diff options
| -rw-r--r-- | db.go | 88 | ||||
| -rw-r--r-- | db_test.go | 18 | ||||
| -rw-r--r-- | example_test.go | 27 |
3 files changed, 83 insertions, 50 deletions
@@ -330,6 +330,26 @@ func (db *DB) removeTransaction(t *Transaction) { } } +// Do executes a function within the context of a RWTransaction. +// If no error is returned from the function then the transaction is committed. +// If an error is returned then the entire transaction is rolled back. +// Any error that is returned from the function or returned from the commit is +// returned from the Do() method. +func (db *DB) Do(fn func(*RWTransaction) error) error { + t, err := db.RWTransaction() + if err != nil { + return err + } + + // If an error is returned from the function then rollback and return error. + if err := fn(t); err != nil { + t.Rollback() + return err + } + + return t.Commit() +} + // Bucket retrieves a reference to a bucket. // This is typically useful for checking the existence of a bucket. func (db *DB) Bucket(name string) (*Bucket, error) { @@ -355,49 +375,29 @@ func (db *DB) Buckets() ([]*Bucket, error) { // This function can return an error if the bucket already exists, if the name // is blank, or the bucket name is too long. func (db *DB) CreateBucket(name string) error { - t, err := db.RWTransaction() - if err != nil { - return err - } - - if err := t.CreateBucket(name); err != nil { - t.Rollback() - return err - } - - return t.Commit() + return db.Do(func(t *RWTransaction) error { + return t.CreateBucket(name) + }) } // DeleteBucket removes a bucket from the database. // Returns an error if the bucket does not exist. func (db *DB) DeleteBucket(name string) error { - t, err := db.RWTransaction() - if err != nil { - return err - } - - if err := t.DeleteBucket(name); err != nil { - t.Rollback() - return err - } - - return t.Commit() + return db.Do(func(t *RWTransaction) error { + return t.DeleteBucket(name) + }) } // NextSequence returns an autoincrementing integer for the bucket. // This function can return an error if the bucket does not exist. func (db *DB) NextSequence(name string) (int, error) { - t, err := db.RWTransaction() - if err != nil { - return 0, err - } - - seq, err := t.NextSequence(name) + var seq int + err := db.Do(func(t *RWTransaction) error { + var err error + seq, err = t.NextSequence(name) + return err + }) if err != nil { - t.Rollback() - return 0, err - } - if err := t.Commit(); err != nil { return 0, err } return seq, nil @@ -417,29 +417,17 @@ func (db *DB) Get(name string, key []byte) ([]byte, error) { // Put sets the value for a key in a bucket. // Returns an error if the bucket is not found, if key is blank, if the key is too large, or if the value is too large. func (db *DB) Put(name string, key []byte, value []byte) error { - t, err := db.RWTransaction() - if err != nil { - return err - } - if err := t.Put(name, key, value); err != nil { - t.Rollback() - return err - } - return t.Commit() + return db.Do(func(t *RWTransaction) error { + return t.Put(name, key, value) + }) } // Delete removes a key from a bucket. // Returns an error if the bucket cannot be found. func (db *DB) Delete(name string, key []byte) error { - t, err := db.RWTransaction() - if err != nil { - return err - } - if err := t.Delete(name, key); err != nil { - t.Rollback() - return err - } - return t.Commit() + return db.Do(func(t *RWTransaction) error { + return t.Delete(name, key) + }) } // Copy writes the entire database to a writer. @@ -178,6 +178,24 @@ func TestDBDelete(t *testing.T) { }) } +// Ensure a database can provide a transactional block. +func TestDBTransactionBlock(t *testing.T) { + withOpenDB(func(db *DB, path string) { + err := db.Do(func(txn *RWTransaction) error { + txn.CreateBucket("widgets") + txn.Put("widgets", []byte("foo"), []byte("bar")) + txn.Put("widgets", []byte("baz"), []byte("bat")) + txn.Delete("widgets", []byte("foo")) + return nil + }) + assert.NoError(t, err) + value, _ := db.Get("widgets", []byte("foo")) + assert.Nil(t, value) + value, _ = db.Get("widgets", []byte("baz")) + assert.Equal(t, value, []byte("bat")) + }) +} + // Ensure that the database can be copied to a writer. func TestDBCopy(t *testing.T) { t.Skip("pending") // TODO(benbjohnson) diff --git a/example_test.go b/example_test.go index 892807e..655e283 100644 --- a/example_test.go +++ b/example_test.go @@ -60,6 +60,33 @@ func ExampleDB_Delete() { // The value of 'foo' is now: nil } +func ExampleDB_Do() { + // Open the database. + var db DB + db.Open("/tmp/bolt/db_do.db", 0666) + defer db.Close() + + // Execute several commands within a write transaction. + err := db.Do(func(t *RWTransaction) error { + if err := t.CreateBucket("widgets"); err != nil { + return err + } + if err := t.Put("widgets", []byte("foo"), []byte("bar")); err != nil { + return err + } + return nil + }) + + // If our transactional block didn't return an error then our data is saved. + if err == nil { + value, _ := db.Get("widgets", []byte("foo")) + fmt.Printf("The value of 'foo' is: %s\n", string(value)) + } + + // Output: + // The value of 'foo' is: bar +} + func ExampleRWTransaction() { // Open the database. var db DB |