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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   https://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.bcel.generic;
20  
21  import java.util.ArrayList;
22  import java.util.Arrays;
23  import java.util.Collections;
24  import java.util.Comparator;
25  import java.util.Hashtable;
26  import java.util.List;
27  import java.util.Objects;
28  import java.util.Stack;
29  import java.util.stream.Collectors;
30  
31  import org.apache.bcel.Const;
32  import org.apache.bcel.classfile.AnnotationEntry;
33  import org.apache.bcel.classfile.Annotations;
34  import org.apache.bcel.classfile.Attribute;
35  import org.apache.bcel.classfile.Code;
36  import org.apache.bcel.classfile.CodeException;
37  import org.apache.bcel.classfile.ExceptionTable;
38  import org.apache.bcel.classfile.LineNumber;
39  import org.apache.bcel.classfile.LineNumberTable;
40  import org.apache.bcel.classfile.LocalVariable;
41  import org.apache.bcel.classfile.LocalVariableTable;
42  import org.apache.bcel.classfile.LocalVariableTypeTable;
43  import org.apache.bcel.classfile.Method;
44  import org.apache.bcel.classfile.ParameterAnnotationEntry;
45  import org.apache.bcel.classfile.ParameterAnnotations;
46  import org.apache.bcel.classfile.RuntimeVisibleParameterAnnotations;
47  import org.apache.bcel.classfile.Utility;
48  import org.apache.bcel.util.BCELComparator;
49  import org.apache.commons.lang3.ArrayUtils;
50  import org.apache.commons.lang3.stream.Streams;
51  
52  /**
53   * Template class for building up a method. This is done by defining exception handlers, adding thrown exceptions, local
54   * variables and attributes, whereas the 'LocalVariableTable' and 'LineNumberTable' attributes will be set automatically
55   * for the code. Use stripAttributes() if you don't like this.
56   *
57   * While generating code it may be necessary to insert NOP operations. You can use the 'removeNOPs' method to get rid
58   * off them. The resulting method object can be obtained via the 'getMethod()' method.
59   *
60   * @see InstructionList
61   * @see Method
62   */
63  public class MethodGen extends FieldGenOrMethodGen {
64  
65      static final class BranchStack {
66  
67          private final Stack<BranchTarget> branchTargets = new Stack<>();
68          private final Hashtable<InstructionHandle, BranchTarget> visitedTargets = new Hashtable<>();
69  
70          public BranchTarget pop() {
71              if (!branchTargets.empty()) {
72                  return branchTargets.pop();
73              }
74              return null;
75          }
76  
77          public void push(final InstructionHandle target, final int stackDepth) {
78              if (visited(target)) {
79                  return;
80              }
81              branchTargets.push(visit(target, stackDepth));
82          }
83  
84          private BranchTarget visit(final InstructionHandle target, final int stackDepth) {
85              final BranchTarget bt = new BranchTarget(target, stackDepth);
86              visitedTargets.put(target, bt);
87              return bt;
88          }
89  
90          private boolean visited(final InstructionHandle target) {
91              return visitedTargets.get(target) != null;
92          }
93      }
94  
95      static final class BranchTarget {
96  
97          final InstructionHandle target;
98          final int stackDepth;
99  
100         BranchTarget(final InstructionHandle target, final int stackDepth) {
101             this.target = target;
102             this.stackDepth = stackDepth;
103         }
104     }
105 
106     private static BCELComparator<FieldGenOrMethodGen> bcelComparator = new BCELComparator<FieldGenOrMethodGen>() {
107 
108         @Override
109         public boolean equals(final FieldGenOrMethodGen a, final FieldGenOrMethodGen b) {
110             return a == b || a != null && b != null && Objects.equals(a.getName(), b.getName()) && Objects.equals(a.getSignature(), b.getSignature());
111         }
112 
113         @Override
114         public int hashCode(final FieldGenOrMethodGen o) {
115             return o != null ? Objects.hash(o.getSignature(), o.getName()) : 0;
116         }
117     };
118 
119     private static byte[] getByteCodes(final Method method) {
120         final Code code = method.getCode();
121         if (code == null) {
122             throw new IllegalStateException(String.format("The method '%s' has no code.", method));
123         }
124         return code.getCode();
125     }
126 
127     /**
128      * @return Comparison strategy object.
129      */
130     public static BCELComparator<FieldGenOrMethodGen> getComparator() {
131         return bcelComparator;
132     }
133 
134     /**
135      * Computes stack usage of an instruction list by performing control flow analysis.
136      *
137      * @return maximum stack depth used by method
138      */
139     public static int getMaxStack(final ConstantPoolGen cp, final InstructionList il, final CodeExceptionGen[] et) {
140         final BranchStack branchTargets = new BranchStack();
141         /*
142          * Initially, populate the branch stack with the exception handlers, because these aren't (necessarily) branched to
143          * explicitly. in each case, the stack will have depth 1, containing the exception object.
144          */
145         for (final CodeExceptionGen element : et) {
146             final InstructionHandle handlerPc = element.getHandlerPC();
147             if (handlerPc != null) {
148                 branchTargets.push(handlerPc, 1);
149             }
150         }
151         int stackDepth = 0;
152         int maxStackDepth = 0;
153         InstructionHandle ih = il.getStart();
154         while (ih != null) {
155             final Instruction instruction = ih.getInstruction();
156             final short opcode = instruction.getOpcode();
157             final int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);
158             stackDepth += delta;
159             if (stackDepth > maxStackDepth) {
160                 maxStackDepth = stackDepth;
161             }
162             // choose the next instruction based on whether current is a branch.
