ImapTempFileLiteral.java revision bc47398187c6ffd132435e51d8d61e6ec79a79db
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 17package com.android.email.mail.store.imap; 18 19import com.android.email.FixedLengthInputStream; 20import com.android.emailcommon.Logging; 21import com.android.emailcommon.TempDirectory; 22import com.android.emailcommon.utility.Utility; 23 24import org.apache.commons.io.IOUtils; 25 26import android.util.Log; 27 28import java.io.ByteArrayInputStream; 29import java.io.File; 30import java.io.FileInputStream; 31import java.io.FileNotFoundException; 32import java.io.FileOutputStream; 33import java.io.IOException; 34import java.io.InputStream; 35import java.io.OutputStream; 36 37/** 38 * Subclass of {@link ImapString} used for literals backed by a temp file. 39 */ 40public class ImapTempFileLiteral extends ImapString { 41 /* package for test */ final File mFile; 42 43 /** Size is purely for toString() */ 44 private final int mSize; 45 46 /* package */ ImapTempFileLiteral(FixedLengthInputStream stream) throws IOException { 47 mSize = stream.getLength(); 48 mFile = File.createTempFile("imap", ".tmp", TempDirectory.getTempDirectory()); 49 50 // Unfortunately, we can't really use deleteOnExit(), because temp filenames are random 51 // so it'd simply cause a memory leak. 52 // deleteOnExit() simply adds filenames to a static list and the list will never shrink. 53 // mFile.deleteOnExit(); 54 OutputStream out = new FileOutputStream(mFile); 55 IOUtils.copy(stream, out); 56 out.close(); 57 } 58 59 /** 60 * Make sure we delete the temp file. 61 * 62 * We should always be calling {@link ImapResponse#destroy()}, but it's here as a last resort. 63 */ 64 @Override 65 protected void finalize() throws Throwable { 66 try { 67 destroy(); 68 } finally { 69 super.finalize(); 70 } 71 } 72 73 @Override 74 public InputStream getAsStream() { 75 checkNotDestroyed(); 76 try { 77 return new FileInputStream(mFile); 78 } catch (FileNotFoundException e) { 79 // It's probably possible if we're low on storage and the system clears the cache dir. 80 Log.w(Logging.LOG_TAG, "ImapTempFileLiteral: Temp file not found"); 81 82 // Return 0 byte stream as a dummy... 83 return new ByteArrayInputStream(new byte[0]); 84 } 85 } 86 87 @Override 88 public String getString() { 89 checkNotDestroyed(); 90 try { 91 return Utility.fromAscii(IOUtils.toByteArray(getAsStream())); 92 } catch (IOException e) { 93 Log.w(Logging.LOG_TAG, "ImapTempFileLiteral: Error while reading temp file"); 94 return ""; 95 } 96 } 97 98 @Override 99 public void destroy() { 100 try { 101 if (!isDestroyed() && mFile.exists()) { 102 mFile.delete(); 103 } 104 } catch (RuntimeException re) { 105 // Just log and ignore. 106 Log.w(Logging.LOG_TAG, "Failed to remove temp file: " + re.getMessage()); 107 } 108 super.destroy(); 109 } 110 111 @Override 112 public String toString() { 113 return String.format("{%d byte literal(file)}", mSize); 114 } 115 116 public boolean tempFileExistsForTest() { 117 return mFile.exists(); 118 } 119} 120