1/*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.  Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25/*
26 * This file is available under and governed by the GNU General Public
27 * License version 2 only, as published by the Free Software Foundation.
28 * However, the following notice accompanied the original version of this
29 * file:
30 *
31 * ASM: a very small and fast Java bytecode manipulation framework
32 * Copyright (c) 2000-2011 INRIA, France Telecom
33 * All rights reserved.
34 *
35 * Redistribution and use in source and binary forms, with or without
36 * modification, are permitted provided that the following conditions
37 * are met:
38 * 1. Redistributions of source code must retain the above copyright
39 *    notice, this list of conditions and the following disclaimer.
40 * 2. Redistributions in binary form must reproduce the above copyright
41 *    notice, this list of conditions and the following disclaimer in the
42 *    documentation and/or other materials provided with the distribution.
43 * 3. Neither the name of the copyright holders nor the names of its
44 *    contributors may be used to endorse or promote products derived from
45 *    this software without specific prior written permission.
46 *
47 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
48 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
49 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
50 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
51 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
52 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
53 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
54 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
55 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
56 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
57 * THE POSSIBILITY OF SUCH DAMAGE.
58 */
59package jdk.internal.org.objectweb.asm;
60
61/**
62 * A visitor to visit a Java method. The methods of this class must be called in
63 * the following order: ( <tt>visitParameter</tt> )* [
64 * <tt>visitAnnotationDefault</tt> ] ( <tt>visitAnnotation</tt> |
65 * <tt>visitParameterAnnotation</tt> <tt>visitTypeAnnotation</tt> |
66 * <tt>visitAttribute</tt> )* [ <tt>visitCode</tt> ( <tt>visitFrame</tt> |
67 * <tt>visit<i>X</i>Insn</tt> | <tt>visitLabel</tt> |
68 * <tt>visitInsnAnnotation</tt> | <tt>visitTryCatchBlock</tt> |
69 * <tt>visitTryCatchAnnotation</tt> | <tt>visitLocalVariable</tt> |
70 * <tt>visitLocalVariableAnnotation</tt> | <tt>visitLineNumber</tt> )*
71 * <tt>visitMaxs</tt> ] <tt>visitEnd</tt>. In addition, the
72 * <tt>visit<i>X</i>Insn</tt> and <tt>visitLabel</tt> methods must be called in
73 * the sequential order of the bytecode instructions of the visited code,
74 * <tt>visitInsnAnnotation</tt> must be called <i>after</i> the annotated
75 * instruction, <tt>visitTryCatchBlock</tt> must be called <i>before</i> the
76 * labels passed as arguments have been visited,
77 * <tt>visitTryCatchBlockAnnotation</tt> must be called <i>after</i> the
78 * corresponding try catch block has been visited, and the
79 * <tt>visitLocalVariable</tt>, <tt>visitLocalVariableAnnotation</tt> and
80 * <tt>visitLineNumber</tt> methods must be called <i>after</i> the labels
81 * passed as arguments have been visited.
82 *
83 * @author Eric Bruneton
84 */
85public abstract class MethodVisitor {
86
87    /**
88     * The ASM API version implemented by this visitor. The value of this field
89     * must be one of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
90     */
91    protected final int api;
92
93    /**
94     * The method visitor to which this visitor must delegate method calls. May
95     * be null.
96     */
97    protected MethodVisitor mv;
98
99    /**
100     * Constructs a new {@link MethodVisitor}.
101     *
102     * @param api
103     *            the ASM API version implemented by this visitor. Must be one
104     *            of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
105     */
106    public MethodVisitor(final int api) {
107        this(api, null);
108    }
109
110    /**
111     * Constructs a new {@link MethodVisitor}.
112     *
113     * @param api
114     *            the ASM API version implemented by this visitor. Must be one
115     *            of {@link Opcodes#ASM4} or {@link Opcodes#ASM5}.
116     * @param mv
117     *            the method visitor to which this visitor must delegate method
118     *            calls. May be null.
