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16 package net.sf.cglib.transform.impl;
17
18 import net.sf.cglib.transform.*;
19 import net.sf.cglib.core.*;
20 import org.objectweb.asm.ClassVisitor;
21 import org.objectweb.asm.MethodAdapter;
22 import org.objectweb.asm.MethodVisitor;
23 import org.objectweb.asm.Attribute;
24 import org.objectweb.asm.Label;
25 import org.objectweb.asm.Type;
26
27
30 public class InterceptFieldTransformer extends ClassEmitterTransformer {
31 private static final String  CALLBACK_FIELD = "$CGLIB_READ_WRITE_CALLBACK";
32 private static final Type CALLBACK =
33 TypeUtils.parseType("net.sf.cglib.transform.impl.InterceptFieldCallback");
34 private static final Type ENABLED =
35 TypeUtils.parseType("net.sf.cglib.transform.impl.InterceptFieldEnabled");
36 private static final Signature ENABLED_SET =
37 new Signature("setInterceptFieldCallback", Type.VOID_TYPE, new Type[]{ CALLBACK });
38 private static final Signature ENABLED_GET =
39 new Signature("getInterceptFieldCallback", CALLBACK, new Type[0]);
40
41 private InterceptFieldFilter filter;
42
43 public InterceptFieldTransformer(InterceptFieldFilter filter) {
44 this.filter = filter;
45 }
46
47 public void begin_class(int version, int access, String className, Type superType, Type[] interfaces, String sourceFile) {
48 if (!TypeUtils.isInterface(access)) {
49 super.begin_class(version, access, className, superType, TypeUtils.add(interfaces, ENABLED), sourceFile);
50
51 super.declare_field(Constants.ACC_PRIVATE | Constants.ACC_TRANSIENT,
52 CALLBACK_FIELD,
53 CALLBACK,
54 null);
55
56 CodeEmitter e;
57 e = super.begin_method(Constants.ACC_PUBLIC, ENABLED_GET, null);
58 e.load_this();
59 e.getfield(CALLBACK_FIELD);
60 e.return_value();
61 e.end_method();
62
63 e = super.begin_method(Constants.ACC_PUBLIC, ENABLED_SET, null);
64 e.load_this();
65 e.load_arg(0);
66 e.putfield(CALLBACK_FIELD);
67 e.return_value();
68 e.end_method();
69 } else {
70 super.begin_class(version, access, className, superType, interfaces, sourceFile);
71 }
72 }
73
74 public void declare_field(int access, String name, Type type, Object value) {
75 super.declare_field(access, name, type, value);
76 if (!TypeUtils.isStatic(access)) {
77 if (filter.acceptRead(getClassType(), name)) {
78 addReadMethod(name, type);
79 }
80 if (filter.acceptWrite(getClassType(), name)) {
81 addWriteMethod(name, type);
82 }
83 }
84 }
85
86 private void addReadMethod(String name, Type type) {
87 CodeEmitter e = super.begin_method(Constants.ACC_PUBLIC,
88 readMethodSig(name, type.getDescriptor()),
89 null);
90 e.load_this();
91 e.getfield(name);
92 e.load_this();
93 e.invoke_interface(ENABLED,ENABLED_GET);
94 Label intercept = e.make_label();
95 e.ifnonnull(intercept);
96 e.return_value();
97
98 e.mark(intercept);
99 Local result = e.make_local(type);
100 e.store_local(result);
101 e.load_this();
102 e.invoke_interface(ENABLED,ENABLED_GET);
103 e.load_this();
104 e.push(name);
105 e.load_local(result);
106 e.invoke_interface(CALLBACK, readCallbackSig(type));
107 if (!TypeUtils.isPrimitive(type)) {
108 e.checkcast(type);
109 }
110 e.return_value();
111 e.end_method();
112 }
113
114 private void addWriteMethod(String name, Type type) {
115 CodeEmitter e = super.begin_method(Constants.ACC_PUBLIC,
116 writeMethodSig(name, type.getDescriptor()),
117 null);
118 e.load_this();
119 e.dup();
120 e.invoke_interface(ENABLED,ENABLED_GET);
121 Label skip = e.make_label();
122 e.ifnull(skip);
123
124 e.load_this();
125 e.invoke_interface(ENABLED,ENABLED_GET);
126 e.load_this();
127 e.push(name);
128 e.load_this();
129 e.getfield(name);
130 e.load_arg(0);
131 e.invoke_interface(CALLBACK, writeCallbackSig(type));
132 if (!TypeUtils.isPrimitive(type)) {
133 e.checkcast(type);
134 }
135 Label go = e.make_label();
136 e.goTo(go);
137 e.mark(skip);
138 e.load_arg(0);
139 e.mark(go);
140 e.putfield(name);
141 e.return_value();
142 e.end_method();
143 }
144
145 public CodeEmitter begin_method(int access, Signature sig, Type[] exceptions) {
146 return new CodeEmitter(super.begin_method(access, sig, exceptions)) {
147 public void visitFieldInsn(int opcode, String owner, String name, String desc) {
148 Type towner = TypeUtils.fromInternalName(owner);
149 switch (opcode) {
150 case Constants.GETFIELD:
151 if (filter.acceptRead(towner, name)) {
152 helper(towner, readMethodSig(name, desc));
153 return;
154 }
155 break;
156 case Constants.PUTFIELD:
157 if (filter.acceptWrite(towner, name)) {
158 helper(towner, writeMethodSig(name, desc));
159 return;
160 }
161 break;
162 }
163 super.visitFieldInsn(opcode, owner, name, desc);
164 }
165
166 private void helper(Type owner, Signature sig) {
167 invoke_virtual(owner, sig);
168 }
169 };
170 }
171
172 private static Signature readMethodSig(String name, String desc) {
173 return new Signature("$cglib_read_" + name, "()" + desc);
174 }
175
176 private static Signature writeMethodSig(String name, String desc) {
177 return new Signature("$cglib_write_" + name, "(" + desc + ")V");
178 }
179
180 private static Signature readCallbackSig(Type type) {
181 Type remap = remap(type);
182 return new Signature("read" + callbackName(remap),
183 remap,
184 new Type[]{ Constants.TYPE_OBJECT,
185 Constants.TYPE_STRING,
186 remap });
187 }
188
189 private static Signature writeCallbackSig(Type type) {
190 Type remap = remap(type);
191 return new Signature("write" + callbackName(remap),
192 remap,
193 new Type[]{ Constants.TYPE_OBJECT,
194 Constants.TYPE_STRING,
195 remap,
196 remap });
197 }
198
199 private static Type remap(Type type) {
200 switch (type.getSort()) {
201 case Type.OBJECT:
202 case Type.ARRAY:
203 return Constants.TYPE_OBJECT;
204 default:
205 return type;
206 }
207 }
208
209 private static String callbackName(Type type) {
210 return (type == Constants.TYPE_OBJECT) ?
211 "Object" :
212 TypeUtils.upperFirst(TypeUtils.getClassName(type));
213 }
214 }
215 |
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