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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
use format;
use snap::Builder;
use snap::Delta;
use snap::Snap;
use snap;
use std::collections::VecDeque;
use warn::Warn;
use warn::wrap;
// TODO: Separate server storage from client storage.
// TODO: Delete snapshots over time.
#[derive(Clone)]
struct StoredSnap {
snap: Snap,
tick: i32,
}
const MAX_STORED_SNAPSHOT: usize = 100;
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct UnknownSnap;
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct WeirdNegativeDeltaTick;
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum Error {
OldDelta,
UnknownSnap,
InvalidCrc,
Unpack(snap::Error),
}
impl From<snap::Error> for Error {
fn from(err: snap::Error) -> Error {
Error::Unpack(err)
}
}
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum Warning {
WeirdNegativeDeltaTick,
Unpack(format::Warning),
}
impl From<format::Warning> for Warning {
fn from(w: format::Warning) -> Warning {
Warning::Unpack(w)
}
}
#[derive(Clone, Default)]
pub struct Storage {
/// Queue that stores received snaps.
///
/// The newest elements are in the front.
snaps: VecDeque<StoredSnap>,
free: Vec<Snap>,
ack_tick: Option<i32>,
delta: Delta,
delta_tick: Option<i32>,
}
impl Storage {
pub fn new() -> Storage {
Default::default()
}
pub fn reset(&mut self) {
let self_free = &mut self.free;
// FIXME: Replace with something like `exhaust`.
self.snaps.drain(..).map(|s| self_free.push(s.snap)).count();
self.ack_tick = None;
}
pub fn ack_tick(&self) -> Option<i32> {
self.ack_tick
}
pub fn add_delta<W>(&mut self, warn: &mut W, crc: Option<i32>, delta_tick: i32, tick: i32, delta: &Delta)
-> Result<&Snap, Error>
where W: Warn<Warning>,
{
if self.snaps.front().map(|s| s.tick).unwrap_or(-1) >= tick {
return Err(Error::OldDelta);
}
{
let empty = Snap::empty();
let delta_snap;
if delta_tick >= 0 {
if let Some(i) = self.snaps.iter().position(|s| s.tick < delta_tick) {
let self_free = &mut self.free;
// FIXME: Replace with something like `exhaust`.
self.snaps.drain(i..).map(|s| self_free.push(s.snap)).count();
}
if let Some(d) = self.snaps.back() {
if d.tick == delta_tick {
delta_snap = &d.snap;
} else {
self.ack_tick = None;
return Err(Error::UnknownSnap);
}
} else {
self.ack_tick = None;
return Err(Error::UnknownSnap);
}
} else {
delta_snap = ∅
if delta_tick != -1 {
warn.warn(Warning::WeirdNegativeDeltaTick);
}
}
if self.free.is_empty() {
self.free.push(Snap::empty());
}
let new_snap: &mut Snap = self.free.last_mut().unwrap();
new_snap.read_with_delta(wrap(warn), delta_snap, delta)?;
if crc.map(|crc| crc != new_snap.crc()).unwrap_or(false) {
self.ack_tick = None;
return Err(Error::InvalidCrc);
}
self.ack_tick = Some(tick);
}
self.snaps.push_front(StoredSnap {
tick: tick,
snap: self.free.pop().unwrap(),
});
if self.snaps.len() > MAX_STORED_SNAPSHOT {
self.free.push(self.snaps.pop_back().unwrap().snap);
}
Ok(&self.snaps.front().unwrap().snap)
}
pub fn new_builder(&mut self) -> Builder {
self.free.pop().unwrap_or_default().recycle()
}
pub fn set_delta_tick<W>(&mut self, warn: &mut W, tick: i32)
-> Result<(), UnknownSnap>
where W: Warn<WeirdNegativeDeltaTick>,
{
if tick < 0 {
if tick != -1 {
warn.warn(WeirdNegativeDeltaTick);
}
self.delta_tick = None;
return Ok(());
}
if let Some(i) = self.snaps.iter().position(|s| s.tick < tick) {
let self_free = &mut self.free;
// FIXME: Replace with something like `exhaust`.
self.snaps.drain(i..).map(|s| self_free.push(s.snap)).count();
}
if !self.snaps.back().map(|s| s.tick == tick).unwrap_or(false) {
self.delta_tick = None;
return Err(UnknownSnap);
}
self.delta_tick = Some(tick);
Ok(())
}
pub fn delta_tick(&self) -> Option<i32> {
self.delta_tick
}
pub fn add_snap(&mut self, tick: i32, snap: Snap) -> &Delta {
self.snaps.push_front(StoredSnap {
snap: snap,
tick: tick,
});
let tmp;
let delta_snap = if self.delta_tick.is_some() {
&self.snaps.back().unwrap().snap
} else {
tmp = Snap::empty();
&tmp
};
self.delta.create(delta_snap, &self.snaps.front().unwrap().snap);
&self.delta
}
}
|
