wip

2014-07-12 07:11:16 -05:00
parent 19537badff
commit f31665c5db
6 changed files with 464 additions and 194 deletions
@@ -0,0 +1,141 @@
+package pgx
+
+import (
+	"errors"
+	"fmt"
+)
+
+func (c *Conn) Begin() (*Tx, error) {
+	return c.begin("")
+}
+
+func (c *Conn) BeginIso(isoLevel string) (*Tx, error) {
+	return c.begin(isoLevel)
+}
+
+func (c *Conn) begin(isoLevel string) (*Tx, error) {
+	var beginSql string
+	if isoLevel == "" {
+		beginSql = "begin"
+	} else {
+		beginSql = fmt.Sprintf("begin isolation level %s", isoLevel)
+	}
+
+	_, err := c.Exec(beginSql)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Tx{conn: c}, nil
+}
+
+type Tx struct {
+	pool   *ConnPool
+	conn   *Conn
+	closed bool
+}
+
+// Commit commits the transaction
+func (tx *Tx) Commit() error {
+	if tx.closed {
+		return errors.New("tx is closed")
+	}
+
+	_, err := tx.conn.Exec("commit")
+	tx.close()
+	return err
+}
+
+// Rollback rolls back the transaction
+func (tx *Tx) Rollback() error {
+	if tx.closed {
+		return errors.New("tx is closed")
+	}
+
+	_, err := tx.conn.Exec("rollback")
+	tx.close()
+	return err
+}
+
+func (tx *Tx) close() {
+	if tx.pool != nil {
+		tx.pool.Release(tx.conn)
+		tx.pool = nil
+	}
+	tx.closed = true
+}
+
+// Exec delegates to the underlying *Conn
+func (tx *Tx) Exec(sql string, arguments ...interface{}) (commandTag CommandTag, err error) {
+	if tx.closed {
+		return CommandTag(""), errors.New("tx is closed")
+	}
+
+	return tx.conn.Exec(sql, arguments...)
+}
+
+// Query delegates to the underlying *Conn
+func (tx *Tx) Query(sql string, args ...interface{}) (*Rows, error) {
+	if tx.closed {
+		// Because checking for errors can be deferred to the *Rows, build one with the error
+		err := errors.New("tx is closed")
+		return &Rows{closed: true, err: err}, err
+	}
+
+	return tx.conn.Query(sql, args...)
+}
+
+// QueryRow delegates to the underlying *Conn
+func (tx *Tx) QueryRow(sql string, args ...interface{}) *Row {
+	rows, _ := tx.conn.Query(sql, args...)
+	return (*Row)(rows)
+}
+
+// Transaction runs f in a transaction. f should return true if the transaction
+// should be committed or false if it should be rolled back. Return value committed
+// is if the transaction was committed or not. committed should be checked separately
+// from err as an explicit rollback is not an error. Transaction will use the default
+// isolation level for the current connection. To use a specific isolation level see
+// TransactionIso
+func (c *Conn) Transaction(f func() bool) (committed bool, err error) {
+	return c.transaction("", f)
+}
+
+// TransactionIso is the same as Transaction except it takes an isoLevel argument that
+// it uses as the transaction isolation level.
+//
+// Valid isolation levels (and their constants) are:
+//   serializable (pgx.Serializable)
+//   repeatable read (pgx.RepeatableRead)
+//   read committed (pgx.ReadCommitted)
+//   read uncommitted (pgx.ReadUncommitted)
+func (c *Conn) TransactionIso(isoLevel string, f func() bool) (committed bool, err error) {
+	return c.transaction(isoLevel, f)
+}
+
+func (c *Conn) transaction(isoLevel string, f func() bool) (committed bool, err error) {
+	var beginSql string
+	if isoLevel == "" {
+		beginSql = "begin"
+	} else {
+		beginSql = fmt.Sprintf("begin isolation level %s", isoLevel)
+	}
+
+	if _, err = c.Exec(beginSql); err != nil {
+		return
+	}
+	defer func() {
+		if committed && c.TxStatus == 'T' {
+			_, err = c.Exec("commit")
+			if err != nil {
+				committed = false
+			}
+		} else {
+			_, err = c.Exec("rollback")
+			committed = false
+		}
+	}()
+
+	committed = f()
+	return
+}