schemaPool.go

// Copyright 2015 xeipuuv ( https://github.com/xeipuuv )
//
// 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.

// author           xeipuuv
// author-github    https://github.com/xeipuuv
// author-mail      xeipuuv@gmail.com
//
// repository-name  gojsonschema
// repository-desc  An implementation of JSON Schema, based on IETF's draft v4 - Go language.
//
// description		Defines resources pooling.
//                  Eases referencing and avoids downloading the same resource twice.
//
// created          26-02-2013

package gojsonschema

import (
	"errors"

	"github.com/xeipuuv/gojsonreference"
)

type schemaPoolDocument struct {
	Document interface{}
}

type schemaPool struct {
	schemaPoolDocuments map[string]*schemaPoolDocument
	standaloneDocument  interface{}
	jsonLoaderFactory   JSONLoaderFactory
}

func newSchemaPool(f JSONLoaderFactory) *schemaPool {

	p := &schemaPool{}
	p.schemaPoolDocuments = make(map[string]*schemaPoolDocument)
	p.standaloneDocument = nil
	p.jsonLoaderFactory = f

	return p
}

func (p *schemaPool) SetStandaloneDocument(document interface{}) {
	p.standaloneDocument = document
}

func (p *schemaPool) GetStandaloneDocument() (document interface{}) {
	return p.standaloneDocument
}

func (p *schemaPool) GetDocument(reference gojsonreference.JsonReference) (*schemaPoolDocument, error) {

	var (
		spd *schemaPoolDocument
		ok  bool
		err error
	)

	if internalLogEnabled {
		internalLog("Get Document ( %s )", reference.String())
	}

	// It is not possible to load anything that is not canonical...
	if !reference.IsCanonical() {
		return nil, errors.New(formatErrorDescription(
			Locale.ReferenceMustBeCanonical(),
			ErrorDetails{"reference": reference},
		))
	}
	refToUrl := reference
	refToUrl.GetUrl().Fragment = ""

	if spd, ok = p.schemaPoolDocuments[refToUrl.String()]; ok {
		if internalLogEnabled {
			internalLog(" From pool")
		}
		return spd, nil
	}

	jsonReferenceLoader := p.jsonLoaderFactory.New(reference.String())
	document, err := jsonReferenceLoader.LoadJSON()
	if err != nil {
		return nil, err
	}

	spd = &schemaPoolDocument{Document: document}
	// add the document to the pool for potential later use
	p.schemaPoolDocuments[refToUrl.String()] = spd

	return spd, nil
}