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
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
|
use sqlx::{sqlite::Sqlite, SqliteConnection, Transaction};
use crate::{
channel::{Channel, History, Id},
clock::DateTime,
event::{Instant, ResumePoint, Sequence},
};
pub trait Provider {
fn channels(&mut self) -> Channels;
}
impl<'c> Provider for Transaction<'c, Sqlite> {
fn channels(&mut self) -> Channels {
Channels(self)
}
}
pub struct Channels<'t>(&'t mut SqliteConnection);
impl<'c> Channels<'c> {
pub async fn create(&mut self, name: &str, created: &Instant) -> Result<History, sqlx::Error> {
let id = Id::generate();
let channel = sqlx::query!(
r#"
insert
into channel (id, name, created_at, created_sequence)
values ($1, $2, $3, $4)
returning
id as "id: Id",
name as "name!", -- known non-null as we just set it
created_at as "created_at: DateTime",
created_sequence as "created_sequence: Sequence"
"#,
id,
name,
created.at,
created.sequence,
)
.map(|row| History {
channel: Channel {
id: row.id,
name: row.name,
deleted_at: None,
},
created: Instant::new(row.created_at, row.created_sequence),
deleted: None,
})
.fetch_one(&mut *self.0)
.await?;
Ok(channel)
}
pub async fn by_id(&mut self, channel: &Id) -> Result<History, sqlx::Error> {
let channel = sqlx::query!(
r#"
select
id as "id: Id",
channel.name,
channel.created_at as "created_at: DateTime",
channel.created_sequence as "created_sequence: Sequence",
deleted.deleted_at as "deleted_at?: DateTime",
deleted.deleted_sequence as "deleted_sequence?: Sequence"
from channel
left join channel_deleted as deleted
using (id)
where id = $1
"#,
channel,
)
.map(|row| History {
channel: Channel {
id: row.id,
name: row.name.unwrap_or_default(),
deleted_at: row.deleted_at,
},
created: Instant::new(row.created_at, row.created_sequence),
deleted: Instant::optional(row.deleted_at, row.deleted_sequence),
})
.fetch_one(&mut *self.0)
.await?;
Ok(channel)
}
pub async fn all(&mut self, resume_at: ResumePoint) -> Result<Vec<History>, sqlx::Error> {
let channels = sqlx::query!(
r#"
select
id as "id: Id",
channel.name,
channel.created_at as "created_at: DateTime",
channel.created_sequence as "created_sequence: Sequence",
deleted.deleted_at as "deleted_at: DateTime",
deleted.deleted_sequence as "deleted_sequence: Sequence"
from channel
left join channel_deleted as deleted
using (id)
where coalesce(channel.created_sequence <= $1, true)
order by channel.name
"#,
resume_at,
)
.map(|row| History {
channel: Channel {
id: row.id,
name: row.name.unwrap_or_default(),
deleted_at: row.deleted_at,
},
created: Instant::new(row.created_at, row.created_sequence),
deleted: Instant::optional(row.deleted_at, row.deleted_sequence),
})
.fetch_all(&mut *self.0)
.await?;
Ok(channels)
}
pub async fn replay(
&mut self,
resume_at: Option<Sequence>,
) -> Result<Vec<History>, sqlx::Error> {
let channels = sqlx::query!(
r#"
select
id as "id: Id",
channel.name,
channel.created_at as "created_at: DateTime",
channel.created_sequence as "created_sequence: Sequence",
deleted.deleted_at as "deleted_at: DateTime",
deleted.deleted_sequence as "deleted_sequence: Sequence"
from channel
left join channel_deleted as deleted
using (id)
where coalesce(channel.created_sequence > $1, true)
"#,
resume_at,
)
.map(|row| History {
channel: Channel {
id: row.id,
name: row.name.unwrap_or_default(),
deleted_at: row.deleted_at,
},
created: Instant::new(row.created_at, row.created_sequence),
deleted: Instant::optional(row.deleted_at, row.deleted_sequence),
})
.fetch_all(&mut *self.0)
.await?;
Ok(channels)
}
pub async fn delete(
&mut self,
channel: &History,
deleted: &Instant,
) -> Result<History, sqlx::Error> {
let id = channel.id();
sqlx::query_scalar!(
r#"
insert into channel_deleted (id, deleted_at, deleted_sequence)
values ($1, $2, $3)
returning 1 as "deleted: bool"
"#,
id,
deleted.at,
deleted.sequence,
)
.fetch_one(&mut *self.0)
.await?;
// Small social responsibility hack here: when a channel is deleted, its name is
// retconned to have been the empty string. Someone reading the event stream
// afterwards, or looking at channels via the API, cannot retrieve the
// "deleted" channel's information by ignoring the deletion event.
//
// This also avoids the need for a separate name reservation table to ensure
// that live channels have unique names, since the `channel` table's name field
// is unique over non-null values.
sqlx::query_scalar!(
r#"
update channel
set name = null
where id = $1
returning 1 as "updated: bool"
"#,
id,
)
.fetch_one(&mut *self.0)
.await?;
let channel = self.by_id(id).await?;
Ok(channel)
}
pub async fn purge(&mut self, purge_at: &DateTime) -> Result<(), sqlx::Error> {
let channels = sqlx::query_scalar!(
r#"
with has_messages as (
select channel
from message
group by channel
)
delete from channel_deleted
where deleted_at < $1
and id not in has_messages
returning id as "id: Id"
"#,
purge_at,
)
.fetch_all(&mut *self.0)
.await?;
for channel in channels {
// Wanted: a way to batch these up into one query.
sqlx::query!(
r#"
delete from channel
where id = $1
"#,
channel,
)
.execute(&mut *self.0)
.await?;
}
Ok(())
}
pub async fn expired(&mut self, expired_at: &DateTime) -> Result<Vec<History>, sqlx::Error> {
let channels = sqlx::query!(
r#"
select
channel.id as "id: Id",
channel.name,
channel.created_at as "created_at: DateTime",
channel.created_sequence as "created_sequence: Sequence",
deleted.deleted_at as "deleted_at?: DateTime",
deleted.deleted_sequence as "deleted_sequence?: Sequence"
from channel
left join channel_deleted as deleted
using (id)
left join message
where channel.created_at < $1
and message.id is null
and deleted.id is null
"#,
expired_at,
)
.map(|row| History {
channel: Channel {
id: row.id,
name: row.name.unwrap_or_default(),
deleted_at: row.deleted_at,
},
created: Instant::new(row.created_at, row.created_sequence),
deleted: Instant::optional(row.deleted_at, row.deleted_sequence),
})
.fetch_all(&mut *self.0)
.await?;
Ok(channels)
}
}
|
