Class Printer

  • Direct Known Subclasses:
    ASMifier, Textifier

    public abstract class Printer
    extends Object
    An abstract converter from visit events to text.
    Author:
    Eric Bruneton
    • Field Detail

      • OPCODES

        public static final String[] OPCODES
        The names of the Java Virtual Machine opcodes.
      • HANDLE_TAG

        public static final String[] HANDLE_TAG
        The names of the tag field values for Handle.
      • api

        protected final int api
        The ASM API version implemented by this class. The value of this field must be one of Opcodes.ASM4 or Opcodes.ASM5.
      • buf

        protected final StringBuffer buf
        A buffer that can be used to create strings.
      • text

        public final List<Object> text
        The text to be printed. Since the code of methods is not necessarily visited in sequential order, one method after the other, but can be interlaced (some instructions from method one, then some instructions from method two, then some instructions from method one again...), it is not possible to print the visited instructions directly to a sequential stream. A class is therefore printed in a two steps process: a string tree is constructed during the visit, and printed to a sequential stream at the end of the visit. This string tree is stored in this field, as a string list that can contain other string lists, which can themselves contain other string lists, and so on.
    • Constructor Detail

      • Printer

        protected Printer​(int api)
        Constructs a new Printer.
        Parameters:
        api - the ASM API version implemented by this printer. Must be one of Opcodes.ASM4 or Opcodes.ASM5.
    • Method Detail

      • visitSource

        public abstract void visitSource​(String source,
                                         String debug)
        Parameters:
        source - the name of the source file from which the class was compiled. May be null.
        debug - additional debug information to compute the correspondance between source and compiled elements of the class. May be null.
      • visitOuterClass

        public abstract void visitOuterClass​(String owner,
                                             String name,
                                             String desc)
        Class outer class. See ClassVisitor.visitOuterClass(java.lang.String, java.lang.String, java.lang.String). Visits the enclosing class of the class. This method must be called only if the class has an enclosing class.
        Parameters:
        owner - internal name of the enclosing class of the class.
        name - the name of the method that contains the class, or null if the class is not enclosed in a method of its enclosing class.
        desc - the descriptor of the method that contains the class, or null if the class is not enclosed in a method of its enclosing class.
      • visitField

        public abstract Printer visitField​(int access,
                                           String name,
                                           String desc,
                                           String signature,
                                           Object value)
        Parameters:
        access - the field's access flags (see Opcodes). This parameter also indicates if the field is synthetic and/or deprecated.
        name - the field's name.
        desc - the field's descriptor (see Type).
        signature - the field's signature. May be null if the field's type does not use generic types.
        value - the field's initial value. This parameter, which may be null if the field does not have an initial value, must be an Integer, a Float, a Long, a Double or a String (for int, float, long or String fields respectively). This parameter is only used for static fields. Its value is ignored for non static fields, which must be initialized through bytecode instructions in constructors or methods.
        Returns:
        the printer
      • visitArray

        public abstract Printer visitArray​(String name)
        Annotation array value. See AnnotationVisitor.visitArray(java.lang.String). Visits an array value of the annotation. Note that arrays of primitive types (such as byte, boolean, short, char, int, long, float or double) can be passed as value to visit. This is what ClassReader does.
        Parameters:
        name - the value name.
        Returns:
        the printer
      • visitFieldTypeAnnotation

        public Printer visitFieldTypeAnnotation​(int typeRef,
                                                TypePath typePath,
                                                String desc,
                                                boolean visible)
        Parameters:
        typeRef - a reference to the annotated type. The sort of this type reference must be FIELD. See TypeReference.
        typePath - the path to the annotated type argument, wildcard bound, array element type, or static inner type within 'typeRef'. May be null if the annotation targets 'typeRef' as a whole.
        desc - the class descriptor of the annotation class.
        visible - true if the annotation is visible at runtime.
        Returns:
        the printer
      • visitParameter

        public void visitParameter​(String name,
                                   int access)
        Parameters:
        name - parameter name or null if none is provided.
        access - the parameter's access flags, only ACC_FINAL, ACC_SYNTHETIC or/and ACC_MANDATED are allowed (see Opcodes).
      • visitMethodTypeAnnotation

