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1 package gnu.expr;
2 import gnu.bytecode.*;
3 import gnu.mapping.*;
4
5 public class SynchronizedExp extends Expression
6 {
7 Expression object;
8 Expression body;
9
10 public SynchronizedExp (Expression object, Expression body)
11 {
12 this.object = object;
13 this.body = body;
14 }
15
16 protected boolean mustCompile () { return false; }
17
18 public void apply (CallContext ctx) throws Throwable 
19 {
20 Object value = object.eval(ctx);
21 Object result;
22 synchronized (value)
23 {
24 result = body.eval(ctx);
25 }
26 ctx.writeValue(result);
27 }
28
29 public void compile (Compilation comp, Target target)
30 {
31 CodeAttr code = comp.getCode();
32 object.compile (comp, Target.pushObject);
33 code.emitDup(1);
34 Scope scope = code.pushScope();
35 Variable objvar = scope.addVariable(code, Type.pointer_type, null);
36 code.emitStore(objvar);
37 code.emitMonitorEnter();
38 code.emitTryStart(false,
39 (target instanceof IgnoreTarget
40 || target instanceof ConsumerTarget) ? null
41 : target.getType());
42
43 body.compileWithPosition(comp, target);
44 code.emitLoad(objvar);
45 code.emitMonitorExit();
46 code.emitTryEnd();
47 code.emitCatchStart(null);
48 code.emitLoad(objvar);
49 code.emitMonitorExit();
50 code.emitThrow();
51 code.emitCatchEnd();
52 code.emitTryCatchEnd();
53 code.popScope();
54 }
55
56 protected Expression walk (ExpWalker walker)
57 {
58 return walker.walkSynchronizedExp(this);
59 }
60
61 protected void walkChildren(ExpWalker walker)
62 {
63 object = walker.walk(object);
64 if (walker.exitValue == null)
65 body = walker.walk(body);
66 }
67
68 public void print (OutPort ps)
69 {
70 ps.print("(Synchronized ");
71 object.print(ps);
72 ps.print(" ");
73 body.print(ps);
74 ps.print(")");
75 }
76 }
77 |
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