init push

internal/repository/mysql/schema_cache.go

@@ -0,0 +1,58 @@
+package mysql
+
+import (
+	"fmt"
+	"reflect"
+
+	"gorm.io/gorm"
+)
+
+// schemaCache memoizes table/column existence checks for a single DB handle.
+// It is intended for startup-time feature detection, not per-request probing.
+type schemaCache struct {
+	db           *gorm.DB
+	tableExists  map[string]bool
+	columnExists map[string]bool
+}
+
+func newSchemaCache(db *gorm.DB) *schemaCache {
+	return &schemaCache{
+		db:           db,
+		tableExists:  make(map[string]bool),
+		columnExists: make(map[string]bool),
+	}
+}
+
+func (s *schemaCache) HasTable(dst any) bool {
+	key := schemaKey(dst)
+	if ok, found := s.tableExists[key]; found {
+		return ok
+	}
+	ok := s.db.Migrator().HasTable(dst)
+	s.tableExists[key] = ok
+	return ok
+}
+
+func (s *schemaCache) HasColumn(dst any, column string) bool {
+	key := schemaKey(dst) + "\x00" + column
+	if ok, found := s.columnExists[key]; found {
+		return ok
+	}
+	ok := s.db.Migrator().HasColumn(dst, column)
+	s.columnExists[key] = ok
+	return ok
+}
+
+func schemaKey(dst any) string {
+	if dst == nil {
+		return "<nil>"
+	}
+	if s, ok := dst.(string); ok {
+		return "table:" + s
+	}
+	t := reflect.TypeOf(dst)
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	return fmt.Sprintf("type:%s.%s", t.PkgPath(), t.Name())
+}