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 21 import java.util.ArrayList; 22 23 /** 24 * Destination for {@link DalvInsn} instances being output. This class 25 * receives and collects instructions in two pieces — a primary 26 * list and a suffix (generally consisting of adjunct data referred to 27 * by the primary list, such as switch case tables) — which it 28 * merges and emits back out in the form of a {@link DalvInsnList} 29 * instance. 30 */ 31 public final class OutputCollector { 32 /** 33 * {@code non-null;} the associated finisher (which holds the instruction 34 * list in-progress) 35 */ 36 private final OutputFinisher finisher; 37 38 /** 39 * {@code null-ok;} suffix for the output, or {@code null} if the suffix 40 * has been appended to the main output (by {@link #appendSuffixToOutput}) 41 */ 42 private ArrayList<DalvInsn> suffix; 43 44 /** 45 * Constructs an instance. 46 * 47 * @param dexOptions {@code non-null;} options for dex output 48 * @param initialCapacity {@code >= 0;} initial capacity of the output list 49 * @param suffixInitialCapacity {@code >= 0;} initial capacity of the output 50 * suffix 51 * @param regCount {@code >= 0;} register count for the method 52 */ 53 public OutputCollector(DexOptions dexOptions, int initialCapacity, int suffixInitialCapacity, 54 int regCount) { 55 this.finisher = new OutputFinisher(dexOptions, initialCapacity, regCount); 56 this.suffix = new ArrayList<DalvInsn>(suffixInitialCapacity); 57 } 58 59 /** 60 * Adds an instruction to the output. 61 * 62 * @param insn {@code non-null;} the instruction to add 63 */ 64 public void add(DalvInsn insn) { 65 finisher.add(insn); 66 } 67 68 /** 69 * Reverses a branch which is buried a given number of instructions 70 * backward in the output. It is illegal to call this unless the 71 * indicated instruction really is a reversible branch. 72 * 73 * @param which how many instructions back to find the branch; 74 * {@code 0} is the most recently added instruction, 75 * {@code 1} is the instruction before that, etc. 76 * @param newTarget {@code non-null;} the new target for the reversed branch 77 */ 78 public void reverseBranch(int which, CodeAddress newTarget) { 79 finisher.reverseBranch(which, newTarget); 80 } 81 82 /** 83 * Adds an instruction to the output suffix. 84 * 85 * @param insn {@code non-null;} the instruction to add 86 */ 87 public void addSuffix(DalvInsn insn) { 88 suffix.add(insn); 89 } 90 91 /** 92 * Gets the results of all the calls on this instance, in the form of 93 * an {@link OutputFinisher}. 94 * 95 * @return {@code non-null;} the output finisher 96 * @throws UnsupportedOperationException if this method has 97 * already been called 98 */ 99 public OutputFinisher getFinisher() { 100 if (suffix == null) { 101 throw new UnsupportedOperationException("already processed"); 102 } 103 104 appendSuffixToOutput(); 105 return finisher; 106 } 107 108 /** 109 * Helper for {@link #getFinisher}, which appends the suffix to 110 * the primary output. 111 */ 112 private void appendSuffixToOutput() { 113 int size = suffix.size(); 114 115 for (int i = 0; i < size; i++) { 116 finisher.add(suffix.get(i)); 117 } 118 119 suffix = null; 120 } 121 } 122