        public Printer visitMethodTypeAnnotation​(int typeRef,
                                                 TypePath typePath,
                                                 String desc,
                                                 boolean visible)
        Parameters:
        typeRef - a reference to the annotated type. The sort of this type reference must be FIELD. See TypeReference.
        typePath - the path to the annotated type argument, wildcard bound, array element type, or static inner type within 'typeRef'. May be null if the annotation targets 'typeRef' as a whole.
        desc - the class descriptor of the annotation class.
        visible - true if the annotation is visible at runtime.
        Returns:
        the printer
      • visitFrame

        public abstract void visitFrame​(int type,
                                        int nLocal,
                                        Object[] local,
                                        int nStack,
                                        Object[] stack)
        Method stack frame. See MethodVisitor.visitFrame(int, int, java.lang.Object[], int, java.lang.Object[]). Visits the current state of the local variables and operand stack elements. This method must(*) be called just before any instruction i that follows an unconditional branch instruction such as GOTO or THROW, that is the target of a jump instruction, or that starts an exception handler block. The visited types must describe the values of the local variables and of the operand stack elements just before i is executed.

        (*) this is mandatory only for classes whose version is greater than or equal to V1_6.

        The frames of a method must be given either in expanded form, or in compressed form (all frames must use the same format, i.e. you must not mix expanded and compressed frames within a single method):
        • In expanded form, all frames must have the F_NEW type.
        • In compressed form, frames are basically "deltas" from the state of the previous frame:
          • Opcodes.F_SAME representing frame with exactly the same locals as the previous frame and with the empty stack.
          • Opcodes.F_SAME1 representing frame with exactly the same locals as the previous frame and with single value on the stack ( nStack is 1 and stack[0] contains value for the type of the stack item).
          • Opcodes.F_APPEND representing frame with current locals are the same as the locals in the previous frame, except that additional locals are defined (nLocal is 1, 2 or 3 and local elements contains values representing added types).
          • Opcodes.F_CHOP representing frame with current locals are the same as the locals in the previous frame, except that the last 1-3 locals are absent and with the empty stack (nLocals is 1, 2 or 3).
          • Opcodes.F_FULL representing complete frame data.

        In both cases the first frame, corresponding to the method's parameters and access flags, is implicit and must not be visited. Also, it is illegal to visit two or more frames for the same code location (i.e., at least one instruction must be visited between two calls to visitFrame).
        Parameters:
        type - the type of this stack map frame. Must be Opcodes.F_NEW for expanded frames, or Opcodes.F_FULL, Opcodes.F_APPEND, Opcodes.F_CHOP, Opcodes.F_SAME or Opcodes.F_APPEND, Opcodes.F_SAME1 for compressed frames.
        nLocal - the number of local variables in the visited frame.
        local - the local variable types in this frame. This array must not be modified. Primitive types are represented by Opcodes.TOP, Opcodes.INTEGER, Opcodes.FLOAT, Opcodes.LONG, Opcodes.DOUBLE,Opcodes.NULL or Opcodes.UNINITIALIZED_THIS (long and double are represented by a single element). Reference types are represented by String objects (representing internal names), and uninitialized types by Label objects (this label designates the NEW instruction that created this uninitialized value).
        nStack - the number of operand stack elements in the visited frame.
        stack - the operand stack types in this frame. This array must not be modified. Its content has the same format as the "local" array.
        Throws:
        IllegalStateException - if a frame is visited just after another one, without any instruction between the two (unless this frame is a Opcodes#F_SAME frame, in which case it is silently ignored).
      • visitInsn

        public abstract void visitInsn​(int opcode)
        Method instruction. See MethodVisitor.visitInsn(int)
        Parameters:
        opcode - the opcode of the instruction to be visited. This opcode is either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S, LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER, or MONITOREXIT.
      • visitVarInsn

        public abstract void visitVarInsn​(int opcode,
                                          int var)
        Method instruction. See MethodVisitor.visitVarInsn(int, int).
        Parameters:
        opcode - the opcode of the local variable instruction to be visited. This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.
        var - the operand of the instruction to be visited. This operand is the index of a local variable.
      • visitTypeInsn

