113 lines
2.6 KiB
Go
113 lines
2.6 KiB
Go
package json
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import (
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"encoding/json"
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"errors"
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"strconv"
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"github.com/yuin/gopher-lua"
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)
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var (
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errFunction = errors.New("cannot encode function to JSON")
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errChannel = errors.New("cannot encode channel to JSON")
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errState = errors.New("cannot encode state to JSON")
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errUserData = errors.New("cannot encode userdata to JSON")
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errNested = errors.New("cannot encode recursively nested tables to JSON")
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)
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type jsonValue struct {
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lua.LValue
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visited map[*lua.LTable]bool
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}
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func (j jsonValue) MarshalJSON() ([]byte, error) {
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return toJSON(j.LValue, j.visited)
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}
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func toJSON(value lua.LValue, visited map[*lua.LTable]bool) (data []byte, err error) {
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switch converted := value.(type) {
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case lua.LBool:
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data, err = json.Marshal(converted)
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case lua.LChannel:
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err = errChannel
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case lua.LNumber:
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data, err = json.Marshal(converted)
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case *lua.LFunction:
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err = errFunction
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case *lua.LNilType:
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data, err = json.Marshal(converted)
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case *lua.LState:
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err = errState
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case lua.LString:
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data, err = json.Marshal(converted)
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case *lua.LTable:
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var arr []jsonValue
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var obj map[string]jsonValue
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if visited[converted] {
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panic(errNested)
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return // unreachable
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}
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visited[converted] = true
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converted.ForEach(func(k lua.LValue, v lua.LValue) {
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i, numberKey := k.(lua.LNumber)
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if numberKey && obj == nil {
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index := int(i) - 1
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if index != len(arr) {
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// map out of order; convert to map
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obj = make(map[string]jsonValue)
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for i, value := range arr {
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obj[strconv.Itoa(i+1)] = value
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}
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obj[strconv.Itoa(index+1)] = jsonValue{v, visited}
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return
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}
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arr = append(arr, jsonValue{v, visited})
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return
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}
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if obj == nil {
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obj = make(map[string]jsonValue)
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for i, value := range arr {
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obj[strconv.Itoa(i+1)] = value
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}
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}
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obj[k.String()] = jsonValue{v, visited}
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})
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if obj != nil {
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data, err = json.Marshal(obj)
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} else {
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data, err = json.Marshal(arr)
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}
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case *lua.LUserData:
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// TODO: call metatable __tostring?
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err = errUserData
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}
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return
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}
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func fromJSON(L *lua.LState, value interface{}) lua.LValue {
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switch converted := value.(type) {
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case bool:
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return lua.LBool(converted)
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case float64:
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return lua.LNumber(converted)
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case string:
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return lua.LString(converted)
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case []interface{}:
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arr := L.CreateTable(len(converted), 0)
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for _, item := range converted {
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arr.Append(fromJSON(L, item))
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}
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return arr
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case map[string]interface{}:
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tbl := L.CreateTable(0, len(converted))
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for key, item := range converted {
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tbl.RawSetH(lua.LString(key), fromJSON(L, item))
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}
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return tbl
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}
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return lua.LNil
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}
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