dynamicclassreferenceinitializer.java

来自「proguard 一个java的混淆器」· Java 代码 · 共 441 行 · 第 1/2 页

                                            WarningPrinter notePrinter,
                                            StringMatcher  noteExceptionMatcher)
    {
        this.programClassPool     = programClassPool;
        this.libraryClassPool     = libraryClassPool;
        this.notePrinter          = notePrinter;
        this.noteExceptionMatcher = noteExceptionMatcher;
    }


    // Implementations for InstructionVisitor.

    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction)
    {
        // Try to match the Class.forName("SomeClass") construct.
        instruction.accept(clazz, method, codeAttribute, offset,
                           constantClassForNameMatcher);

        // Did we find a match?
        if (constantClassForNameMatcher.isMatching())
        {
            // Fill out the matched string constant.
            clazz.constantPoolEntryAccept(constantClassForNameMatcher.matchedConstantIndex(X), this);

            // Don't look for the dynamic construct.
            classForNameCastMatcher.reset();
        }

        // Try to match the (SomeClass)Class.forName(someName).newInstance()
        // construct.
        instruction.accept(clazz, method, codeAttribute, offset,
                           classForNameCastMatcher);

        // Did we find a match?
        if (classForNameCastMatcher.isMatching())
        {
            // Print out a note about the construct.
            clazz.constantPoolEntryAccept(classForNameCastMatcher.matchedConstantIndex(X), this);
        }

        // Try to match the javac .class construct.
        instruction.accept(clazz, method, codeAttribute, offset,
                           dotClassJavacMatcher);

        // Did we find a match?
        if (dotClassJavacMatcher.isMatching() &&
            isDotClassMethodref(clazz, dotClassJavacMatcher.matchedConstantIndex(0)))
        {
            // Fill out the matched string constant.
            clazz.constantPoolEntryAccept(dotClassJavacMatcher.matchedConstantIndex(X), this);
        }

        // Try to match the jikes .class construct.
        instruction.accept(clazz, method, codeAttribute, offset,
                           dotClassJikesMatcher);

        // Did we find a match?
        if (dotClassJikesMatcher.isMatching() &&
            isDotClassMethodref(clazz, dotClassJikesMatcher.matchedConstantIndex(0)))
        {
            // Fill out the matched string constant.
            clazz.constantPoolEntryAccept(dotClassJikesMatcher.matchedConstantIndex(X), this);
        }
    }


    // Implementations for ConstantVisitor.

    /**
     * Fills out the link to the referenced class.
     */
    public void visitStringConstant(Clazz clazz, StringConstant stringConstant)
    {
        // Save a reference to the corresponding class.
        String externalClassName = stringConstant.getString(clazz);
        String internalClassName = ClassUtil.internalClassName(externalClassName);

        stringConstant.referencedClass = findClass(internalClassName);
    }


    /**
     * Prints out a note about the class cast to this class, if applicable.
     */
    public void visitClassConstant(Clazz clazz, ClassConstant classConstant)
    {
        // Print out a note about the class cast.
        if (notePrinter != null &&
            (noteExceptionMatcher == null ||
             !noteExceptionMatcher.matches(classConstant.getName(clazz))))
        {
            notePrinter.print("Note: " +
                              ClassUtil.externalClassName(clazz.getName()) +
                              " calls '(" +
                              ClassUtil.externalClassName(classConstant.getName(clazz)) +
                              ")Class.forName(variable).newInstance()'");
        }
    }


    /**
     * Checks whether the referenced method is a .class method.
     */
    public void visitMethodrefConstant(Clazz clazz, MethodrefConstant methodrefConstant)
    {
        String methodType = methodrefConstant.getType(clazz);

        // Do the method's class and type match?
        if (methodType.equals(ClassConstants.INTERNAL_METHOD_TYPE_DOT_CLASS_JAVAC) ||
            methodType.equals(ClassConstants.INTERNAL_METHOD_TYPE_DOT_CLASS_JIKES))
        {
            String methodName = methodrefConstant.getName(clazz);

            // Does the method's name match one of the special names?
            isClassForNameInvocation =
                methodName.equals(ClassConstants.INTERNAL_METHOD_NAME_DOT_CLASS_JAVAC) ||
                methodName.equals(ClassConstants.INTERNAL_METHOD_NAME_DOT_CLASS_JIKES);

            if (isClassForNameInvocation)
            {
                return;
            }

            String className  = methodrefConstant.getClassName(clazz);

            // Note that we look for the class by name, since the referenced
            // class has not been initialized yet.
            Clazz referencedClass = programClassPool.getClass(className);
            if (referencedClass != null)
            {
                // Check if the code of the referenced method is .class code.
                // Note that we look for the method by name and type, since the
                // referenced method has not been initialized yet.
                referencedClass.methodAccept(methodName,
                                             methodType,
                                             new AllAttributeVisitor(this));
            }
        }
    }


    // Implementations for AttributeVisitor.

    public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}


    public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute)
    {
        // Check whether this is class$(String), as generated by javac, or
        // class(String, boolean), as generated by jikes, or an optimized
        // version.
        isClassForNameInvocation =
            isDotClassMethodCode(clazz, method, codeAttribute,
                                 dotClassJavacImplementationMatcher, 5)  ||
            isDotClassMethodCode(clazz, method, codeAttribute,
                                 dotClassJikesImplementationMatcher, 12) ||
            isDotClassMethodCode(clazz, method, codeAttribute,
                                 dotClassJikesImplementationMatcher2, 8);
    }


    // Small utility methods.

    /**
     * Returns whether the given method reference corresponds to a .class
     * method, as generated by javac or by jikes.
     */
    private boolean isDotClassMethodref(Clazz clazz, int methodrefConstantIndex)
    {
        isClassForNameInvocation = false;

        // Check if the code of the referenced method is .class code.
        clazz.constantPoolEntryAccept(methodrefConstantIndex, this);

        return isClassForNameInvocation;
    }


    /**
     * Returns whether the first whether the first instructions of the
     * given code attribute match with the given instruction matcher.
     */
    private boolean isDotClassMethodCode(Clazz                      clazz,
                                         Method                     method,
                                         CodeAttribute              codeAttribute,
                                         InstructionSequenceMatcher codeMatcher,
                                         int                        codeLength)
    {
        // Check the minimum code length.
        if (codeAttribute.u4codeLength < codeLength)
        {
            return false;
        }

        // Check the actual instructions.
        codeMatcher.reset();
        codeAttribute.instructionsAccept(clazz, method, 0, codeLength, codeMatcher);
        return codeMatcher.isMatching();
    }


    /**
     * Returns the class with the given name, either for the program class pool
     * or from the library class pool, or <code>null</code> if it can't be found.
     */
    private Clazz findClass(String name)
    {
        // First look for the class in the program class pool.
        Clazz clazz = programClassPool.getClass(name);

        // Otherwise look for the class in the library class pool.
        if (clazz == null)
        {
            clazz = libraryClassPool.getClass(name);
        }

        return clazz;
    }
}