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https://github.com/isar/rusqlite.git
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Reorganize: Extract Statement and its impl into its own module.
This commit is contained in:
John Gallagher
376
src/statement.rs
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376
src/statement.rs
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use std::{convert, fmt, mem, ptr, result, str};
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use std::ffi::CStr;
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use std::os::raw::{c_char, c_int, c_void};
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use std::slice::from_raw_parts;
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use super::ffi;
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use super::{Connection, RawStatement, Result, Error, ValueRef, Row, Rows, AndThenRows, MappedRows};
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use super::str_to_cstring;
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use types::{ToSql, ToSqlOutput};
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/// A prepared statement.
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pub struct Statement<'conn> {
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conn: &'conn Connection,
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stmt: RawStatement,
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}
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impl<'conn> Statement<'conn> {
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/// Get all the column names in the result set of the prepared statement.
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pub fn column_names(&self) -> Vec<&str> {
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let n = self.column_count();
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let mut cols = Vec::with_capacity(n as usize);
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for i in 0..n {
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let slice = self.stmt.column_name(i);
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let s = str::from_utf8(slice.to_bytes()).unwrap();
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cols.push(s);
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}
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cols
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}
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/// Return the number of columns in the result set returned by the prepared statement.
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pub fn column_count(&self) -> i32 {
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self.stmt.column_count()
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}
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/// Returns the column index in the result set for a given column name.
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///
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/// If there is no AS clause then the name of the column is unspecified and may change from one
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/// release of SQLite to the next.
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///
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/// # Failure
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///
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/// Will return an `Error::InvalidColumnName` when there is no column with the specified `name`.
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pub fn column_index(&self, name: &str) -> Result<i32> {
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let bytes = name.as_bytes();
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let n = self.column_count();
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for i in 0..n {
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if bytes == self.stmt.column_name(i).to_bytes() {
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return Ok(i);
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}
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}
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Err(Error::InvalidColumnName(String::from(name)))
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}
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/// Execute the prepared statement.
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///
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/// On success, returns the number of rows that were changed or inserted or deleted (via
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/// `sqlite3_changes`).
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///
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/// ## Example
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///
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/// ```rust,no_run
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/// # use rusqlite::{Connection, Result};
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/// fn update_rows(conn: &Connection) -> Result<()> {
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/// let mut stmt = try!(conn.prepare("UPDATE foo SET bar = 'baz' WHERE qux = ?"));
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///
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/// try!(stmt.execute(&[&1i32]));
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/// try!(stmt.execute(&[&2i32]));
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///
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/// Ok(())
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/// }
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/// ```
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///
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/// # Failure
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///
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/// Will return `Err` if binding parameters fails, the executed statement returns rows (in
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/// which case `query` should be used instead), or the underling SQLite call fails.
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pub fn execute(&mut self, params: &[&ToSql]) -> Result<c_int> {
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try!(self.bind_parameters(params));
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self.execute_()
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}
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/// Execute the prepared statement, returning a handle to the resulting rows.
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///
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/// Due to lifetime restricts, the rows handle returned by `query` does not
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/// implement the `Iterator` trait. Consider using `query_map` or `query_and_then`
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/// instead, which do.
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///
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/// ## Example
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///
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/// ```rust,no_run
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/// # use rusqlite::{Connection, Result};
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/// fn get_names(conn: &Connection) -> Result<Vec<String>> {
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/// let mut stmt = try!(conn.prepare("SELECT name FROM people"));
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/// let mut rows = try!(stmt.query(&[]));
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///
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/// let mut names = Vec::new();
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/// while let Some(result_row) = rows.next() {
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/// let row = try!(result_row);
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/// names.push(row.get(0));
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/// }
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///
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/// Ok(names)
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/// }
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/// ```
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///
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/// ## Failure
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///
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/// Will return `Err` if binding parameters fails.
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pub fn query<'a>(&'a mut self, params: &[&ToSql]) -> Result<Rows<'a>> {
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try!(self.bind_parameters(params));
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Ok(Rows::new(self))
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}
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/// Executes the prepared statement and maps a function over the resulting rows, returning
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/// an iterator over the mapped function results.
