move files

backend/v3/storage/database/statement.go

@@ -0,0 +1,50 @@
+package database
+
+import (
+	"strconv"
+	"strings"
+)
+
+type Instruction string
+
+const (
+	NowInstruction  Instruction = "NOW()"
+	NullInstruction Instruction = "NULL"
+)
+
+type StatementBuilder struct {
+	strings.Builder
+	args         []any
+	existingArgs map[any]string
+}
+
+func (b *StatementBuilder) WriteArg(arg any) {
+	b.WriteString(b.AppendArg(arg))
+}
+
+func (b *StatementBuilder) AppendArg(arg any) (placeholder string) {
+	if b.existingArgs == nil {
+		b.existingArgs = make(map[any]string)
+	}
+	if placeholder, ok := b.existingArgs[arg]; ok {
+		return placeholder
+	}
+	if instruction, ok := arg.(Instruction); ok {
+		return string(instruction)
+	}
+
+	b.args = append(b.args, arg)
+	placeholder = "$" + strconv.Itoa(len(b.args))
+	b.existingArgs[arg] = placeholder
+	return placeholder
+}
+
+func (b *StatementBuilder) AppendArgs(args ...any) {
+	for _, arg := range args {
+		b.AppendArg(arg)
+	}
+}
+
+func (b *StatementBuilder) Args() []any {
+	return b.args
+}