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1
15
16 package javassist.convert;
17
18 import javassist.CtClass;
19 import javassist.CtMethod;
20 import javassist.NotFoundException;
21 import javassist.bytecode.*;
22
23 public class TransformBefore extends TransformCall {
24 protected CtClass[] parameterTypes;
25 protected int locals;
26 protected int maxLocals;
27 protected byte[] saveCode, loadCode;
28
29 public TransformBefore(Transformer next,
30 CtMethod origMethod, CtMethod beforeMethod)
31 throws NotFoundException
32 {
33 super(next, origMethod, beforeMethod);
34 parameterTypes = origMethod.getParameterTypes();
35 locals = 0;
36 maxLocals = 0;
37 saveCode = loadCode = null;
38 }
39
40 public void initialize(ConstPool cp, CodeAttribute attr) {
41 super.initialize(cp, attr);
42 locals = 0;
43 maxLocals = attr.getMaxLocals();
44 saveCode = loadCode = null;
45 }
46
47 protected int match(int c, int pos, CodeIterator iterator,
48 int typedesc, ConstPool cp) throws BadBytecode
49 {
50 if (newIndex == 0) {
51 String  desc = Descriptor.ofParameters(parameterTypes) + 'V';
52 desc = Descriptor.insertParameter(classname, desc);
53 int nt = cp.addNameAndTypeInfo(newMethodname, desc);
54 int ci = cp.addClassInfo(newClassname);
55 newIndex = cp.addMethodrefInfo(ci, nt);
56 constPool = cp;
57 }
58
59 if (saveCode == null)
60 makeCode(parameterTypes, cp);
61
62 return match2(pos, iterator);
63 }
64
65 protected int match2(int pos, CodeIterator iterator) throws BadBytecode {
66 iterator.move(pos);
67 iterator.insert(saveCode);
68 iterator.insert(loadCode);
69 int p = iterator.insertGap(3);
70 iterator.writeByte(INVOKESTATIC, p);
71 iterator.write16bit(newIndex, p + 1);
72 iterator.insert(loadCode);
73 return iterator.next();
74 }
75
76 public int extraLocals() { return locals; }
77
78 protected void makeCode(CtClass[] paramTypes, ConstPool cp) {
79 Bytecode save = new Bytecode(cp, 0, 0);
80 Bytecode load = new Bytecode(cp, 0, 0);
81
82 int var = maxLocals;
83 int len = (paramTypes == null) ? 0 : paramTypes.length;
84 load.addAload(var);
85 makeCode2(save, load, 0, len, paramTypes, var + 1);
86 save.addAstore(var);
87
88 saveCode = save.get();
89 loadCode = load.get();
90 }
91
92 private void makeCode2(Bytecode save, Bytecode load,
93 int i, int n, CtClass[] paramTypes, int var)
94 {
95 if (i < n) {
96 int size = load.addLoad(var, paramTypes[i]);
97 makeCode2(save, load, i + 1, n, paramTypes, var + size);
98 save.addStore(var, paramTypes[i]);
99 }
100 else
101 locals = var - maxLocals;
102 }
103 }
104 |
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