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

#![deny(warnings)]
//! # Sqlite support for the `r2d2` connection pool.
//!
//! Library crate: [r2d2-sqlite](https://crates.io/crates/r2d2-sqlite/)
//!
//! Integrated with: [r2d2](https://crates.io/crates/r2d2)
//! and [rusqlite](https://crates.io/crates/rusqlite)
//!
//! ## Example
//!
//! ```rust,no_run
//! extern crate r2d2;
//! extern crate r2d2_sqlite;
//! extern crate rusqlite;
//!
//! use std::thread;
//! use r2d2_sqlite::SqliteConnectionManager;
//!
//! fn main() {
//!     let manager = SqliteConnectionManager::file("file.db");
//!     let pool = r2d2::Pool::new(manager).unwrap();
//!
//!     for i in 0..10i32 {
//!         let pool = pool.clone();
//!         thread::spawn(move || {
//!             let conn = pool.get().unwrap();
//!             conn.execute("INSERT INTO foo (bar) VALUES (?)", &[&i]).unwrap();
//!         });
//!     }
//! }
//! ```
extern crate r2d2;
extern crate rusqlite;

use rusqlite::{Connection, Error, OpenFlags};
use std::fmt;
use std::path::{Path, PathBuf};

#[derive(Debug)]
enum Source {
    File(PathBuf),
    Memory,
}

type InitFn = Fn(&Connection) -> Result<(), rusqlite::Error> + Send + Sync + 'static;

/// An `r2d2::ManageConnection` for `rusqlite::Connection`s.
pub struct SqliteConnectionManager {
    source: Source,
    flags: OpenFlags,
    init: Option<Box<InitFn>>,
}

impl fmt::Debug for SqliteConnectionManager {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let mut builder = f.debug_struct("SqliteConnectionManager");
        let _ = builder.field("source", &self.source);
        let _ = builder.field("flags", &self.source);
        let _ = builder.field("init", &self.init.as_ref().map(|_| "InitFn"));
        builder.finish()
    }
}

impl SqliteConnectionManager {
    /// Creates a new `SqliteConnectionManager` from file.
    ///
    /// See `rusqlite::Connection::open`
    pub fn file<P: AsRef<Path>>(path: P) -> Self {
        Self {
            source: Source::File(path.as_ref().to_path_buf()),
            flags: OpenFlags::default(),
            init: None,
        }
    }

    /// Creates a new `SqliteConnectionManager` from memory.
    pub fn memory() -> Self {
        Self {
            source: Source::Memory,
            flags: OpenFlags::default(),
            init: None,
        }
    }

    /// Converts `SqliteConnectionManager` into one that sets OpenFlags upon
    /// connection creation.
    ///
    /// See `rustqlite::OpenFlags` for a list of available flags.
    pub fn with_flags(self, flags: OpenFlags) -> Self {
        Self { flags, ..self }
    }

    /// Converts `SqliteConnectionManager` into one that calls an initialization
    /// function upon connection creation. Could be used to set PRAGMAs, for
    /// example.
    ///
    /// ### Example
    ///
    /// Make a `SqliteConnectionManager` that sets the `foreign_keys` pragma to
    /// true for every connection.
    ///
    /// ```rust,no_run
    /// # use r2d2_sqlite::{SqliteConnectionManager};
    /// let manager = SqliteConnectionManager::file("app.db")
    ///     .with_init(|c| c.execute_batch("PRAGMA foreign_keys=1;"));
    /// ```
    pub fn with_init<F>(self, init: F) -> Self
    where
        F: Fn(&Connection) -> Result<(), rusqlite::Error> + Send + Sync + 'static,
    {
        let init: Option<Box<InitFn>> = Some(Box::new(init));
        Self { init, ..self }
    }
}

impl r2d2::ManageConnection for SqliteConnectionManager {
    type Connection = Connection;
    type Error = rusqlite::Error;

    fn connect(&self) -> Result<Connection, Error> {
        match self.source {
            Source::File(ref path) => Connection::open_with_flags(path, self.flags),
            Source::Memory => Connection::open_in_memory_with_flags(self.flags),
        }.map_err(Into::into)
        .and_then(|c| match self.init {
            None => Ok(c),
            Some(ref init) => init(&c).map(|_| c),
        })
    }

    fn is_valid(&self, conn: &mut Connection) -> Result<(), Error> {
        conn.execute_batch("").map_err(Into::into)
    }

    fn has_broken(&self, _: &mut Connection) -> bool {
        false
    }
}