Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
ExecutionPath |
|
| 2.75;2.75 |
1 | package org.apache.commons.javaflow.bytecode.transformation.bcel.analyser; | |
2 | ||
3 | import org.apache.bcel.generic.Instruction; | |
4 | import org.apache.bcel.generic.RET; | |
5 | import org.apache.bcel.generic.JsrInstruction; | |
6 | ||
7 | /** | |
8 | * List of {@link InstructionContext} that represents a sequence of an execution. | |
9 | * | |
10 | * <p> | |
11 | * This object is immutable. | |
12 | * The sequence is represented in left-associative style; that is, | |
13 | * a sequence of [a,b,c,d] is represented as prev=[a,b,c] and last=d. | |
14 | * | |
15 | * @author Kohsuke Kawaguchi | |
16 | */ | |
17 | public final class ExecutionPath { | |
18 | /** | |
19 | * Singleton {@link ExecutionPath} that represents an empty sequence []. | |
20 | */ | |
21 | 0 | public static final ExecutionPath EMPTY = new ExecutionPath(null,null); |
22 | ||
23 | private final ExecutionPath prev; | |
24 | private final InstructionContext last; | |
25 | ||
26 | 0 | private ExecutionPath(ExecutionPath prev, InstructionContext last) { |
27 | 0 | this.prev = prev; |
28 | 0 | this.last = last; |
29 | 0 | } |
30 | ||
31 | /** | |
32 | * Creates a new {@link ExecutionPath} that has | |
33 | * <tt>[... list in this ExecutionPath ..., ins]</tt>. | |
34 | */ | |
35 | public ExecutionPath append(InstructionContext ins) { | |
36 | 0 | return new ExecutionPath(this,ins); |
37 | } | |
38 | ||
39 | /** | |
40 | * Returns the InstructionContextImpl with an JSR/JSR_W | |
41 | * that was last in the ExecutionChain, without | |
42 | * a corresponding RET, i.e. | |
43 | * we were called by this one. | |
44 | * Returns null if we were called from the top level. | |
45 | */ | |
46 | public InstructionContext lastExecutionJSR(){ | |
47 | 0 | int retcount = 0; |
48 | ||
49 | 0 | for( ExecutionPath ptr = this; ptr!=EMPTY; ptr=ptr.prev) { |
50 | 0 | Instruction i = ptr.last.getInstruction().getInstruction(); |
51 | 0 | if (i instanceof RET) retcount++; |
52 | 0 | if (i instanceof JsrInstruction){ |
53 | 0 | retcount--; |
54 | 0 | if (retcount == -1) |
55 | 0 | return ptr.last; |
56 | } | |
57 | } | |
58 | ||
59 | 0 | return null; |
60 | } | |
61 | ||
62 | /** | |
63 | * Returns a human readable representation. | |
64 | */ | |
65 | public String toString() { | |
66 | 0 | if(this==EMPTY) |
67 | 0 | return ""; |
68 | else { | |
69 | 0 | return prev.toString()+"\n"+last.toString(); |
70 | } | |
71 | } | |
72 | } |