Refactor: Extract FromSql into its own module.

This commit is contained in:
John Gallagher 2016-05-22 20:01:03 -04:00
parent 1950158c87
commit 0e96e2269c
2 changed files with 124 additions and 114 deletions

119
src/types/from_sql.rs Normal file
View File

@ -0,0 +1,119 @@
use std::ffi::CStr;
use std::mem;
use std::str;
use libc::{c_char, c_double, c_int};
use super::Value;
use ffi::{sqlite3_stmt, sqlite3_column_type};
use ::{ffi, Result};
use ::error::Error;
/// A trait for types that can be created from a SQLite value.
pub trait FromSql: Sized {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Self>;
/// FromSql types can implement this method and use sqlite3_column_type to check that
/// the type reported by SQLite matches a type suitable for Self. This method is used
/// by `Row::get_checked` to confirm that the column contains a valid type before
/// attempting to retrieve the value.
unsafe fn column_has_valid_sqlite_type(_: *mut sqlite3_stmt, _: c_int) -> bool {
true
}
}
macro_rules! raw_from_impl(
($t:ty, $f:ident, $c:expr) => (
impl FromSql for $t {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<$t> {
Ok(ffi::$f(stmt, col))
}
unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
sqlite3_column_type(stmt, col) == $c
}
}
)
);
raw_from_impl!(c_int, sqlite3_column_int, ffi::SQLITE_INTEGER); // i32
raw_from_impl!(i64, sqlite3_column_int64, ffi::SQLITE_INTEGER);
raw_from_impl!(c_double, sqlite3_column_double, ffi::SQLITE_FLOAT); // f64
impl FromSql for bool {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<bool> {
match ffi::sqlite3_column_int(stmt, col) {
0 => Ok(false),
_ => Ok(true),
}
}
unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
sqlite3_column_type(stmt, col) == ffi::SQLITE_INTEGER
}
}
impl FromSql for String {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<String> {
let c_text = ffi::sqlite3_column_text(stmt, col);
if c_text.is_null() {
Ok("".to_owned())
} else {
let c_slice = CStr::from_ptr(c_text as *const c_char).to_bytes();
let utf8_str = try!(str::from_utf8(c_slice));
Ok(utf8_str.into())
}
}
unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
sqlite3_column_type(stmt, col) == ffi::SQLITE_TEXT
}
}
impl FromSql for Vec<u8> {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Vec<u8>> {
use std::slice::from_raw_parts;
let c_blob = ffi::sqlite3_column_blob(stmt, col);
let len = ffi::sqlite3_column_bytes(stmt, col);
// The documentation for sqlite3_column_bytes indicates it is always non-negative,
// but we should assert here just to be sure.
assert!(len >= 0,
"unexpected negative return from sqlite3_column_bytes");
let len = len as usize;
Ok(from_raw_parts(mem::transmute(c_blob), len).to_vec())
}
unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
sqlite3_column_type(stmt, col) == ffi::SQLITE_BLOB
}
}
impl<T: FromSql> FromSql for Option<T> {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Option<T>> {
if sqlite3_column_type(stmt, col) == ffi::SQLITE_NULL {
Ok(None)
} else {
FromSql::column_result(stmt, col).map(Some)
}
}
unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
sqlite3_column_type(stmt, col) == ffi::SQLITE_NULL ||
T::column_has_valid_sqlite_type(stmt, col)
}
}
impl FromSql for Value {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Value> {
match sqlite3_column_type(stmt, col) {
ffi::SQLITE_TEXT => FromSql::column_result(stmt, col).map(Value::Text),
ffi::SQLITE_INTEGER => Ok(Value::Integer(ffi::sqlite3_column_int64(stmt, col))),
ffi::SQLITE_FLOAT => Ok(Value::Real(ffi::sqlite3_column_double(stmt, col))),
ffi::SQLITE_NULL => Ok(Value::Null),
ffi::SQLITE_BLOB => FromSql::column_result(stmt, col).map(Value::Blob),
_ => Err(Error::InvalidColumnType),
}
}
}