163             if (instruction instanceof BranchInstruction) {
164                 final BranchInstruction branch = (BranchInstruction) instruction;
165                 if (instruction instanceof Select) {
166                     // explore all of the select's targets. the default target is handled below.
167                     final Select select = (Select) branch;
168                     final InstructionHandle[] targets = select.getTargets();
169                     for (final InstructionHandle target : targets) {
170                         branchTargets.push(target, stackDepth);
171                     }
172                     // nothing to fall through to.
173                     ih = null;
174                 } else if (!(branch instanceof IfInstruction)) {
175                     // if an instruction that comes back to following PC,
176                     // push next instruction, with stack depth reduced by 1.
177                     if (opcode == Const.JSR || opcode == Const.JSR_W) {
178                         branchTargets.push(ih.getNext(), stackDepth - 1);
179                     }
180                     ih = null;
181                 }
182                 // for all branches, the target of the branch is pushed on the branch stack.
183                 // conditional branches have a fall through case, selects don't, and
184                 // jsr/jsr_w return to the next instruction.
185                 branchTargets.push(branch.getTarget(), stackDepth);
186             } else // check for instructions that terminate the method.
187             if (opcode == Const.ATHROW || opcode == Const.RET || opcode >= Const.IRETURN && opcode <= Const.RETURN) {
188                 ih = null;
189             }
190             // normal case, go to the next instruction.
191             if (ih != null) {
192                 ih = ih.getNext();
193             }
194             // if we have no more instructions, see if there are any deferred branches to explore.
195             if (ih == null) {
196                 final BranchTarget bt = branchTargets.pop();
197                 if (bt != null) {
198                     ih = bt.target;
199                     stackDepth = bt.stackDepth;
200                 }
201             }
202         }
203         return maxStackDepth;
204     }
205 
206     /**
207      * @param comparator Comparison strategy object.
208      */
209     public static void setComparator(final BCELComparator<FieldGenOrMethodGen> comparator) {
210         bcelComparator = comparator;
211     }
212 
213     private String className;
214     private Type[] argTypes;
215     private String[] argNames;
216     private int maxLocals;
217     private int maxStack;
218     private InstructionList il;
219 
220     private boolean stripAttributes;
221     private LocalVariableTypeTable localVariableTypeTable;
222     private final List<LocalVariableGen> variableList = new ArrayList<>();
223 
224     private final List<LineNumberGen> lineNumberList = new ArrayList<>();
225 
226     private final List<CodeExceptionGen> exceptionList = new ArrayList<>();
227 
228     private final List<String> throwsList = new ArrayList<>();
229 
230     private final List<Attribute> codeAttrsList = new ArrayList<>();
231 
232     private List<AnnotationEntryGen>[] paramAnnotations; // Array of lists containing AnnotationGen objects
233 
234     private boolean hasParameterAnnotations;
235 
236     private boolean haveUnpackedParameterAnnotations;
237 
238     private List<MethodObserver> observers;
239 
240     /**
241      * Declare method. If the method is non-static the constructor automatically declares a local variable '$this' in slot
242      * 0. The actual code is contained in the 'il' parameter, which may further manipulated by the user. But they must take
243      * care not to remove any instruction (handles) that are still referenced from this object.
244      *
245      * For example one may not add a local variable and later remove the instructions it refers to without causing havoc. It
246      * is safe however if you remove that local variable, too.
247      *
248      * @param accessFlags access qualifiers
249      * @param returnType method type
250      * @param argTypes argument types
251      * @param argNames argument names (if this is null, default names will be provided for them)
252      * @param methodName name of method
253      * @param className class name containing this method (may be null, if you don't care)
254      * @param il instruction list associated with this method, may be null only for abstract or native methods
255      * @param cp constant pool
256      */
257     public MethodGen(final int accessFlags, final Type returnType, final Type[] argTypes, String[] argNames, final String methodName, final String className,
258         final InstructionList il, final ConstantPoolGen cp) {
259         super(accessFlags);
260         setType(returnType);
261         setArgumentTypes(argTypes);
262         setArgumentNames(argNames);
263         setName(methodName);
264         setClassName(className);
265         setInstructionList(il);
266         setConstantPool(cp);
267         final boolean abstract_ = isAbstract() || isNative();
268         InstructionHandle start = null;
269         final InstructionHandle end = null;
270         if (!abstract_) {
271             start = il.getStart();
272             // end == null => live to end of method
273             /*
274              * Add local variables, namely the implicit 'this' and the arguments
275              */
276             if (!isStatic() && className != null) { // Instance method -> 'this' is local var 0
277                 addLocalVariable("this", ObjectType.getInstance(className), start, end);
278             }
279         }
280         if (argTypes != null) {
281             final int size = argTypes.length;
282             for (final Type argType : argTypes) {
283                 if (Type.VOID == argType) {
284                     throw new ClassGenException("'void' is an illegal argument type for a method");
285                 }
286             }
287             if (argNames != null) { // Names for variables provided?
