Merge pull request #1532 from seddonm1/feat/set-transaction-behavior

Allow setting default connection transaction behavior

src/lib.rs

@@ -377,6 +377,7 @@ impl DatabaseName<'_> {
 pub struct Connection {
     db: RefCell<InnerConnection>,
     cache: StatementCache,
+    transaction_behavior: TransactionBehavior,
 }
 
 unsafe impl Send for Connection {}
@@ -473,6 +474,7 @@ impl Connection {
         InnerConnection::open_with_flags(&c_path, flags, None).map(|db| Connection {
             db: RefCell::new(db),
             cache: StatementCache::with_capacity(STATEMENT_CACHE_DEFAULT_CAPACITY),
+            transaction_behavior: TransactionBehavior::Deferred,
         })
     }
 
@@ -497,6 +499,7 @@ impl Connection {
         InnerConnection::open_with_flags(&c_path, flags, Some(&c_vfs)).map(|db| Connection {
             db: RefCell::new(db),
             cache: StatementCache::with_capacity(STATEMENT_CACHE_DEFAULT_CAPACITY),
+            transaction_behavior: TransactionBehavior::Deferred,
         })
     }
 
@@ -949,6 +952,7 @@ impl Connection {
         Ok(Connection {
             db: RefCell::new(db),
             cache: StatementCache::with_capacity(STATEMENT_CACHE_DEFAULT_CAPACITY),
+            transaction_behavior: TransactionBehavior::Deferred,
         })
     }
 
@@ -997,6 +1001,7 @@ impl Connection {
         Ok(Connection {
             db: RefCell::new(db),
             cache: StatementCache::with_capacity(STATEMENT_CACHE_DEFAULT_CAPACITY),
+            transaction_behavior: TransactionBehavior::Deferred,
         })
     }
 

src/transaction.rs

@@ -414,7 +414,7 @@ impl Connection {
     /// Will return `Err` if the underlying SQLite call fails.
     #[inline]
     pub fn transaction(&mut self) -> Result<Transaction<'_>> {
-        Transaction::new(self, TransactionBehavior::Deferred)
+        Transaction::new(self, self.transaction_behavior)
     }
 
     /// Begin a new transaction with a specified behavior.
@@ -464,7 +464,7 @@ impl Connection {
     /// Will return `Err` if the underlying SQLite call fails. The specific
     /// error returned if transactions are nested is currently unspecified.
     pub fn unchecked_transaction(&self) -> Result<Transaction<'_>> {
-        Transaction::new_unchecked(self, TransactionBehavior::Deferred)
+        Transaction::new_unchecked(self, self.transaction_behavior)
     }
 
     /// Begin a new savepoint with the default behavior (DEFERRED).
@@ -518,6 +518,34 @@ impl Connection {
     ) -> Result<TransactionState> {
         self.db.borrow().txn_state(db_name)
     }
+
+    /// Set the default transaction behavior for the connection.
+    ///
+    /// ## Note
+    ///
+    /// This will only apply to transactions initiated by [`transaction`](Connection::transaction)
+    /// or [`unchecked_transaction`](Connection::unchecked_transaction).
+    ///
+    /// ## Example
+    ///
+    /// ```rust,no_run
+    /// # use rusqlite::{Connection, Result, TransactionBehavior};
+    /// # fn do_queries_part_1(_conn: &Connection) -> Result<()> { Ok(()) }
+    /// # fn do_queries_part_2(_conn: &Connection) -> Result<()> { Ok(()) }
+    /// fn perform_queries(conn: &mut Connection) -> Result<()> {
+    ///     conn.set_transaction_behavior(TransactionBehavior::Immediate);
+    ///
+    ///     let tx = conn.transaction()?;
+    ///
+    ///     do_queries_part_1(&tx)?; // tx causes rollback if this fails
+    ///     do_queries_part_2(&tx)?; // tx causes rollback if this fails
+    ///
+    ///     tx.commit()
+    /// }
+    /// ```
+    pub fn set_transaction_behavior(&mut self, behavior: TransactionBehavior) {
+        self.transaction_behavior = behavior;
+    }
 }
 
 #[cfg(test)]