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1
5 package com.tc.object.bytecode;
6
7 import com.tc.asm.ClassAdapter;
8 import com.tc.asm.ClassVisitor;
9 import com.tc.asm.MethodAdapter;
10 import com.tc.asm.MethodVisitor;
11 import com.tc.asm.Opcodes;
12 import com.tc.asm.Type;
13
14 public class JavaUtilWeakHashMapAdapter extends ClassAdapter implements Opcodes, ClassAdapterFactory {
15 private static final String  HASH_MAP_CLASS = "java/util/HashMap";
16 private static final String WEAK_HASH_MAP_CLASS = "java/util/WeakHashMap";
17
18 private static final int SYNTHETIC_METHOD_ACCESS = ACC_PROTECTED | ACC_SYNTHETIC;
19
20 private static final String HASH_MAP_HASH_METHOD_NAME = "hash";
21
22 private static final String TC_HASH_METHOD_NAME = ByteCodeUtil.TC_METHOD_PREFIX + "hash";
23 private static final String HASH_METHOD_DESCRIPTION = "(Ljava/lang/Object;)I";
24
25 private static final String TC_EQUAL_METHOD_NAME = ByteCodeUtil.TC_METHOD_PREFIX + "equal";
26 private static final String EQ_METHOD_DESCRIPTION = "(Ljava/lang/Object;Ljava/lang/Object;)Z";
27
28 private static final String EQ_METHOD_NAME = "eq";
29
30 private String hashMapHashMethodDesc = null;
31
32 public JavaUtilWeakHashMapAdapter() {
33 super(null);
34 }
35
36 private JavaUtilWeakHashMapAdapter(ClassVisitor cv, ClassLoader caller) {
37 super(cv);
38 }
39
40 public ClassAdapter create(ClassVisitor visitor, ClassLoader loader) {
41 return new JavaUtilWeakHashMapAdapter(visitor, loader);
42 }
43
44 public void visitEnd() {
45 generateSyntheticHashMethod();
46 generateSyntheticEqualMethod();
47 super.visitEnd();
48 }
49
50 private void generateSyntheticHashMethod() {
51 MethodVisitor mv = super.visitMethod(SYNTHETIC_METHOD_ACCESS, TC_HASH_METHOD_NAME, HASH_METHOD_DESCRIPTION, null,
52 null);
53 mv.visitCode();
54 mv.visitVarInsn(ALOAD, 1);
55
56 if (hashMapHashMethodDesc == null) { throw new AssertionError (); }
57 Type[] args = Type.getArgumentTypes(hashMapHashMethodDesc);
58 if (args.length != 1) { throw new AssertionError ("unexpected HashMap.hash() signature: " + hashMapHashMethodDesc); }
59
60 if (args[0].getSort() == Type.INT) {
61 mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Object", "hashCode", "()I");
62 } else if (!args[0].getInternalName().equals("java/lang/Object")) { throw new AssertionError ("unexpected type: "
63 + args[0]); }
64
65 mv.visitMethodInsn(INVOKESTATIC, HASH_MAP_CLASS, HASH_MAP_HASH_METHOD_NAME, hashMapHashMethodDesc);
66 mv.visitInsn(IRETURN);
67 mv.visitMaxs(0, 0);
68 mv.visitEnd();
69 }
70
71 private void generateSyntheticEqualMethod() {
72 MethodVisitor mv = super.visitMethod(SYNTHETIC_METHOD_ACCESS, TC_EQUAL_METHOD_NAME, EQ_METHOD_DESCRIPTION, null,
73 null);
74 mv.visitCode();
75 mv.visitVarInsn(ALOAD, 1);
76 mv.visitVarInsn(ALOAD, 2);
77 mv.visitMethodInsn(INVOKESTATIC, WEAK_HASH_MAP_CLASS, EQ_METHOD_NAME, EQ_METHOD_DESCRIPTION);
78 mv.visitInsn(IRETURN);
79 mv.visitMaxs(1, 2);
80 mv.visitEnd();
81 }
82
83 public MethodVisitor visitMethod(int access, String name, String desc, String signature, String [] exceptions) {
84 MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
85 return new JavaUtilWeakHashMapMethodAdapter(mv);
86 }
87
88 private class JavaUtilWeakHashMapMethodAdapter extends MethodAdapter {
89 public JavaUtilWeakHashMapMethodAdapter(MethodVisitor mv) {
90 super(mv);
91 }
92
93 public void visitMethodInsn(int opcode, String owner, String name, String desc) {
94 if ((INVOKEVIRTUAL == opcode) && "java/lang/Object".equals(owner) && "hashCode".equals(name)) { return; }
95
96 if (INVOKESTATIC == opcode && HASH_MAP_CLASS.equals(owner) && HASH_MAP_HASH_METHOD_NAME.equals(name)) {
97 hashMapHashMethodDesc = desc;
98 ByteCodeUtil.pushThis(this);
99 super.visitInsn(SWAP);
100 super.visitMethodInsn(INVOKEVIRTUAL, WEAK_HASH_MAP_CLASS, TC_HASH_METHOD_NAME, HASH_METHOD_DESCRIPTION);
101 } else if (INVOKESTATIC == opcode && WEAK_HASH_MAP_CLASS.equals(owner) && EQ_METHOD_NAME.equals(name)
102 && EQ_METHOD_DESCRIPTION.equals(desc)) {
103 ByteCodeUtil.pushThis(mv);
104 super.visitInsn(SWAP);
105 super.visitInsn(DUP2_X1);
106 super.visitInsn(POP2);
107 super.visitInsn(SWAP);
108 super.visitMethodInsn(INVOKEVIRTUAL, WEAK_HASH_MAP_CLASS, TC_EQUAL_METHOD_NAME, desc);
109 } else {
110 super.visitMethodInsn(opcode, owner, name, desc);
111 }
112 }
113 }
114 } |
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