Add PrepareStmt support

prepare_stmt.go

@@ -0,0 +1,92 @@
+package gorm
+
+import (
+	"context"
+	"database/sql"
+	"sync"
+)
+
+type PreparedStmtDB struct {
+	stmts map[string]*sql.Stmt
+	mux   sync.RWMutex
+	ConnPool
+}
+
+func (db *PreparedStmtDB) prepare(query string) (*sql.Stmt, error) {
+	db.mux.RLock()
+	if stmt, ok := db.stmts[query]; ok {
+		db.mux.RUnlock()
+		return stmt, nil
+	}
+	db.mux.RUnlock()
+
+	db.mux.Lock()
+	stmt, err := db.ConnPool.PrepareContext(context.Background(), query)
+	if err == nil {
+		db.stmts[query] = stmt
+	}
+	db.mux.Unlock()
+
+	return stmt, err
+}
+
+func (db *PreparedStmtDB) BeginTx(ctx context.Context, opt *sql.TxOptions) (ConnPool, error) {
+	if beginner, ok := db.ConnPool.(TxBeginner); ok {
+		tx, err := beginner.BeginTx(ctx, opt)
+		return &PreparedStmtTX{PreparedStmtDB: db, Tx: tx}, err
+	}
+	return nil, ErrInvalidTransaction
+}
+
+func (db *PreparedStmtDB) ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error) {
+	stmt, err := db.prepare(query)
+	if err == nil {
+		return stmt.ExecContext(ctx, args...)
+	}
+	return nil, err
+}
+
+func (db *PreparedStmtDB) QueryContext(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error) {
+	stmt, err := db.prepare(query)
+	if err == nil {
+		return stmt.QueryContext(ctx, args...)
+	}
+	return nil, err
+}
+
+func (db *PreparedStmtDB) QueryRowContext(ctx context.Context, query string, args ...interface{}) *sql.Row {
+	stmt, err := db.prepare(query)
+	if err == nil {
+		return stmt.QueryRowContext(ctx, args...)
+	}
+	return &sql.Row{}
+}
+
+type PreparedStmtTX struct {
+	*sql.Tx
+	PreparedStmtDB *PreparedStmtDB
+}
+
+func (tx *PreparedStmtTX) ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error) {
+	stmt, err := tx.PreparedStmtDB.prepare(query)
+	if err == nil {
+		return tx.Tx.Stmt(stmt).ExecContext(ctx, args...)
+	}
+	return nil, err
+}
+
+func (tx *PreparedStmtTX) QueryContext(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error) {
+	stmt, err := tx.PreparedStmtDB.prepare(query)
+	if err == nil {
+		return tx.Tx.Stmt(stmt).QueryContext(ctx, args...)
+	}
+	return nil, err
+}
+
+func (tx *PreparedStmtTX) QueryRowContext(ctx context.Context, query string, args ...interface{}) *sql.Row {
+	stmt, err := tx.PreparedStmtDB.prepare(query)
+	if err == nil {
+		return tx.Tx.Stmt(stmt).QueryRowContext(ctx, args...)
+	}
+	return &sql.Row{}
+}