288                 if (size != argNames.length) {
289                     throw new ClassGenException("Mismatch in argument array lengths: " + size + " vs. " + argNames.length);
290                 }
291             } else { // Give them dummy names
292                 argNames = new String[size];
293                 for (int i = 0; i < size; i++) {
294                     argNames[i] = "arg" + i;
295                 }
296                 setArgumentNames(argNames);
297             }
298             if (!abstract_) {
299                 for (int i = 0; i < size; i++) {
300                     addLocalVariable(argNames[i], argTypes[i], start, end);
301                 }
302             }
303         }
304     }
305 
306     /**
307      * Instantiate from existing method.
308      *
309      * @param method method
310      * @param className class name containing this method
311      * @param cp constant pool
312      */
313     public MethodGen(final Method method, final String className, final ConstantPoolGen cp) {
314         this(method.getAccessFlags(), Type.getReturnType(method.getSignature()), Type.getArgumentTypes(method.getSignature()),
315             null /* may be overridden anyway */
316             , method.getName(), className,
317             (method.getAccessFlags() & (Const.ACC_ABSTRACT | Const.ACC_NATIVE)) == 0 ? new InstructionList(getByteCodes(method)) : null, cp);
318         final Attribute[] attributes = method.getAttributes();
319         for (final Attribute attribute : attributes) {
320             Attribute a = attribute;
321             if (a instanceof Code) {
322                 final Code c = (Code) a;
323                 setMaxStack(c.getMaxStack());
324                 setMaxLocals(c.getMaxLocals());
325                 final CodeException[] ces = c.getExceptionTable();
326                 if (ces != null) {
327                     for (final CodeException ce : ces) {
328                         final int type = ce.getCatchType();
329                         ObjectType cType = null;
330                         if (type > 0) {
331                             final String cen = method.getConstantPool().getConstantString(type, Const.CONSTANT_Class);
332                             cType = ObjectType.getInstance(cen);
333                         }
334                         final int endPc = ce.getEndPC();
335                         final int length = getByteCodes(method).length;
336                         InstructionHandle end;
337                         if (length == endPc) { // May happen, because end_pc is exclusive
338                             end = il.getEnd();
339                         } else {
340                             end = il.findHandle(endPc);
341                             end = end.getPrev(); // Make it inclusive
342                         }
343                         addExceptionHandler(il.findHandle(ce.getStartPC()), end, il.findHandle(ce.getHandlerPC()), cType);
344                     }
345                 }
346                 final Attribute[] cAttributes = c.getAttributes();
347                 for (final Attribute cAttribute : cAttributes) {
348                     a = cAttribute;
349                     if (a instanceof LineNumberTable) {
350                         ((LineNumberTable) a).forEach(l -> {
351                             final InstructionHandle ih = il.findHandle(l.getStartPC());
352                             if (ih != null) {
353                                 addLineNumber(ih, l.getLineNumber());
354                             }
355                         });
356                     } else if (a instanceof LocalVariableTable) {
357                         updateLocalVariableTable((LocalVariableTable) a);
358                     } else if (a instanceof LocalVariableTypeTable) {
359                         this.localVariableTypeTable = (LocalVariableTypeTable) a.copy(cp.getConstantPool());
360                     } else {
361                         addCodeAttribute(a);
362                     }
363                 }
364             } else if (a instanceof ExceptionTable) {
365                 Collections.addAll(throwsList, ((ExceptionTable) a).getExceptionNames());
366             } else if (a instanceof Annotations) {
367                 final Annotations runtimeAnnotations = (Annotations) a;
368                 runtimeAnnotations.forEach(element -> addAnnotationEntry(new AnnotationEntryGen(element, cp, false)));
369             } else {
370                 addAttribute(a);
371             }
372         }
373     }
374 
375     /**
376      * @since 6.0
377      */
378     public void addAnnotationsAsAttribute(final ConstantPoolGen cp) {
379         addAll(AnnotationEntryGen.getAnnotationAttributes(cp, super.getAnnotationEntries()));
380     }
381 
382     /**
383      * Add an attribute to the code. Currently, the JVM knows about the LineNumberTable, LocalVariableTable and StackMap
384      * attributes, where the former two will be generated automatically and the latter is used for the MIDP only. Other
385      * attributes will be ignored by the JVM but do no harm.
386      *
387      * @param a attribute to be added
388      */
389     public void addCodeAttribute(final Attribute a) {
390         codeAttrsList.add(a);
391     }
392 
393     /**
394      * Add an exception possibly thrown by this method.
395      *
396      * @param className (fully qualified) name of exception
397      */
398     public void addException(final String className) {
399         throwsList.add(className);
400     }
401 
402     /**
403      * Add an exception handler, i.e., specify region where a handler is active and an instruction where the actual handling
404      * is done.
405      *
406      * @param startPc Start of region (inclusive)
407      * @param endPc End of region (inclusive)
408      * @param handlerPc Where handling is done
409      * @param catchType class type of handled exception or null if any exception is handled
410      * @return new exception handler object
411      */
412     public CodeExceptionGen addExceptionHandler(final InstructionHandle startPc, final InstructionHandle endPc, final InstructionHandle handlerPc,
413         final ObjectType catchType) {
414         if (startPc == null || endPc == null || handlerPc == null) {
415             throw new ClassGenException("Exception handler target is null instruction");
416         }
417         final CodeExceptionGen c = new CodeExceptionGen(startPc, endPc, handlerPc, catchType);
418         exceptionList.add(c);
419         return c;
420     }
421 
422     /**
423      * Give an instruction a line number corresponding to the source code line.
