mysql_async 0.3.0

Tokio based asynchronous MySql client library.
Documentation 
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

// Copyright (c) 2016 Anatoly Ikorsky
//
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. All files in the project carrying such notice may not be copied,
// modified, or distributed except according to those terms.

use conn::Conn;
use conn::futures::Query;
use conn::futures::query_result::futures::DropResult;
use conn::futures::query_result::TextQueryResult;
use conn::futures::query_result::UnconsumedQueryResult;
use conn::transaction::IsolationLevel;
use conn::transaction::Transaction;
use either::*;
use errors::*;
use lib_futures::Async;
use lib_futures::Async::Ready;
use lib_futures::Failed;
use lib_futures::failed;
use lib_futures::Future;
use lib_futures::Poll;


steps! {
    StartTransaction {
        Failed(Failed<(), Error>),
        SetIsolationLevel(Query),
        DropSetIsolationLevel(DropResult<TextQueryResult>),
        SetReadOnly(Query),
        DropSetReadOnly(DropResult<TextQueryResult>),
        StartTransaction(Query),
        DropStartTransaction(DropResult<TextQueryResult>),
    }
}

/// Future that starts transaction and resolves to `Transaction`.
pub struct StartTransaction {
    step: Step,
    consistent_snapshot: bool,
    readonly: Option<bool>,
}

fn set_isolation_level(conn: Conn, isolation_level: Option<IsolationLevel>) -> Either<Step, Conn> {
    if let Some(isolation_level) = isolation_level {
        let query = conn.query(format!("SET TRANSACTION ISOLATION LEVEL {}", isolation_level));
        Left(Step::SetIsolationLevel(query))
    } else {
        Right(conn)
    }
}

fn start_trans(conn: Conn, consistent_snapshot: bool) -> Step {
    let query = if consistent_snapshot {
        conn.query("START TRANSACTION WITH CONSISTENT SNAPSHOT")
    } else {
        conn.query("START TRANSACTION")
    };
    Step::StartTransaction(query)
}

fn set_read_only(conn: Conn, readonly: Option<bool>) -> Either<Step, Conn> {
    if let Some(readonly) = readonly {
        let query = if readonly {
            conn.query("SET TRANSACTION READ ONLY")
        } else {
            conn.query("SET TRANSACTION READ WRITE")
        };
        Left(Step::SetReadOnly(query))
    } else {
        Right(conn)
    }
}

pub fn new(conn: Conn,
           consistent_snapshot: bool,
           isolation_level: Option<IsolationLevel>,
           readonly: Option<bool>)
           -> StartTransaction {
    if readonly.is_some() {
        if conn.version < (5, 6, 5) {
            return StartTransaction {
                step: Step::Failed(failed(ErrorKind::ReadOnlyTransNotSupported.into())),
                consistent_snapshot: false,
                readonly: None,
            };
        }
    }

    let step = set_isolation_level(conn, isolation_level).either(|step| step, |conn| {
        set_read_only(conn, readonly)
            .either(|step| step, |conn| start_trans(conn, consistent_snapshot))
    });

    StartTransaction {
        step: step,
        consistent_snapshot: consistent_snapshot,
        readonly: readonly,
    }
}

impl Future for StartTransaction {
    type Item = Transaction;
    type Error = Error;

    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
        match try_ready!(self.either_poll()) {
            Out::SetIsolationLevel(result) => {
                self.step = Step::DropSetIsolationLevel(result.drop_result());
                self.poll()
            },
            Out::DropSetIsolationLevel(conn) => {
                let step = set_read_only(conn, self.readonly).either(|step| step, |conn| {
                    start_trans(conn, self.consistent_snapshot)
                });
                self.step = step;
                self.poll()
            },
            Out::SetReadOnly(result) => {
                self.step = Step::DropSetReadOnly(result.drop_result());
                self.poll()
            },
            Out::DropSetReadOnly(conn) => {
                let step = start_trans(conn, self.consistent_snapshot);
                self.step = step;
                self.poll()
            },
            Out::StartTransaction(result) => {
                self.step = Step::DropStartTransaction(result.drop_result());
                self.poll()
            },
            Out::DropStartTransaction(conn) => Ok(Ready(Transaction::new(conn))),
            Out::Failed(_) => unreachable!(),
        }
    }
}