1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
/*
* Copyright (C) 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "SerializedLogChunk.h"
#include <android-base/logging.h>
#include "CompressionEngine.h"
SerializedLogChunk::~SerializedLogChunk() {
CHECK_EQ(reader_ref_count_, 0U);
}
void SerializedLogChunk::Compress() {
if (compressed_log_.empty()) {
CompressionEngine::GetInstance().Compress({contents_.data(), write_offset_},
compressed_log_);
LOG(INFO) << "Compressed Log, buffer max size: " << contents_.size()
<< " size used: " << write_offset_
<< " compressed size: " << compressed_log_.size();
}
contents_.resize(0);
}
// TODO: Develop a better reference counting strategy to guard against the case where the writer is
// much faster than the reader, and we needlessly compess / decompress the logs.
void SerializedLogChunk::IncReaderRefCount() {
if (++reader_ref_count_ != 1 || writer_active_) {
return;
}
CompressionEngine::GetInstance().Decompress(compressed_log_, contents_, write_offset_);
}
void SerializedLogChunk::DecReaderRefCount(bool compress) {
CHECK_NE(reader_ref_count_, 0U);
if (--reader_ref_count_ != 0) {
return;
}
if (compress && !writer_active_) {
Compress();
}
}
bool SerializedLogChunk::ClearUidLogs(uid_t uid, log_id_t log_id, LogStatistics* stats) {
CHECK_EQ(reader_ref_count_, 0U);
if (write_offset_ == 0) {
return true;
}
IncReaderRefCount();
int read_offset = 0;
int new_write_offset = 0;
while (read_offset < write_offset_) {
const auto* entry = log_entry(read_offset);
if (entry->uid() == uid) {
read_offset += entry->total_len();
if (stats != nullptr) {
stats->Subtract(entry->ToLogStatisticsElement(log_id));
}
continue;
}
size_t entry_total_len = entry->total_len();
if (read_offset != new_write_offset) {
memmove(contents_.data() + new_write_offset, contents_.data() + read_offset,
entry_total_len);
}
read_offset += entry_total_len;
new_write_offset += entry_total_len;
}
if (new_write_offset == 0) {
DecReaderRefCount(false);
return true;
}
// Clear the old compressed logs and set write_offset_ appropriately for DecReaderRefCount()
// to compress the new partially cleared log.
if (new_write_offset != write_offset_) {
compressed_log_.clear();
write_offset_ = new_write_offset;
}
DecReaderRefCount(true);
return false;
}
bool SerializedLogChunk::CanLog(size_t len) {
return write_offset_ + len <= contents_.size();
}
SerializedLogEntry* SerializedLogChunk::Log(uint64_t sequence, log_time realtime, uid_t uid,
pid_t pid, pid_t tid, const char* msg, uint16_t len) {
auto new_log_address = contents_.data() + write_offset_;
auto* entry = new (new_log_address) SerializedLogEntry(uid, pid, tid, sequence, realtime, len);
memcpy(entry->msg(), msg, len);
write_offset_ += entry->total_len();
highest_sequence_number_ = sequence;
return entry;
}
|
