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      1 /*
      2  * Copyright (C) 2010 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.email.service;
     18 
     19 import com.android.email.FixedLengthInputStream;
     20 import com.android.email.mail.store.imap.ImapResponse;
     21 import com.android.email.mail.store.imap.ImapResponseParser;
     22 import com.android.email.mail.store.imap.ImapString;
     23 import com.android.emailcommon.Logging;
     24 import com.android.emailcommon.TempDirectory;
     25 import com.android.emailcommon.utility.Utility;
     26 import com.android.mail.utils.LogUtils;
     27 
     28 import org.apache.commons.io.IOUtils;
     29 
     30 import java.io.ByteArrayInputStream;
     31 import java.io.File;
     32 import java.io.FileInputStream;
     33 import java.io.FileNotFoundException;
     34 import java.io.FileOutputStream;
     35 import java.io.IOException;
     36 import java.io.InputStream;
     37 import java.io.OutputStream;
     38 
     39 /**
     40  * Subclass of {@link ImapString} used for literals backed by a temp file.
     41  */
     42 public class ImapTempFileLiteral extends ImapString {
     43     /* package for test */ final File mFile;
     44 
     45     /** Size is purely for toString() */
     46     private final int mSize;
     47 
     48     /* package */  ImapTempFileLiteral(FixedLengthInputStream stream) throws IOException {
     49         mSize = stream.getLength();
     50         mFile = File.createTempFile("imap", ".tmp", TempDirectory.getTempDirectory());
     51 
     52         // Unfortunately, we can't really use deleteOnExit(), because temp filenames are random
     53         // so it'd simply cause a memory leak.
     54         // deleteOnExit() simply adds filenames to a static list and the list will never shrink.
     55         // mFile.deleteOnExit();
     56         OutputStream out = new FileOutputStream(mFile);
     57         IOUtils.copy(stream, out);
     58         out.close();
     59     }
     60 
     61     /**
     62      * Make sure we delete the temp file.
     63      *
     64      * We should always be calling {@link ImapResponse#destroy()}, but it's here as a last resort.
     65      */
     66     @Override
     67     protected void finalize() throws Throwable {
     68         try {
     69             destroy();
     70         } finally {
     71             super.finalize();
     72         }
     73     }
     74 
     75     @Override
     76     public InputStream getAsStream() {
     77         checkNotDestroyed();
     78         try {
     79             return new FileInputStream(mFile);
     80         } catch (FileNotFoundException e) {
     81             // It's probably possible if we're low on storage and the system clears the cache dir.
     82             LogUtils.w(Logging.LOG_TAG, "ImapTempFileLiteral: Temp file not found");
     83 
     84             // Return 0 byte stream as a dummy...
     85             return new ByteArrayInputStream(new byte[0]);
     86         }
     87     }
     88 
     89     @Override
     90     public String getString() {
     91         checkNotDestroyed();
     92         try {
     93             byte[] bytes = IOUtils.toByteArray(getAsStream());
     94             // Prevent crash from OOM; we've seen this, but only rarely and not reproducibly
     95             if (bytes.length > ImapResponseParser.LITERAL_KEEP_IN_MEMORY_THRESHOLD) {
     96                 throw new IOException();
     97             }
     98             return Utility.fromAscii(bytes);
     99         } catch (IOException e) {
    100             LogUtils.w(Logging.LOG_TAG, "ImapTempFileLiteral: Error while reading temp file", e);
    101             return "";
    102         }
    103     }
    104 
    105     @Override
    106     public void destroy() {
    107         try {
    108             if (!isDestroyed() && mFile.exists()) {
    109                 mFile.delete();
    110             }
    111         } catch (RuntimeException re) {
    112             // Just log and ignore.
    113             LogUtils.w(Logging.LOG_TAG, "Failed to remove temp file: " + re.getMessage());
    114         }
    115         super.destroy();
    116     }
    117 
    118     @Override
    119     public String toString() {
    120         return String.format("{%d byte literal(file)}", mSize);
    121     }
    122 
    123     public boolean tempFileExistsForTest() {
    124         return mFile.exists();
    125     }
    126 }
    127