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lib.rs
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//! Rusqlite is an ergonomic wrapper for using SQLite from Rust. It attempts to expose
//! an interface similar to [rust-postgres](https://github.com/sfackler/rust-postgres).
//!
//! ```rust
//! extern crate rusqlite;
//! extern crate time;
//!
//! use time::Timespec;
//! use rusqlite::SqliteConnection;
//!
//! #[derive(Debug)]
//! struct Person {
//! id: i32,
//! name: String,
//! time_created: Timespec,
//! data: Option<Vec<u8>>
//! }
//!
//! fn main() {
//! let conn = SqliteConnection::open_in_memory().unwrap();
//!
//! conn.execute("CREATE TABLE person (
//! id INTEGER PRIMARY KEY,
//! name TEXT NOT NULL,
//! time_created TEXT NOT NULL,
//! data BLOB
//! )", &[]).unwrap();
//! let me = Person {
//! id: 0,
//! name: "Steven".to_string(),
//! time_created: time::get_time(),
//! data: None
//! };
//! conn.execute("INSERT INTO person (name, time_created, data)
//! VALUES ($1, $2, $3)",
//! &[&me.name, &me.time_created, &me.data]).unwrap();
//!
//! let mut stmt = conn.prepare("SELECT id, name, time_created, data FROM person").unwrap();
//! let mut person_iter = stmt.query_map(&[], |row| {
//! Person {
//! id: row.get(0),
//! name: row.get(1),
//! time_created: row.get(2),
//! data: row.get(3)
//! }
//! }).unwrap();
//!
//! for person in person_iter {
//! println!("Found person {:?}", person.unwrap());
//! }
//! }
//! ```
extern crate libc;
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;
use std::path::{Path,PathBuf};
use std::error;
use std::rc::{Rc};
use std::cell::{RefCell, Cell};
use std::ffi::{CStr, CString};
use std::str;
use libc::{c_int, c_void, c_char};
use types::{ToSql, FromSql};
pub use transaction::{SqliteTransaction};
pub use transaction::{SqliteTransactionBehavior,
SqliteTransactionDeferred,
SqliteTransactionImmediate,
SqliteTransactionExclusive};
#[cfg(feature = "load_extension")] pub use load_extension_guard::{SqliteLoadExtensionGuard};
pub mod types;
mod transaction;
#[cfg(feature = "load_extension")] mod load_extension_guard;
/// A typedef of the result returned by many methods.
pub type SqliteResult<T> = Result<T, SqliteError>;
unsafe fn errmsg_to_string(errmsg: *const c_char) -> String {
let c_slice = CStr::from_ptr(errmsg).to_bytes();
let utf8_str = str::from_utf8(c_slice);
utf8_str.unwrap_or("Invalid string encoding").to_string()
}
/// Encompasses an error result from a call to the SQLite C API.
#[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.
pub code: c_int,
/// The error message provided by [sqlite3_errmsg](http://www.sqlite.org/c3ref/errcode.html),
/// if possible, or a generic error message based on `code` otherwise.
pub message: String,
}
impl fmt::Display for SqliteError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{} (SQLite error {})", self.message, self.code)
}
}
impl error::Error for SqliteError {
fn description(&self) -> &str {
&self.message
}
}
impl SqliteError {
fn from_handle(db: *mut ffi::Struct_sqlite3, code: c_int) -> SqliteError {
let message = if db.is_null() {
ffi::code_to_str(code).to_string()
} else {
unsafe { errmsg_to_string(ffi::sqlite3_errmsg(db)) }
};
SqliteError{ code: code, message: message }
}
}
fn str_to_cstring(s: &str) -> SqliteResult<CString> {
CString::new(s).map_err(|_| SqliteError{
code: ffi::SQLITE_MISUSE,
message: "Could not convert path to C-combatible string".to_string()
})
}
fn path_to_cstring(p: &Path) -> SqliteResult<CString> {
let s = try!(p.to_str().ok_or(SqliteError{
code: ffi::SQLITE_MISUSE,
message: "Could not convert path to UTF-8 string".to_string()
}));
str_to_cstring(s)
}
/// A connection to a SQLite database.
