lfs: implement HTTP routes (#6035)

* Bootstrap with GORM

* Fix lint error

* Set conn max lifetime to one minute

* Fallback to use gorm v1

* Define HTTP routes

* Finish authentication

* Save token updated

* Add docstring

* Finish authorization

* serveBatch rundown

* Define types in lfsutil

* Finish Batch

* authutil

* Finish basic

* Formalize response error

* Fix lint errors

* authutil: add tests

* dbutil: add tests

* lfsutil: add tests

* strutil: add tests

* Formalize 401 response

1 files changed, 56 insertions, 0 deletions

diff --git a/internal/db/perms.go b/internal/db/perms.go
new file mode 100644
index 00000000..6dc5d423
--- /dev/null
+++ b/internal/db/perms.go
@@ -0,0 +1,56 @@
+// Copyright 2020 The Gogs Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package db
+
+import (
+	"github.com/jinzhu/gorm"
+	log "unknwon.dev/clog/v2"
+)
+
+// PermsStore is the persistent interface for permissions.
+//
+// NOTE: All methods are sorted in alphabetical order.
+type PermsStore interface {
+	// AccessMode returns the access mode of given user has to the repository.
+	AccessMode(userID int64, repo *Repository) AccessMode
+	// Authorize returns true if the user has as good as desired access mode to
+	// the repository.
+	Authorize(userID int64, repo *Repository, desired AccessMode) bool
+}
+
+var Perms PermsStore
+
+type perms struct {
+	*gorm.DB
+}
+
+func (db *perms) AccessMode(userID int64, repo *Repository) AccessMode {
+	var mode AccessMode
+	// Everyone has read access to public repository.
+	if !repo.IsPrivate {
+		mode = AccessModeRead
+	}
+
+	// Quick check to avoid a DB query.
+	if userID <= 0 {
+		return mode
+	}
+
+	if userID == repo.OwnerID {
+		return AccessModeOwner
+	}
+
+	access := new(Access)
+	err := db.Where("user_id = ? AND repo_id = ?", userID, repo.ID).First(access).Error
+	if err != nil {
+		log.Error("Failed to get access [user_id: %d, repo_id: %d]: %v", userID, repo.ID, err)
+		return mode
+	}
+	return access.Mode
+}
+
+func (db *perms) Authorize(userID int64, repo *Repository, desired AccessMode) bool {
+	return desired <= db.AccessMode(userID, repo)
+}