Daichi Hirono | f4e7fa8 | 2016-03-28 16:07:45 +0900 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 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.mtp; |
| 18 | |
| 19 | import android.content.Context; |
| 20 | import android.mtp.MtpObjectInfo; |
| 21 | import android.os.ParcelFileDescriptor; |
| 22 | import android.system.ErrnoException; |
| 23 | import android.system.Os; |
| 24 | import android.system.OsConstants; |
| 25 | |
| 26 | import com.android.internal.util.Preconditions; |
| 27 | |
| 28 | import java.io.File; |
| 29 | import java.io.IOException; |
| 30 | |
| 31 | class MtpFileWriter implements AutoCloseable { |
| 32 | final ParcelFileDescriptor mCacheFd; |
| 33 | final String mDocumentId; |
| 34 | boolean mDirty; |
| 35 | |
| 36 | MtpFileWriter(Context context, String documentId) throws IOException { |
| 37 | mDocumentId = documentId; |
| 38 | mDirty = false; |
| 39 | final File tempFile = File.createTempFile("mtp", "tmp", context.getCacheDir()); |
| 40 | mCacheFd = ParcelFileDescriptor.open( |
| 41 | tempFile, |
| 42 | ParcelFileDescriptor.MODE_READ_WRITE | |
| 43 | ParcelFileDescriptor.MODE_TRUNCATE | |
| 44 | ParcelFileDescriptor.MODE_CREATE); |
| 45 | tempFile.delete(); |
| 46 | } |
| 47 | |
| 48 | String getDocumentId() { |
| 49 | return mDocumentId; |
| 50 | } |
| 51 | |
| 52 | int write(long offset, int size, byte[] bytes) throws IOException, ErrnoException { |
| 53 | Preconditions.checkArgumentNonnegative(offset, "offset"); |
| 54 | Preconditions.checkArgumentNonnegative(size, "size"); |
| 55 | Preconditions.checkArgument(size <= bytes.length); |
| 56 | if (size == 0) { |
| 57 | return 0; |
| 58 | } |
| 59 | mDirty = true; |
| 60 | Os.lseek(mCacheFd.getFileDescriptor(), offset, OsConstants.SEEK_SET); |
| 61 | return Os.write(mCacheFd.getFileDescriptor(), bytes, 0, size); |
| 62 | } |
| 63 | |
| 64 | void flush(MtpManager manager, MtpDatabase database, int[] operationsSupported) |
| 65 | throws IOException, ErrnoException { |
| 66 | // Skip unnecessary flush. |
| 67 | if (!mDirty) { |
| 68 | return; |
| 69 | } |
| 70 | |
| 71 | // Get the placeholder object info. |
| 72 | final Identifier identifier = database.createIdentifier(mDocumentId); |
| 73 | final MtpObjectInfo placeholderObjectInfo = |
| 74 | manager.getObjectInfo(identifier.mDeviceId, identifier.mObjectHandle); |
| 75 | |
| 76 | // Delete the target object info if it already exists (as a placeholder). |
| 77 | manager.deleteDocument(identifier.mDeviceId, identifier.mObjectHandle); |
| 78 | |
| 79 | // Create the target object info with a correct file size and upload the file. |
| 80 | final long size = Os.lseek(mCacheFd.getFileDescriptor(), 0, OsConstants.SEEK_END); |
| 81 | final MtpObjectInfo targetObjectInfo = new MtpObjectInfo.Builder(placeholderObjectInfo) |
| 82 | .setCompressedSize(size) |
| 83 | .build(); |
| 84 | |
| 85 | Os.lseek(mCacheFd.getFileDescriptor(), 0, OsConstants.SEEK_SET); |
| 86 | final int newObjectHandle = manager.createDocument( |
| 87 | identifier.mDeviceId, targetObjectInfo, mCacheFd); |
| 88 | |
| 89 | final MtpObjectInfo newObjectInfo = manager.getObjectInfo( |
| 90 | identifier.mDeviceId, newObjectHandle); |
| 91 | final Identifier parentIdentifier = |
| 92 | database.getParentIdentifier(identifier.mDocumentId); |
| 93 | database.updateObject( |
| 94 | identifier.mDocumentId, |
| 95 | identifier.mDeviceId, |
| 96 | parentIdentifier.mDocumentId, |
| 97 | operationsSupported, |
| 98 | newObjectInfo, |
| 99 | size); |
| 100 | |
| 101 | mDirty = false; |
| 102 | } |
| 103 | |
| 104 | @Override |
| 105 | public void close() throws IOException { |
| 106 | mCacheFd.close(); |
| 107 | } |
| 108 | } |