///
/// ## Warning
///
/// Note that despite the fact that most `SqliteConnection` methods take an immutable reference to
/// `self`, `SqliteConnection` is NOT threadsafe, and using it from multiple threads may result in
/// runtime panics or data races. The SQLite connection handle has at least two pieces of internal
/// state (the last insertion ID and the last error message) that rusqlite uses, but wrapping these
/// APIs in a safe way from Rust would be too restrictive (for example, you would not be able to
/// prepare multiple statements at the same time).
pub struct SqliteConnection {
db: RefCell<InnerSqliteConnection>,
path: Option<PathBuf>,
}
unsafe impl Send for SqliteConnection {}
impl SqliteConnection {
/// Open a new connection to a SQLite database.
///
/// `SqliteConnection::open(path)` is equivalent to `SqliteConnection::open_with_flags(path,
/// SQLITE_OPEN_READ_WRITE | SQLITE_OPEN_CREATE)`.
pub fn open<P: AsRef<Path>>(path: P) -> SqliteResult<SqliteConnection> {
let flags = Default::default();
SqliteConnection::open_with_flags(path, flags)
}
/// Open a new connection to an in-memory SQLite database.
pub fn open_in_memory() -> SqliteResult<SqliteConnection> {
let flags = Default::default();
SqliteConnection::open_in_memory_with_flags(flags)
}
/// Open a new connection to a SQLite database.
///
/// Database Connection](http://www.sqlite.org/c3ref/open.html) for a description of valid
/// flag combinations.
pub fn open_with_flags<P: AsRef<Path>>(path: P, flags: SqliteOpenFlags)
-> SqliteResult<SqliteConnection> {
let c_path = try!(path_to_cstring(path.as_ref()));
InnerSqliteConnection::open_with_flags(&c_path, flags).map(|db| {
SqliteConnection{ db: RefCell::new(db), path: Some(path.as_ref().to_path_buf()) }
})
}
/// Open a new connection to an in-memory SQLite database.
///
/// Database Connection](http://www.sqlite.org/c3ref/open.html) for a description of valid
/// flag combinations.
pub fn open_in_memory_with_flags(flags: SqliteOpenFlags) -> SqliteResult<SqliteConnection> {
let c_memory = try!(str_to_cstring(":memory:"));
InnerSqliteConnection::open_with_flags(&c_memory, flags).map(|db| {
SqliteConnection{ db: RefCell::new(db), path: None }
})
}
/// Begin a new transaction with the default behavior (DEFERRED).
///
/// The transaction defaults to rolling back when it is dropped. If you want the transaction to
/// commit, you must call `commit` or `set_commit`.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// # fn do_queries_part_1(conn: &SqliteConnection) -> SqliteResult<()> { Ok(()) }
/// # fn do_queries_part_2(conn: &SqliteConnection) -> SqliteResult<()> { Ok(()) }
/// fn perform_queries(conn: &SqliteConnection) -> SqliteResult<()> {
/// let tx = try!(conn.transaction());
///
/// try!(do_queries_part_1(conn)); // tx causes rollback if this fails
/// try!(do_queries_part_2(conn)); // tx causes rollback if this fails
///
/// tx.commit()
/// }
/// ```
pub fn transaction<'a>(&'a self) -> SqliteResult<SqliteTransaction<'a>> {
SqliteTransaction::new(self, SqliteTransactionDeferred)
}
/// Begin a new transaction with a specified behavior.
///
/// See `transaction`.
pub fn transaction_with_behavior<'a>(&'a self, behavior: SqliteTransactionBehavior)
-> SqliteResult<SqliteTransaction<'a>> {
SqliteTransaction::new(self, behavior)
}
/// Convenience method to run multiple SQL statements (that cannot take any parameters).
///
/// Uses [sqlite3_exec](http://www.sqlite.org/c3ref/exec.html) under the hood.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn create_tables(conn: &SqliteConnection) -> SqliteResult<()> {
/// conn.execute_batch("BEGIN;
/// CREATE TABLE foo(x INTEGER);
/// CREATE TABLE bar(y TEXT);
/// COMMIT;")
/// }
/// ```
pub fn execute_batch(&self, sql: &str) -> SqliteResult<()> {
self.db.borrow_mut().execute_batch(sql)
}
/// Convenience method to prepare and execute a single SQL statement.
///
/// On success, returns the number of rows that were changed or inserted or deleted (via
/// `sqlite3_changes`).