119     */
120    public MethodVisitor(final int api, final MethodVisitor mv) {
121        if (api != Opcodes.ASM4 && api != Opcodes.ASM5) {
122            throw new IllegalArgumentException();
123        }
124        this.api = api;
125        this.mv = mv;
126    }
127
128    // -------------------------------------------------------------------------
129    // Parameters, annotations and non standard attributes
130    // -------------------------------------------------------------------------
131
132    /**
133     * Visits a parameter of this method.
134     *
135     * @param name
136     *            parameter name or null if none is provided.
137     * @param access
138     *            the parameter's access flags, only <tt>ACC_FINAL</tt>,
139     *            <tt>ACC_SYNTHETIC</tt> or/and <tt>ACC_MANDATED</tt> are
140     *            allowed (see {@link Opcodes}).
141     */
142    public void visitParameter(String name, int access) {
143        if (api < Opcodes.ASM5) {
144            throw new RuntimeException();
145        }
146        if (mv != null) {
147            mv.visitParameter(name, access);
148        }
149    }
150
151    /**
152     * Visits the default value of this annotation interface method.
153     *
154     * @return a visitor to the visit the actual default value of this
155     *         annotation interface method, or <tt>null</tt> if this visitor is
156     *         not interested in visiting this default value. The 'name'
157     *         parameters passed to the methods of this annotation visitor are
158     *         ignored. Moreover, exacly one visit method must be called on this
159     *         annotation visitor, followed by visitEnd.
160     */
161    public AnnotationVisitor visitAnnotationDefault() {
162        if (mv != null) {
163            return mv.visitAnnotationDefault();
164        }
165        return null;
166    }
167
168    /**
169     * Visits an annotation of this method.
170     *
171     * @param desc
172     *            the class descriptor of the annotation class.
173     * @param visible
174     *            <tt>true</tt> if the annotation is visible at runtime.
175     * @return a visitor to visit the annotation values, or <tt>null</tt> if
176     *         this visitor is not interested in visiting this annotation.
177     */
178    public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
179        if (mv != null) {
180            return mv.visitAnnotation(desc, visible);
181        }
182        return null;
183    }
184
185    /**
186     * Visits an annotation on a type in the method signature.
187     *
188     * @param typeRef
189     *            a reference to the annotated type. The sort of this type
190     *            reference must be {@link TypeReference#METHOD_TYPE_PARAMETER
191     *            METHOD_TYPE_PARAMETER},
192     *            {@link TypeReference#METHOD_TYPE_PARAMETER_BOUND
193     *            METHOD_TYPE_PARAMETER_BOUND},
194     *            {@link TypeReference#METHOD_RETURN METHOD_RETURN},
195     *            {@link TypeReference#METHOD_RECEIVER METHOD_RECEIVER},
196     *            {@link TypeReference#METHOD_FORMAL_PARAMETER
197     *            METHOD_FORMAL_PARAMETER} or {@link TypeReference#THROWS
198     *            THROWS}. See {@link TypeReference}.
199     * @param typePath
200     *            the path to the annotated type argument, wildcard bound, array
201     *            element type, or static inner type within 'typeRef'. May be
202     *            <tt>null</tt> if the annotation targets 'typeRef' as a whole.
203     * @param desc
204     *            the class descriptor of the annotation class.
205     * @param visible
206     *            <tt>true</tt> if the annotation is visible at runtime.
207     * @return a visitor to visit the annotation values, or <tt>null</tt> if
208     *         this visitor is not interested in visiting this annotation.
209     */
210    public AnnotationVisitor visitTypeAnnotation(int typeRef,
211            TypePath typePath, String desc, boolean visible) {
212        if (api < Opcodes.ASM5) {
213            throw new RuntimeException();
214        }
215        if (mv != null) {
216            return mv.visitTypeAnnotation(typeRef, typePath, desc, visible);
217        }
218        return null;
219    }
220
221    /**
222     * Visits an annotation of a parameter this method.
223     *
224     * @param parameter
225     *            the parameter index.
226     * @param desc
227     *            the class descriptor of the annotation class.
228     * @param visible
229     *            <tt>true</tt> if the annotation is visible at runtime.
230     * @return a visitor to visit the annotation values, or <tt>null</tt> if
231     *         this visitor is not interested in visiting this annotation.
