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use crate::any::{Any, AnyArguments, AnyQueryResult, AnyRow, AnyStatement, AnyTypeInfo};
use crate::describe::Describe;
use either::Either;
use futures_core::future::BoxFuture;
use futures_core::stream::BoxStream;
use std::borrow::Cow;
use std::fmt::Debug;
pub trait AnyConnectionBackend: std::any::Any + Debug + Send + 'static {
/// The backend name.
fn name(&self) -> &str;
/// Explicitly close this database connection.
///
/// This method is **not required** for safe and consistent operation. However, it is
/// recommended to call it instead of letting a connection `drop` as the database backend
/// will be faster at cleaning up resources.
fn close(self: Box<Self>) -> BoxFuture<'static, crate::Result<()>>;
/// Immediately close the connection without sending a graceful shutdown.
///
/// This should still at least send a TCP `FIN` frame to let the server know we're dying.
#[doc(hidden)]
fn close_hard(self: Box<Self>) -> BoxFuture<'static, crate::Result<()>>;
/// Checks if a connection to the database is still valid.
fn ping(&mut self) -> BoxFuture<'_, crate::Result<()>>;
/// Begin a new transaction or establish a savepoint within the active transaction.
///
/// If this is a new transaction, `statement` may be used instead of the
/// default "BEGIN" statement.
///
/// If we are already inside a transaction and `statement.is_some()`, then
/// `Error::InvalidSavePoint` is returned without running any statements.
fn begin(&mut self, statement: Option<Cow<'static, str>>) -> BoxFuture<'_, crate::Result<()>>;
fn commit(&mut self) -> BoxFuture<'_, crate::Result<()>>;
fn rollback(&mut self) -> BoxFuture<'_, crate::Result<()>>;
fn start_rollback(&mut self);
/// Returns the current transaction depth.
///
/// Transaction depth indicates the level of nested transactions:
/// - Level 0: No active transaction.
/// - Level 1: A transaction is active.
/// - Level 2 or higher: A transaction is active and one or more SAVEPOINTs have been created within it.
fn get_transaction_depth(&self) -> usize {
unimplemented!("get_transaction_depth() is not implemented for this backend. This is a provided method to avoid a breaking change, but it will become a required method in version 0.9 and later.");
}
/// Checks if the connection is currently in a transaction.
///
/// This method returns `true` if the current transaction depth is greater than 0,
/// indicating that a transaction is active. It returns `false` if the transaction depth is 0,
/// meaning no transaction is active.
#[inline]
fn is_in_transaction(&self) -> bool {
self.get_transaction_depth() != 0
}
/// The number of statements currently cached in the connection.
fn cached_statements_size(&self) -> usize {
0
}
/// Removes all statements from the cache, closing them on the server if
/// needed.
fn clear_cached_statements(&mut self) -> BoxFuture<'_, crate::Result<()>> {
Box::pin(async move { Ok(()) })
}
/// Forward to [`Connection::shrink_buffers()`].
///
/// [`Connection::shrink_buffers()`]: method@crate::connection::Connection::shrink_buffers
fn shrink_buffers(&mut self);
#[doc(hidden)]
fn flush(&mut self) -> BoxFuture<'_, crate::Result<()>>;
#[doc(hidden)]
fn should_flush(&self) -> bool;
#[cfg(feature = "migrate")]
fn as_migrate(&mut self) -> crate::Result<&mut (dyn crate::migrate::Migrate + Send + 'static)> {
Err(crate::Error::Configuration(
format!(
"{} driver does not support migrations or `migrate` feature was not enabled",
self.name()
)
.into(),
))
}
fn fetch_many<'q>(
&'q mut self,
query: &'q str,
persistent: bool,
arguments: Option<AnyArguments<'q>>,
) -> BoxStream<'q, crate::Result<Either<AnyQueryResult, AnyRow>>>;
fn fetch_optional<'q>(
&'q mut self,
query: &'q str,
persistent: bool,
arguments: Option<AnyArguments<'q>>,
) -> BoxFuture<'q, crate::Result<Option<AnyRow>>>;
fn prepare_with<'c, 'q: 'c>(
&'c mut self,
sql: &'q str,
parameters: &[AnyTypeInfo],
) -> BoxFuture<'c, crate::Result<AnyStatement<'q>>>;
fn describe<'q>(&'q mut self, sql: &'q str) -> BoxFuture<'q, crate::Result<Describe<Any>>>;
}