gerrit/url.go

// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package gerrit

import (
	"fmt"
	"net/url"
	"strconv"
	"strings"

	"go.chromium.org/luci/common/api/gerrit"
)

const (
	fuchsiaReviewHost           = "fuchsia-review.googlesource.com/"
	turquoiseInternalReviewHost = "turquoise-internal-review.googlesource.com/"
)

var prefixes = []string{
	"https://",
	"http://",
	"go/",
}

var shortLinkMap = map[string]string{
	"fxrev.dev/": fuchsiaReviewHost,
	"fxr/":       fuchsiaReviewHost,
	"tqr/":       turquoiseInternalReviewHost,
}

// ResolveChangeUrl resolves common change URLs for fuchsia hosts,
// returning a canonical gerrit host and change ID.
//
// Note: only supports numeric change IDs, and does not support
// deprecated change IDs.
// See https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#change-id
// In practice however, deprecated change IDs are very unlikely to be
// used as inputs.
//
// Examples:
//
// fxr/<change_id>
//   -> fuchsia-review.googlesource.com, <change_id>
// tqr/<change_id>
//   -> turquoise-internal-review.googlesource.com, <change_id>
// go/fxr/<change_id>
//   -> fuchsia-review.googlesource.com, <change_id>
// go/tqr/<change_id>
//   -> turquoise-internal-review.googlesource.com, <change_id>
// http://go/fxr/<change_id>
//   -> fuchsia-review.googlesource.com, <change_id>
// fxrev.dev/<change_id>
//   -> fuchsia-review.googlesource.com, <change_id>
// https://fxrev.dev/<change_id>
//   -> fuchsia-review.googlesource.com, <change_id>
// http://go/tqr/<change_id>
//   -> turquoise-internal-review.googlesource.com, <change_id>
// https://fuchsia-review.googlesource.com/<change_id>
//   -> fuchsia-review.googlesource.com, <change_id>
// https://fuchsia-review.googlesource.com/<change_id>/
//   -> fuchsia-review.googlesource.com, <change_id>
// https://turquoise-internal-review.googlesource.com/<change_id>
//   -> turquoise-internal-review.googlesource.com, <change_id>
// https://fuchsia-review.googlesource.com/c/<project>/+/<change_id>
//   -> fuchsia-review.googlesource.com, <change_id>
// https://turquoise-internal-review.googlesource.com/c/<project>/+/<change_id>
//   -> turquoise-internal-review.googlesource.com, <change_id>
// https://turquoise-internal-review.git.corp.google.com/c/<project>/+/<change_id>
//   -> turquoise-internal-review.googlesource.com, <change_id>
func ResolveChangeUrl(changeUrl *url.URL) (host string, changeId int64, err error) {
	host, changeId, err = "", 0, nil
	change := changeUrl.String()
	// Replace corp with googlesource.
	change = strings.Replace(change, ".git.corp.google.com", ".googlesource.com", 1)
	// Trim prefixes in order.
	for _, prefix := range prefixes {
		if strings.HasPrefix(change, prefix) {
			change = strings.TrimPrefix(change, prefix)
		}
	}
	// Map short-link to full host.
	for k, v := range shortLinkMap {
		if strings.HasPrefix(change, k) {
			change = strings.Replace(change, k, v, 1)
			break
		}
	}
	// Trim trailing slash.
	change = strings.TrimSuffix(change, "/")
	// Split by slash and take the first and last elements, ignoring anything in-between.
	// This should be the host and change ID.
	sp := strings.Split(change, "/")
	if len(sp) < 2 {
		err = fmt.Errorf("%s is not a valid change URL", changeUrl)
		return
	}
	host = sp[0]
	err = gerrit.ValidateGerritURL("https://" + host)
	if err != nil {
		return
	}
	// Change ID can only be numeric.
	num, err := strconv.Atoi(sp[len(sp)-1])
	if err != nil {
		err = fmt.Errorf("%s is not a valid numeric changeID: %v", sp[len(sp)-1], err)
		return
	}
	changeId = int64(num)
	return
}