From 54a9544044a0a7c6cbcff559dc662eb271bfcdcc Mon Sep 17 00:00:00 2001
From: Nurahmadie <nurahmadie@gmail.com>
Date: Sat, 15 Feb 2014 20:16:54 +0700
Subject: [PATCH] Integrate MigrationDriver to migrate.go

---
 pkg/database/migrate/migrate.go | 36 +++++++++++++++++++++++++++++----
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/pkg/database/migrate/migrate.go b/pkg/database/migrate/migrate.go
index 715596ad2..66bc96095 100644
--- a/pkg/database/migrate/migrate.go
+++ b/pkg/database/migrate/migrate.go
@@ -49,17 +49,41 @@ const deleteRevisionStmt = `
 DELETE FROM migration where revision = ?
 `
 
+// Operation interface covers basic migration operations.
+// Implementation details is specific for each database,
+// see migrate/sqlite.go for implementation reference.
+type Operation interface {
+
+	CreateTable(tableName string, args []string) (sql.Result, error)
+
+	RenameTable(tableName, newName string) (sql.Result, error)
+
+	DropTable(tableName string) (sql.Result, error)
+
+	AddColumn(tableName, columnSpec string) (sql.Result, error)
+
+	DropColumns(tableName string, columnsToDrop []string) (sql.Result, error)
+
+	RenameColumns(tableName string, columnChanges map[string]string) (sql.Result, error)
+}
+
 type Revision interface {
-	Up(tx *sql.Tx) error
-	Down(tx *sql.Tx) error
+	Up(op Operation) error
+	Down(op Operation) error
 	Revision() int64
 }
 
+type MigrationDriver struct {
+	Tx *sql.Tx
+}
+
 type Migration struct {
 	db   *sql.DB
 	revs []Revision
 }
 
+var Driver func(tx *sql.Tx) Operation
+
 func New(db *sql.DB) *Migration {
 	return &Migration{db: db}
 }
@@ -119,12 +143,14 @@ func (m *Migration) up(target, current int64) error {
 		return err
 	}
 
+	op := Driver(tx)
+
 	// loop through and execute revisions
 	for _, rev := range m.revs {
 		if rev.Revision() >= target {
 			current = rev.Revision()
 			// execute the revision Upgrade.
-			if err := rev.Up(tx); err != nil {
+			if err := rev.Up(op); err != nil {
 				log.Printf("Failed to upgrade to Revision Number %v\n", current)
 				log.Println(err)
 				return tx.Rollback()
@@ -150,6 +176,8 @@ func (m *Migration) down(target, current int64) error {
 		return err
 	}
 
+	op := Driver(tx)
+
 	// reverse the list of revisions
 	revs := []Revision{}
 	for _, rev := range m.revs {
@@ -162,7 +190,7 @@ func (m *Migration) down(target, current int64) error {
 		if rev.Revision() > target {
 			current = rev.Revision()
 			// execute the revision Upgrade.
-			if err := rev.Down(tx); err != nil {
+			if err := rev.Down(op); err != nil {
 				log.Printf("Failed to downgrade to Revision Number %v\n", current)
 				log.Println(err)
 				return tx.Rollback()