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
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
/*
* 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 "SerializedFlushToState.h"
#include <android-base/logging.h>
SerializedFlushToState::SerializedFlushToState(uint64_t start, LogMask log_mask)
: FlushToState(start, log_mask) {
log_id_for_each(i) {
if (((1 << i) & log_mask) == 0) {
continue;
}
logs_needed_from_next_position_[i] = true;
}
}
SerializedFlushToState::~SerializedFlushToState() {
log_id_for_each(i) {
if (log_positions_[i]) {
log_positions_[i]->buffer_it->DecReaderRefCount(true);
}
}
}
void SerializedFlushToState::CreateLogPosition(log_id_t log_id) {
CHECK(!logs_[log_id].empty());
LogPosition log_position;
auto it = logs_[log_id].begin();
while (it != logs_[log_id].end() && start() > it->highest_sequence_number()) {
++it;
}
if (it == logs_[log_id].end()) {
--it;
}
it->IncReaderRefCount();
log_position.buffer_it = it;
// Find the offset of the first log with sequence number >= start().
int read_offset = 0;
while (read_offset < it->write_offset()) {
const auto* entry = it->log_entry(read_offset);
if (entry->sequence() >= start()) {
break;
}
read_offset += entry->total_len();
}
log_position.read_offset = read_offset;
log_positions_[log_id].emplace(std::move(log_position));
}
void SerializedFlushToState::AddMinHeapEntry(log_id_t log_id) {
auto& buffer_it = log_positions_[log_id]->buffer_it;
auto read_offset = log_positions_[log_id]->read_offset;
// If there is another log to read in this buffer, add it to the min heap.
if (read_offset < buffer_it->write_offset()) {
auto* entry = buffer_it->log_entry(read_offset);
min_heap_.emplace(log_id, entry);
} else if (read_offset == buffer_it->write_offset()) {
// If there are no more logs to read in this buffer and it's the last buffer, then
// set logs_needed_from_next_position_ to wait until more logs get logged.
if (buffer_it == std::prev(logs_[log_id].end())) {
logs_needed_from_next_position_[log_id] = true;
} else {
// Otherwise, if there is another buffer piece, move to that and do the same check.
buffer_it->DecReaderRefCount(true);
++buffer_it;
buffer_it->IncReaderRefCount();
log_positions_[log_id]->read_offset = 0;
if (buffer_it->write_offset() == 0) {
logs_needed_from_next_position_[log_id] = true;
} else {
auto* entry = buffer_it->log_entry(0);
min_heap_.emplace(log_id, entry);
}
}
} else {
// read_offset > buffer_it->write_offset() should never happen.
CHECK(false);
}
}
void SerializedFlushToState::CheckForNewLogs() {
log_id_for_each(i) {
if (!logs_needed_from_next_position_[i]) {
continue;
}
if (!log_positions_[i]) {
if (logs_[i].empty()) {
continue;
}
CreateLogPosition(i);
}
logs_needed_from_next_position_[i] = false;
// If it wasn't possible to insert, logs_needed_from_next_position will be set back to true.
AddMinHeapEntry(i);
}
}
MinHeapElement SerializedFlushToState::PopNextUnreadLog() {
auto top = min_heap_.top();
min_heap_.pop();
auto* entry = top.entry;
auto log_id = top.log_id;
log_positions_[log_id]->read_offset += entry->total_len();
AddMinHeapEntry(log_id);
return top;
}
void SerializedFlushToState::Prune(log_id_t log_id,
const std::list<SerializedLogChunk>::iterator& buffer_it) {
// If we don't have a position for this log or if we're not referencing buffer_it, ignore.
if (!log_positions_[log_id].has_value() || log_positions_[log_id]->buffer_it != buffer_it) {
return;
}
// // Decrease the ref count since we're deleting our reference.
buffer_it->DecReaderRefCount(false);
// Delete in the reference.
log_positions_[log_id].reset();
// Remove the MinHeapElement referencing log_id, if it exists, but retain the others.
std::vector<MinHeapElement> old_elements;
while (!min_heap_.empty()) {
auto& element = min_heap_.top();
if (element.log_id != log_id) {
old_elements.emplace_back(element);
}
min_heap_.pop();
}
for (auto&& element : old_elements) {
min_heap_.emplace(std::move(element));
}
// Finally set logs_needed_from_next_position_, so CheckForNewLogs() will re-create the
// log_position_ object during the next read.
logs_needed_from_next_position_[log_id] = true;
}
|