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///
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/// ## Example
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///
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/// ```rust,no_run
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/// # use rusqlite::{Connection, Result};
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/// fn get_names(conn: &Connection) -> Result<Vec<String>> {
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/// let mut stmt = try!(conn.prepare("SELECT name FROM people"));
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/// let rows = try!(stmt.query_map(&[], |row| row.get(0)));
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///
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/// let mut names = Vec::new();
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/// for name_result in rows {
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/// names.push(try!(name_result));
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/// }
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///
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/// Ok(names)
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/// }
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/// ```
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///
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/// ## Failure
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///
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/// Will return `Err` if binding parameters fails.
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pub fn query_map<'a, T, F>(&'a mut self, params: &[&ToSql], f: F) -> Result<MappedRows<'a, F>>
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where F: FnMut(&Row) -> T
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{
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let row_iter = try!(self.query(params));
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Ok(MappedRows {
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rows: row_iter,
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map: f,
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})
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}
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/// Executes the prepared statement and maps a function over the resulting
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/// rows, where the function returns a `Result` with `Error` type implementing
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/// `std::convert::From<Error>` (so errors can be unified).
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///
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/// # Failure
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///
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/// Will return `Err` if binding parameters fails.
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pub fn query_and_then<'a, T, E, F>(&'a mut self,
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params: &[&ToSql],
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f: F)
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-> Result<AndThenRows<'a, F>>
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where E: convert::From<Error>,
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F: FnMut(&Row) -> result::Result<T, E>
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{
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let row_iter = try!(self.query(params));
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Ok(AndThenRows {
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rows: row_iter,
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map: f,
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})
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}
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/// Consumes the statement.
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///
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/// Functionally equivalent to the `Drop` implementation, but allows callers to see any errors
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/// that occur.
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///
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/// # Failure
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///
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/// Will return `Err` if the underlying SQLite call fails.
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pub fn finalize(mut self) -> Result<()> {
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self.finalize_()
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}
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fn bind_parameters(&mut self, params: &[&ToSql]) -> Result<()> {
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assert!(params.len() as c_int == self.stmt.bind_parameter_count(),
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"incorrect number of parameters to query(): expected {}, got {}",
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self.stmt.bind_parameter_count(),
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params.len());
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for (i, p) in params.iter().enumerate() {
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try!(self.bind_parameter(*p, (i + 1) as c_int));
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}
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Ok(())
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}
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fn finalize_(&mut self) -> Result<()> {
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let mut stmt = RawStatement::new(ptr::null_mut());
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mem::swap(&mut stmt, &mut self.stmt);
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self.conn.decode_result(stmt.finalize())
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}
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}
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impl<'conn> Into<RawStatement> for Statement<'conn> {
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fn into(mut self) -> RawStatement {
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let mut stmt = RawStatement::new(ptr::null_mut());
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mem::swap(&mut stmt, &mut self.stmt);
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stmt
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}
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}
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impl<'conn> fmt::Debug for Statement<'conn> {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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let sql = str::from_utf8(self.stmt.sql().to_bytes());
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f.debug_struct("Statement")
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.field("conn", self.conn)
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.field("stmt", &self.stmt)
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.field("sql", &sql)
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.finish()
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}
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}
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impl<'conn> Drop for Statement<'conn> {
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#[allow(unused_must_use)]
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fn drop(&mut self) {
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self.finalize_();
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}
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}
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// TODO: This trait lets us have "pub(crate)" visibility on some Statement methods. Remove this
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// once pub(crate) is stable.
