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author | Runxi Yu <me@runxiyu.org> | 2025-04-06 09:26:46 +0800 |
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committer | Runxi Yu <me@runxiyu.org> | 2025-04-06 09:27:53 +0800 |
commit | da1d8f4e7c332c7109427915e6459b10209cedce (patch) | |
tree | 280b921be3b51f93d82d916b4eaa89387b7102cc /internal/scfg/unmarshal.go | |
parent | git2c, git2d: Rename cmd1 and cmd2 descriptively (diff) | |
download | forge-0.1.32.tar.gz forge-0.1.32.tar.zst forge-0.1.32.zip |
Move the Go stuff to ./forged/v0.1.32
Diffstat (limited to 'internal/scfg/unmarshal.go')
-rw-r--r-- | internal/scfg/unmarshal.go | 375 |
1 files changed, 0 insertions, 375 deletions
diff --git a/internal/scfg/unmarshal.go b/internal/scfg/unmarshal.go deleted file mode 100644 index e9e1a52..0000000 --- a/internal/scfg/unmarshal.go +++ /dev/null @@ -1,375 +0,0 @@ -// SPDX-License-Identifier: MIT -// SPDX-FileCopyrightText: Copyright (c) 2020 Simon Ser <https://emersion.fr> -// SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org> - -package scfg - -import ( - "encoding" - "fmt" - "io" - "reflect" - "strconv" -) - -// Decoder reads and decodes an scfg document from an input stream. -type Decoder struct { - r io.Reader - unknownDirectives []*Directive -} - -// NewDecoder returns a new decoder which reads from r. -func NewDecoder(r io.Reader) *Decoder { - return &Decoder{r: r} -} - -// UnknownDirectives returns a slice of all unknown directives encountered -// during Decode. -func (dec *Decoder) UnknownDirectives() []*Directive { - return dec.unknownDirectives -} - -// Decode reads scfg document from the input and stores it in the value pointed -// to by v. -// -// If v is nil or not a pointer, Decode returns an error. -// -// Blocks can be unmarshaled to: -// -// - Maps. Each directive is unmarshaled into a map entry. The map key must -// be a string. -// - Structs. Each directive is unmarshaled into a struct field. -// -// Duplicate directives are not allowed, unless the struct field or map value -// is a slice of values representing a directive: structs or maps. -// -// Directives can be unmarshaled to: -// -// - Maps. The children block is unmarshaled into the map. Parameters are not -// allowed. -// - Structs. The children block is unmarshaled into the struct. Parameters -// are allowed if one of the struct fields contains the "param" option in -// its tag. -// - Slices. Parameters are unmarshaled into the slice. Children blocks are -// not allowed. -// - Arrays. Parameters are unmarshaled into the array. The number of -// parameters must match exactly the length of the array. Children blocks -// are not allowed. -// - Strings, booleans, integers, floating-point values, values implementing -// encoding.TextUnmarshaler. Only a single parameter is allowed and is -// unmarshaled into the value. Children blocks are not allowed. -// -// The decoding of each struct field can be customized by the format string -// stored under the "scfg" key in the struct field's tag. The tag contains the -// name of the field possibly followed by a comma-separated list of options. -// The name may be empty in order to specify options without overriding the -// default field name. As a special case, if the field name is "-", the field -// is ignored. The "param" option specifies that directive parameters are -// stored in this field (the name must be empty). -func (dec *Decoder) Decode(v interface{}) error { - block, err := Read(dec.r) - if err != nil { - return err - } - - rv := reflect.ValueOf(v) - if rv.Kind() != reflect.Ptr || rv.IsNil() { - return fmt.Errorf("scfg: invalid value for unmarshaling") - } - - return dec.unmarshalBlock(block, rv) -} - -func (dec *Decoder) unmarshalBlock(block Block, v