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection};
/// fn update_rows(conn: &SqliteConnection) {
/// match conn.execute("UPDATE foo SET bar = 'baz' WHERE qux = ?", &[&1i32]) {
/// Ok(updated) => println!("{} rows were updated", updated),
/// Err(err) => println!("update failed: {}", err),
/// }
/// }
/// ```
pub fn execute(&self, sql: &str, params: &[&ToSql]) -> SqliteResult<c_int> {
self.prepare(sql).and_then(|mut stmt| stmt.execute(params))
}
/// Get the SQLite rowid of the most recent successful INSERT.
///
/// Uses [sqlite3_last_insert_rowid](https://www.sqlite.org/c3ref/last_insert_rowid.html) under
/// the hood.
pub fn last_insert_rowid(&self) -> i64 {
self.db.borrow_mut().last_insert_rowid()
}
/// Convenience method to execute a query that is expected to return a single row.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteResult,SqliteConnection};
/// fn preferred_locale(conn: &SqliteConnection) -> SqliteResult<String> {
/// conn.query_row("SELECT value FROM preferences WHERE name='locale'", &[], |row| {
/// row.get(0)
/// })
/// }
/// ```
///
/// If the query returns more than one row, all rows except the first are ignored.
pub fn query_row<T, F>(&self, sql: &str, params: &[&ToSql], f: F) -> SqliteResult<T>
where F: FnOnce(SqliteRow) -> T {
let mut stmt = try!(self.prepare(sql));
let mut rows = try!(stmt.query(params));
match rows.next() {
Some(row) => row.map(f),
None => Err(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,
/// 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
///
/// ```rust,no_run
/// # use rusqlite::{SqliteResult,SqliteConnection};
/// fn preferred_locale(conn: &SqliteConnection) -> SqliteResult<String> {
/// conn.query_row_safe("SELECT value FROM preferences WHERE name='locale'", &[], |row| {
/// row.get(0)
/// })
/// }
/// ```
///
/// If the query returns more than one row, all rows except the first are ignored.
///
/// ## Deprecated
///
/// This method should be considered deprecated. Use `query_row` instead, which now
/// does exactly the same thing.
pub fn query_row_safe<T, F>(&self, sql: &str, params: &[&ToSql], f: F) -> SqliteResult<T>
where F: FnOnce(SqliteRow) -> T {
self.query_row(sql, params, f)
}
/// Prepare a SQL statement for execution.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn insert_new_people(conn: &SqliteConnection) -> SqliteResult<()> {
/// let mut stmt = try!(conn.prepare("INSERT INTO People (name) VALUES (?)"));
/// try!(stmt.execute(&[&"Joe Smith"]));
/// try!(stmt.execute(&[&"Bob Jones"]));
/// Ok(())
/// }
/// ```
pub fn prepare<'a>(&'a self, sql: &str) -> SqliteResult<SqliteStatement<'a>> {
self.db.borrow_mut().prepare(self, sql)
}
/// Close the SQLite connection.
///
/// This is functionally equivalent to the `Drop` implementation for `SqliteConnection` except
/// that it returns any error encountered to the caller.
pub fn close(self) -> SqliteResult<()> {
let mut db = self.db.borrow_mut();
db.close()
}
/// Enable loading of SQLite extensions. Strongly consider using `SqliteLoadExtensionGuard`
/// instead of this function.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// # use std::path::{Path};
/// fn load_my_extension(conn: &SqliteConnection) -> SqliteResult<()> {
/// try!(conn.load_extension_enable());
/// try!(conn.load_extension(Path::new("my_sqlite_extension"), None));
/// conn.load_extension_disable()
/// }
/// ```
#[cfg(feature = "load_extension")]
pub fn load_extension_enable(&self) -> SqliteResult<()> {
self.db.borrow_mut().enable_load_extension(1)
}
/// Disable loading of SQLite extensions.
///
/// See `load_extension_enable` for an example.
#[cfg(feature = "load_extension")]
pub fn load_extension_disable(&self) -> SqliteResult<()> {
self.db.borrow_mut().enable_load_extension(0)
}
/// Load the SQLite extension at `dylib_path`. `dylib_path` is passed through to
/// `sqlite3_load_extension`, which may attempt OS-specific modifications if the file
/// cannot be loaded directly.
