1 /* 2 * Copyright (C) 2007 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.dx.dex.code; 18 19 import com.android.dx.dex.DexOptions; 20 import java.util.ArrayList; 21 22 /** 23 * Destination for {@link DalvInsn} instances being output. This class 24 * receives and collects instructions in two pieces — a primary 25 * list and a suffix (generally consisting of adjunct data referred to 26 * by the primary list, such as switch case tables) — which it 27 * merges and emits back out in the form of a {@link DalvInsnList} 28 * instance. 29 */ 30 public final class OutputCollector { 31 /** 32 * {@code non-null;} the associated finisher (which holds the instruction 33 * list in-progress) 34 */ 35 private final OutputFinisher finisher; 36 37 /** 38 * {@code null-ok;} suffix for the output, or {@code null} if the suffix 39 * has been appended to the main output (by {@link #appendSuffixToOutput}) 40 */ 41 private ArrayList<DalvInsn> suffix; 42 43 /** 44 * Constructs an instance. 45 * 46 * @param dexOptions {@code non-null;} options for dex output 47 * @param initialCapacity {@code >= 0;} initial capacity of the output list 48 * @param suffixInitialCapacity {@code >= 0;} initial capacity of the output 49 * suffix 50 * @param regCount {@code >= 0;} register count for the method 51 */ 52 public OutputCollector(DexOptions dexOptions, int initialCapacity, int suffixInitialCapacity, 53 int regCount) { 54 this.finisher = new OutputFinisher(dexOptions, initialCapacity, regCount); 55 this.suffix = new ArrayList<DalvInsn>(suffixInitialCapacity); 56 } 57 58 /** 59 * Adds an instruction to the output. 60 * 61 * @param insn {@code non-null;} the instruction to add 62 */ 63 public void add(DalvInsn insn) { 64 finisher.add(insn); 65 } 66 67 /** 68 * Reverses a branch which is buried a given number of instructions 69 * backward in the output. It is illegal to call this unless the 70 * indicated instruction really is a reversible branch. 71 * 72 * @param which how many instructions back to find the branch; 73 * {@code 0} is the most recently added instruction, 74 * {@code 1} is the instruction before that, etc. 75 * @param newTarget {@code non-null;} the new target for the reversed branch 76 */ 77 public void reverseBranch(int which, CodeAddress newTarget) { 78 finisher.reverseBranch(which, newTarget); 79 } 80 81 /** 82 * Adds an instruction to the output suffix. 83 * 84 * @param insn {@code non-null;} the instruction to add 85 */ 86 public void addSuffix(DalvInsn insn) { 87 suffix.add(insn); 88 } 89 90 /** 91 * Gets the results of all the calls on this instance, in the form of 92 * an {@link OutputFinisher}. 93 * 94 * @return {@code non-null;} the output finisher 95 * @throws UnsupportedOperationException if this method has 96 * already been called 97 */ 98 public OutputFinisher getFinisher() { 99 if (suffix == null) { 100 throw new UnsupportedOperationException("already processed"); 101 } 102 103 appendSuffixToOutput(); 104 return finisher; 105 } 106 107 /** 108 * Helper for {@link #getFinisher}, which appends the suffix to 109 * the primary output. 110 */ 111 private void appendSuffixToOutput() { 112 int size = suffix.size(); 113 114 for (int i = 0; i < size; i++) { 115 finisher.add(suffix.get(i)); 116 } 117 118 suffix = null; 119 } 120 } 121