424      *
425      * @param ih instruction to tag
426      * @return new line number object
427      * @see LineNumber
428      */
429     public LineNumberGen addLineNumber(final InstructionHandle ih, final int srcLine) {
430         final LineNumberGen l = new LineNumberGen(ih, srcLine);
431         lineNumberList.add(l);
432         return l;
433     }
434 
435     /**
436      * Adds a local variable to this method and assigns an index automatically.
437      *
438      * @param name variable name
439      * @param type variable type
440      * @param start from where the variable is valid, if this is null, it is valid from the start
441      * @param end until where the variable is valid, if this is null, it is valid to the end
442      * @return new local variable object
443      * @see LocalVariable
444      */
445     public LocalVariableGen addLocalVariable(final String name, final Type type, final InstructionHandle start, final InstructionHandle end) {
446         return addLocalVariable(name, type, maxLocals, start, end);
447     }
448 
449     /**
450      * Adds a local variable to this method.
451      *
452      * @param name variable name
453      * @param type variable type
454      * @param slot the index of the local variable, if type is long or double, the next available index is slot+2
455      * @param start from where the variable is valid
456      * @param end until where the variable is valid
457      * @return new local variable object
458      * @see LocalVariable
459      */
460     public LocalVariableGen addLocalVariable(final String name, final Type type, final int slot, final InstructionHandle start, final InstructionHandle end) {
461         return addLocalVariable(name, type, slot, start, end, slot);
462     }
463 
464     /**
465      * Adds a local variable to this method.
466      *
467      * @param name variable name
468      * @param type variable type
469      * @param slot the index of the local variable, if type is long or double, the next available index is slot+2
470      * @param start from where the variable is valid
471      * @param end until where the variable is valid
472      * @param origIndex the index of the local variable prior to any modifications
473      * @return new local variable object
474      * @see LocalVariable
475      */
476     public LocalVariableGen addLocalVariable(final String name, final Type type, final int slot, final InstructionHandle start, final InstructionHandle end,
477         final int origIndex) {
478         final byte t = type.getType();
479         if (t != Const.T_ADDRESS) {
480             final int add = type.getSize();
481             if (slot + add > maxLocals) {
482                 maxLocals = slot + add;
483             }
484             final LocalVariableGen l = new LocalVariableGen(slot, name, type, start, end, origIndex);
485             final int i;
486             if ((i = variableList.indexOf(l)) >= 0) {
487                 variableList.set(i, l);
488             } else {
489                 variableList.add(l);
490             }
491             return l;
492         }
493         throw new IllegalArgumentException("Can not use " + type + " as type for local variable");
494     }
495 
496     /**
497      * Add observer for this object.
498      */
499     public void addObserver(final MethodObserver o) {
500         if (observers == null) {
501             observers = new ArrayList<>();
502         }
503         observers.add(o);
504     }
505 
506     public void addParameterAnnotation(final int parameterIndex, final AnnotationEntryGen annotation) {
507         ensureExistingParameterAnnotationsUnpacked();
508         if (!hasParameterAnnotations) {
509             @SuppressWarnings("unchecked") // OK
510             final List<AnnotationEntryGen>[] parmList = new List[argTypes.length];
511             paramAnnotations = parmList;
512             hasParameterAnnotations = true;
513         }
514         final List<AnnotationEntryGen> existingAnnotations = paramAnnotations[parameterIndex];
515         if (existingAnnotations != null) {
516             existingAnnotations.add(annotation);
517         } else {
518             final List<AnnotationEntryGen> l = new ArrayList<>();
519             l.add(annotation);
520             paramAnnotations[parameterIndex] = l;
521         }
522     }
523 
524     /**
525      * @since 6.0
526      */
527     public void addParameterAnnotationsAsAttribute(final ConstantPoolGen cp) {
528         if (!hasParameterAnnotations) {
529             return;
530         }
531         final Attribute[] attrs = AnnotationEntryGen.getParameterAnnotationAttributes(cp, paramAnnotations);
532         if (attrs != null) {
533             addAll(attrs);
534         }
535     }
536 
537     private Attribute[] addRuntimeAnnotationsAsAttribute(final ConstantPoolGen cp) {
538         final Attribute[] attrs = AnnotationEntryGen.getAnnotationAttributes(cp, super.getAnnotationEntries());
539         addAll(attrs);
540         return attrs;
541     }
542 
543     private Attribute[] addRuntimeParameterAnnotationsAsAttribute(final ConstantPoolGen cp) {
544         if (!hasParameterAnnotations) {
545             return Attribute.EMPTY_ARRAY;
546         }
547         final Attribute[] attrs = AnnotationEntryGen.getParameterAnnotationAttributes(cp, paramAnnotations);
548         addAll(attrs);
549         return attrs;
550     }
551 
552     private void adjustLocalVariableTypeTable(final LocalVariableTable lvt) {
553         final LocalVariable[] lv = lvt.getLocalVariableTable();
554         for (final LocalVariable element : localVariableTypeTable.getLocalVariableTypeTable()) {
555             for (final LocalVariable l : lv) {
556                 if (element.getName().equals(l.getName()) && element.getIndex() == l.getOrigIndex()) {
557                     element.setLength(l.getLength());
558                     element.setStartPC(l.getStartPC());
559                     element.setIndex(l.getIndex());
560                     break;
561                 }
562             }
563         }
564     }
565 
566     /**
567      * @return deep copy of this method
568      */
569     public MethodGen copy(final String className, final ConstantPoolGen cp) {
570         final Method m = ((MethodGen) clone()).getMethod();
571         final MethodGen mg = new MethodGen(m, className, super.getConstantPool());
572         if (super.getConstantPool() != cp) {
573             mg.setConstantPool(cp);
574             mg.getInstructionList().replaceConstantPool(super.getConstantPool(), cp);
575         }
576         return mg;
577     }
578 
579     /**
580      * Goes through the attributes on the method and identifies any that are RuntimeParameterAnnotations, extracting their
581      * contents and storing them as parameter annotations. There are two kinds of parameter annotation - visible and
582      * invisible. Once they have been unpacked, these attributes are deleted. (The annotations will be rebuilt as attributes
583      * when someone builds a Method object out of this MethodGen object).
