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Merge pull request #70 from jgallagher/pfernie-master

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Replace get_opt with get_checked. Add query_and_then and query_row_and_then.
This commit is contained in:
John Gallagher 2015-09-21 10:38:07 -04:00
commit d23667870e
1 changed files with 292 additions and 28 deletions
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320
src/lib.rs
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@ -55,6 +55,7 @@ extern crate libsqlite3_sys as ffi;
#[macro_use] extern crate bitflags;
use std::default::Default;
use std::convert;
use std::mem;
use std::ptr;
use std::fmt;
@ -90,7 +91,7 @@ unsafe fn errmsg_to_string(errmsg: *const c_char) -> String {
}
/// Encompasses an error result from a call to the SQLite C API.
#[derive(Debug)]
#[derive(Debug, PartialEq)]
pub struct SqliteError {
/// The error code returned by a SQLite C API call. See [SQLite Result
/// Codes](http://www.sqlite.org/rescode.html) for details.
@ -302,6 +303,37 @@ impl SqliteConnection {
}
}
/// Convenience method to execute a query that is expected to return a single row,
/// and execute a mapping via `f` on that returned row with the possibility of failure.
/// The `Result` type of `f` must implement `std::convert::From<SqliteError>`.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteResult,SqliteConnection};
/// fn preferred_locale(conn: &SqliteConnection) -> SqliteResult<String> {
/// conn.query_row_and_then("SELECT value FROM preferences WHERE name='locale'", &[], |row| {
/// row.get_checked(0)
/// })
/// }
/// ```
///
/// If the query returns more than one row, all rows except the first are ignored.
pub fn query_row_and_then<T, E, F>(&self, sql: &str, params: &[&ToSql], f: F) -> Result<T, E>
where F: FnOnce(SqliteRow) -> Result<T, E>,
E: convert::From<SqliteError> {
let mut stmt = try!(self.prepare(sql));
let mut rows = try!(stmt.query(params));
match rows.next() {
Some(row) => row.map_err(E::from).and_then(f),
None => Err(E::from(SqliteError{
code: ffi::SQLITE_NOTICE,
message: "Query did not return a row".to_string(),
}))
}
}
/// Convenience method to execute a query that is expected to return a single row.
///
/// ## Example
@ -696,6 +728,25 @@ impl<'conn> SqliteStatement<'conn> {
})
}
/// Executes the prepared statement and maps a function over the resulting
/// rows, where the function returns a `Result` with `Error` type implementing
/// `std::convert::From<SqliteError>` (so errors can be unified).
///
/// Unlike the iterator produced by `query`, the returned iterator does not expose the possibility
/// for accessing stale rows.
pub fn query_and_then<'a, T, E, F>(&'a mut self, params: &[&ToSql], f: F)
-> SqliteResult<AndThenRows<'a, F>>
where T: 'static,
E: convert::From<SqliteError>,
F: FnMut(SqliteRow) -> Result<T, E> {
let row_iter = try!(self.query(params));
Ok(AndThenRows{
rows: row_iter,
map: f,
})
}
/// Consumes the statement.
///
/// Functionally equivalent to the `Drop` implementation, but allows callers to see any errors
@ -766,6 +817,26 @@ impl<'stmt, T, F> Iterator for MappedRows<'stmt, F>
}
}
/// An iterator over the mapped resulting rows of a query, with an Error type
/// unifying with SqliteError.
pub struct AndThenRows<'stmt, F> {
rows: SqliteRows<'stmt>,
map: F,
}
impl<'stmt, T, E, F> Iterator for AndThenRows<'stmt, F>
where T: 'static,
E: convert::From<SqliteError>,
F: FnMut(SqliteRow) -> Result<T, E> {
type Item = Result<T, E>;
fn next(&mut self) -> Option<Self::Item> {
self.rows.next().map(|row_result| row_result
.map_err(E::from)
.and_then(|row| (self.map)(row)))
}
}
/// An iterator over the resulting rows of a query.
///
/// ## Warning
@ -876,7 +947,7 @@ impl<'stmt> SqliteRow<'stmt> {
/// Panics if `idx` is outside the range of columns in the returned query or if this row
/// is stale.
pub fn get<T: FromSql>(&self, idx: c_int) -> T {
self.get_opt(idx).unwrap()
self.get_checked(idx).unwrap()
}
/// Get the value of a particular column of the result row.
@ -886,30 +957,9 @@ impl<'stmt> SqliteRow<'stmt> {
/// Returns a `SQLITE_MISMATCH`-coded `SqliteError` if the underlying SQLite column
/// type is not a valid type as a source for `T`.
