opencontrol/compliance-masonry

/*
 Copyright (C) 2018 OpenControl Contributors. See LICENSE.md for license.
*/

package opencontrol

import (
    "errors"
    "github.com/blang/semver"
    "github.com/opencontrol/compliance-masonry/pkg/lib/common"
    v1_0_0 "github.com/opencontrol/compliance-masonry/pkg/lib/opencontrol/versions/1.0.0"
    "gopkg.in/yaml.v2"
)

var (
    // SchemaV1_0_0 is the semantic versioning representation in object form for version 1.0.0
    SchemaV1_0_0 = semver.Version{Major: 1, Minor: 0, Patch: 0, Pre: nil, Build: nil}
)

const (
    // ErrMalformedBaseYamlPrefix is just the prefix to the error message for when the program is unable to parse
    // data into the base yaml struct.
    ErrMalformedBaseYamlPrefix = "Unable to parse yaml data"
)

// YAMLParser is the concrete implementation of parsing different schema versions in YAML format.
type YAMLParser struct{}

// Parse will try to parse the data and determine which specific version of schema to further parse.
func (parser YAMLParser) Parse(data []byte) (common.OpenControl, error) {
    if data == nil || len(data) == 0 {
        return nil, common.ErrNoDataToParse
    }
    b := Base{}
    err := yaml.Unmarshal(data, &b)
    if err != nil {
        return nil, errors.New(ErrMalformedBaseYamlPrefix + " - " + err.Error())
    }

    var opencontrol common.OpenControl
    var parseError error
    v, err := semver.Parse(b.SchemaVersion)
    if err != nil {
        return nil, common.ErrCantParseSemver
    }
    switch {
    case SchemaV1_0_0.Equals(v):
        opencontrol = new(v1_0_0.OpenControl)
        parseError = yaml.Unmarshal(data, opencontrol)
    default:
        return nil, common.ErrUnknownSchemaVersion
    }
    if parseError != nil {
        return nil, parseError
    }

    return opencontrol, nil
}