Allow specifying transaction behaviors DEFERRED, IMMEDIATE, and EXCLUSIVE

include/SQLiteCpp/Transaction.h

@@ -20,6 +20,16 @@ namespace SQLite
 // Forward declaration
 class Database;
 
+/**
+ * @brief Transaction behaviors when opening an SQLite transaction.
+ * Names correspond directly to the behavior.
+ */
+enum class TransactionBehavior {
+    DEFERRED,
+    IMMEDIATE,
+    EXCLUSIVE,
+};
+
 /**
  * @brief RAII encapsulation of a SQLite Transaction.
  *
@@ -44,7 +54,7 @@ class Transaction
 {
 public:
     /**
-     * @brief Begins the SQLite transaction
+     * @brief Begins the SQLite transaction using the default transaction behavior.
      *
      * @param[in] aDatabase the SQLite Database Connection
      *
@@ -52,6 +62,16 @@ public:
      */
     explicit Transaction(Database& aDatabase);
 
+    /**
+     * @brief Begins the SQLite transaction with the specified behavior.
+     *
+     * @param[in] aDatabase the SQLite Database Connection
+     * @param[in] behavior the requested transaction behavior
+     *
+     * Exception is thrown in case of error, then the Transaction is NOT initiated.
+     */
+    explicit Transaction(Database& aDatabase, TransactionBehavior behavior);
+
     // Transaction is non-copyable
     Transaction(const Transaction&) = delete;
     Transaction& operator=(const Transaction&) = delete;

src/Transaction.cpp

@@ -13,11 +13,34 @@
 #include <SQLiteCpp/Database.h>
 #include <SQLiteCpp/Assertion.h>
 
+#include <sqlite3.h>
 
 namespace SQLite
 {
 
 
+// Begins the SQLite transaction
+Transaction::Transaction(Database& aDatabase, TransactionBehavior behavior) :
+    mDatabase(aDatabase),
+    mbCommited(false)
+{
+    const char *stmt;
+    switch (behavior) {
+        case TransactionBehavior::DEFERRED:
+            stmt = "BEGIN DEFERRED";
+            break;
+        case TransactionBehavior::IMMEDIATE:
+            stmt = "BEGIN IMMEDIATE";
+            break;
+        case TransactionBehavior::EXCLUSIVE:
+            stmt = "BEGIN EXCLUSIVE";
+            break;
+        default:
+            throw SQLite::Exception("invalid/unknown transaction behavior", SQLITE_ERROR);
+    }
+    mDatabase.exec(stmt);
+}
+
 // Begins the SQLite transaction
 Transaction::Transaction(Database &aDatabase) :
     mDatabase(aDatabase),

tests/Transaction_test.cpp

@@ -42,6 +42,20 @@ TEST(Transaction, commitRollback)
         EXPECT_THROW(transaction.commit(), SQLite::Exception);
     }
 
+    // ensure transactions with different types are well-formed
+    {
+        for (auto behavior : {
+            SQLite::TransactionBehavior::DEFERRED,
+            SQLite::TransactionBehavior::IMMEDIATE,
+            SQLite::TransactionBehavior::EXCLUSIVE })
+        {
+            SQLite::Transaction transaction(db, behavior);
+            transaction.commit();
+        }
+
+        EXPECT_THROW(SQLite::Transaction(db, static_cast<SQLite::TransactionBehavior>(-1)), SQLite::Exception);
+    }
+
     // Auto rollback if no commit() before the end of scope
     {
         // Begin transaction