232     */
233    public AnnotationVisitor visitParameterAnnotation(int parameter,
234            String desc, boolean visible) {
235        if (mv != null) {
236            return mv.visitParameterAnnotation(parameter, desc, visible);
237        }
238        return null;
239    }
240
241    /**
242     * Visits a non standard attribute of this method.
243     *
244     * @param attr
245     *            an attribute.
246     */
247    public void visitAttribute(Attribute attr) {
248        if (mv != null) {
249            mv.visitAttribute(attr);
250        }
251    }
252
253    /**
254     * Starts the visit of the method's code, if any (i.e. non abstract method).
255     */
256    public void visitCode() {
257        if (mv != null) {
258            mv.visitCode();
259        }
260    }
261
262    /**
263     * Visits the current state of the local variables and operand stack
264     * elements. This method must(*) be called <i>just before</i> any
265     * instruction <b>i</b> that follows an unconditional branch instruction
266     * such as GOTO or THROW, that is the target of a jump instruction, or that
267     * starts an exception handler block. The visited types must describe the
268     * values of the local variables and of the operand stack elements <i>just
269     * before</i> <b>i</b> is executed.<br>
270     * <br>
271     * (*) this is mandatory only for classes whose version is greater than or
272     * equal to {@link Opcodes#V1_6 V1_6}. <br>
273     * <br>
274     * The frames of a method must be given either in expanded form, or in
275     * compressed form (all frames must use the same format, i.e. you must not
276     * mix expanded and compressed frames within a single method):
277     * <ul>
278     * <li>In expanded form, all frames must have the F_NEW type.</li>
279     * <li>In compressed form, frames are basically "deltas" from the state of
280     * the previous frame:
281     * <ul>
282     * <li>{@link Opcodes#F_SAME} representing frame with exactly the same
283     * locals as the previous frame and with the empty stack.</li>
284     * <li>{@link Opcodes#F_SAME1} representing frame with exactly the same
285     * locals as the previous frame and with single value on the stack (
286     * <code>nStack</code> is 1 and <code>stack[0]</code> contains value for the
287     * type of the stack item).</li>
288     * <li>{@link Opcodes#F_APPEND} representing frame with current locals are
289     * the same as the locals in the previous frame, except that additional
290     * locals are defined (<code>nLocal</code> is 1, 2 or 3 and
291     * <code>local</code> elements contains values representing added types).</li>
292     * <li>{@link Opcodes#F_CHOP} representing frame with current locals are the
293     * same as the locals in the previous frame, except that the last 1-3 locals
294     * are absent and with the empty stack (<code>nLocals</code> is 1, 2 or 3).</li>
295     * <li>{@link Opcodes#F_FULL} representing complete frame data.</li>
296     * </ul>
297     * </li>
298     * </ul>
299     * <br>
300     * In both cases the first frame, corresponding to the method's parameters
301     * and access flags, is implicit and must not be visited. Also, it is
302     * illegal to visit two or more frames for the same code location (i.e., at
303     * least one instruction must be visited between two calls to visitFrame).
304     *
305     * @param type
306     *            the type of this stack map frame. Must be
307     *            {@link Opcodes#F_NEW} for expanded frames, or
308     *            {@link Opcodes#F_FULL}, {@link Opcodes#F_APPEND},
309     *            {@link Opcodes#F_CHOP}, {@link Opcodes#F_SAME} or
310     *            {@link Opcodes#F_APPEND}, {@link Opcodes#F_SAME1} for
311     *            compressed frames.
312     * @param nLocal
313     *            the number of local variables in the visited frame.
314     * @param local
315     *            the local variable types in this frame. This array must not be
316     *            modified. Primitive types are represented by
317     *            {@link Opcodes#TOP}, {@link Opcodes#INTEGER},
318     *            {@link Opcodes#FLOAT}, {@link Opcodes#LONG},
319     *            {@link Opcodes#DOUBLE},{@link Opcodes#NULL} or
320     *            {@link Opcodes#UNINITIALIZED_THIS} (long and double are
321     *            represented by a single element). Reference types are
322     *            represented by String objects (representing internal names),
323     *            and uninitialized types by Label objects (this label
324     *            designates the NEW instruction that created this uninitialized
325     *            value).