///
/// Panics if `idx` is outside the range of columns in the returned query or if this row
/// is stale.
pub fn get_checked<T: FromSql>(&self, idx: c_int) -> SqliteResult<T> {
let valid_column_type = unsafe {
T::column_has_valid_sqlite_type(self.stmt.stmt, idx)
};
if valid_column_type {
Ok(self.get(idx))
} else {
Err(SqliteError{
code: ffi::SQLITE_MISMATCH,
message: "Invalid column type".to_string(),
})
}
}
/// Attempt to get the value of a particular column of the result row.
///
/// ## Failure
///
/// Returns a `SQLITE_MISUSE`-coded `SqliteError` if `idx` is outside the valid column range
/// for this row or if this row is stale.
pub fn get_opt<T: FromSql>(&self, idx: c_int) -> SqliteResult<T> {
pub fn get_checked<T: FromSql>(&self, idx: c_int) -> SqliteResult<T> {
if self.row_idx != self.current_row.get() {
return Err(SqliteError{ code: ffi::SQLITE_MISUSE,
message: "Cannot get values from a row after advancing to next row".to_string() });
@ -919,7 +969,15 @@ impl<'stmt> SqliteRow<'stmt> {
return Err(SqliteError{ code: ffi::SQLITE_MISUSE,
message: "Invalid column index".to_string() });
}
FromSql::column_result(self.stmt.stmt, idx)
if T::column_has_valid_sqlite_type(self.stmt.stmt, idx) {
FromSql::column_result(self.stmt.stmt, idx)
} else {
Err(SqliteError{
code: ffi::SQLITE_MISMATCH,
message: "Invalid column type".to_string(),
})
}
}
}
}
@ -928,8 +986,10 @@ impl<'stmt> SqliteRow<'stmt> {
mod test {
extern crate libsqlite3_sys as ffi;
extern crate tempdir;
use super::*;
pub use super::*;
use self::tempdir::TempDir;
pub use std::error::Error as StdError;
pub use std::fmt;
// this function is never called, but is still type checked; in
// particular, calls with specific instantiations will require
@ -939,7 +999,7 @@ mod test {
ensure_send::<SqliteConnection>();
}
fn checked_memory_handle() -> SqliteConnection {
pub fn checked_memory_handle() -> SqliteConnection {
SqliteConnection::open_in_memory().unwrap()
}
@ -1149,7 +1209,7 @@ mod test {
assert_eq!(2i32, second.get(0));
let result = first.get_opt::<i32>(0);
let result = first.get_checked::<i32>(0);
assert!(result.unwrap_err().message.contains("advancing to next row"));
}
@ -1176,4 +1236,208 @@ mod test {
assert!(format!("{:?}", stmt).contains(query));
}
mod query_and_then_tests {
extern crate libsqlite3_sys as ffi;
use super::*;
#[derive(Debug, PartialEq)]
enum CustomError {
SomeError,
Sqlite(SqliteError),
}
impl fmt::Display for CustomError {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
match *self {
CustomError::SomeError => write!(f, "{}", self.description()),
CustomError::Sqlite(ref se) => write!(f, "{}: {}", self.description(), se),
}
}
}
impl StdError for CustomError {
fn description(&self) -> &str { "my custom error" }
fn cause(&self) -> Option<&StdError> {
match *self {
CustomError::SomeError => None,
CustomError::Sqlite(ref se) => Some(se),
}
}
}
impl From<SqliteError> for CustomError {
fn from(se: SqliteError) -> CustomError {
CustomError::Sqlite(se)
}
}
type CustomResult<T> = Result<T, CustomError>;
#[test]
fn test_query_and_then() {
let db = checked_memory_handle();
let sql = "BEGIN;
CREATE TABLE foo(x INTEGER, y TEXT);
INSERT INTO foo VALUES(4, \"hello\");
INSERT INTO foo VALUES(3, \", \");
INSERT INTO foo VALUES(2, \"world\");
INSERT INTO foo VALUES(1, \"!\");
END;";
db.execute_batch(sql).unwrap();
let mut query = db.prepare("SELECT x, y FROM foo ORDER BY x DESC").unwrap();
let results: SqliteResult<Vec<String>> = query
.query_and_then(&[], |row| row.get_checked(1))
.unwrap()
.collect();
assert_eq!(results.unwrap().concat(), "hello, world!");
}
#[test]
fn test_query_and_then_fails() {
let db = checked_memory_handle();
let sql = "BEGIN;
CREATE TABLE foo(x INTEGER, y TEXT);
INSERT INTO foo VALUES(4, \"hello\");
INSERT INTO foo VALUES(3, \", \");