584      */
585     private void ensureExistingParameterAnnotationsUnpacked() {
586         if (haveUnpackedParameterAnnotations) {
587             return;
588         }
589         // Find attributes that contain parameter annotation data
590         final Attribute[] attrs = getAttributes();
591         ParameterAnnotations paramAnnVisAttr = null;
592         ParameterAnnotations paramAnnInvisAttr = null;
593         for (final Attribute attribute : attrs) {
594             if (attribute instanceof ParameterAnnotations) {
595                 // Initialize paramAnnotations
596                 if (!hasParameterAnnotations) {
597                     @SuppressWarnings("unchecked") // OK
598                     final List<AnnotationEntryGen>[] parmList = new List[argTypes.length];
599                     paramAnnotations = parmList;
600                     Arrays.setAll(paramAnnotations, i -> new ArrayList<>());
601                 }
602                 hasParameterAnnotations = true;
603                 final ParameterAnnotations rpa = (ParameterAnnotations) attribute;
604                 if (rpa instanceof RuntimeVisibleParameterAnnotations) {
605                     paramAnnVisAttr = rpa;
606                 } else {
607                     paramAnnInvisAttr = rpa;
608                 }
609                 final ParameterAnnotationEntry[] parameterAnnotationEntries = rpa.getParameterAnnotationEntries();
610                 for (int j = 0; j < parameterAnnotationEntries.length; j++) {
611                     // This returns Annotation[] ...
612                     final ParameterAnnotationEntry immutableArray = rpa.getParameterAnnotationEntries()[j];
613                     // ... which needs transforming into an AnnotationGen[] ...
614                     final List<AnnotationEntryGen> mutable = makeMutableVersion(immutableArray.getAnnotationEntries());
615                     // ... then add these to any we already know about
616                     paramAnnotations[j].addAll(mutable);
617                 }
618             }
619         }
620         if (paramAnnVisAttr != null) {
621             removeAttribute(paramAnnVisAttr);
622         }
623         if (paramAnnInvisAttr != null) {
624             removeAttribute(paramAnnInvisAttr);
625         }
626         haveUnpackedParameterAnnotations = true;
627     }
628 
629     /**
630      * Return value as defined by given BCELComparator strategy. By default two MethodGen objects are said to be equal when
631      * their names and signatures are equal.
632      *
633      * @see Object#equals(Object)
634      */
635     @Override
636     public boolean equals(final Object obj) {
637         return obj instanceof FieldGenOrMethodGen && bcelComparator.equals(this, (FieldGenOrMethodGen) obj);
638     }
639 
640     // J5TODO: Should paramAnnotations be an array of arrays? Rather than an array of lists, this
641     // is more likely to suggest to the caller it is readonly (which a List does not).
642     /**
643      * Return a list of AnnotationGen objects representing parameter annotations
644      *
645      * @since 6.0
646      */
647     public List<AnnotationEntryGen> getAnnotationsOnParameter(final int i) {
648         ensureExistingParameterAnnotationsUnpacked();
649         if (!hasParameterAnnotations || i > argTypes.length) {
650             return null;
651         }
652         return paramAnnotations[i];
653     }
654 
655     public String getArgumentName(final int i) {
656         return argNames[i];
657     }
658 
659     public String[] getArgumentNames() {
660         return argNames.clone();
661     }
662 
663     public Type getArgumentType(final int i) {
664         return argTypes[i];
665     }
666 
667     public Type[] getArgumentTypes() {
668         return argTypes.clone();
669     }
670 
671     /**
672      * @return class that contains this method
673      */
674     public String getClassName() {
675         return className;
676     }
677 
678     /**
679      * @return all attributes of this method.
680      */
681     public Attribute[] getCodeAttributes() {
682         return codeAttrsList.toArray(Attribute.EMPTY_ARRAY);
683     }
684 
685     /**
686      * @return code exceptions for 'Code' attribute
687      */
688     private CodeException[] getCodeExceptions() {
689         final int size = exceptionList.size();
690         final CodeException[] cExc = new CodeException[size];
691         Arrays.setAll(cExc, i -> exceptionList.get(i).getCodeException(super.getConstantPool()));
692         return cExc;
693     }
694 
695     /*
696      * @return array of declared exception handlers
697      */
698     public CodeExceptionGen[] getExceptionHandlers() {
699         return exceptionList.toArray(CodeExceptionGen.EMPTY_ARRAY);
700     }
701 
702     /*
703      * @return array of thrown exceptions
704      */
705     public String[] getExceptions() {
706         return throwsList.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
707     }
708 
709     /**
710      * @return 'Exceptions' attribute of all the exceptions thrown by this method.
