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