classreader.java

是一款用JAVA 编写的编译器 具有很强的编译功能

     */
    void readClassAttrs(ClassSymbol c) {
        char ac = nextChar();
        for (int i = 0; i < ac; i++) {
            Name attrName = readName(nextChar());
            int attrLen = nextInt();
            readClassAttr(c, attrName, attrLen);
        }
    }

    /** Read code block.
     */
    Code readCode(Symbol owner) {
        nextChar(); // max_stack
        nextChar(); // max_locals
        final int  code_length = nextInt();
        bp += code_length;
        final char exception_table_length = nextChar();
        bp += exception_table_length * 8;
        readMemberAttrs(owner);
        return null;
    }

/************************************************************************
 * Reading Java-language annotations
 ***********************************************************************/

    /** Attach annotations.
     */
    void attachAnnotations(final Symbol sym) {
        int numAttributes = nextChar();
        if (numAttributes != 0) {
            ListBuffer<CompoundAnnotationProxy> proxies =
                new ListBuffer<CompoundAnnotationProxy>();
            for (int i = 0; i<numAttributes; i++) {
                CompoundAnnotationProxy proxy = readCompoundAnnotation();
                if (proxy.type.tsym == syms.proprietaryType.tsym)
                    sym.flags_field |= PROPRIETARY;
                else
                    proxies.append(proxy);
            }
            annotate.later(new AnnotationCompleter(sym, proxies.toList()));
        }
    }

    /** Attach parameter annotations.
     */
    void attachParameterAnnotations(final Symbol method) {
        final MethodSymbol meth = (MethodSymbol)method;
        int numParameters = buf[bp++] & 0xFF;
        List<VarSymbol> parameters = meth.params();
        int pnum = 0;
        while (parameters.tail != null) {
            attachAnnotations(parameters.head);
            parameters = parameters.tail;
            pnum++;
        }
        if (pnum != numParameters) {
            throw badClassFile("bad.runtime.invisible.param.annotations", meth);
        }
    }

    /** Attach the default value for an annotation element.
     */
    void attachAnnotationDefault(final Symbol sym) {
        final MethodSymbol meth = (MethodSymbol)sym; // only on methods
        final Attribute value = readAttributeValue();
        annotate.later(new AnnotationDefaultCompleter(meth, value));
    }

    Type readTypeOrClassSymbol(int i) {
        // support preliminary jsr175-format class files
        if (buf[poolIdx[i]] == CONSTANT_Class)
            return readClassSymbol(i).type;
        return readType(i);
    }
    Type readEnumType(int i) {
        // support preliminary jsr175-format class files
        int index = poolIdx[i];
        int length = getChar(index + 1);
        if (buf[index + length + 2] != ';')
            return enterClass(readName(i)).type;
        return readType(i);
    }

    CompoundAnnotationProxy readCompoundAnnotation() {
        Type t = readTypeOrClassSymbol(nextChar());
        int numFields = nextChar();
        ListBuffer<Pair<Name,Attribute>> pairs =
            new ListBuffer<Pair<Name,Attribute>>();
        for (int i=0; i<numFields; i++) {
            Name name = readName(nextChar());
            Attribute value = readAttributeValue();
            pairs.append(new Pair<Name,Attribute>(name, value));
        }
        return new CompoundAnnotationProxy(t, pairs.toList());
    }

    Attribute readAttributeValue() {
        char c = (char) buf[bp++];
        switch (c) {
        case 'B':
            return new Attribute.Constant(syms.byteType, readPool(nextChar()));
        case 'C':
            return new Attribute.Constant(syms.charType, readPool(nextChar()));
        case 'D':
            return new Attribute.Constant(syms.doubleType, readPool(nextChar()));
        case 'F':
            return new Attribute.Constant(syms.floatType, readPool(nextChar()));
        case 'I':
            return new Attribute.Constant(syms.intType, readPool(nextChar()));
        case 'J':
            return new Attribute.Constant(syms.longType, readPool(nextChar()));
        case 'S':
            return new Attribute.Constant(syms.shortType, readPool(nextChar()));
        case 'Z':
            return new Attribute.Constant(syms.booleanType, readPool(nextChar()));
        case 's':
            return new Attribute.Constant(syms.stringType, readPool(nextChar()).toString());
        case 'e':
            return new EnumAttributeProxy(readEnumType(nextChar()), readName(nextChar()));
        case 'c':
            return new Attribute.Class(types, readTypeOrClassSymbol(nextChar()));
        case '[': {
            int n = nextChar();
            ListBuffer<Attribute> l = new ListBuffer<Attribute>();
            for (int i=0; i<n; i++)
                l.append(readAttributeValue());
            return new ArrayAttributeProxy(l.toList());
        }
        case '@':
            return readCompoundAnnotation();
        default:
            throw new AssertionError("unknown annotation tag '" + c + "'");
        }
    }