711      */
712     private ExceptionTable getExceptionTable(final ConstantPoolGen cp) {
713         final int size = throwsList.size();
714         final int[] ex = new int[size];
715         Arrays.setAll(ex, i -> cp.addClass(throwsList.get(i)));
716         return new ExceptionTable(cp.addUtf8("Exceptions"), 2 + 2 * size, ex, cp.getConstantPool());
717     }
718 
719     public InstructionList getInstructionList() {
720         return il;
721     }
722 
723     /*
724      * @return array of line numbers
725      */
726     public LineNumberGen[] getLineNumbers() {
727         return lineNumberList.toArray(LineNumberGen.EMPTY_ARRAY);
728     }
729 
730     /**
731      * @return 'LineNumberTable' attribute of all the local variables of this method.
732      */
733     public LineNumberTable getLineNumberTable(final ConstantPoolGen cp) {
734         final int size = lineNumberList.size();
735         final LineNumber[] ln = new LineNumber[size];
736         Arrays.setAll(ln, i -> lineNumberList.get(i).getLineNumber());
737         return new LineNumberTable(cp.addUtf8("LineNumberTable"), 2 + ln.length * 4, ln, cp.getConstantPool());
738     }
739 
740     /*
741      * If the range of the variable has not been set yet, it will be set to be valid from the start to the end of the
742      * instruction list.
743      *
744      * @return array of declared local variables sorted by index
745      */
746     public LocalVariableGen[] getLocalVariables() {
747         final int size = variableList.size();
748         final LocalVariableGen[] lg = new LocalVariableGen[size];
749         variableList.toArray(lg);
750         for (int i = 0; i < size; i++) {
751             if (lg[i].getStart() == null && il != null) {
752                 lg[i].setStart(il.getStart());
753             }
754             if (lg[i].getEnd() == null && il != null) {
755                 lg[i].setEnd(il.getEnd());
756             }
757         }
758         if (size > 1) {
759             Arrays.sort(lg, Comparator.comparingInt(LocalVariableGen::getIndex));
760         }
761         return lg;
762     }
763 
764     /**
765      * @return 'LocalVariableTable' attribute of all the local variables of this method.
766      */
767     public LocalVariableTable getLocalVariableTable(final ConstantPoolGen cp) {
768         final LocalVariableGen[] lg = getLocalVariables();
769         final int size = lg.length;
770         final LocalVariable[] lv = new LocalVariable[size];
771         Arrays.setAll(lv, i -> lg[i].getLocalVariable(cp));
772         return new LocalVariableTable(cp.addUtf8("LocalVariableTable"), 2 + lv.length * 10, lv, cp.getConstantPool());
773     }
774 
775     /**
776      * @return 'LocalVariableTypeTable' attribute of this method.
777      */
778     public LocalVariableTypeTable getLocalVariableTypeTable() {
779         return localVariableTypeTable;
780     }
781 
782     public int getMaxLocals() {
783         return maxLocals;
784     }
785 
786     public int getMaxStack() {
787         return maxStack;
788     }
789 
790     /**
791      * Gets method object. Never forget to call setMaxStack() or setMaxStack(max), respectively, before calling this method
792      * (the same applies for max locals).
793      *
794      * @return method object
795      */
796     public Method getMethod() {
797         final String signature = getSignature();
798         final ConstantPoolGen cp = super.getConstantPool();
799         final int nameIndex = cp.addUtf8(super.getName());
800         final int signatureIndex = cp.addUtf8(signature);
801         /*
802          * Also updates positions of instructions, i.e., their indices
803          */
804         final byte[] byteCode = il != null ? il.getByteCode() : null;
805         LineNumberTable lnt = null;
806         LocalVariableTable lvt = null;
807         /*
808          * Create LocalVariableTable and LineNumberTable attributes (for debuggers, for example)
809          */
810         if (!variableList.isEmpty() && !stripAttributes) {
811             updateLocalVariableTable(getLocalVariableTable(cp));
812             addCodeAttribute(lvt = getLocalVariableTable(cp));
813         }
814         if (localVariableTypeTable != null) {
815             // LocalVariable length in LocalVariableTypeTable is not updated automatically. It's a difference with
816             // LocalVariableTable.
