1 files changed, 284 insertions, 0 deletions
diff --git a/parser/metadecoders/decoder.go b/parser/metadecoders/decoder.go
new file mode 100644
index 000000000..f90dc5703
--- /dev/null
+++ b/parser/metadecoders/decoder.go
@@ -0,0 +1,284 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metadecoders
+
+import (
+	"bytes"
+	"encoding/csv"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/gohugoio/hugo/common/herrors"
+	"github.com/niklasfasching/go-org/org"
+
+	"github.com/BurntSushi/toml"
+	"github.com/pkg/errors"
+	"github.com/spf13/afero"
+	"github.com/spf13/cast"
+	jww "github.com/spf13/jwalterweatherman"
+	yaml "gopkg.in/yaml.v2"
+)
+
+// Decoder provides some configuration options for the decoders.
+type Decoder struct {
+	// Delimiter is the field delimiter used in the CSV decoder. It defaults to ','.
+	Delimiter rune
+
+	// Comment, if not 0, is the comment character ued in the CSV decoder. Lines beginning with the
+	// Comment character without preceding whitespace are ignored.
+	Comment rune
+}
+
+// OptionsKey is used in cache keys.
+func (d Decoder) OptionsKey() string {
+	var sb strings.Builder
+	sb.WriteRune(d.Delimiter)
+	sb.WriteRune(d.Comment)
+	return sb.String()
+}
+
+// Default is a Decoder in its default configuration.
+var Default = Decoder{
+	Delimiter: ',',
+}
+
+// UnmarshalToMap will unmarshall data in format f into a new map. This is
+// what's needed for Hugo's front matter decoding.
+func (d Decoder) UnmarshalToMap(data []byte, f Format) (map[string]interface{}, error) {
+	m := make(map[string]interface{})
+	if data == nil {
+		return m, nil
+	}
+
+	err := d.unmarshal(data, f, &m)
+
+	return m, err
+}
+
+// UnmarshalFileToMap is the same as UnmarshalToMap, but reads the data from
+// the given filename.
+func (d Decoder) UnmarshalFileToMap(fs afero.Fs, filename string) (map[string]interface{}, error) {
+	format := FormatFromString(filename)
+	if format == "" {
+		return nil, errors.Errorf("%q is not a valid configuration format", filename)
+	}
+
+	data, err := afero.ReadFile(fs, filename)
+	if err != nil {
+		return nil, err
+	}
+	return d.UnmarshalToMap(data, format)
+}
+
+// UnmarshalStringTo tries to unmarshal data to a new instance of type typ.
+func (d Decoder) UnmarshalStringTo(data string, typ interface{}) (interface{}, error) {
+	data = strings.TrimSpace(data)
+	// We only check for the possible types in YAML, JSON and TOML.
+	switch typ.(type) {
+	case string:
+		return data, nil
+	case map[string]interface{}:
+		format := d.FormatFromContentString(data)
+		return d.UnmarshalToMap([]byte(data), format)
+	case []interface{}:
+		// A standalone slice. Let YAML handle it.
+		return d.Unmarshal([]byte(data), YAML)
+	case bool:
+		return cast.ToBoolE(data)
+	case int:
+		return cast.ToIntE(data)
+	case int64:
+		return cast.ToInt64E(data)
+	case float64:
+		return cast.ToFloat64E(data)
+	default:
+		return nil, errors.Errorf("unmarshal: %T not supportedd", typ)
+	}
+}
+
+// Unmarshal will unmarshall data in format f into an interface{}.
+// This is what's needed for Hugo's /data handling.
+func (d Decoder) Unmarshal(data []byte, f Format) (interface{}, error) {
+	if data == nil {
+		switch f {
+		case CSV:
+			return make([][]string, 0), nil
+		default:
+			return make(map[string]interface{}), nil
+		}
+
+	}
+	var v interface{}
+	err := d.unmarshal(data, f, &v)
+
+	return v, err
+}
+
+// unmarshal unmarshals data in format f into v.
+func (d Decoder) unmarshal(data []byte, f Format, v interface{}) error {
+
+	var err error
+
+	switch f {
+	case ORG:
+		err = d.unmarshalORG(data, v)
+	case JSON:
+		err = json.Unmarshal(data, v)
+	case TOML:
+		err = toml.Unmarshal(data, v)
+	case YAML:
+		err = yaml.Unmarshal(data, v)
+		if err != nil {
+			return toFileError(f, errors.Wrap(err, "failed to unmarshal YAML"))
+		}
+
+		// To support boolean keys, the YAML package unmarshals maps to
+		// map[interface{}]interface{}. Here we recurse through the result
+		// and change all maps to map[string]interface{} like we would've
+		// gotten from `json`.
