rusqlite/src/types/mod.rs

//! Traits dealing with SQLite data types.
//!
//! SQLite uses a [dynamic type system](https://www.sqlite.org/datatype3.html). Implementations of
//! the `ToSql` and `FromSql` traits are provided for the basic types that SQLite provides methods
//! for:
//!
//! * Integers (`i32` and `i64`; SQLite uses `i64` internally, so getting an `i32` will truncate
//!   if the value is too large or too small).
//! * Reals (`f64`)
//! * Strings (`String` and `&str`)
//! * Blobs (`Vec<u8>` and `&[u8]`)
//!
//! Additionally, because it is such a common data type, implementations are provided for
//! `time::Timespec` that use a string for storage (using the same format string,
//! `"%Y-%m-%d %H:%M:%S"`, as SQLite's builtin
//! [datetime](https://www.sqlite.org/lang_datefunc.html) function.  Note that this storage
//! truncates timespecs to the nearest second. If you want different storage for timespecs, you can
//! use a newtype. For example, to store timespecs as `f64`s:
//!
//! ```rust
//! extern crate rusqlite;
//! extern crate time;
//!
//! use rusqlite::types::{FromSql, FromSqlResult, ValueRef, ToSql, ToSqlOutput};
//! use rusqlite::{Result};
//!
//! pub struct TimespecSql(pub time::Timespec);
//!
//! impl FromSql for TimespecSql {
//!     fn column_result(value: ValueRef) -> FromSqlResult<Self> {
//!         f64::column_result(value).map(|as_f64| {
//!             TimespecSql(time::Timespec{ sec: as_f64.trunc() as i64,
//!                                         nsec: (as_f64.fract() * 1.0e9) as i32 })
//!         })
//!     }
//! }
//!
//! impl ToSql for TimespecSql {
//!     fn to_sql(&self) -> Result<ToSqlOutput> {
//!         let TimespecSql(ts) = *self;
//!         let as_f64 = ts.sec as f64 + (ts.nsec as f64) / 1.0e9;
//!         Ok(as_f64.into())
//!     }
//! }
//!
//! # // Prevent this doc test from being wrapped in a `fn main()` so that it will compile.
//! # fn main() {}
//! ```
//!
//! `ToSql` and `FromSql` are also implemented for `Option<T>` where `T` implements `ToSql` or
//! `FromSql` for the cases where you want to know if a value was NULL (which gets translated to
//! `None`).

pub use self::from_sql::{FromSql, FromSqlError, FromSqlResult};
pub use self::to_sql::{ToSql, ToSqlOutput};
pub use self::value::Value;
pub use self::value_ref::ValueRef;

use std::fmt;

mod value;
mod value_ref;
mod from_sql;
mod to_sql;
mod time;
#[cfg(feature = "chrono")]
mod chrono;
#[cfg(feature = "serde_json")]
mod serde_json;

/// Empty struct that can be used to fill in a query parameter as `NULL`.
///
/// ## Example
///
/// ```rust,no_run
/// # extern crate libc;
/// # extern crate rusqlite;
/// # use rusqlite::{Connection, Result};
/// # use rusqlite::types::{Null};
/// # use libc::{c_int};
/// fn main() {
/// }
/// fn insert_null(conn: &Connection) -> Result<c_int> {
///     conn.execute("INSERT INTO people (name) VALUES (?)", &[&Null])
/// }
/// ```
#[derive(Copy,Clone)]
pub struct Null;

#[derive(Clone,Debug,PartialEq)]
pub enum Type {
    Null,
    Integer,
    Real,
    Text,
    Blob,
}

impl fmt::Display for Type {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            Type::Null => write!(f, "Null"),
            Type::Integer => write!(f, "Integer"),
            Type::Real => write!(f, "Real"),
            Type::Text => write!(f, "Text"),
            Type::Blob => write!(f, "Blob"),
        }
    }
}

#[cfg(test)]
mod test {
    extern crate time;

    use Connection;
    use Error;
    use libc::{c_int, c_double};
    use std::f64::EPSILON;
    use super::Value;

    fn checked_memory_handle() -> Connection {
        let db = Connection::open_in_memory().unwrap();
        db.execute_batch("CREATE TABLE foo (b BLOB, t TEXT, i INTEGER, f FLOAT, n)").unwrap();
        db
    }

    #[test]
    fn test_blob() {
        let db = checked_memory_handle();

        let v1234 = vec![1u8, 2, 3, 4];
        db.execute("INSERT INTO foo(b) VALUES (?)", &[&v1234]).unwrap();

        let v: Vec<u8> = db.query_row("SELECT b FROM foo", &[], |r| r.get(0)).unwrap();
        assert_eq!(v, v1234);
    }

    #[test]
    fn test_empty_blob() {
        let db = checked_memory_handle();

        let empty = vec![];
        db.execute("INSERT INTO foo(b) VALUES (?)", &[&empty]).unwrap();

        let v: Vec<u8> = db.query_row("SELECT b FROM foo", &[], |r| r.get(0)).unwrap();
        assert_eq!(v, empty);
    }

    #[test]
    fn test_str() {
        let db = checked_memory_handle();

        let s = "hello, world!";
        db.execute("INSERT INTO foo(t) VALUES (?)", &[&s]).unwrap();

        let from: String = db.query_row("SELECT t FROM foo", &[], |r| r.get(0)).unwrap();
        assert_eq!(from, s);
    }

