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      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.rop.code.RegisterSpec;
     20 import com.android.dx.rop.code.RegisterSpecList;
     21 import com.android.dx.rop.code.RegisterSpecSet;
     22 import com.android.dx.rop.code.SourcePosition;
     23 import com.android.dx.ssa.RegisterMapper;
     24 
     25 /**
     26  * Pseudo-instruction which is used to hold a snapshot of the
     27  * state of local variable name mappings that exists immediately after
     28  * the instance in an instruction array.
     29  */
     30 public final class LocalSnapshot extends ZeroSizeInsn {
     31     /** {@code non-null;} local state associated with this instance */
     32     private final RegisterSpecSet locals;
     33 
     34     /**
     35      * Constructs an instance. The output address of this instance is initially
     36      * unknown ({@code -1}).
     37      *
     38      * @param position {@code non-null;} source position
     39      * @param locals {@code non-null;} associated local variable state
     40      */
     41     public LocalSnapshot(SourcePosition position, RegisterSpecSet locals) {
     42         super(position);
     43 
     44         if (locals == null) {
     45             throw new NullPointerException("locals == null");
     46         }
     47 
     48         this.locals = locals;
     49     }
     50 
     51     /** {@inheritDoc} */
     52     @Override
     53     public DalvInsn withRegisterOffset(int delta) {
     54         return new LocalSnapshot(getPosition(), locals.withOffset(delta));
     55     }
     56 
     57     /** {@inheritDoc} */
     58     @Override
     59     public DalvInsn withRegisters(RegisterSpecList registers) {
     60         return new LocalSnapshot(getPosition(), locals);
     61     }
     62 
     63     /**
     64      * Gets the local state associated with this instance.
     65      *
     66      * @return {@code non-null;} the state
     67      */
     68     public RegisterSpecSet getLocals() {
     69         return locals;
     70     }
     71 
     72     /** {@inheritDoc} */
     73     @Override
     74     protected String argString() {
     75         return locals.toString();
     76     }
     77 
     78     /** {@inheritDoc} */
     79     @Override
     80     protected String listingString0(boolean noteIndices) {
     81         int sz = locals.size();
     82         int max = locals.getMaxSize();
     83         StringBuffer sb = new StringBuffer(100 + sz * 40);
     84 
     85         sb.append("local-snapshot");
     86 
     87         for (int i = 0; i < max; i++) {
     88             RegisterSpec spec = locals.get(i);
     89             if (spec != null) {
     90                 sb.append("\n  ");
     91                 sb.append(LocalStart.localString(spec));
     92             }
     93         }
     94 
     95         return sb.toString();
     96     }
     97 
     98     /** {@inheritDoc} */
     99     @Override
    100     public DalvInsn withMapper(RegisterMapper mapper) {
    101       return new LocalSnapshot(getPosition(), mapper.map(locals));
    102     }
    103 }
    104