///
/// If `entry_point` is `None`, SQLite will attempt to find the entry point. If it is not
/// `None`, the entry point will be passed through to `sqlite3_load_extension`.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult, SqliteLoadExtensionGuard};
/// # use std::path::{Path};
/// fn load_my_extension(conn: &SqliteConnection) -> SqliteResult<()> {
/// let _guard = try!(SqliteLoadExtensionGuard::new(conn));
///
/// conn.load_extension("my_sqlite_extension", None)
/// }
#[cfg(feature = "load_extension")]
pub fn load_extension<P: AsRef<Path>>(&self, dylib_path: P, entry_point: Option<&str>) -> SqliteResult<()> {
self.db.borrow_mut().load_extension(dylib_path, entry_point)
}
fn decode_result(&self, code: c_int) -> SqliteResult<()> {
self.db.borrow_mut().decode_result(code)
}
fn changes(&self) -> c_int {
self.db.borrow_mut().changes()
}
}
impl fmt::Debug for SqliteConnection {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "SqliteConnection( path: {:?} )", &self.path)
}
}
struct InnerSqliteConnection {
db: *mut ffi::Struct_sqlite3,
}
bitflags! {
#[doc = "Flags for opening SQLite database connections."]
#[doc = "See [sqlite3_open_v2](http://www.sqlite.org/c3ref/open.html) for details."]
#[repr(C)]
flags SqliteOpenFlags: c_int {
const SQLITE_OPEN_READ_ONLY = 0x00000001,
const SQLITE_OPEN_READ_WRITE = 0x00000002,
const SQLITE_OPEN_CREATE = 0x00000004,
const SQLITE_OPEN_URI = 0x00000040,
const SQLITE_OPEN_MEMORY = 0x00000080,
const SQLITE_OPEN_NO_MUTEX = 0x00008000,
const SQLITE_OPEN_FULL_MUTEX = 0x00010000,
const SQLITE_OPEN_SHARED_CACHE = 0x00020000,
const SQLITE_OPEN_PRIVATE_CACHE = 0x00040000,
}
}
impl Default for SqliteOpenFlags {
fn default() -> SqliteOpenFlags {
SQLITE_OPEN_READ_WRITE
| SQLITE_OPEN_CREATE
| SQLITE_OPEN_NO_MUTEX
| SQLITE_OPEN_URI
}
}
impl InnerSqliteConnection {
fn open_with_flags(c_path: &CString, flags: SqliteOpenFlags)
-> SqliteResult<InnerSqliteConnection> {
unsafe {
let mut db: *mut ffi::sqlite3 = mem::uninitialized();
let r = ffi::sqlite3_open_v2(c_path.as_ptr(), &mut db, flags.bits(), ptr::null());
if r != ffi::SQLITE_OK {
let e = if db.is_null() {
SqliteError{ code: r,
message: ffi::code_to_str(r).to_string() }
} else {
let e = SqliteError::from_handle(db, r);
ffi::sqlite3_close(db);
e
};
return Err(e);
}
let r = ffi::sqlite3_busy_timeout(db, 5000);
if r != ffi::SQLITE_OK {
let e = SqliteError::from_handle(db, r);
ffi::sqlite3_close(db);
return Err(e);
}
Ok(InnerSqliteConnection{ db: db })
}
}
fn db(&self) -> *mut ffi::Struct_sqlite3 {
self.db
}
fn decode_result(&mut self, code: c_int) -> SqliteResult<()> {
if code == ffi::SQLITE_OK {
Ok(())
} else {
Err(SqliteError::from_handle(self.db(), code))
}
}
unsafe fn decode_result_with_errmsg(&self, code: c_int, errmsg: *mut c_char) -> SqliteResult<()> {
if code == ffi::SQLITE_OK {
Ok(())
} else {
let message = errmsg_to_string(&*errmsg);
ffi::sqlite3_free(errmsg as *mut c_void);
Err(SqliteError{ code: code, message: message })
}
}
fn close(&mut self) -> SqliteResult<()> {
unsafe {
let r = ffi::sqlite3_close(self.db());
self.db = ptr::null_mut();
self.decode_result(r)
}
}
fn execute_batch(&mut self, sql: &str) -> SqliteResult<()> {
let c_sql = try!(str_to_cstring(sql));
unsafe {
let mut errmsg: *mut c_char = mem::uninitialized();
let r = ffi::sqlite3_exec(self.db(), c_sql.as_ptr(), None, ptr::null_mut(), &mut errmsg);
self.decode_result_with_errmsg(r, errmsg)
}
}
#[cfg(feature = "load_extension")]
