asteris-llc/converge

// Copyright © 2016 Asteris, LLC
//
// 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 fetch

import (
    "path"
    "strings"

    log "github.com/Sirupsen/logrus"
)

// ResolveInContext resolves a path relative to another
func ResolveInContext(loc, ctx string) (string, error) {
    log.WithField("target", loc).WithField("context", ctx).Debug("resolving target in context")

    var (
        locScheme, locPath = parse(loc)
        ctxScheme, ctxPath = parse(ctx)
    )

    if ctx != "" && loc != ctx && !path.IsAbs(locPath) && (locScheme == "" || locScheme == ctxScheme) {
        locPath = path.Join(path.Dir(ctxPath), locPath)
        locScheme = ctxScheme
    }

    if locScheme == "" {
        locScheme = "file"
    }

    return locScheme + "://" + locPath, nil
}

func parse(loc string) (scheme, path string) {
    if strings.Contains(loc, "://") {
        parts := strings.SplitN(loc, "://", 2)
        return parts[0], parts[1]
    }

    return "", loc
}