// ASM: a very small and fast Java bytecode manipulation framework
// Copyright (c) 2000-2011 INRIA, France Telecom
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//
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package net.hasor.utils.asm;
/**
 * A {@link ModuleVisitor} that generates the corresponding Module, ModulePackages and
 * ModuleMainClass attributes, 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-4.7.25">JVMS 4.7.25</a>
 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.26">JVMS 4.7.26</a>
 * @see <a href="https://docs.oracle.com/javase/specs/jvms/se9/html/jvms-4.html#jvms-4.7.27">JVMS 4.7.27</a>
 * @author Remi Forax
 * @author Eric Bruneton
 */
final class ModuleWriter extends ModuleVisitor {
    /** Where the constants used in this AnnotationWriter must be stored. */
    private final SymbolTable symbolTable;
    /** The module_name_index field of the JVMS Module attribute. */
    private final int         moduleNameIndex;
    /** The module_flags field of the JVMS Module attribute. */
    private final int         moduleFlags;
    /** The module_version_index field of the JVMS Module attribute. */
    private final int         moduleVersionIndex;
    /** The requires_count field of the JVMS Module attribute. */
    private       int         requiresCount;
    /** The binary content of the 'requires' array of the JVMS Module attribute. */
    private final ByteVector  requires;
    /** The exports_count field of the JVMS Module attribute. */
    private       int         exportsCount;
    /** The binary content of the 'exports' array of the JVMS Module attribute. */
    private final ByteVector  exports;
    /** The opens_count field of the JVMS Module attribute. */
    private       int         opensCount;
    /** The binary content of the 'opens' array of the JVMS Module attribute. */
    private final ByteVector  opens;
    /** The uses_count field of the JVMS Module attribute. */
    private       int         usesCount;
    /** The binary content of the 'uses_index' array of the JVMS Module attribute. */
    private final ByteVector  usesIndex;
    /** The provides_count field of the JVMS Module attribute. */
    private       int         providesCount;
    /** The binary content of the 'provides' array of the JVMS Module attribute. */
    private final ByteVector  provides;
    /** The provides_count field of the JVMS ModulePackages attribute. */
    private       int         packageCount;
    /** The binary content of the 'package_index' array of the JVMS ModulePackages attribute. */
    private final ByteVector  packageIndex;
    /** The main_class_index field of the JVMS ModuleMainClass attribute, or 0. */
    private       int         mainClassIndex;

    ModuleWriter(final SymbolTable symbolTable, final int name, final int access, final int version) {
        super(/* latest api = */ Opcodes.ASM7);
        this.symbolTable = symbolTable;
        this.moduleNameIndex = name;
        this.moduleFlags = access;
        this.moduleVersionIndex = version;
        this.requires = new ByteVector();
        this.exports = new ByteVector();
        this.opens = new ByteVector();
        this.usesIndex = new ByteVector();
        this.provides = new ByteVector();
        this.packageIndex = new ByteVector();
    }

    @Override
    public void visitMainClass(final String mainClass) {
        this.mainClassIndex = symbolTable.addConstantClass(mainClass).index;
    }

    @Override
    public void visitPackage(final String packaze) {
        packageIndex.putShort(symbolTable.addConstantPackage(packaze).index);
        packageCount++;
    }

    @Override
    public void visitRequire(final String module, final int access, final String version) {
        requires.putShort(symbolTable.addConstantModule(module).index).putShort(access).putShort(version == null ? 0 : symbolTable.addConstantUtf8(version));
        requiresCount++;
    }

    @Override
    public void visitExport(final String packaze, final int access, final String... modules) {
        exports.putShort(symbolTable.addConstantPackage(packaze).index).putShort(access);
        if (modules == null) {
            exports.putShort(0);
        } else {
            exports.putShort(modules.length);
            for (String module : modules) {
                exports.putShort(symbolTable.addConstantModule(module).index);
            }
        }
        exportsCount++;
    }

    @Override
    public void visitOpen(final String packaze, final int access, final String... modules) {
        opens.putShort(symbolTable.addConstantPackage(packaze).index).putShort(access);
        if (modules == null) {
            opens.putShort(0);
        } else {
            opens.putShort(modules.length);
            for (String module : modules) {
                opens.putShort(symbolTable.addConstantModule(module).index);
            }
        }
        opensCount++;
    }

    @Override
    public void visitUse(final String service) {
        usesIndex.putShort(symbolTable.addConstantClass(service).index);
        usesCount++;
    }

    @Override
    public void visitProvide(final String service, final String... providers) {
        provides.putShort(symbolTable.addConstantClass(service).index);
        provides.putShort(providers.length);
        for (String provider : providers) {
            provides.putShort(symbolTable.addConstantClass(provider).index);
        }
        providesCount++;
    }

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

    /**
     * Returns the number of Module, ModulePackages and ModuleMainClass attributes generated by this
     * ModuleWriter.
     *
     * @return the number of Module, ModulePackages and ModuleMainClass attributes (between 1 and 3).
     */
    int getAttributeCount() {
        return 1 + (packageCount > 0 ? 1 : 0) + (mainClassIndex > 0 ? 1 : 0);
    }

    /**
     * Returns the size of the Module, ModulePackages and ModuleMainClass attributes generated by this
     * ModuleWriter. Also add the names of these attributes in the constant pool.
     *
     * @return the size in bytes of the Module, ModulePackages and ModuleMainClass attributes.
     */
    int computeAttributesSize() {
        symbolTable.addConstantUtf8(Constants.MODULE);
        // 6 attribute header bytes, 6 bytes for name, flags and version, and 5 * 2 bytes for counts.
        int size = 22 + requires.length + exports.length + opens.length + usesIndex.length + provides.length;
        if (packageCount > 0) {
            symbolTable.addConstantUtf8(Constants.MODULE_PACKAGES);
            // 6 attribute header bytes, and 2 bytes for package_count.
            size += 8 + packageIndex.length;
        }
        if (mainClassIndex > 0) {
            symbolTable.addConstantUtf8(Constants.MODULE_MAIN_CLASS);
            // 6 attribute header bytes, and 2 bytes for main_class_index.
            size += 8;
        }
        return size;
    }

    /**
     * Puts the Module, ModulePackages and ModuleMainClass attributes generated by this ModuleWriter
     * in the given ByteVector.
     *
     * @param output where the attributes must be put.
     */
    void putAttributes(final ByteVector output) {
        // 6 bytes for name, flags and version, and 5 * 2 bytes for counts.
        int moduleAttributeLength = 16 + requires.length + exports.length + opens.length + usesIndex.length + provides.length;
        output.putShort(symbolTable.addConstantUtf8(Constants.MODULE)).putInt(moduleAttributeLength).putShort(moduleNameIndex).putShort(moduleFlags).putShort(moduleVersionIndex).putShort(requiresCount).putByteArray(requires.data, 0, requires.length).putShort(exportsCount).putByteArray(exports.data, 0, exports.length).putShort(opensCount).putByteArray(opens.data, 0, opens.length).putShort(usesCount).putByteArray(usesIndex.data, 0, usesIndex.length).putShort(providesCount).putByteArray(provides.data, 0, provides.length);
        if (packageCount > 0) {
            output.putShort(symbolTable.addConstantUtf8(Constants.MODULE_PACKAGES)).putInt(2 + packageIndex.length).putShort(packageCount).putByteArray(packageIndex.data, 0, packageIndex.length);
        }
        if (mainClassIndex > 0) {
            output.putShort(symbolTable.addConstantUtf8(Constants.MODULE_MAIN_CLASS)).putInt(2).putShort(mainClassIndex);
        }
    }
}