326     * @param nStack
327     *            the number of operand stack elements in the visited frame.
328     * @param stack
329     *            the operand stack types in this frame. This array must not be
330     *            modified. Its content has the same format as the "local"
331     *            array.
332     * @throws IllegalStateException
333     *             if a frame is visited just after another one, without any
334     *             instruction between the two (unless this frame is a
335     *             Opcodes#F_SAME frame, in which case it is silently ignored).
336     */
337    public void visitFrame(int type, int nLocal, Object[] local, int nStack,
338            Object[] stack) {
339        if (mv != null) {
340            mv.visitFrame(type, nLocal, local, nStack, stack);
341        }
342    }
343
344    // -------------------------------------------------------------------------
345    // Normal instructions
346    // -------------------------------------------------------------------------
347
348    /**
349     * Visits a zero operand instruction.
350     *
351     * @param opcode
352     *            the opcode of the instruction to be visited. This opcode is
353     *            either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1,
354     *            ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1,
355     *            FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD,
356     *            LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD,
357     *            IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE,
358     *            SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1,
359     *            DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB,
360     *            IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM,
361     *            FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR,
362     *            IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D,
363     *            L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S,
364     *            LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN,
365     *            DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER,
366     *            or MONITOREXIT.
367     */
368    public void visitInsn(int opcode) {
369        if (mv != null) {
370            mv.visitInsn(opcode);
371        }
372    }
373
374    /**
375     * Visits an instruction with a single int operand.
376     *
377     * @param opcode
378     *            the opcode of the instruction to be visited. This opcode is
379     *            either BIPUSH, SIPUSH or NEWARRAY.
380     * @param operand
381     *            the operand of the instruction to be visited.<br>
382     *            When opcode is BIPUSH, operand value should be between
383     *            Byte.MIN_VALUE and Byte.MAX_VALUE.<br>
384     *            When opcode is SIPUSH, operand value should be between
385     *            Short.MIN_VALUE and Short.MAX_VALUE.<br>
386     *            When opcode is NEWARRAY, operand value should be one of
387     *            {@link Opcodes#T_BOOLEAN}, {@link Opcodes#T_CHAR},
388     *            {@link Opcodes#T_FLOAT}, {@link Opcodes#T_DOUBLE},
389     *            {@link Opcodes#T_BYTE}, {@link Opcodes#T_SHORT},
390     *            {@link Opcodes#T_INT} or {@link Opcodes#T_LONG}.
391     */
392    public void visitIntInsn(int opcode, int operand) {
393        if (mv != null) {
394            mv.visitIntInsn(opcode, operand);
395        }
396    }
397
398    /**
399     * Visits a local variable instruction. A local variable instruction is an
400     * instruction that loads or stores the value of a local variable.
401     *
402     * @param opcode
403     *            the opcode of the local variable instruction to be visited.
404     *            This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD,
405     *            ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.
406     * @param var
407     *            the operand of the instruction to be visited. This operand is
408     *            the index of a local variable.
409     */
410    public void visitVarInsn(int opcode, int var) {
411        if (mv != null) {
412            mv.visitVarInsn(opcode, var);
413        }
414    }
415
416    /**
417     * Visits a type instruction. A type instruction is an instruction that
418     * takes the internal name of a class as parameter.
419     *
420     * @param opcode
421     *            the opcode of the type instruction to be visited. This opcode
422     *            is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
423     * @param type
424     *            the operand of the instruction to be visited. This operand
425     *            must be the internal name of an object or array class (see
426     *            {@link Type#getInternalName() getInternalName}).
427     */
428    public void visitTypeInsn(int opcode, String type) {
429        if (mv != null) {
430            mv.visitTypeInsn(opcode, type);
431        }
432    }
433
434    /**
435     * Visits a field instruction. A field instruction is an instruction that
436     * loads or stores the value of a field of an object.
437     *
438     * @param opcode
439     *            the opcode of the type instruction to be visited. This opcode
440     *            is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.
441     * @param owner
442     *            the internal name of the field's owner class (see
443     *            {@link Type#getInternalName() getInternalName}).
444     * @param name
445     *            the field's name.