817             if (lvt != null) {
818                 adjustLocalVariableTypeTable(lvt);
819             }
820             addCodeAttribute(localVariableTypeTable);
821         }
822         if (!lineNumberList.isEmpty() && !stripAttributes) {
823             addCodeAttribute(lnt = getLineNumberTable(cp));
824         }
825         final Attribute[] codeAttrs = getCodeAttributes();
826         /*
827          * Each attribute causes 6 additional header bytes
828          */
829         int attrsLen = 0;
830         for (final Attribute codeAttr : codeAttrs) {
831             attrsLen += codeAttr.getLength() + 6;
832         }
833         final CodeException[] cExc = getCodeExceptions();
834         final int excLen = cExc.length * 8; // Every entry takes 8 bytes
835         Code code = null;
836         if (byteCode != null && !isAbstract() && !isNative()) {
837             // Remove any stale code attribute
838             final Attribute[] attributes = getAttributes();
839             for (final Attribute a : attributes) {
840                 if (a instanceof Code) {
841                     removeAttribute(a);
842                 }
843             }
844             code = new Code(cp.addUtf8("Code"), 8 + byteCode.length + // prologue byte code
845                 2 + excLen + // exceptions
846                 2 + attrsLen, // attributes
847                 maxStack, maxLocals, byteCode, cExc, codeAttrs, cp.getConstantPool());
848             addAttribute(code);
849         }
850         final Attribute[] annotations = addRuntimeAnnotationsAsAttribute(cp);
851         final Attribute[] parameterAnnotations = addRuntimeParameterAnnotationsAsAttribute(cp);
852         ExceptionTable et = null;
853         if (!throwsList.isEmpty()) {
854             addAttribute(et = getExceptionTable(cp));
855             // Add 'Exceptions' if there are "throws" clauses
856         }
857         final Method m = new Method(super.getAccessFlags(), nameIndex, signatureIndex, getAttributes(), cp.getConstantPool());
858         // Undo effects of adding attributes
859         if (lvt != null) {
860             removeCodeAttribute(lvt);
861         }
862         if (localVariableTypeTable != null) {
863             removeCodeAttribute(localVariableTypeTable);
864         }
865         if (lnt != null) {
866             removeCodeAttribute(lnt);
867         }
868         if (code != null) {
869             removeAttribute(code);
870         }
871         if (et != null) {
872             removeAttribute(et);
873         }
874         removeRuntimeAttributes(annotations);
875         removeRuntimeAttributes(parameterAnnotations);
876         return m;
877     }
878 
879     public Type getReturnType() {
880         return getType();
881     }
882 
883     @Override
884     public String getSignature() {
885         return Type.getMethodSignature(super.getType(), argTypes);
886     }
887 
888     /**
889      * Return value as defined by given BCELComparator strategy. By default return the hash code of the method's name XOR
890      * signature.
891      *
892      * @see Object#hashCode()
893      */
894     @Override
895     public int hashCode() {
896         return bcelComparator.hashCode(this);
897     }
898 
899     private List<AnnotationEntryGen> makeMutableVersion(final AnnotationEntry[] mutableArray) {
900         return Streams.of(mutableArray).map(ae -> new AnnotationEntryGen(ae, getConstantPool(), false)).collect(Collectors.toList());
901     }
902 
903     /**
904      * Remove a code attribute.
905      */
906     public void removeCodeAttribute(final Attribute a) {
907         codeAttrsList.remove(a);
908     }
909 
910     /**
911      * Remove all code attributes.
912      */
913     public void removeCodeAttributes() {
914         localVariableTypeTable = null;
915         codeAttrsList.clear();
916     }
917 
918     /**
919      * Remove an exception.
920      */
921     public void removeException(final String c) {
922         throwsList.remove(c);
923     }
924 
925     /**
926      * Remove an exception handler.
927      */
928     public void removeExceptionHandler(final CodeExceptionGen c) {
929         exceptionList.remove(c);
930     }
931 
932     /**
933      * Remove all line numbers.
934      */
935     public void removeExceptionHandlers() {
936         exceptionList.clear();
937     }
938 
939     /**
940      * Remove all exceptions.
941      */
942     public void removeExceptions() {
943         throwsList.clear();
944     }
945 
946     /**
947      * Remove a line number.
948      */
949     public void removeLineNumber(final LineNumberGen l) {
950         lineNumberList.remove(l);
951     }
952 
953     /**
954      * Remove all line numbers.
955      */
956     public void removeLineNumbers() {
957         lineNumberList.clear();
958     }
959 
960     /**
961      * Remove a local variable, its slot will not be reused, if you do not use addLocalVariable with an explicit index
962      * argument.
963      */
964     public void removeLocalVariable(final LocalVariableGen l) {
965         l.dispose();
966         variableList.remove(l);
967     }
968 
969     /**
970      * Remove all local variables.
971      */
972     public void removeLocalVariables() {
973         variableList.forEach(LocalVariableGen::dispose);
974         variableList.clear();
975     }
976 
977     /**
978      * Remove the LocalVariableTypeTable
979      */
980     public void removeLocalVariableTypeTable() {
981         localVariableTypeTable = null;
982     }
983 
984     /**
985      * Remove all NOPs from the instruction list (if possible) and update every object referring to them, i.e., branch
986      * instructions, local variables and exception handlers.
987      */
988     public void removeNOPs() {
989         if (il != null) {
990             InstructionHandle next;
991             /*
992              * Check branch instructions.
993              */
994             for (InstructionHandle ih = il.getStart(); ih != null; ih = next) {
995                 next = ih.getNext();
996                 if (next != null && ih.getInstruction() instanceof NOP) {
997                     try {
998                         il.delete(ih);
999                     } catch (final TargetLostException e) {
1000                         for (final InstructionHandle target : e.getTargets()) {
1001                             for (final InstructionTargeter targeter : target.getTargeters()) {
1002                                 targeter.updateTarget(target, next);
1003                             }
1004                         }
1005                     }
1006                 }
1007             }
1008         }
1009     }
1010 
1011     /**
1012      * Remove observer for this object.
1013      */
1014     public void removeObserver(final MethodObserver o) {
1015         if (observers != null) {
1016             observers.remove(o);
1017         }
1018     }
1019 
1020     /**
1021      * Would prefer to make this private, but need a way to test if client is using BCEL version 6.5.0 or later that
1022      * contains fix for BCEL-329.
