Adding upstream version 0.28.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

core/db_model.go

@@ -0,0 +1,59 @@
+package core
+
+// Model defines an interface with common methods that all db models should have.
+//
+// Note: for simplicity composite pk are not supported.
+type Model interface {
+	TableName() string
+	PK() any
+	LastSavedPK() any
+	IsNew() bool
+	MarkAsNew()
+	MarkAsNotNew()
+}
+
+// BaseModel defines a base struct that is intended to be embedded into other custom models.
+type BaseModel struct {
+	lastSavedPK string
+
+	// Id is the primary key of the model.
+	// It is usually autogenerated by the parent model implementation.
+	Id string `db:"id" json:"id" form:"id" xml:"id"`
+}
+
+// LastSavedPK returns the last saved primary key of the model.
+//
+// Its value is updated to the latest PK value after MarkAsNotNew() or PostScan() calls.
+func (m *BaseModel) LastSavedPK() any {
+	return m.lastSavedPK
+}
+
+func (m *BaseModel) PK() any {
+	return m.Id
+}
+
+// IsNew indicates what type of db query (insert or update)
+// should be used with the model instance.
+func (m *BaseModel) IsNew() bool {
+	return m.lastSavedPK == ""
+}
+
+// MarkAsNew clears the pk field and marks the current model as "new"
+// (aka. forces m.IsNew() to be true).
+func (m *BaseModel) MarkAsNew() {
+	m.lastSavedPK = ""
+}
+
+// MarkAsNew set the pk field to the Id value and marks the current model
+// as NOT "new" (aka. forces m.IsNew() to be false).
+func (m *BaseModel) MarkAsNotNew() {
+	m.lastSavedPK = m.Id
+}
+
+// PostScan implements the [dbx.PostScanner] interface.
+//
+// It is usually executed right after the model is populated with the db row values.
+func (m *BaseModel) PostScan() error {
+	m.MarkAsNotNew()
+	return nil
+}