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use crate::{Client, Error, Transaction};
#[derive(Debug, Copy, Clone)]
#[non_exhaustive]
pub enum IsolationLevel {
ReadUncommitted,
ReadCommitted,
RepeatableRead,
Serializable,
}
pub struct TransactionBuilder<'a> {
client: &'a mut Client,
isolation_level: Option<IsolationLevel>,
read_only: Option<bool>,
deferrable: Option<bool>,
}
impl<'a> TransactionBuilder<'a> {
pub(crate) fn new(client: &'a mut Client) -> TransactionBuilder<'a> {
TransactionBuilder {
client,
isolation_level: None,
read_only: None,
deferrable: None,
}
}
pub fn isolation_level(mut self, isolation_level: IsolationLevel) -> Self {
self.isolation_level = Some(isolation_level);
self
}
pub fn read_only(mut self, read_only: bool) -> Self {
self.read_only = Some(read_only);
self
}
pub fn deferrable(mut self, deferrable: bool) -> Self {
self.deferrable = Some(deferrable);
self
}
pub async fn start(self) -> Result<Transaction<'a>, Error> {
let mut query = "START TRANSACTION".to_string();
let mut first = true;
if let Some(level) = self.isolation_level {
first = false;
query.push_str(" ISOLATION LEVEL ");
let level = match level {
IsolationLevel::ReadUncommitted => "READ UNCOMMITTED",
IsolationLevel::ReadCommitted => "READ COMMITTED",
IsolationLevel::RepeatableRead => "REPEATABLE READ",
IsolationLevel::Serializable => "SERIALIZABLE",
};
query.push_str(level);
}
if let Some(read_only) = self.read_only {
if !first {
query.push(',');
}
first = false;
let s = if read_only {
" READ ONLY"
} else {
" READ WRITE"
};
query.push_str(s);
}
if let Some(deferrable) = self.deferrable {
if !first {
query.push(',');
}
let s = if deferrable {
" DEFERRABLE"
} else {
" NOT DEFERRABLE"
};
query.push_str(s);
}
self.client.batch_execute(&query).await?;
Ok(Transaction::new(self.client))
}
}