+		var ptr interface{}
+		switch v.(type) {
+		case *map[string]interface{}:
+			ptr = *v.(*map[string]interface{})
+		case *interface{}:
+			ptr = *v.(*interface{})
+		default:
+			return errors.Errorf("unknown type %T in YAML unmarshal", v)
+		}
+
+		if mm, changed := stringifyMapKeys(ptr); changed {
+			switch v.(type) {
+			case *map[string]interface{}:
+				*v.(*map[string]interface{}) = mm.(map[string]interface{})
+			case *interface{}:
+				*v.(*interface{}) = mm
+			}
+		}
+	case CSV:
+		return d.unmarshalCSV(data, v)
+
+	default:
+		return errors.Errorf("unmarshal of format %q is not supported", f)
+	}
+
+	if err == nil {
+		return nil
+	}
+
+	return toFileError(f, errors.Wrap(err, "unmarshal failed"))
+
+}
+
+func (d Decoder) unmarshalCSV(data []byte, v interface{}) error {
+	r := csv.NewReader(bytes.NewReader(data))
+	r.Comma = d.Delimiter
+	r.Comment = d.Comment
+
+	records, err := r.ReadAll()
+	if err != nil {
+		return err
+	}
+
+	switch v.(type) {
+	case *interface{}:
+		*v.(*interface{}) = records
+	default:
+		return errors.Errorf("CSV cannot be unmarshaled into %T", v)
+
+	}
+
+	return nil
+
+}
+
+func (d Decoder) unmarshalORG(data []byte, v interface{}) error {
+	config := org.New()
+	config.Log = jww.WARN
+	document := config.Parse(bytes.NewReader(data), "")
+	if document.Error != nil {
+		return document.Error
+	}
+	frontMatter := make(map[string]interface{}, len(document.BufferSettings))
+	for k, v := range document.BufferSettings {
+		k = strings.ToLower(k)
+		if strings.HasSuffix(k, "[]") {
+			frontMatter[k[:len(k)-2]] = strings.Fields(v)
+		} else if k == "tags" || k == "categories" || k == "aliases" {
+			jww.WARN.Printf("Please use '#+%s[]:' notation, automatic conversion is deprecated.", k)
+			frontMatter[k] = strings.Fields(v)
+		} else {
+			frontMatter[k] = v
+		}
+	}
+	switch v.(type) {
+	case *map[string]interface{}:
+		*v.(*map[string]interface{}) = frontMatter
+	default:
+		*v.(*interface{}) = frontMatter
+	}
+	return nil
+}
+
+func toFileError(f Format, err error) error {
+	return herrors.ToFileError(string(f), err)
+}
+
+// stringifyMapKeys recurses into in and changes all instances of
+// map[interface{}]interface{} to map[string]interface{}. This is useful to
+// work around the impedance mismatch between JSON and YAML unmarshaling that's
+// described here: https://github.com/go-yaml/yaml/issues/139
+//
+// Inspired by https://github.com/stripe/stripe-mock, MIT licensed
+func stringifyMapKeys(in interface{}) (interface{}, bool) {
+
+	switch in := in.(type) {
+	case []interface{}:
+		for i, v := range in {
+			if vv, replaced := stringifyMapKeys(v); replaced {
+				in[i] = vv
+			}
+		}
+	case map[string]interface{}:
+		for k, v := range in {
+			if vv, changed := stringifyMapKeys(v); changed {
+				in[k] = vv
+			}
+		}
+	case map[interface{}]interface{}:
+		res := make(map[string]interface{})
+		var (
+			ok  bool
+			err error
+		)
+		for k, v := range in {
+			var ks string
+
+			if ks, ok = k.(string); !ok {
+				ks, err = cast.ToStringE(k)
+				if err != nil {
+					ks = fmt.Sprintf("%v", k)
+				}
+			}
+			if vv, replaced := stringifyMapKeys(v); replaced {
+				res[ks] = vv
+			} else {
+				res[ks] = v
+			}
+		}
+		return res, true
+	}
+
+	return nil, false
+}