Add basic "post resource publish support"

Fixes #7146

resources/postpub/fields.go

@@ -0,0 +1,59 @@
+// Copyright 2020 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 postpub
+
+import (
+	"reflect"
+)
+
+const (
+	FieldNotSupported = "__field_not_supported"
+)
+
+func structToMapWithPlaceholders(root string, in interface{}, createPlaceholder func(s string) string) map[string]interface{} {
+	m := structToMap(in)
+	insertFieldPlaceholders(root, m, createPlaceholder)
+	return m
+}
+
+func structToMap(s interface{}) map[string]interface{} {
+	m := make(map[string]interface{})
+	t := reflect.TypeOf(s)
+
+	for i := 0; i < t.NumMethod(); i++ {
+		method := t.Method(i)
+		if method.PkgPath != "" {
+			continue
+		}
+		if method.Type.NumIn() == 1 {
+			m[method.Name] = ""
+		}
+	}
+
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		if field.PkgPath != "" {
+			continue
+		}
+		m[field.Name] = ""
+	}
+	return m
+}
+
+// insert placeholder for the templates. Do it very shallow for now.
+func insertFieldPlaceholders(root string, m map[string]interface{}, createPlaceholder func(s string) string) {
+	for k, _ := range m {
+		m[k] = createPlaceholder(root + "." + k)
+	}
+}