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use super::{
as_handle::AsHandle, buffer::buf_ptr, drop_handle, error::Error, error::IntoResult,
statement::Statement,
};
use odbc_sys::{
CompletionType, ConnectionAttribute, DriverConnectOption, HDbc, HEnv, HStmt, Handle,
HandleType, Pointer, SQLAllocHandle, SQLConnectW, SQLDisconnect, SQLDriverConnectW, SQLEndTran,
SQLSetConnectAttrW,
};
use std::{convert::TryInto, marker::PhantomData, ptr::null_mut};
use widestring::U16Str;
/// The connection handle references storage of all information about the connection to the data
/// source, including status, transaction state, and error information.
pub struct Connection<'c> {
parent: PhantomData<&'c HEnv>,
handle: HDbc,
}
unsafe impl<'c> AsHandle for Connection<'c> {
fn as_handle(&self) -> Handle {
self.handle as Handle
}
fn handle_type(&self) -> HandleType {
HandleType::Dbc
}
}
impl<'c> Drop for Connection<'c> {
fn drop(&mut self) {
unsafe {
drop_handle(self.handle as Handle, HandleType::Dbc);
}
}
}
impl<'c> Connection<'c> {
/// # Safety
///
/// Call this method only with a valid (successfully allocated) ODBC connection handle.
pub unsafe fn new(handle: HDbc) -> Self {
Self {
handle,
parent: PhantomData,
}
}
/// Establishes connections to a driver and a data source.
///
/// * See [Connecting with SQLConnect][1]
/// * See [SQLConnectFunction][2]
///
/// # Arguments
///
/// * `data_source_name` - Data source name. The data might be located on the same computer as
/// the program, or on another computer somewhere on a network.
/// * `user` - User identifier.
/// * `pwd` - Authentication string (typically the password).
/// [1]: https://docs.microsoft.com/sql/odbc/reference/syntax/sqlconnect-function
/// [2]: https://docs.microsoft.com/sql/odbc/reference/syntax/sqlconnect-function
pub fn connect(
&mut self,
data_source_name: &U16Str,
user: &U16Str,
pwd: &U16Str,
) -> Result<(), Error> {
unsafe {
SQLConnectW(
self.handle,
buf_ptr(data_source_name.as_slice()),
data_source_name.len().try_into().unwrap(),
buf_ptr(user.as_slice()),
user.len().try_into().unwrap(),
buf_ptr(pwd.as_slice()),
pwd.len().try_into().unwrap(),
)
.into_result(self)?;
Ok(())
}
}
/// An alternative to `connect`. It supports data sources that require more connection
/// information than the three arguments in `connect` and data sources that are not defined in
/// the system information.
pub fn connect_with_connection_string(
&mut self,
connection_string: &U16Str,
) -> Result<(), Error> {
unsafe {
let window_handle = null_mut();
let out_connection_string = null_mut();
let out_connection_string_len = null_mut();
SQLDriverConnectW(
self.handle,
window_handle,
buf_ptr(connection_string.as_slice()),
connection_string.len().try_into().unwrap(),
out_connection_string,
0,
out_connection_string_len,
DriverConnectOption::NoPrompt,
)
.into_result(self)?;
Ok(())
}
}
/// Disconnect from an ODBC data source.
pub fn disconnect(&mut self) -> Result<(), Error> {
unsafe { SQLDisconnect(self.handle).into_result(self) }
}
/// Allocate a new statement handle. The `Statement` must not outlive the `Connection`.
pub fn allocate_statement(&self) -> Result<Statement, Error> {
let mut out = null_mut();
unsafe {
SQLAllocHandle(HandleType::Stmt, self.as_handle(), &mut out).into_result(self)?;
Ok(Statement::new(out as HStmt))
}
}
/// Specify the transaction mode. By default, ODBC transactions are in auto-commit mode (unless
/// SQLSetConnectAttr and SQLSetConnectOption are not supported, which is unlikely). Switching
/// from manual-commit mode to auto-commit mode automatically commits any open transaction on
/// the connection.
pub fn set_autocommit(&mut self, enabled: bool) -> Result<(), Error> {
let val = if enabled { 1u32 } else { 0u32 };
unsafe {
SQLSetConnectAttrW(
self.handle,
ConnectionAttribute::AutoCommit,
val as Pointer,
0, // will be ignored according to ODBC spec
)
.into_result(self)
}
}
/// To commit a transaction in manual-commit mode.
pub fn commit(&mut self) -> Result<(), Error> {
unsafe {
SQLEndTran(HandleType::Dbc, self.as_handle(), CompletionType::Commit).into_result(self)
}
}
/// Roll back a transaction in manual-commit mode.
pub fn rollback(&mut self) -> Result<(), Error> {
unsafe {
SQLEndTran(HandleType::Dbc, self.as_handle(), CompletionType::Rollback)
.into_result(self)
}
}
}