fn enable_load_extension(&mut self, onoff: c_int) -> SqliteResult<()> {
let r = unsafe { ffi::sqlite3_enable_load_extension(self.db, onoff) };
self.decode_result(r)
}
#[cfg(feature = "load_extension")]
fn load_extension(&self, dylib_path: &Path, entry_point: Option<&str>) -> SqliteResult<()> {
let dylib_str = try!(path_to_cstring(dylib_path));
unsafe {
let mut errmsg: *mut c_char = mem::uninitialized();
let r = if let Some(entry_point) = entry_point {
let c_entry = try!(str_to_cstring(entry_point));
ffi::sqlite3_load_extension(self.db, dylib_str.as_ptr(), c_entry.as_ptr(), &mut errmsg)
} else {
ffi::sqlite3_load_extension(self.db, dylib_str.as_ptr(), ptr::null(), &mut errmsg)
};
self.decode_result_with_errmsg(r, errmsg)
}
}
fn last_insert_rowid(&self) -> i64 {
unsafe {
ffi::sqlite3_last_insert_rowid(self.db())
}
}
fn prepare<'a>(&mut self,
conn: &'a SqliteConnection,
sql: &str) -> SqliteResult<SqliteStatement<'a>> {
if sql.len() >= ::std::i32::MAX as usize {
return Err(SqliteError {
code: ffi::SQLITE_TOOBIG,
message: "statement too long".to_string()
});
}
let mut c_stmt: *mut ffi::sqlite3_stmt = unsafe { mem::uninitialized() };
let c_sql = try!(str_to_cstring(sql));
let r = unsafe {
let len_with_nul = (sql.len() + 1) as c_int;
ffi::sqlite3_prepare_v2(self.db(), c_sql.as_ptr(), len_with_nul, &mut c_stmt,
ptr::null_mut())
};
self.decode_result(r).map(|_| {
SqliteStatement::new(conn, c_stmt)
})
}
fn changes(&mut self) -> c_int {
unsafe{ ffi::sqlite3_changes(self.db()) }
}
}
impl Drop for InnerSqliteConnection {
#[allow(unused_must_use)]
fn drop(&mut self) {
self.close();
}
}
/// A prepared statement.
pub struct SqliteStatement<'conn> {
conn: &'conn SqliteConnection,
stmt: *mut ffi::sqlite3_stmt,
needs_reset: bool,
column_count: c_int,
}
impl<'conn> SqliteStatement<'conn> {
fn new(conn: &SqliteConnection, stmt: *mut ffi::sqlite3_stmt) -> SqliteStatement {
SqliteStatement{ conn: conn, stmt: stmt, needs_reset: false,
column_count: unsafe { ffi::sqlite3_column_count(stmt) }}
}
/// Get all the column names in the result set of the prepared statement.
pub fn column_names(&self) -> Vec<&str> {
let n = self.column_count;
let mut cols = Vec::with_capacity(n as usize);
for i in 0..n {
let slice = unsafe {
CStr::from_ptr(ffi::sqlite3_column_name(self.stmt, i))
};
let s = str::from_utf8(slice.to_bytes()).unwrap();
cols.push(s);
}
cols
}
/// Execute the prepared statement.
///
/// On success, returns the number of rows that were changed or inserted or deleted (via
/// `sqlite3_changes`).
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn update_rows(conn: &SqliteConnection) -> SqliteResult<()> {
/// let mut stmt = try!(conn.prepare("UPDATE foo SET bar = 'baz' WHERE qux = ?"));
///
/// try!(stmt.execute(&[&1i32]));
/// try!(stmt.execute(&[&2i32]));
///
/// Ok(())
/// }
/// ```
pub fn execute(&mut self, params: &[&ToSql]) -> SqliteResult<c_int> {
unsafe {
try!(self.bind_parameters(params));
let r = ffi::sqlite3_step(self.stmt);
ffi::sqlite3_reset(self.stmt);
match r {
ffi::SQLITE_DONE => {
if self.column_count != 0 {
Err(SqliteError{ code: ffi::SQLITE_MISUSE,
message: "Unexpected column count - did you mean to call query?".to_string() })
} else {
Ok(self.conn.changes())
}
},
ffi::SQLITE_ROW => Err(SqliteError{ code: r,
message: "Unexpected row result - did you mean to call query?".to_string() }),
_ => Err(self.conn.decode_result(r).unwrap_err()),
}
}
}
/// Execute the prepared statement, returning an iterator over the resulting rows.