reflect.Value) error { - v = unwrapPointers(v) - t := v.Type() - - dirsByName := make(map[string][]*Directive, len(block)) - for _, dir := range block { - dirsByName[dir.Name] = append(dirsByName[dir.Name], dir) - } - - switch v.Kind() { - case reflect.Map: - if t.Key().Kind() != reflect.String { - return fmt.Errorf("scfg: map key type must be string") - } - if v.IsNil() { - v.Set(reflect.MakeMap(t)) - } else if v.Len() > 0 { - clearMap(v) - } - - for name, dirs := range dirsByName { - mv := reflect.New(t.Elem()).Elem() - if err := dec.unmarshalDirectiveList(dirs, mv); err != nil { - return err - } - v.SetMapIndex(reflect.ValueOf(name), mv) - } - - case reflect.Struct: - si, err := getStructInfo(t) - if err != nil { - return err - } - - seen := make(map[int]bool) - - for name, dirs := range dirsByName { - fieldIndex, ok := si.children[name] - if !ok { - dec.unknownDirectives = append(dec.unknownDirectives, dirs...) - continue - } - fv := v.Field(fieldIndex) - if err := dec.unmarshalDirectiveList(dirs, fv); err != nil { - return err - } - seen[fieldIndex] = true - } - - for name, fieldIndex := range si.children { - if fieldIndex == si.param { - continue - } - if _, ok := seen[fieldIndex]; !ok { - return fmt.Errorf("scfg: missing required directive %q", name) - } - } - - default: - return fmt.Errorf("scfg: unsupported type for unmarshaling blocks: %v", t) - } - - return nil -} - -func (dec *Decoder) unmarshalDirectiveList(dirs []*Directive, v reflect.Value) error { - v = unwrapPointers(v) - t := v.Type() - - if v.Kind() != reflect.Slice || !isDirectiveType(t.Elem()) { - if len(dirs) > 1 { - return newUnmarshalDirectiveError(dirs[1], "directive must not be specified more than once") - } - return dec.unmarshalDirective(dirs[0], v) - } - - sv := reflect.MakeSlice(t, len(dirs), len(dirs)) - for i, dir := range dirs { - if err := dec.unmarshalDirective(dir, sv.Index(i)); err != nil { - return err - } - } - v.Set(sv) - return nil -} - -// isDirectiveType checks whether a type can only be unmarshaled as a -// directive, not as a parameter. Accepting too many types here would result in -// ambiguities, see: -// https://lists.sr.ht/~emersion/public-inbox/%3C20230629132458.152205-1-contact%40emersion.fr%3E#%3Ch4Y2peS_YBqY3ar4XlmPDPiNBFpYGns3EBYUx3_6zWEhV2o8_-fBQveRujGADWYhVVCucHBEryFGoPtpC3d3mQ-x10pWnFogfprbQTSvtxc=@emersion.fr%3E -func isDirectiveType(t reflect.Type) bool { - for t.Kind() == reflect.Ptr { - t = t.Elem() - } - - textUnmarshalerType := reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem() - if reflect.PtrTo(t).Implements(textUnmarshalerType) { - return false - } - - switch t.Kind() { - case reflect.Struct, reflect.Map: - return true - default: - return false - } -} - -func (dec *Decoder) unmarshalDirective(dir *Directive, v reflect.Value) error { - v = unwrapPointers(v) - t := v.Type() - - if v.CanAddr() { - if _, ok := v.Addr().Interface().(encoding.TextUnmarshaler); ok { - if len(dir.Children) != 0 { - return newUnmarshalDirectiveError(dir, "directive requires zero children") - } - return unmarshalParamList(dir, v) - } - } - - switch v.Kind() { - case reflect.Map: - if len(dir.Params) > 0 { - return newUnmarshalDirectiveError(dir, "directive requires zero parameters") - } - if err := dec.unmarshalBlock(dir.Children, v); err != nil { - return err - } - case reflect.Struct: - si, err := getStructInfo(t) - if err != nil { - return err - } - - if si.param >= 0 { - if err := unmarshalParamList(dir, v.Field(si.param)); err != nil { - return err - } - } else { - if len(dir.Params) > 0 { - return newUnmarshalDirectiveError(dir, "directive requires zero parameters") - } - } - - if err := dec.unmarshalBlock(dir.Children, v); err != nil { - return err - } - default: - if len(dir.Children) != 0 { - return newUnmarshalDirectiveError(dir, "directive requires zero children") - } - if err := unmarshalParamList(dir, v); err != nil { - return err - } - } - return nil -} - -func unmarshalParamList(dir *Directive, v reflect.Value) error { - switch v.Kind() { - case reflect.Slice: - t := v.Type() - sv := reflect.MakeSlice(t, len(dir.Params), len(dir.Params)) - for i, param := range dir.Params { - if err := unmarshalParam(param, sv.Index(i)); err != nil { - return newUnmarshalParamError(dir, i, err) - } - } - v.Set(sv) - case reflect.Array: - if len(dir.Params) != v.Len() { - return newUnmarshalDirectiveError(dir, fmt.Sprintf("directive requires exactly %v parameters", v.Len())) - } - for i, param := range dir.Params { - if err := unmarshalParam(param, v.Index(i)); err != nil { - return newUnmarshalParamError(dir, i, err) - } - } - default: - if len(dir.Params) != 1 { - return newUnmarshalDirectiveError(dir, "directive requires exactly one parameter") - } - if err := unmarshalParam(dir.Params[0], v); err != nil { - return newUnmarshalParamError(dir, 0, err) - } - } - - return nil -} - -func unmarshalParam(param string, v reflect.Value) error { - v = unwrapPointers(v) - t := v.Type() - - // TODO: improve our logic following: - // https://cs.opensource.google/go/go/+/refs/tags/go1.21.5:src/encoding/json/decode.go;drc=b9b8cecbfc72168ca03ad586cc2ed52b0e8db409;l=421 - if v.CanAddr() { - if v, ok := v.Addr().Interface().(encoding.TextUnmarshaler); ok { - return v.UnmarshalText([]byte(param)) - } - } - - switch v.Kind() { - case reflect.String: - v.Set(reflect.ValueOf(param)) - case reflect.Bool: - switch param { - case "true": - v.Set(reflect.ValueOf(true)) - case "false": - v.Set(reflect.ValueOf(false)) - default: - return fmt.Errorf("invalid bool parameter %q", param) - } - case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: - i, err := strconv.ParseInt(param, 10, t.Bits()) - if err != nil { - return fmt.Errorf("invalid %v parameter: %v", t, err) - } - v.Set(reflect.ValueOf(i).Convert(t)) - case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64: - u, err := strconv.ParseUint(param, 10, t.Bits()) - if err != nil { - return fmt.Errorf("invalid %v parameter: %v", t, err) - } - v.Set(reflect.ValueOf(u).Convert(t)) - case reflect.Float32, reflect.Float64: - f, err := strconv.ParseFloat(param, t.Bits()) - if err != nil { - return fmt.Errorf("invalid %v parameter: %v", t, err) - } - v.Set(reflect.ValueOf(f).Convert(t)) - default: - return fmt.Errorf("unsupported type for unmarshaling parameter: %v", t) - } - - return nil -} - -func unwrapPointers(v reflect.Value) reflect.Value { - for v.Kind() == reflect.Ptr { - if v.IsNil() { - v.Set(reflect.New(v.Type().Elem())) - } - v = v.Elem() - } - return v -} - -func clearMap(v reflect.Value) { - for _, k := range v.MapKeys() { - v.SetMapIndex(k, reflect.Value{}) - } -} - -type unmarshalDirectiveError struct { - lineno int - name string - msg string -} - -func newUnmarshalDirectiveError(dir *Directive, msg string) *unmarshalDirectiveError { - return &unmarshalDirectiveError{ - name: dir.Name, - lineno: dir.lineno, - msg: msg, - } -} - -func (err *unmarshalDirectiveError) Error() string { - return fmt.Sprintf("line %v, directive %q: %v", err.lineno, err.name, err.msg) -} - -type unmarshalParamError struct { - lineno int - directive string - paramIndex int - err error -} - -func newUnmarshalParamError(dir *Directive, paramIndex int, err error) *unmarshalParamError { - return &unmarshalParamError{ - directive: dir.Name, - lineno: dir.lineno, - paramIndex: paramIndex, - err: err, - } -} - -func (err *unmarshalParamError) Error() string { - return fmt.Sprintf("line %v, directive %q, parameter %v: %v", err.lineno, err.directive, err.paramIndex+1, err.err) -} |