    interface ProxyVisitor extends Attribute.Visitor {
        void visitEnumAttributeProxy(EnumAttributeProxy proxy);
        void visitArrayAttributeProxy(ArrayAttributeProxy proxy);
        void visitCompoundAnnotationProxy(CompoundAnnotationProxy proxy);
    }

    static class EnumAttributeProxy extends Attribute {
        Type enumType;
        Name enumerator;
        public EnumAttributeProxy(Type enumType, Name enumerator) {
            super(null);
            this.enumType = enumType;
            this.enumerator = enumerator;
        }
        public void accept(Visitor v) { ((ProxyVisitor)v).visitEnumAttributeProxy(this); }
        public String toString() {
            return "/*proxy enum*/" + enumType + "." + enumerator;
        }
    }

    static class ArrayAttributeProxy extends Attribute {
        List<Attribute> values;
        ArrayAttributeProxy(List<Attribute> values) {
            super(null);
            this.values = values;
        }
        public void accept(Visitor v) { ((ProxyVisitor)v).visitArrayAttributeProxy(this); }
        public String toString() {
            return "{" + values + "}";
        }
    }

    /** A temporary proxy representing a compound attribute.
     */
    static class CompoundAnnotationProxy extends Attribute {
        final List<Pair<Name,Attribute>> values;
        public CompoundAnnotationProxy(Type type,
                                      List<Pair<Name,Attribute>> values) {
            super(type);
            this.values = values;
        }
        public void accept(Visitor v) { ((ProxyVisitor)v).visitCompoundAnnotationProxy(this); }
        public String toString() {
            StringBuffer buf = new StringBuffer();
            buf.append("@");
            buf.append(type.tsym.getQualifiedName());
            buf.append("/*proxy*/{");
            boolean first = true;
            for (List<Pair<Name,Attribute>> v = values;
                 v.nonEmpty(); v = v.tail) {
                Pair<Name,Attribute> value = v.head;
                if (!first) buf.append(",");
                first = false;
                buf.append(value.fst);
                buf.append("=");
                buf.append(value.snd);
            }
            buf.append("}");
            return buf.toString();
        }
    }

    class AnnotationDeproxy implements ProxyVisitor {
        private ClassSymbol requestingOwner = currentOwner.kind == MTH
            ? currentOwner.enclClass() : (ClassSymbol)currentOwner;

        List<Attribute.Compound> deproxyCompoundList(List<CompoundAnnotationProxy> pl) {
            // also must fill in types!!!!
            ListBuffer<Attribute.Compound> buf =
                new ListBuffer<Attribute.Compound>();
            for (List<CompoundAnnotationProxy> l = pl; l.nonEmpty(); l=l.tail) {
                buf.append(deproxyCompound(l.head));
            }
            return buf.toList();
        }

        Attribute.Compound deproxyCompound(CompoundAnnotationProxy a) {
            ListBuffer<Pair<Symbol.MethodSymbol,Attribute>> buf =
                new ListBuffer<Pair<Symbol.MethodSymbol,Attribute>>();
            for (List<Pair<Name,Attribute>> l = a.values;
                 l.nonEmpty();
                 l = l.tail) {
                MethodSymbol meth = findAccessMethod(a.type, l.head.fst);
                buf.append(new Pair<Symbol.MethodSymbol,Attribute>
                           (meth, deproxy(meth.type.getReturnType(), l.head.snd)));
            }
            return new Attribute.Compound(a.type, buf.toList());
        }

