checkmethodadapter.java

asm的源码包 并且包含英文的文档

    void checkEndCode() {
        if (endCode) {
            throw new IllegalStateException("Cannot visit instructions after visitMaxs has been called.");
        }
    }

    /**
     * Checks that the visitEnd method has not been called.
     */
    void checkEndMethod() {
        if (endMethod) {
            throw new IllegalStateException("Cannot visit elements after visitEnd has been called.");
        }
    }

    /**
     * Checks that the type of the given opcode is equal to the given type.
     * 
     * @param opcode the opcode to be checked.
     * @param type the expected opcode type.
     */
    static void checkOpcode(final int opcode, final int type) {
        if (opcode < 0 || opcode > 199 || TYPE[opcode] != type) {
            throw new IllegalArgumentException("Invalid opcode: " + opcode);
        }
    }

    /**
     * Checks that the given value is a signed byte.
     * 
     * @param value the value to be checked.
     * @param msg an message to be used in case of error.
     */
    static void checkSignedByte(final int value, final String msg) {
        if (value < Byte.MIN_VALUE || value > Byte.MAX_VALUE) {
            throw new IllegalArgumentException(msg
                    + " (must be a signed byte): " + value);
        }
    }

    /**
     * Checks that the given value is a signed short.
     * 
     * @param value the value to be checked.
     * @param msg an message to be used in case of error.
     */
    static void checkSignedShort(final int value, final String msg) {
        if (value < Short.MIN_VALUE || value > Short.MAX_VALUE) {
            throw new IllegalArgumentException(msg
                    + " (must be a signed short): " + value);
        }
    }

    /**
     * Checks that the given value is an unsigned short.
     * 
     * @param value the value to be checked.
     * @param msg an message to be used in case of error.
     */
    static void checkUnsignedShort(final int value, final String msg) {
        if (value < 0 || value > 65535) {
            throw new IllegalArgumentException(msg
                    + " (must be an unsigned short): " + value);
        }
    }

    /**
     * Checks that the given value is an {@link Integer}, a{@link Float}, a
     * {@link Long}, a {@link Double} or a {@link String}.
     * 
     * @param cst the value to be checked.
     */
    static void checkConstant(final Object cst) {
        if (!(cst instanceof Integer) && !(cst instanceof Float)
                && !(cst instanceof Long) && !(cst instanceof Double)
                && !(cst instanceof String))
        {
            throw new IllegalArgumentException("Invalid constant: " + cst);
        }
    }

    /**
     * Checks that the given string is a valid Java identifier.
     * 
     * @param name the string to be checked.
     * @param msg a message to be used in case of error.
     */
    static void checkIdentifier(final String name, final String msg) {
        checkIdentifier(name, 0, -1, msg);
    }

    /**
     * Checks that the given substring is a valid Java identifier.
     * 
     * @param name the string to be checked.
     * @param start index of the first character of the identifier (inclusive).
     * @param end index of the last character of the identifier (exclusive). -1
     *        is equivalent to <tt>name.length()</tt> if name is not
     *        <tt>null</tt>.
     * @param msg a message to be used in case of error.
     */
    static void checkIdentifier(
        final String name,
        final int start,
        final int end,
        final String msg)
    {
        if (name == null || (end == -1 ? name.length() <= start : end <= start))
        {
            throw new IllegalArgumentException("Invalid " + msg
                    + " (must not be null or empty)");
        }
        if (!Character.isJavaIdentifierStart(name.charAt(start))) {
            throw new IllegalArgumentException("Invalid " + msg
                    + " (must be a valid Java identifier): " + name);
        }
        int max = end == -1 ? name.length() : end;
        for (int i = start + 1; i < max; ++i) {
            if (!Character.isJavaIdentifierPart(name.charAt(i))) {
                throw new IllegalArgumentException("Invalid " + msg
                        + " (must be a valid Java identifier): " + name);
            }
        }
    }

    /**
     * Checks that the given string is a valid Java identifier or is equal to
     * '&lt;init&gt;' or '&lt;clinit&gt;'.
     * 
     * @param name the string to be checked.
     * @param msg a message to be used in case of error.
     */
    static void checkMethodIdentifier(final String name, final String msg) {
        if (name == null || name.length() == 0) {
            throw new IllegalArgumentException("Invalid " + msg
                    + " (must not be null or empty)");
        }
        if (name.equals("<init>") || name.equals("<clinit>")) {
            return;
        }
        if (!Character.isJavaIdentifierStart(name.charAt(0))) {
            throw new IllegalArgumentException("Invalid "
                    + msg
                    + " (must be a '<init>', '<clinit>' or a valid Java identifier): "
                    + name);
        }
        for (int i = 1; i < name.length(); ++i) {
            if (!Character.isJavaIdentifierPart(name.charAt(i))) {
                throw new IllegalArgumentException("Invalid "
                        + msg
                        + " (must be '<init>' or '<clinit>' or a valid Java identifier): "
                        + name);
            }
        }
    }