446     * @param desc
447     *            the field's descriptor (see {@link Type Type}).
448     */
449    public void visitFieldInsn(int opcode, String owner, String name,
450            String desc) {
451        if (mv != null) {
452            mv.visitFieldInsn(opcode, owner, name, desc);
453        }
454    }
455
456    /**
457     * Visits a method instruction. A method instruction is an instruction that
458     * invokes a method.
459     *
460     * @param opcode
461     *            the opcode of the type instruction to be visited. This opcode
462     *            is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or
463     *            INVOKEINTERFACE.
464     * @param owner
465     *            the internal name of the method's owner class (see
466     *            {@link Type#getInternalName() getInternalName}).
467     * @param name
468     *            the method's name.
469     * @param desc
470     *            the method's descriptor (see {@link Type Type}).
471     */
472    @Deprecated
473    public void visitMethodInsn(int opcode, String owner, String name,
474            String desc) {
475        if (api >= Opcodes.ASM5) {
476            boolean itf = opcode == Opcodes.INVOKEINTERFACE;
477            visitMethodInsn(opcode, owner, name, desc, itf);
478            return;
479        }
480        if (mv != null) {
481            mv.visitMethodInsn(opcode, owner, name, desc);
482        }
483    }
484
485    /**
486     * Visits a method instruction. A method instruction is an instruction that
487     * invokes a method.
488     *
489     * @param opcode
490     *            the opcode of the type instruction to be visited. This opcode
491     *            is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or
492     *            INVOKEINTERFACE.
493     * @param owner
494     *            the internal name of the method's owner class (see
495     *            {@link Type#getInternalName() getInternalName}).
496     * @param name
497     *            the method's name.
498     * @param desc
499     *            the method's descriptor (see {@link Type Type}).
500     * @param itf
501     *            if the method's owner class is an interface.
502     */
503    public void visitMethodInsn(int opcode, String owner, String name,
504            String desc, boolean itf) {
505        if (api < Opcodes.ASM5) {
506            if (itf != (opcode == Opcodes.INVOKEINTERFACE)) {
507                throw new IllegalArgumentException(
508                        "INVOKESPECIAL/STATIC on interfaces require ASM 5");
509            }
510            visitMethodInsn(opcode, owner, name, desc);
511            return;
512        }
513        if (mv != null) {
514            mv.visitMethodInsn(opcode, owner, name, desc, itf);
515        }
516    }
517
518    /**
519     * Visits an invokedynamic instruction.
520     *
521     * @param name
522     *            the method's name.
523     * @param desc
524     *            the method's descriptor (see {@link Type Type}).
525     * @param bsm
526     *            the bootstrap method.
527     * @param bsmArgs
528     *            the bootstrap method constant arguments. Each argument must be
529     *            an {@link Integer}, {@link Float}, {@link Long},
530     *            {@link Double}, {@link String}, {@link Type} or {@link Handle}
531     *            value. This method is allowed to modify the content of the
532     *            array so a caller should expect that this array may change.
533     */
534    public void visitInvokeDynamicInsn(String name, String desc, Handle bsm,
535            Object... bsmArgs) {
536        if (mv != null) {
537            mv.visitInvokeDynamicInsn(name, desc, bsm, bsmArgs);
538        }
539    }
540
541    /**
542     * Visits a jump instruction. A jump instruction is an instruction that may
543     * jump to another instruction.
544     *
545     * @param opcode
546     *            the opcode of the type instruction to be visited. This opcode
547     *            is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ,
548     *            IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE,
549     *            IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.
550     * @param label
551     *            the operand of the instruction to be visited. This operand is
552     *            a label that designates the instruction to which the jump
553     *            instruction may jump.
554     */
555    public void visitJumpInsn(int opcode, Label label) {
556        if (mv != null) {
557            mv.visitJumpInsn(opcode, label);
558        }
559    }
560
561    /**
562     * Visits a label. A label designates the instruction that will be visited
563     * just after it.
564     *
565     * @param label
566     *            a {@link Label Label} object.