1023      *
1024      * @since 6.5.0
1025      */
1026     public void removeRuntimeAttributes(final Attribute[] attributes) {
1027         Streams.of(attributes).forEach(this::removeAttribute);
1028     }
1029 
1030     public void setArgumentName(final int i, final String name) {
1031         argNames[i] = name;
1032     }
1033 
1034     public void setArgumentNames(final String[] argNames) {
1035         this.argNames = ArrayUtils.nullToEmpty(argNames);
1036     }
1037 
1038     public void setArgumentType(final int i, final Type type) {
1039         argTypes[i] = type;
1040     }
1041 
1042     public void setArgumentTypes(final Type[] argTypes) {
1043         this.argTypes = argTypes != null ? argTypes : Type.NO_ARGS;
1044     }
1045 
1046     public void setClassName(final String className) { // TODO could be package-protected?
1047         this.className = className;
1048     }
1049 
1050     public void setInstructionList(final InstructionList il) { // TODO could be package-protected?
1051         this.il = il;
1052     }
1053 
1054     /**
1055      * Compute maximum number of local variables.
1056      */
1057     public void setMaxLocals() { // TODO could be package-protected? (some tests would need repackaging)
1058         if (il != null) {
1059             int max = isStatic() ? 0 : 1;
1060             for (final Type argType : argTypes) {
1061                 max += argType.getSize();
1062             }
1063             for (InstructionHandle ih = il.getStart(); ih != null; ih = ih.getNext()) {
1064                 final Instruction ins = ih.getInstruction();
1065                 if (ins instanceof LocalVariableInstruction || ins instanceof RET || ins instanceof IINC) {
1066                     final int index = ((IndexedInstruction) ins).getIndex() + ((TypedInstruction) ins).getType(super.getConstantPool()).getSize();
1067                     if (index > max) {
1068                         max = index;
1069                     }
1070                 }
1071             }
1072             maxLocals = max;
1073         } else {
1074             maxLocals = 0;
1075         }
1076     }
1077 
1078     /**
1079      * Sets maximum number of local variables.
1080      */
1081     public void setMaxLocals(final int m) {
1082         maxLocals = m;
1083     }
1084 
1085     /**
1086      * Computes max. stack size by performing control flow analysis.
1087      */
1088     public void setMaxStack() { // TODO could be package-protected? (some tests would need repackaging)
1089         if (il != null) {
1090             maxStack = getMaxStack(super.getConstantPool(), il, getExceptionHandlers());
1091         } else {
1092             maxStack = 0;
1093         }
1094     }
1095 
1096     /**
1097      * Sets maximum stack size for this method.
1098      */
1099     public void setMaxStack(final int m) { // TODO could be package-protected?
1100         maxStack = m;
1101     }
1102 
1103     public void setReturnType(final Type returnType) {
1104         setType(returnType);
1105     }
1106 
1107     /**
1108      * Do not/Do produce attributes code attributesLineNumberTable and LocalVariableTable, like javac -O
1109      */
1110     public void stripAttributes(final boolean flag) {
1111         stripAttributes = flag;
1112     }
1113 
1114     /**
1115      * Return string representation close to declaration format, 'public static void main(String[]) throws IOException',
1116      * for example.
1117      *
1118      * @return String representation of the method.
1119      */
1120     @Override
1121     public final String toString() {
1122         final String access = Utility.accessToString(super.getAccessFlags());
1123         String signature = Type.getMethodSignature(super.getType(), argTypes);
1124         signature = Utility.methodSignatureToString(signature, super.getName(), access, true, getLocalVariableTable(super.getConstantPool()));
1125         final StringBuilder buf = new StringBuilder(signature);
1126         for (final Attribute a : getAttributes()) {
1127             if (!(a instanceof Code || a instanceof ExceptionTable)) {
1128                 buf.append(" [").append(a).append("]");
1129             }
1130         }
1131 
1132         if (!throwsList.isEmpty()) {
1133             for (final String throwsDescriptor : throwsList) {
1134                 buf.append("\n\t\tthrows ").append(throwsDescriptor);
1135             }
1136         }
1137         return buf.toString();
1138     }
1139 
1140     /**
1141      * Call notify() method on all observers. This method is not called automatically whenever the state has changed, but
1142      * has to be called by the user after they have finished editing the object.
1143      */
1144     public void update() {
1145         if (observers != null) {
1146             for (final MethodObserver observer : observers) {
1147                 observer.notify(this);
1148             }
1149         }
1150     }
1151 
1152     private void updateLocalVariableTable(final LocalVariableTable a) {
1153         removeLocalVariables();
1154         for (final LocalVariable l : a.getLocalVariableTable()) {
1155             InstructionHandle start = il.findHandle(l.getStartPC());
1156             final InstructionHandle end = il.findHandle(l.getStartPC() + l.getLength());
1157             // Repair malformed handles
1158             if (null == start) {
1159                 start = il.getStart();
1160             }
1161             // end == null => live to end of method
1162             // Since we are recreating the LocalVaraible, we must
1163             // propagate the orig_index to new copy.
1164             addLocalVariable(l.getName(), Type.getType(l.getSignature()), l.getIndex(), start, end, l.getOrigIndex());
1165         }
1166     }
1167 }