    /**
     * Checks that the given string is a valid internal class name.
     * 
     * @param name the string to be checked.
     * @param msg a message to be used in case of error.
     */
    static void checkInternalName(final String name, final String msg) {
        checkInternalName(name, 0, -1, msg);
    }

    /**
     * Checks that the given substring is a valid internal class name.
     * 
     * @param name the string to be checked.
     * @param start index of the first character of the identifier (inclusive).
     * @param end index of the last character of the identifier (exclusive). -1
     *        is equivalent to <tt>name.length()</tt> if name is not
     *        <tt>null</tt>.
     * @param msg a message to be used in case of error.
     */
    static void checkInternalName(
        final String name,
        final int start,
        final int end,
        final String msg)
    {
        if (name == null || name.length() == 0) {
            throw new IllegalArgumentException("Invalid " + msg
                    + " (must not be null or empty)");
        }
        int max = end == -1 ? name.length() : end;
        try {
            int begin = start;
            int slash;
            do {
                slash = name.indexOf('/', begin + 1);
                if (slash == -1 || slash > max) {
                    slash = max;
                }
                checkIdentifier(name, begin, slash, null);
                begin = slash + 1;
            } while (slash != max);
        } catch (IllegalArgumentException _) {
            throw new IllegalArgumentException("Invalid "
                    + msg
                    + " (must be a fully qualified class name in internal form): "
                    + name);
        }
    }

    /**
     * Checks that the given string is a valid type descriptor.
     * 
     * @param desc the string to be checked.
     * @param canBeVoid <tt>true</tt> if <tt>V</tt> can be considered valid.
     */
    static void checkDesc(final String desc, final boolean canBeVoid) {
        int end = checkDesc(desc, 0, canBeVoid);
        if (end != desc.length()) {
            throw new IllegalArgumentException("Invalid descriptor: " + desc);
        }
    }

    /**
     * Checks that a the given substring is a valid type descriptor.
     * 
     * @param desc the string to be checked.
     * @param start index of the first character of the identifier (inclusive).
     * @param canBeVoid <tt>true</tt> if <tt>V</tt> can be considered valid.
     * @return the index of the last character of the type decriptor, plus one.
     */
    static int checkDesc(
        final String desc,
        final int start,
        final boolean canBeVoid)
    {
        if (desc == null || start >= desc.length()) {
            throw new IllegalArgumentException("Invalid type descriptor (must not be null or empty)");
        }
        int index;
        switch (desc.charAt(start)) {
            case 'V':
                if (canBeVoid) {
                    return start + 1;
                } else {
                    throw new IllegalArgumentException("Invalid descriptor: "
                            + desc);
                }
            case 'Z':
            case 'C':
            case 'B':
            case 'S':
            case 'I':
            case 'F':
            case 'J':
            case 'D':
                return start + 1;
            case '[':
                index = start + 1;
                while (index < desc.length() && desc.charAt(index) == '[') {
                    ++index;
                }
                if (index < desc.length()) {
                    return checkDesc(desc, index, false);
                } else {
                    throw new IllegalArgumentException("Invalid descriptor: "
                            + desc);
                }
            case 'L':
                index = desc.indexOf(';', start);
                if (index == -1 || index - start < 2) {
                    throw new IllegalArgumentException("Invalid descriptor: "
                            + desc);
                }
                try {
                    checkInternalName(desc, start + 1, index, null);
                } catch (IllegalArgumentException _) {
                    throw new IllegalArgumentException("Invalid descriptor: "
                            + desc);
                }
                return index + 1;
            default:
                throw new IllegalArgumentException("Invalid descriptor: "
                        + desc);
        }
    }

    /**
     * Checks that the given string is a valid method descriptor.
     * 
     * @param desc the string to be checked.
     */
    static void checkMethodDesc(final String desc) {
        if (desc == null || desc.length() == 0) {
            throw new IllegalArgumentException("Invalid method descriptor (must not be null or empty)");
        }
        if (desc.charAt(0) != '(' || desc.length() < 3) {
            throw new IllegalArgumentException("Invalid descriptor: " + desc);
        }
        int start = 1;
        if (desc.charAt(start) != ')') {
            do {
                if (desc.charAt(start) == 'V') {
                    throw new IllegalArgumentException("Invalid descriptor: "
                            + desc);
                }
                start = checkDesc(desc, start, false);
            } while (start < desc.length() && desc.charAt(start) != ')');
        }
        start = checkDesc(desc, start + 1, true);
        if (start != desc.length()) {
            throw new IllegalArgumentException("Invalid descriptor: " + desc);
        }
    }

    /**
     * Checks that the given label is not null. This method can also check that
     * the label has been visited.
     * 
     * @param label the label to be checked.
     * @param checkVisited <tt>true</tt> to check that the label has been
     *        visited.
     * @param msg a message to be used in case of error.
     */
    void checkLabel(
        final Label label,
        final boolean checkVisited,
        final String msg)
    {
        if (label == null) {
            throw new IllegalArgumentException("Invalid " + msg
                    + " (must not be null)");
        }
        if (checkVisited && labels.get(label) == null) {
            throw new IllegalArgumentException("Invalid " + msg
                    + " (must be visited first)");
        }
    }
}