567     */
568    public void visitLabel(Label label) {
569        if (mv != null) {
570            mv.visitLabel(label);
571        }
572    }
573
574    // -------------------------------------------------------------------------
575    // Special instructions
576    // -------------------------------------------------------------------------
577
578    /**
579     * Visits a LDC instruction. Note that new constant types may be added in
580     * future versions of the Java Virtual Machine. To easily detect new
581     * constant types, implementations of this method should check for
582     * unexpected constant types, like this:
583     *
584     * <pre>
585     * if (cst instanceof Integer) {
586     *     // ...
587     * } else if (cst instanceof Float) {
588     *     // ...
589     * } else if (cst instanceof Long) {
590     *     // ...
591     * } else if (cst instanceof Double) {
592     *     // ...
593     * } else if (cst instanceof String) {
594     *     // ...
595     * } else if (cst instanceof Type) {
596     *     int sort = ((Type) cst).getSort();
597     *     if (sort == Type.OBJECT) {
598     *         // ...
599     *     } else if (sort == Type.ARRAY) {
600     *         // ...
601     *     } else if (sort == Type.METHOD) {
602     *         // ...
603     *     } else {
604     *         // throw an exception
605     *     }
606     * } else if (cst instanceof Handle) {
607     *     // ...
608     * } else {
609     *     // throw an exception
610     * }
611     * </pre>
612     *
613     * @param cst
614     *            the constant to be loaded on the stack. This parameter must be
615     *            a non null {@link Integer}, a {@link Float}, a {@link Long}, a
616     *            {@link Double}, a {@link String}, a {@link Type} of OBJECT or
617     *            ARRAY sort for <tt>.class</tt> constants, for classes whose
618     *            version is 49.0, a {@link Type} of METHOD sort or a
619     *            {@link Handle} for MethodType and MethodHandle constants, for
620     *            classes whose version is 51.0.
621     */
622    public void visitLdcInsn(Object cst) {
623        if (mv != null) {
624            mv.visitLdcInsn(cst);
625        }
626    }
627
628    /**
629     * Visits an IINC instruction.
630     *
631     * @param var
632     *            index of the local variable to be incremented.
633     * @param increment
634     *            amount to increment the local variable by.
635     */
636    public void visitIincInsn(int var, int increment) {
637        if (mv != null) {
638            mv.visitIincInsn(var, increment);
639        }
640    }
641
642    /**
643     * Visits a TABLESWITCH instruction.
644     *
645     * @param min
646     *            the minimum key value.
647     * @param max
648     *            the maximum key value.
649     * @param dflt
650     *            beginning of the default handler block.
651     * @param labels
652     *            beginnings of the handler blocks. <tt>labels[i]</tt> is the
653     *            beginning of the handler block for the <tt>min + i</tt> key.
654     */
655    public void visitTableSwitchInsn(int min, int max, Label dflt,
656            Label... labels) {
657        if (mv != null) {
658            mv.visitTableSwitchInsn(min, max, dflt, labels);
659        }
660    }
661
662    /**
663     * Visits a LOOKUPSWITCH instruction.
664     *
665     * @param dflt
666     *            beginning of the default handler block.
667     * @param keys
668     *            the values of the keys.
669     * @param labels
670     *            beginnings of the handler blocks. <tt>labels[i]</tt> is the
671     *            beginning of the handler block for the <tt>keys[i]</tt> key.
672     */
673    public void visitLookupSwitchInsn(Label dflt, int[] keys, Label[] labels) {
674        if (mv != null) {
675            mv.visitLookupSwitchInsn(dflt, keys, labels);
676        }
677    }
678
679    /**
680     * Visits a MULTIANEWARRAY instruction.
681     *
682     * @param desc
683     *            an array type descriptor (see {@link Type Type}).
684     * @param dims
685     *            number of dimensions of the array to allocate.
686     */
687    public void visitMultiANewArrayInsn(String desc, int dims) {
688        if (mv != null) {
689            mv.visitMultiANewArrayInsn(desc, dims);
690        }
691    }
692
693    /**
694     * Visits an annotation on an instruction. This method must be called just
695     * <i>after</i> the annotated instruction. It can be called several times
696     * for the same instruction.