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@ -52,18 +52,18 @@
//! }
//! ```
use libc::{c_int, c_double, c_char};
use std::ffi::CStr;
use libc::{c_int, c_double};
use std::mem;
use std::str;
use super::ffi;
use super::{Result, Error, str_to_cstring};
use super::str_to_cstring;
pub use ffi::sqlite3_stmt;
pub use ffi::sqlite3_column_type;
pub use ffi::{SQLITE_INTEGER, SQLITE_FLOAT, SQLITE_TEXT, SQLITE_BLOB, SQLITE_NULL};
pub use self::from_sql::FromSql;
mod from_sql;
mod time;
#[cfg(feature = "chrono")]
mod chrono;
@ -75,19 +75,6 @@ pub trait ToSql {
unsafe fn bind_parameter(&self, stmt: *mut sqlite3_stmt, col: c_int) -> c_int;
}
/// A trait for types that can be created from a SQLite value.
pub trait FromSql: Sized {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Self>;
/// FromSql types can implement this method and use sqlite3_column_type to check that
/// the type reported by SQLite matches a type suitable for Self. This method is used
/// by `Row::get_checked` to confirm that the column contains a valid type before
/// attempting to retrieve the value.
unsafe fn column_has_valid_sqlite_type(_: *mut sqlite3_stmt, _: c_int) -> bool {
true
}
}
macro_rules! raw_to_impl(
($t:ty, $f:ident) => (
impl ToSql for $t {
@ -190,89 +177,6 @@ impl ToSql for Null {
}
}
macro_rules! raw_from_impl(
($t:ty, $f:ident, $c:expr) => (
impl FromSql for $t {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<$t> {
Ok(ffi::$f(stmt, col))
}
unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
sqlite3_column_type(stmt, col) == $c
}
}
)
);
raw_from_impl!(c_int, sqlite3_column_int, ffi::SQLITE_INTEGER); // i32
raw_from_impl!(i64, sqlite3_column_int64, ffi::SQLITE_INTEGER);
raw_from_impl!(c_double, sqlite3_column_double, ffi::SQLITE_FLOAT); // f64
impl FromSql for bool {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<bool> {
match ffi::sqlite3_column_int(stmt, col) {
0 => Ok(false),
_ => Ok(true),
}
}
unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
sqlite3_column_type(stmt, col) == ffi::SQLITE_INTEGER
}
}
impl FromSql for String {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<String> {
let c_text = ffi::sqlite3_column_text(stmt, col);
if c_text.is_null() {
Ok("".to_owned())
} else {
let c_slice = CStr::from_ptr(c_text as *const c_char).to_bytes();
let utf8_str = try!(str::from_utf8(c_slice));
Ok(utf8_str.into())
}
}
unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
sqlite3_column_type(stmt, col) == ffi::SQLITE_TEXT
}
}
impl FromSql for Vec<u8> {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Vec<u8>> {
use std::slice::from_raw_parts;
let c_blob = ffi::sqlite3_column_blob(stmt, col);
let len = ffi::sqlite3_column_bytes(stmt, col);
// The documentation for sqlite3_column_bytes indicates it is always non-negative,
// but we should assert here just to be sure.
assert!(len >= 0,
"unexpected negative return from sqlite3_column_bytes");
let len = len as usize;
Ok(from_raw_parts(mem::transmute(c_blob), len).to_vec())
}
unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
sqlite3_column_type(stmt, col) == ffi::SQLITE_BLOB
}
}
impl<T: FromSql> FromSql for Option<T> {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Option<T>> {
if sqlite3_column_type(stmt, col) == ffi::SQLITE_NULL {
Ok(None)
} else {
FromSql::column_result(stmt, col).map(Some)
}
}
unsafe fn column_has_valid_sqlite_type(stmt: *mut sqlite3_stmt, col: c_int) -> bool {
sqlite3_column_type(stmt, col) == ffi::SQLITE_NULL ||
T::column_has_valid_sqlite_type(stmt, col)
}
}
/// Dynamic type value (http://sqlite.org/datatype3.html)
/// Value's type is dictated by SQLite (not by the caller).
#[derive(Clone,Debug,PartialEq)]
@ -289,19 +193,6 @@ pub enum Value {
Blob(Vec<u8>),
}
impl FromSql for Value {
unsafe fn column_result(stmt: *mut sqlite3_stmt, col: c_int) -> Result<Value> {
match sqlite3_column_type(stmt, col) {
ffi::SQLITE_TEXT => FromSql::column_result(stmt, col).map(Value::Text),
ffi::SQLITE_INTEGER => Ok(Value::Integer(ffi::sqlite3_column_int64(stmt, col))),
ffi::SQLITE_FLOAT => Ok(Value::Real(ffi::sqlite3_column_double(stmt, col))),
ffi::SQLITE_NULL => Ok(Value::Null),
ffi::SQLITE_BLOB => FromSql::column_result(stmt, col).map(Value::Blob),
_ => Err(Error::InvalidColumnType),
}
}
}
#[cfg(test)]
#[cfg_attr(feature="clippy", allow(similar_names))]
mod test {