add new db interface beginnings

1 files changed, 88 insertions, 0 deletions

diff --git a/database/postgres/postgres.go b/database/postgres/postgres.go
new file mode 100644
index 0000000..80cb7ca
--- /dev/null
+++ b/database/postgres/postgres.go
@@ -0,0 +1,88 @@
+package postgres
+
+import (
+	"database/sql"
+
+	"github.com/ewhal/nyaa/util/log"
+	_ "github.com/lib/pq"
+)
+
+func New(param string) (db *Database, err error) {
+	db = new(Database)
+	db.conn, err = sql.Open("postgres", param)
+	if err != nil {
+		db = nil
+	}
+	return
+}
+
+type Database struct {
+	conn     *sql.DB
+	prepared map[string]*sql.Stmt
+}
+
+func (db *Database) getPrepared(name string) *sql.Stmt {
+	return db.prepared[name]
+}
+
+func (db *Database) Query(q string, param ...interface{}) (*sql.Rows, error) {
+	return db.conn.Query(q, param)
+}
+
+func (db *Database) Init() (err error) {
+
+	// ensure tables
+	for idx := range tables {
+		log.Debugf("ensure table %s", tables[idx].name)
+		err = tables[idx].Exec(db.conn)
+		if err != nil {
+			log.Errorf("Failed to ensure table %s: %s", tables[idx].name, err.Error())
+			return
+		}
+	}
+
+	// generate prepared statements
+	for k := range statements {
+		var stmt *sql.Stmt
+		stmt, err = db.conn.Prepare(statements[k])
+		if err != nil {
+			log.Errorf("failed to build prepared statement %s: %s", k, err.Error())
+			return
+		}
+		db.prepared[k] = stmt
+	}
+	return
+}
+
+// execute prepared statement with arguments, visit result and autoclose rows after done visiting
+func (db *Database) queryWithPrepared(name string, visit func(*sql.Rows) error, params ...interface{}) (err error) {
+	var rows *sql.Rows
+	rows, err = db.getPrepared(name).Query(params)
+	if err == sql.ErrNoRows {
+		err = nil
+	} else if err == nil {
+		err = visit(rows)
+		rows.Close()
+	}
+	return
+}
+
+// execute prepared statement with arguments, visit single row
+func (db *Database) queryRowWithPrepared(name string, visit func(*sql.Row) error, params ...interface{}) (err error) {
+	err = visit(db.getPrepared(name).QueryRow(params))
+	return
+}
+
+// execute a query by name and return how many rows were affected
+func (db *Database) execQuery(name string, p ...interface{}) (affected uint32, err error) {
+	var result sql.Result
+	result, err = db.getPrepared(name).Exec(p)
+	if err == nil {
+		var d int64
+		d, err = result.RowsAffected()
+		if err == nil {
+			affected = uint32(d)
+		}
+	}
+	return
+}