697     *
698     * @param typeRef
699     *            a reference to the annotated type. The sort of this type
700     *            reference must be {@link TypeReference#INSTANCEOF INSTANCEOF},
701     *            {@link TypeReference#NEW NEW},
702     *            {@link TypeReference#CONSTRUCTOR_REFERENCE
703     *            CONSTRUCTOR_REFERENCE}, {@link TypeReference#METHOD_REFERENCE
704     *            METHOD_REFERENCE}, {@link TypeReference#CAST CAST},
705     *            {@link TypeReference#CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT
706     *            CONSTRUCTOR_INVOCATION_TYPE_ARGUMENT},
707     *            {@link TypeReference#METHOD_INVOCATION_TYPE_ARGUMENT
708     *            METHOD_INVOCATION_TYPE_ARGUMENT},
709     *            {@link TypeReference#CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT
710     *            CONSTRUCTOR_REFERENCE_TYPE_ARGUMENT}, or
711     *            {@link TypeReference#METHOD_REFERENCE_TYPE_ARGUMENT
712     *            METHOD_REFERENCE_TYPE_ARGUMENT}. See {@link TypeReference}.
713     * @param typePath
714     *            the path to the annotated type argument, wildcard bound, array
715     *            element type, or static inner type within 'typeRef'. May be
716     *            <tt>null</tt> if the annotation targets 'typeRef' as a whole.
717     * @param desc
718     *            the class descriptor of the annotation class.
719     * @param visible
720     *            <tt>true</tt> if the annotation is visible at runtime.
721     * @return a visitor to visit the annotation values, or <tt>null</tt> if
722     *         this visitor is not interested in visiting this annotation.
723     */
724    public AnnotationVisitor visitInsnAnnotation(int typeRef,
725            TypePath typePath, String desc, boolean visible) {
726        if (api < Opcodes.ASM5) {
727            throw new RuntimeException();
728        }
729        if (mv != null) {
730            return mv.visitInsnAnnotation(typeRef, typePath, desc, visible);
731        }
732        return null;
733    }
734
735    // -------------------------------------------------------------------------
736    // Exceptions table entries, debug information, max stack and max locals
737    // -------------------------------------------------------------------------
738
739    /**
740     * Visits a try catch block.
741     *
742     * @param start
743     *            beginning of the exception handler's scope (inclusive).
744     * @param end
745     *            end of the exception handler's scope (exclusive).
746     * @param handler
747     *            beginning of the exception handler's code.
748     * @param type
749     *            internal name of the type of exceptions handled by the
750     *            handler, or <tt>null</tt> to catch any exceptions (for
751     *            "finally" blocks).
752     * @throws IllegalArgumentException
753     *             if one of the labels has already been visited by this visitor
754     *             (by the {@link #visitLabel visitLabel} method).
755     */
756    public void visitTryCatchBlock(Label start, Label end, Label handler,
757            String type) {
758        if (mv != null) {
759            mv.visitTryCatchBlock(start, end, handler, type);
760        }
761    }
762
763    /**
764     * Visits an annotation on an exception handler type. This method must be
765     * called <i>after</i> the {@link #visitTryCatchBlock} for the annotated
766     * exception handler. It can be called several times for the same exception
767     * handler.
768     *
769     * @param typeRef
770     *            a reference to the annotated type. The sort of this type
771     *            reference must be {@link TypeReference#EXCEPTION_PARAMETER
772     *            EXCEPTION_PARAMETER}. See {@link TypeReference}.
773     * @param typePath
774     *            the path to the annotated type argument, wildcard bound, array
775     *            element type, or static inner type within 'typeRef'. May be
776     *            <tt>null</tt> if the annotation targets 'typeRef' as a whole.
777     * @param desc
778     *            the class descriptor of the annotation class.
779     * @param visible
780     *            <tt>true</tt> if the annotation is visible at runtime.
781     * @return a visitor to visit the annotation values, or <tt>null</tt> if
782     *         this visitor is not interested in visiting this annotation.
783     */
784    public AnnotationVisitor visitTryCatchAnnotation(int typeRef,
785            TypePath typePath, String desc, boolean visible) {
786        if (api < Opcodes.ASM5) {
787            throw new RuntimeException();
788        }
789        if (mv != null) {
790            return mv.visitTryCatchAnnotation(typeRef, typePath, desc, visible);
791        }
792        return null;
793    }
794
795    /**
796     * Visits a local variable declaration.
