() {
        // The access_flags, name_index, descriptor_index and attributes_count fields use 8 bytes.
        int size = 8;
        // For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS.
        if (constantValueIndex != 0) {
            // ConstantValue attributes always use 8 bytes.
            symbolTable.addConstantUtf8(Constants.CONSTANT_VALUE);
            size += 8;
        }
        size += Attribute.computeAttributesSize(symbolTable, accessFlags, signatureIndex);
        size += AnnotationWriter.computeAnnotationsSize(lastRuntimeVisibleAnnotation, lastRuntimeInvisibleAnnotation, lastRuntimeVisibleTypeAnnotation, lastRuntimeInvisibleTypeAnnotation);
        if (firstAttribute != null) {
            size += firstAttribute.computeAttributesSize(symbolTable);
        }
        return size;
    }

    /**
     * Puts the content of the field_info JVMS structure generated by this FieldWriter into the given
     * ByteVector.
     *
     * @param output where the field_info structure must be put.
     */
    void putFieldInfo(final ByteVector output) {
        boolean useSyntheticAttribute = symbolTable.getMajorVersion() < Opcodes.V1_5;
        // Put the access_flags, name_index and descriptor_index fields.
        int mask = useSyntheticAttribute ? Opcodes.ACC_SYNTHETIC : 0;
        output.putShort(accessFlags & ~mask).putShort(nameIndex).putShort(descriptorIndex);
        // Compute and put the attributes_count field.
        // For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS.
        int attributesCount = 0;
        if (constantValueIndex != 0) {
            ++attributesCount;
        }
        if ((accessFlags & Opcodes.ACC_SYNTHETIC) != 0 && useSyntheticAttribute) {
            ++attributesCount;
        }
        if (signatureIndex != 0) {
            ++attributesCount;
        }
        if ((accessFlags & Opcodes.ACC_DEPRECATED) != 0) {
            ++attributesCount;
        }
        if (lastRuntimeVisibleAnnotation != null) {
            ++attributesCount;
        }
        if (lastRuntimeInvisibleAnnotation != null) {
            ++attributesCount;
        }
        if (lastRuntimeVisibleTypeAnnotation != null) {
            ++attributesCount;
        }
        if (lastRuntimeInvisibleTypeAnnotation != null) {
            ++attributesCount;
        }
        if (firstAttribute != null) {
            attributesCount += firstAttribute.getAttributeCount();
        }
        output.putShort(attributesCount);
        // Put the field_info attributes.
        // For ease of reference, we use here the same attribute order as in Section 4.7 of the JVMS.
        if (constantValueIndex != 0) {
            output.putShort(symbolTable.addConstantUtf8(Constants.CONSTANT_VALUE)).putInt(2).putShort(constantValueIndex);
        }
        Attribute.putAttributes(symbolTable, accessFlags, signatureIndex, output);
        AnnotationWriter.putAnnotations(symbolTable, lastRuntimeVisibleAnnotation, lastRuntimeInvisibleAnnotation, lastRuntimeVisibleTypeAnnotation, lastRuntimeInvisibleTypeAnnotation, output);
        if (firstAttribute != null) {
            firstAttribute.putAttributes(symbolTable, output);
        }
    }

    /**
     * Collects the attributes of this field into the given set of attribute prototypes.
     *
     * @param attributePrototypes a set of attribute prototypes.
     */
    final void collectAttributePrototypes(final Attribute.Set attributePrototypes) {
        attributePrototypes.addAttributes(firstAttribute);
    }
}