INSERT INTO foo VALUES(2, \"world\");
INSERT INTO foo VALUES(1, \"!\");
END;";
db.execute_batch(sql).unwrap();
let mut query = db.prepare("SELECT x, y FROM foo ORDER BY x DESC").unwrap();
let bad_type: SqliteResult<Vec<f64>> = query
.query_and_then(&[], |row| row.get_checked(1))
.unwrap()
.collect();
assert_eq!(bad_type, Err(SqliteError{
code: ffi::SQLITE_MISMATCH,
message: "Invalid column type".to_owned(),
}));
let bad_idx: SqliteResult<Vec<String>> = query
.query_and_then(&[], |row| row.get_checked(3))
.unwrap()
.collect();
assert_eq!(bad_idx, Err(SqliteError{
code: ffi::SQLITE_MISUSE,
message: "Invalid column index".to_owned(),
}));
}
#[test]
fn test_query_and_then_custom_error() {
let db = checked_memory_handle();
let sql = "BEGIN;
CREATE TABLE foo(x INTEGER, y TEXT);
INSERT INTO foo VALUES(4, \"hello\");
INSERT INTO foo VALUES(3, \", \");
INSERT INTO foo VALUES(2, \"world\");
INSERT INTO foo VALUES(1, \"!\");
END;";
db.execute_batch(sql).unwrap();
let mut query = db.prepare("SELECT x, y FROM foo ORDER BY x DESC").unwrap();
let results: CustomResult<Vec<String>> = query
.query_and_then(&[], |row| row.get_checked(1).map_err(CustomError::Sqlite))
.unwrap()
.collect();
assert_eq!(results.unwrap().concat(), "hello, world!");
}
#[test]
fn test_query_and_then_custom_error_fails() {
let db = checked_memory_handle();
let sql = "BEGIN;
CREATE TABLE foo(x INTEGER, y TEXT);
INSERT INTO foo VALUES(4, \"hello\");
INSERT INTO foo VALUES(3, \", \");
INSERT INTO foo VALUES(2, \"world\");
INSERT INTO foo VALUES(1, \"!\");
END;";
db.execute_batch(sql).unwrap();
let mut query = db.prepare("SELECT x, y FROM foo ORDER BY x DESC").unwrap();
let bad_type: CustomResult<Vec<f64>> = query
.query_and_then(&[], |row| row.get_checked(1).map_err(CustomError::Sqlite))
.unwrap()
.collect();
assert_eq!(bad_type, Err(CustomError::Sqlite(SqliteError{
code: ffi::SQLITE_MISMATCH,
message: "Invalid column type".to_owned(),
})));
let bad_idx: CustomResult<Vec<String>> = query
.query_and_then(&[], |row| row.get_checked(3).map_err(CustomError::Sqlite))
.unwrap()
.collect();
assert_eq!(bad_idx, Err(CustomError::Sqlite(SqliteError{
code: ffi::SQLITE_MISUSE,
message: "Invalid column index".to_owned(),
})));
let non_sqlite_err: CustomResult<Vec<String>> = query
.query_and_then(&[], |_| Err(CustomError::SomeError))
.unwrap()
.collect();
assert_eq!(non_sqlite_err, Err(CustomError::SomeError));
}
#[test]
fn test_query_row_and_then_custom_error() {
let db = checked_memory_handle();
let sql = "BEGIN;
CREATE TABLE foo(x INTEGER, y TEXT);
INSERT INTO foo VALUES(4, \"hello\");
END;";
db.execute_batch(sql).unwrap();
let query = "SELECT x, y FROM foo ORDER BY x DESC";
let results: CustomResult<String> = db
.query_row_and_then(query, &[], |row| row.get_checked(1).map_err(CustomError::Sqlite));
assert_eq!(results.unwrap(), "hello");
}
#[test]
fn test_query_row_and_then_custom_error_fails() {
let db = checked_memory_handle();
let sql = "BEGIN;
CREATE TABLE foo(x INTEGER, y TEXT);
INSERT INTO foo VALUES(4, \"hello\");
END;";
db.execute_batch(sql).unwrap();
let query = "SELECT x, y FROM foo ORDER BY x DESC";
let bad_type: CustomResult<f64> = db
.query_row_and_then(query, &[], |row| row.get_checked(1).map_err(CustomError::Sqlite));
assert_eq!(bad_type, Err(CustomError::Sqlite(SqliteError{
code: ffi::SQLITE_MISMATCH,
message: "Invalid column type".to_owned(),
})));
let bad_idx: CustomResult<String> = db
.query_row_and_then(query, &[], |row| row.get_checked(3).map_err(CustomError::Sqlite));
assert_eq!(bad_idx, Err(CustomError::Sqlite(SqliteError{
code: ffi::SQLITE_MISUSE,
message: "Invalid column index".to_owned(),
})));
let non_sqlite_err: CustomResult<String> = db
.query_row_and_then(query, &[], |_| Err(CustomError::SomeError));
assert_eq!(non_sqlite_err, Err(CustomError::SomeError));
}
}
}