797     *
798     * @param name
799     *            the name of a local variable.
800     * @param desc
801     *            the type descriptor of this local variable.
802     * @param signature
803     *            the type signature of this local variable. May be
804     *            <tt>null</tt> if the local variable type does not use generic
805     *            types.
806     * @param start
807     *            the first instruction corresponding to the scope of this local
808     *            variable (inclusive).
809     * @param end
810     *            the last instruction corresponding to the scope of this local
811     *            variable (exclusive).
812     * @param index
813     *            the local variable's index.
814     * @throws IllegalArgumentException
815     *             if one of the labels has not already been visited by this
816     *             visitor (by the {@link #visitLabel visitLabel} method).
817     */
818    public void visitLocalVariable(String name, String desc, String signature,
819            Label start, Label end, int index) {
820        if (mv != null) {
821            mv.visitLocalVariable(name, desc, signature, start, end, index);
822        }
823    }
824
825    /**
826     * Visits an annotation on a local variable type.
827     *
828     * @param typeRef
829     *            a reference to the annotated type. The sort of this type
830     *            reference must be {@link TypeReference#LOCAL_VARIABLE
831     *            LOCAL_VARIABLE} or {@link TypeReference#RESOURCE_VARIABLE
832     *            RESOURCE_VARIABLE}. See {@link TypeReference}.
833     * @param typePath
834     *            the path to the annotated type argument, wildcard bound, array
835     *            element type, or static inner type within 'typeRef'. May be
836     *            <tt>null</tt> if the annotation targets 'typeRef' as a whole.
837     * @param start
838     *            the fist instructions corresponding to the continuous ranges
839     *            that make the scope of this local variable (inclusive).
840     * @param end
841     *            the last instructions corresponding to the continuous ranges
842     *            that make the scope of this local variable (exclusive). This
843     *            array must have the same size as the 'start' array.
844     * @param index
845     *            the local variable's index in each range. This array must have
846     *            the same size as the 'start' array.
847     * @param desc
848     *            the class descriptor of the annotation class.
849     * @param visible
850     *            <tt>true</tt> if the annotation is visible at runtime.
851     * @return a visitor to visit the annotation values, or <tt>null</tt> if
852     *         this visitor is not interested in visiting this annotation.
853     */
854    public AnnotationVisitor visitLocalVariableAnnotation(int typeRef,
855            TypePath typePath, Label[] start, Label[] end, int[] index,
856            String desc, boolean visible) {
857        if (api < Opcodes.ASM5) {
858            throw new RuntimeException();
859        }
860        if (mv != null) {
861            return mv.visitLocalVariableAnnotation(typeRef, typePath, start,
862                    end, index, desc, visible);
863        }
864        return null;
865    }
866
867    /**
868     * Visits a line number declaration.
869     *
870     * @param line
871     *            a line number. This number refers to the source file from
872     *            which the class was compiled.
873     * @param start
874     *            the first instruction corresponding to this line number.
875     * @throws IllegalArgumentException
876     *             if <tt>start</tt> has not already been visited by this
877     *             visitor (by the {@link #visitLabel visitLabel} method).
878     */
879    public void visitLineNumber(int line, Label start) {
880        if (mv != null) {
881            mv.visitLineNumber(line, start);
882        }
883    }
884
885    /**
886     * Visits the maximum stack size and the maximum number of local variables
887     * of the method.
888     *
889     * @param maxStack
890     *            maximum stack size of the method.
891     * @param maxLocals
892     *            maximum number of local variables for the method.
893     */
894    public void visitMaxs(int maxStack, int maxLocals) {
895        if (mv != null) {
896            mv.visitMaxs(maxStack, maxLocals);
897        }
898    }
899
900    /**
901     * Visits the end of the method. This method, which is the last one to be
902     * called, is used to inform the visitor that all the annotations and
903     * attributes of the method have been visited.
904     */
905    public void visitEnd() {
906        if (mv != null) {
907            mv.visitEnd();
908        }
909    }
910}
911