chore: import upstream snapshot with attribution

luaplugin/api_json.go

@@ -0,0 +1,100 @@
+package luaplugin
+
+import (
+	"encoding/json"
+
+	lua "github.com/yuin/gopher-lua"
+)
+
+// registerJSONAPI adds cliamp.json.{encode,decode} to the cliamp table.
+func registerJSONAPI(L *lua.LState, cliamp *lua.LTable) {
+	tbl := L.NewTable()
+
+	// cliamp.json.decode(str) -> table
+	L.SetField(tbl, "decode", L.NewFunction(func(L *lua.LState) int {
+		str := L.CheckString(1)
+		var v any
+		if err := json.Unmarshal([]byte(str), &v); err != nil {
+			L.Push(lua.LNil)
+			L.Push(lua.LString(err.Error()))
+			return 2
+		}
+		L.Push(jsonToLua(L, v))
+		return 1
+	}))
+
+	// cliamp.json.encode(table) -> string
+	L.SetField(tbl, "encode", L.NewFunction(func(L *lua.LState) int {
+		val := L.Get(1)
+		goVal := luaToGo(val)
+		data, err := json.Marshal(goVal)
+		if err != nil {
+			L.Push(lua.LNil)
+			L.Push(lua.LString(err.Error()))
+			return 2
+		}
+		L.Push(lua.LString(string(data)))
+		return 1
+	}))
+
+	L.SetField(cliamp, "json", tbl)
+}
+
+func jsonToLua(L *lua.LState, v any) lua.LValue {
+	switch val := v.(type) {
+	case nil:
+		return lua.LNil
+	case bool:
+		return lua.LBool(val)
+	case float64:
+		return lua.LNumber(val)
+	case string:
+		return lua.LString(val)
+	case []any:
+		tbl := L.NewTable()
+		for i, item := range val {
+			tbl.RawSetInt(i+1, jsonToLua(L, item))
+		}
+		return tbl
+	case map[string]any:
+		tbl := L.NewTable()
+		for k, item := range val {
+			tbl.RawSetString(k, jsonToLua(L, item))
+		}
+		return tbl
+	default:
+		return lua.LNil
+	}
+}
+
+func luaToGo(val lua.LValue) any {
+	switch v := val.(type) {
+	case *lua.LNilType:
+		return nil
+	case lua.LBool:
+		return bool(v)
+	case lua.LNumber:
+		return float64(v)
+	case lua.LString:
+		return string(v)
+	case *lua.LTable:
+		// Detect if it's an array (sequential integer keys starting at 1).
+		maxN := v.MaxN()
+		if maxN > 0 {
+			arr := make([]any, 0, maxN)
+			for i := 1; i <= maxN; i++ {
+				arr = append(arr, luaToGo(v.RawGetInt(i)))
+			}
+			return arr
+		}
+		m := make(map[string]any)
+		v.ForEach(func(key, value lua.LValue) {
+			if ks, ok := key.(lua.LString); ok {
+				m[string(ks)] = luaToGo(value)
+			}
+		})
+		return m
+	default:
+		return nil
+	}
+}