///
/// ## Example
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn get_names(conn: &SqliteConnection) -> SqliteResult<Vec<String>> {
/// let mut stmt = try!(conn.prepare("SELECT name FROM people"));
/// let mut rows = try!(stmt.query(&[]));
///
/// let mut names = Vec::new();
/// for result_row in rows {
/// let row = try!(result_row);
/// names.push(row.get(0));
/// }
///
/// Ok(names)
/// }
/// ```
pub fn query<'a>(&'a mut self, params: &[&ToSql]) -> SqliteResult<SqliteRows<'a>> {
self.reset_if_needed();
unsafe {
try!(self.bind_parameters(params));
}
self.needs_reset = true;
Ok(SqliteRows::new(self))
}
/// Executes the prepared statement and maps a function over the resulting
/// rows.
///
/// Unlike the iterator produced by `query`, the returned iterator does not expose the possibility
/// for accessing stale rows.
pub fn query_map<'a, T, F>(&'a mut self, params: &[&ToSql], f: F)
-> SqliteResult<MappedRows<'a, F>>
where T: 'static,
F: FnMut(SqliteRow) -> T {
let row_iter = try!(self.query(params));
Ok(MappedRows{
rows: row_iter,
map: f,
})
}
/// 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
/// that occur.
pub fn finalize(mut self) -> SqliteResult<()> {
self.finalize_()
}
unsafe fn bind_parameters(&mut self, params: &[&ToSql]) -> SqliteResult<()> {
assert!(params.len() as c_int == ffi::sqlite3_bind_parameter_count(self.stmt),
"incorrect number of parameters to query(): expected {}, got {}",
ffi::sqlite3_bind_parameter_count(self.stmt),
params.len());
for (i, p) in params.iter().enumerate() {
try!(self.conn.decode_result(p.bind_parameter(self.stmt, (i + 1) as c_int)));
}
Ok(())
}
fn reset_if_needed(&mut self) {
if self.needs_reset {
unsafe { ffi::sqlite3_reset(self.stmt); };
self.needs_reset = false;
}
}
fn finalize_(&mut self) -> SqliteResult<()> {
let r = unsafe { ffi::sqlite3_finalize(self.stmt) };
self.stmt = ptr::null_mut();
self.conn.decode_result(r)
}
}
impl<'conn> fmt::Debug for SqliteStatement<'conn> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let sql = unsafe {
let c_slice = CStr::from_ptr(ffi::sqlite3_sql(self.stmt)).to_bytes();
str::from_utf8(c_slice)
};
write!(f, "SqliteStatement( conn: {:?}, stmt: {:?}, sql: {:?} )", self.conn, self.stmt, sql)
}
}
impl<'conn> Drop for SqliteStatement<'conn> {
#[allow(unused_must_use)]
fn drop(&mut self) {
self.finalize_();
}
}
/// An iterator over the mapped resulting rows of a query.
pub struct MappedRows<'stmt, F> {
rows: SqliteRows<'stmt>,
map: F,
}
impl<'stmt, T, F> Iterator for MappedRows<'stmt, F>
where T: 'static,
F: FnMut(SqliteRow) -> T {
type Item = SqliteResult<T>;
fn next(&mut self) -> Option<SqliteResult<T>> {
self.rows.next().map(|row_result| row_result.map(|row| (self.map)(row)))
}
}
/// 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
///
/// Due to the way SQLite returns result rows of a query, it is not safe to attempt to get values
/// from a row after it has become stale (i.e., `next()` has been called again on the `SqliteRows`
/// iterator). For example:
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn bad_function_will_panic(conn: &SqliteConnection) -> SqliteResult<i64> {
/// let mut stmt = try!(conn.prepare("SELECT id FROM my_table"));
/// let mut rows = try!(stmt.query(&[]));
///
/// let row0 = try!(rows.next().unwrap());
/// // row 0 is value now...