        public abstract void visitTypeInsn​(int opcode,
                                           String type)
        Method instruction. See MethodVisitor.visitTypeInsn(int, java.lang.String). /** Visits a type instruction. A type instruction is an instruction that takes the internal name of a class as parameter.
        Parameters:
        opcode - the opcode of the type instruction to be visited. This opcode is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
        type - the operand of the instruction to be visited. This operand must be the internal name of an object or array class (see getInternalName).
      • visitJumpInsn

        public abstract void visitJumpInsn​(int opcode,
                                           Label label)
        Parameters:
        opcode - the opcode of the type instruction to be visited. This opcode is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.
        label - the operand of the instruction to be visited. This operand is a label that designates the instruction to which the jump instruction may jump.
      • visitLdcInsn

        public abstract void visitLdcInsn​(Object cst)
        Method instruction. See MethodVisitor.visitLdcInsn(java.lang.Object). Visits a LDC instruction. Note that new constant types may be added in future versions of the Java Virtual Machine. To easily detect new constant types, implementations of this method should check for unexpected constant types, like this:
         if (cst instanceof Integer) {
             // ...
         } else if (cst instanceof Float) {
             // ...
         } else if (cst instanceof Long) {
             // ...
         } else if (cst instanceof Double) {
             // ...
         } else if (cst instanceof String) {
             // ...
         } else if (cst instanceof Type) {
             int sort = ((Type) cst).getSort();
             if (sort == Type.OBJECT) {
                 // ...
             } else if (sort == Type.ARRAY) {
                 // ...
             } else if (sort == Type.METHOD) {
                 // ...
             } else {
                 // throw an exception
             }
         } else if (cst instanceof Handle) {
             // ...
         } else {
             // throw an exception
         }
         
        Parameters:
        cst - the constant to be loaded on the stack. This parameter must be a non null Integer, a Float, a Long, a Double, a String, a Type of OBJECT or ARRAY sort for .class constants, for classes whose version is 49.0, a Type of METHOD sort or a Handle for MethodType and MethodHandle constants, for classes whose version is 51.0.
      • visitIincInsn

        public abstract void visitIincInsn​(int var,
                                           int increment)
        Method instruction. See MethodVisitor.visitIincInsn(int, int).
        Parameters:
        var - index of the local variable to be incremented.
        increment - amount to increment the local variable by.
      • visitLocalVariableAnnotation

        public Printer visitLocalVariableAnnotation​(int typeRef,
                                                    TypePath typePath,
                                                    Label[] start,
                                                    Label[] end,
                                                    int[] index,
                                                    String desc,
                                                    boolean visible)
        Parameters:
        typeRef - a reference to the annotated type. The sort of this type reference must be LOCAL_VARIABLE or RESOURCE_VARIABLE. See TypeReference.
        typePath - the path to the annotated type argument, wildcard bound, array element type, or static inner type within 'typeRef'. May be null if the annotation targets 'typeRef' as a whole.
        start - the fist instructions corresponding to the continuous ranges that make the scope of this local variable (inclusive).
        end - the last instructions corresponding to the continuous ranges that make the scope of this local variable (exclusive). This array must have the same size as the 'start' array.
        index - the local variable's index in each range. This array must have the same size as the 'start' array.
        desc - the class descriptor of the annotation class.
        visible - true if the annotation is visible at runtime.
        Returns:
        the printer
      • visitMaxs

        public abstract void visitMaxs​(int maxStack,
                                       int maxLocals)
        Method max stack and max locals. See MethodVisitor.visitMaxs(int, int).
        Parameters:
        maxStack - maximum stack size of the method.
        maxLocals - maximum number of local variables for the method.
      • getText

        public List<Object> getText()
        Returns the text constructed by this visitor.
        Returns:
        the text constructed by this visitor.
      • print

        public void print​(PrintWriter pw)
        Prints the text constructed by this visitor.
        Parameters:
        pw - the print writer to be used.
      • appendString

        public static void appendString​(StringBuffer buf,
                                        String s)
        Appends a quoted string to a given buffer.
        Parameters:
        buf - the buffer where the string must be added.
        s - the string to be added.