David Chen | 1481fe1 | 2017-10-16 13:16:34 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 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 android.os; |
| 17 | |
| 18 | import java.io.ByteArrayOutputStream; |
| 19 | import java.nio.charset.StandardCharsets; |
| 20 | |
| 21 | /** |
| 22 | * Wrapper class for sending data from Android OS to StatsD. |
| 23 | * |
| 24 | * @hide |
| 25 | */ |
| 26 | public final class StatsLogEventWrapper implements Parcelable { |
| 27 | private ByteArrayOutputStream mStorage = new ByteArrayOutputStream(); |
| 28 | |
| 29 | // Below are constants copied from log/log.h |
| 30 | private static final int EVENT_TYPE_INT = 0; /* int32_t */ |
| 31 | private static final int EVENT_TYPE_LONG = 1; /* int64_t */ |
| 32 | private static final int EVENT_TYPE_STRING = 2; |
| 33 | private static final int EVENT_TYPE_LIST = 3; |
| 34 | private static final int EVENT_TYPE_FLOAT = 4; |
| 35 | |
Chenjie Yu | 6842a8c | 2017-12-05 22:34:34 -0800 | [diff] [blame] | 36 | // Keep this in sync with system/core/logcat/event.logtags |
| 37 | private static final int STATS_BUFFER_TAG_ID = 1937006964; |
David Chen | 1481fe1 | 2017-10-16 13:16:34 -0700 | [diff] [blame] | 38 | /** |
| 39 | * Creates a log_event that is binary-encoded as implemented in |
| 40 | * system/core/liblog/log_event_list.c; this allows us to use the same parsing logic in statsd |
| 41 | * for pushed and pulled data. The write* methods must be called in the same order as their |
| 42 | * field number. There is no checking that the correct number of write* methods is called. |
| 43 | * We also write an END_LIST character before beginning to write to parcel, but this END_LIST |
| 44 | * may be unnecessary. |
| 45 | * |
| 46 | * @param tag The integer representing the tag for this event. |
| 47 | * @param fields The number of fields specified in this event. |
| 48 | */ |
Yangster-mac | c552b35 | 2018-02-22 10:00:45 -0800 | [diff] [blame] | 49 | public StatsLogEventWrapper(long elapsedNanos, int tag, int fields) { |
David Chen | 1481fe1 | 2017-10-16 13:16:34 -0700 | [diff] [blame] | 50 | // Write four bytes from tag, starting with least-significant bit. |
Chenjie Yu | 6842a8c | 2017-12-05 22:34:34 -0800 | [diff] [blame] | 51 | // For pulled data, this tag number is not really used. We use the same tag number as |
| 52 | // pushed ones to be consistent. |
| 53 | write4Bytes(STATS_BUFFER_TAG_ID); |
David Chen | 1481fe1 | 2017-10-16 13:16:34 -0700 | [diff] [blame] | 54 | mStorage.write(EVENT_TYPE_LIST); // This is required to start the log entry. |
Yangster-mac | c552b35 | 2018-02-22 10:00:45 -0800 | [diff] [blame] | 55 | mStorage.write(fields + 2); // Indicate number of elements in this list. +1 for the tag |
| 56 | // The first element is the elapsed realtime. |
| 57 | writeLong(elapsedNanos); |
| 58 | // The second element is the real atom tag number |
| 59 | writeInt(tag); |
David Chen | 1481fe1 | 2017-10-16 13:16:34 -0700 | [diff] [blame] | 60 | } |
| 61 | |
| 62 | /** |
| 63 | * Boilerplate for Parcel. |
| 64 | */ |
| 65 | public static final Parcelable.Creator<StatsLogEventWrapper> CREATOR = new |
| 66 | Parcelable.Creator<StatsLogEventWrapper>() { |
| 67 | public StatsLogEventWrapper createFromParcel(Parcel in) { |
| 68 | return new StatsLogEventWrapper(in); |
| 69 | } |
| 70 | |
| 71 | public StatsLogEventWrapper[] newArray(int size) { |
| 72 | return new StatsLogEventWrapper[size]; |
| 73 | } |
| 74 | }; |
| 75 | |
| 76 | private void write4Bytes(int val) { |
| 77 | mStorage.write(val); |
| 78 | mStorage.write(val >>> 8); |
| 79 | mStorage.write(val >>> 16); |
| 80 | mStorage.write(val >>> 24); |
| 81 | } |
| 82 | |
| 83 | private void write8Bytes(long val) { |
| 84 | write4Bytes((int) (val & 0xFFFFFFFF)); // keep the lowe 32-bits |
| 85 | write4Bytes((int) (val >>> 32)); // Write the high 32-bits. |
| 86 | } |
| 87 | |
| 88 | /** |
| 89 | * Adds 32-bit integer to output. |
| 90 | */ |
| 91 | public void writeInt(int val) { |
| 92 | mStorage.write(EVENT_TYPE_INT); |
| 93 | write4Bytes(val); |
| 94 | } |
| 95 | |
| 96 | /** |
| 97 | * Adds 64-bit long to output. |
| 98 | */ |
| 99 | public void writeLong(long val) { |
| 100 | mStorage.write(EVENT_TYPE_LONG); |
| 101 | write8Bytes(val); |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Adds a 4-byte floating point value to output. |
| 106 | */ |
| 107 | public void writeFloat(float val) { |
| 108 | int v = Float.floatToIntBits(val); |
| 109 | mStorage.write(EVENT_TYPE_FLOAT); |
| 110 | write4Bytes(v); |
| 111 | } |
| 112 | |
| 113 | /** |
| 114 | * Adds a string to the output. |
| 115 | */ |
| 116 | public void writeString(String val) { |
| 117 | mStorage.write(EVENT_TYPE_STRING); |
| 118 | write4Bytes(val.length()); |
| 119 | byte[] bytes = val.getBytes(StandardCharsets.UTF_8); |
| 120 | mStorage.write(bytes, 0, bytes.length); |
| 121 | } |
| 122 | |
| 123 | private StatsLogEventWrapper(Parcel in) { |
| 124 | readFromParcel(in); |
| 125 | } |
| 126 | |
| 127 | /** |
| 128 | * Writes the stored fields to a byte array. Will first write a new-line character to denote |
| 129 | * END_LIST before writing contents to byte array. |
| 130 | */ |
| 131 | public void writeToParcel(Parcel out, int flags) { |
| 132 | mStorage.write(10); // new-line character is same as END_LIST |
| 133 | out.writeByteArray(mStorage.toByteArray()); |
| 134 | } |
| 135 | |
| 136 | /** |
| 137 | * Not implemented. |
| 138 | */ |
| 139 | public void readFromParcel(Parcel in) { |
| 140 | // Not needed since this java class is for sending to statsd only. |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * Boilerplate for Parcel. |
| 145 | */ |
| 146 | public int describeContents() { |
| 147 | return 0; |
| 148 | } |
| 149 | } |