///
/// let row1 = try!(rows.next().unwrap());
/// // row 0 is now STALE, and row 1 is valid
///
/// let my_id = row0.get(0); // WILL PANIC because row 0 is stale
/// Ok(my_id)
/// }
/// ```
///
/// Please note that this means some of the methods on `Iterator` are not useful, such as `collect`
/// (which would result in a collection of rows, only the last of which can safely be used) and
/// `min`/`max` (which could return a stale row unless the last row happened to be the min or max,
/// respectively).
///
/// This problem could be solved by changing the signature of `next` to tie the lifetime of the
/// returned row to the lifetime of (a mutable reference to) the result rows handle, but this would
/// no longer implement `Iterator`, and therefore you would lose access to the majority of
/// functions which are useful (such as support for `for ... in ...` looping, `map`, `filter`,
/// etc.).
pub struct SqliteRows<'stmt> {
stmt: &'stmt SqliteStatement<'stmt>,
current_row: Rc<Cell<c_int>>,
failed: bool,
}
impl<'stmt> SqliteRows<'stmt> {
fn new(stmt: &'stmt SqliteStatement<'stmt>) -> SqliteRows<'stmt> {
SqliteRows{ stmt: stmt, current_row: Rc::new(Cell::new(0)), failed: false }
}
}
impl<'stmt> Iterator for SqliteRows<'stmt> {
type Item = SqliteResult<SqliteRow<'stmt>>;
fn next(&mut self) -> Option<SqliteResult<SqliteRow<'stmt>>> {
if self.failed {
return None;
}
match unsafe { ffi::sqlite3_step(self.stmt.stmt) } {
ffi::SQLITE_ROW => {
let current_row = self.current_row.get() + 1;
self.current_row.set(current_row);
Some(Ok(SqliteRow{
stmt: self.stmt,
current_row: self.current_row.clone(),
row_idx: current_row,
}))
},
ffi::SQLITE_DONE => None,
code => {
self.failed = true;
Some(Err(self.stmt.conn.decode_result(code).unwrap_err()))
}
}
}
}
/// A single result row of a query.
pub struct SqliteRow<'stmt> {
stmt: &'stmt SqliteStatement<'stmt>,
current_row: Rc<Cell<c_int>>,
row_idx: c_int,
}
impl<'stmt> SqliteRow<'stmt> {
/// Get the value of a particular column of the result row.
///
/// Note that `SqliteRow` can panic at runtime if you use it incorrectly. When you are
/// retrieving the rows of a query, a row becomes stale once you have requested the next row,
/// and the values can no longer be retrieved. In general (when using looping over the rows,
/// for example) this isn't an issue, but it means you cannot do something like this:
///
/// ```rust,no_run
/// # use rusqlite::{SqliteConnection, SqliteResult};
/// fn bad_function_will_panic(conn: &SqliteConnection) -> SqliteResult<i64> {
/// let mut stmt = try!(conn.prepare("SELECT id FROM my_table"));
/// let mut rows = try!(stmt.query(&[]));
///
/// let row0 = try!(rows.next().unwrap());
/// // row 0 is value now...
///
/// let row1 = try!(rows.next().unwrap());
/// // row 0 is now STALE, and row 1 is valid
///
/// let my_id = row0.get(0); // WILL PANIC because row 0 is stale
/// Ok(my_id)
/// }
/// ```
///
/// ## Failure
///
/// 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_checked(idx).unwrap()
}
/// Get the value of a particular column of the result row.
///
/// ## Failure
///
/// Returns a `SQLITE_MISMATCH`-coded `SqliteError` if the underlying SQLite column
/// type is not a valid type as a source for `T`.
///
/// 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_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() });
}
unsafe {
if idx < 0 || idx >= self.stmt.column_count {
return Err(SqliteError{ code: ffi::SQLITE_MISUSE,
message: "Invalid column index".to_string() });
}
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(),
})
}
}
}
}
#[cfg(test)]
mod test {
extern crate libsqlite3_sys as ffi;
extern crate tempdir;
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
// that those types are `Send`.
#[allow(dead_code, unconditional_recursion)]
fn ensure_send<T: Send>() {
ensure_send::<SqliteConnection>();
}
pub fn checked_memory_handle() -> SqliteConnection {
SqliteConnection::open_in_memory().unwrap()
}
#[test]
fn test_persistence() {
let temp_dir = TempDir::new("test_open_file").unwrap();
let path = temp_dir.path().join("test.db3");