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pub trait StatementCrateImpl<'conn> {
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fn new(conn: &'conn Connection, stmt: RawStatement) -> Self;
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fn execute_(&mut self) -> Result<c_int>;
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fn bind_parameter(&self, param: &ToSql, col: c_int) -> Result<()>;
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fn bind_parameter_index(&self, name: &CStr) -> Option<c_int>;
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fn last_insert_rowid(&self) -> i64;
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fn value_ref(&self, col: c_int) -> ValueRef;
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fn step(&self) -> c_int;
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fn reset(&self) -> c_int;
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fn decode_result(&self, code: c_int) -> Result<()>;
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}
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impl<'conn> StatementCrateImpl<'conn> for Statement<'conn> {
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fn new(conn: &Connection, stmt: RawStatement) -> Statement {
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Statement {
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conn: conn,
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stmt: stmt,
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}
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}
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fn execute_(&mut self) -> Result<c_int> {
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let r = self.stmt.step();
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self.stmt.reset();
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match r {
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ffi::SQLITE_DONE => {
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if self.column_count() == 0 {
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Ok(self.conn.changes())
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} else {
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Err(Error::ExecuteReturnedResults)
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}
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}
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ffi::SQLITE_ROW => Err(Error::ExecuteReturnedResults),
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_ => Err(self.conn.decode_result(r).unwrap_err()),
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}
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}
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fn bind_parameter(&self, param: &ToSql, col: c_int) -> Result<()> {
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let value = try!(param.to_sql());
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let ptr = unsafe { self.stmt.ptr() };
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let value = match value {
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ToSqlOutput::Borrowed(v) => v,
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ToSqlOutput::Owned(ref v) => ValueRef::from(v),
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#[cfg(feature = "blob")]
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ToSqlOutput::ZeroBlob(len) => {
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return self.conn
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.decode_result(unsafe { ffi::sqlite3_bind_zeroblob(ptr, col, len) });
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}
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};
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self.conn.decode_result(match value {
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ValueRef::Null => unsafe { ffi::sqlite3_bind_null(ptr, col) },
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ValueRef::Integer(i) => unsafe { ffi::sqlite3_bind_int64(ptr, col, i) },
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ValueRef::Real(r) => unsafe { ffi::sqlite3_bind_double(ptr, col, r) },
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ValueRef::Text(s) => unsafe {
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let length = s.len();
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if length > ::std::i32::MAX as usize {
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ffi::SQLITE_TOOBIG
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} else {
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let c_str = try!(str_to_cstring(s));
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let destructor = if length > 0 {
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ffi::SQLITE_TRANSIENT()
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} else {
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ffi::SQLITE_STATIC()
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};
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ffi::sqlite3_bind_text(ptr, col, c_str.as_ptr(), length as c_int, destructor)
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}
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},
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ValueRef::Blob(b) => unsafe {
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let length = b.len();
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if length > ::std::i32::MAX as usize {
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ffi::SQLITE_TOOBIG
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} else if length == 0 {
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ffi::sqlite3_bind_zeroblob(ptr, col, 0)
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} else {
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ffi::sqlite3_bind_blob(ptr,
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col,
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b.as_ptr() as *const c_void,
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length as c_int,
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ffi::SQLITE_TRANSIENT())
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}
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},
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})
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}
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fn bind_parameter_index(&self, name: &CStr) -> Option<c_int> {
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self.stmt.bind_parameter_index(name)
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}
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fn last_insert_rowid(&self) -> i64 {
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self.conn.last_insert_rowid()
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}
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fn value_ref(&self, col: c_int) -> ValueRef {
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let raw = unsafe { self.stmt.ptr() };
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match self.stmt.column_type(col) {
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ffi::SQLITE_NULL => ValueRef::Null,
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ffi::SQLITE_INTEGER => {
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ValueRef::Integer(unsafe { ffi::sqlite3_column_int64(raw, col) })
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}
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ffi::SQLITE_FLOAT => ValueRef::Real(unsafe { ffi::sqlite3_column_double(raw, col) }),
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ffi::SQLITE_TEXT => {
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let s = unsafe {
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let text = ffi::sqlite3_column_text(raw, col);
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assert!(!text.is_null(),
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"unexpected SQLITE_TEXT column type with NULL data");
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CStr::from_ptr(text as *const c_char)
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};
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// sqlite3_column_text returns UTF8 data, so our unwrap here should be fine.
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let s = s.to_str().expect("sqlite3_column_text returned invalid UTF-8");
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ValueRef::Text(s)
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}
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ffi::SQLITE_BLOB => {
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let (blob, len) = unsafe {
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(ffi::sqlite3_column_blob(raw, col), ffi::sqlite3_column_bytes(raw, col))
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};
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assert!(len >= 0,
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"unexpected negative return from sqlite3_column_bytes");
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if len > 0 {
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assert!(!blob.is_null(),
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"unexpected SQLITE_BLOB column type with NULL data");
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ValueRef::Blob(unsafe { from_raw_parts(blob as *const u8, len as usize) })
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} else {
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// The return value from sqlite3_column_blob() for a zero-length BLOB
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// is a NULL pointer.
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ValueRef::Blob(&[])
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}
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}
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_ => unreachable!("sqlite3_column_type returned invalid value"),
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}
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}
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fn step(&self) -> i32 {
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self.stmt.step()
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}
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fn reset(&self) -> c_int {
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self.stmt.reset()
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}
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fn decode_result(&self, code: c_int) -> Result<()> {
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self.conn.decode_result(code)
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}
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}
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