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      1 /*
      2  * Copyright (C) 2011 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 package com.android.tradefed.result;
     17 
     18 import com.android.tradefed.log.LogUtil.CLog;
     19 import com.android.tradefed.util.FileUtil;
     20 
     21 import java.io.File;
     22 import java.io.FileInputStream;
     23 import java.io.IOException;
     24 import java.io.InputStream;
     25 
     26 /**
     27  * A File-backed InputStreamSource.  Creates a snapshot of original {@link InputStream} contents to
     28  * ensure that {@link #createInputStream()} will return identically-behaving {@link InputStream}s as
     29  * required.
     30  */
     31 public class SnapshotInputStreamSource implements InputStreamSource {
     32     private File mBackingFile;
     33     private boolean mIsCancelled = false;
     34 
     35     /** Constructor for a file-backed {@link InputStreamSource} */
     36     public SnapshotInputStreamSource(String name, InputStream stream) {
     37         if (stream == null) {
     38             throw new NullPointerException();
     39         }
     40 
     41         try {
     42             mBackingFile = createBackingFile(name, stream);
     43         } catch (IOException e) {
     44             // Log an error and invalidate ourself
     45             CLog.e("Received IOException while trying to wrap a stream");
     46             CLog.e(e);
     47             close();
     48         }
     49     }
     50 
     51     /**
     52      * Create the backing file and fill it with the contents of {@code stream}.
     53      *
     54      * <p>Exposed for unit testing
     55      */
     56     File createBackingFile(String name, InputStream stream) throws IOException {
     57         File backingFile =
     58                 FileUtil.createTempFile(name + "_" + this.getClass().getSimpleName() + "_", ".txt");
     59         FileUtil.writeToFile(stream, backingFile);
     60         return backingFile;
     61     }
     62 
     63     /**
     64      * {@inheritDoc}
     65      */
     66     @Override
     67     public synchronized InputStream createInputStream() {
     68         if (mIsCancelled) {
     69             return null;
     70         }
     71 
     72         try {
     73             return new FileInputStream(mBackingFile);
     74         } catch (IOException e) {
     75             return null;
     76         }
     77     }
     78 
     79     /** {@inheritDoc} */
     80     @Override
     81     public synchronized void close() {
     82         mIsCancelled = true;
     83         FileUtil.deleteFile(mBackingFile);
     84         mBackingFile = null;
     85     }
     86 
     87     /**
     88      * {@inheritDoc}
     89      */
     90     @Override
     91     public long size() {
     92         return mBackingFile.length();
     93     }
     94 }
     95 
     96