        MethodSymbol findAccessMethod(Type container, Name name) {
            CompletionFailure failure = null;
            try {
                for (Scope.Entry e = container.tsym.members().lookup(name);
                     e.scope != null;
                     e = e.next()) {
                    Symbol sym = e.sym;
                    if (sym.kind == MTH && sym.type.getParameterTypes().length() == 0)
                        return (MethodSymbol) sym;
                }
            } catch (CompletionFailure ex) {
                failure = ex;
            }
            // The method wasn't found: emit a warning and recover
            JavaFileObject prevSource = log.useSource(requestingOwner.classfile);
            try {
                if (failure == null) {
                    log.warning("annotation.method.not.found",
                                container,
                                name);
                } else {
                    log.warning("annotation.method.not.found.reason",
                                container,
                                name,
                                failure.getMessage());
                }
            } finally {
                log.useSource(prevSource);
            }
            // Construct a new method type and symbol.  Use bottom
            // type (typeof null) as return type because this type is
            // a subtype of all reference types and can be converted
            // to primitive types by unboxing.
            MethodType mt = new MethodType(List.<Type>nil(),
                                           syms.botType,
                                           List.<Type>nil(),
                                           syms.methodClass);
            return new MethodSymbol(PUBLIC | ABSTRACT, name, mt, container.tsym);
        }

        Attribute result;
        Type type;
        Attribute deproxy(Type t, Attribute a) {
            Type oldType = type;
            try {
                type = t;
                a.accept(this);
                return result;
            } finally {
                type = oldType;
            }
        }

        // implement Attribute.Visitor below

        public void visitConstant(Attribute.Constant value) {
            // assert value.type == type;
            result = value;
        }

        public void visitClass(Attribute.Class clazz) {
            result = clazz;
        }

        public void visitEnum(Attribute.Enum e) {
            throw new AssertionError(); // shouldn't happen
        }

        public void visitCompound(Attribute.Compound compound) {
            throw new AssertionError(); // shouldn't happen
        }

        public void visitArray(Attribute.Array array) {
            throw new AssertionError(); // shouldn't happen
        }

        public void visitError(Attribute.Error e) {
            throw new AssertionError(); // shouldn't happen
        }

        public void visitEnumAttributeProxy(EnumAttributeProxy proxy) {
            // type.tsym.flatName() should == proxy.enumFlatName
            TypeSymbol enumTypeSym = proxy.enumType.tsym;
            VarSymbol enumerator = null;
            for (Scope.Entry e = enumTypeSym.members().lookup(proxy.enumerator);
                 e.scope != null;
                 e = e.next()) {
                if (e.sym.kind == VAR) {
                    enumerator = (VarSymbol)e.sym;
                    break;
                }
            }
            if (enumerator == null) {
                log.error("unknown.enum.constant",
                          currentClassFile, enumTypeSym, proxy.enumerator);
                result = new Attribute.Error(enumTypeSym.type);
            } else {
                result = new Attribute.Enum(enumTypeSym.type, enumerator);
            }
        }

        public void visitArrayAttributeProxy(ArrayAttributeProxy proxy) {
            int length = proxy.values.length();
            Attribute[] ats = new Attribute[length];
            Type elemtype = types.elemtype(type);
            int i = 0;
            for (List<Attribute> p = proxy.values; p.nonEmpty(); p = p.tail) {
                ats[i++] = deproxy(elemtype, p.head);
            }
            result = new Attribute.Array(type, ats);
        }

        public void visitCompoundAnnotationProxy(CompoundAnnotationProxy proxy) {
            result = deproxyCompound(proxy);
        }
    }

    class AnnotationDefaultCompleter extends AnnotationDeproxy implements Annotate.Annotator {
        final MethodSymbol sym;
        final Attribute value;
        final JavaFileObject classFile = currentClassFile;
        public String toString() {
            return " ClassReader store default for " + sym.owner + "." + sym + " is " + value;
        }
        AnnotationDefaultCompleter(MethodSymbol sym, Attribute value) {
            this.sym = sym;
            this.value = value;
        }
        // implement Annotate.Annotator.enterAnnotation()
        public void enterAnnotation() {
            JavaFileObject previousClassFile = currentClassFile;
            try {