    #[test]
    fn test_string() {
        let db = checked_memory_handle();

        let s = "hello, world!";
        db.execute("INSERT INTO foo(t) VALUES (?)", &[&s.to_owned()]).unwrap();

        let from: String = db.query_row("SELECT t FROM foo", &[], |r| r.get(0)).unwrap();
        assert_eq!(from, s);
    }

    #[test]
    fn test_value() {
        let db = checked_memory_handle();

        db.execute("INSERT INTO foo(i) VALUES (?)", &[&Value::Integer(10)]).unwrap();

        assert_eq!(10i64,
                   db.query_row("SELECT i FROM foo", &[], |r| r.get(0)).unwrap());
    }

    #[test]
    fn test_option() {
        let db = checked_memory_handle();

        let s = Some("hello, world!");
        let b = Some(vec![1u8, 2, 3, 4]);

        db.execute("INSERT INTO foo(t) VALUES (?)", &[&s]).unwrap();
        db.execute("INSERT INTO foo(b) VALUES (?)", &[&b]).unwrap();

        let mut stmt = db.prepare("SELECT t, b FROM foo ORDER BY ROWID ASC").unwrap();
        let mut rows = stmt.query(&[]).unwrap();

        {
            let row1 = rows.next().unwrap().unwrap();
            let s1: Option<String> = row1.get(0);
            let b1: Option<Vec<u8>> = row1.get(1);
            assert_eq!(s.unwrap(), s1.unwrap());
            assert!(b1.is_none());
        }

        {
            let row2 = rows.next().unwrap().unwrap();
            let s2: Option<String> = row2.get(0);
            let b2: Option<Vec<u8>> = row2.get(1);
            assert!(s2.is_none());
            assert_eq!(b, b2);
        }
    }

    #[test]
    fn test_mismatched_types() {
        fn is_invalid_column_type(err: Error) -> bool {
            match err {
                Error::InvalidColumnType(_, _) => true,
                _ => false,
            }
        }

        let db = checked_memory_handle();

        db.execute("INSERT INTO foo(b, t, i, f) VALUES (X'0102', 'text', 1, 1.5)",
                     &[])
            .unwrap();

        let mut stmt = db.prepare("SELECT b, t, i, f, n FROM foo").unwrap();
        let mut rows = stmt.query(&[]).unwrap();

        let row = rows.next().unwrap().unwrap();

        // check the correct types come back as expected
        assert_eq!(vec![1, 2], row.get_checked::<i32, Vec<u8>>(0).unwrap());
        assert_eq!("text", row.get_checked::<i32, String>(1).unwrap());
        assert_eq!(1, row.get_checked::<i32, c_int>(2).unwrap());
        assert!((1.5 - row.get_checked::<i32, c_double>(3).unwrap()).abs() < EPSILON);
        assert!(row.get_checked::<i32, Option<c_int>>(4).unwrap().is_none());
        assert!(row.get_checked::<i32, Option<c_double>>(4).unwrap().is_none());
        assert!(row.get_checked::<i32, Option<String>>(4).unwrap().is_none());

        // check some invalid types

        // 0 is actually a blob (Vec<u8>)
        assert!(is_invalid_column_type(row.get_checked::<i32, c_int>(0).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, c_int>(0).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, i64>(0).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, c_double>(0).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, String>(0).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, time::Timespec>(0).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, Option<c_int>>(0).err().unwrap()));

        // 1 is actually a text (String)
        assert!(is_invalid_column_type(row.get_checked::<i32, c_int>(1).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, i64>(1).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, c_double>(1).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, Vec<u8>>(1).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, Option<c_int>>(1).err().unwrap()));

        // 2 is actually an integer
        assert!(is_invalid_column_type(row.get_checked::<i32, String>(2).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, Vec<u8>>(2).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, Option<String>>(2).err().unwrap()));

        // 3 is actually a float (c_double)
        assert!(is_invalid_column_type(row.get_checked::<i32, c_int>(3).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, i64>(3).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, String>(3).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, Vec<u8>>(3).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, Option<c_int>>(3).err().unwrap()));

        // 4 is actually NULL
        assert!(is_invalid_column_type(row.get_checked::<i32, c_int>(4).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, i64>(4).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, c_double>(4).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, String>(4).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, Vec<u8>>(4).err().unwrap()));
        assert!(is_invalid_column_type(row.get_checked::<i32, time::Timespec>(4).err().unwrap()));
    }

    #[test]
    fn test_dynamic_type() {
        use super::Value;
        let db = checked_memory_handle();

        db.execute("INSERT INTO foo(b, t, i, f) VALUES (X'0102', 'text', 1, 1.5)",
                     &[])
            .unwrap();

        let mut stmt = db.prepare("SELECT b, t, i, f, n FROM foo").unwrap();
        let mut rows = stmt.query(&[]).unwrap();

        let row = rows.next().unwrap().unwrap();
        assert_eq!(Value::Blob(vec![1, 2]),
                   row.get_checked::<i32, Value>(0).unwrap());
        assert_eq!(Value::Text(String::from("text")),
                   row.get_checked::<i32, Value>(1).unwrap());
        assert_eq!(Value::Integer(1), row.get_checked::<i32, Value>(2).unwrap());
        match row.get_checked::<i32, Value>(3).unwrap() {
            Value::Real(val) => assert!((1.5 - val).abs() < EPSILON),
            x => panic!("Invalid Value {:?}", x),
        }
        assert_eq!(Value::Null, row.get_checked::<i32, Value>(4).unwrap());
    }
}