blob: 83e3bd07a6b12dd68eaa0163a2352fc6a6853c21 [file] [log] [blame]
// Copyright 2016 Google Inc. All rights reserved.
//
// 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 cache
import (
"log"
"sync"
git "github.com/libgit2/git2go"
)
// LazyRepo represents a git repository that might be fetched on
// demand.
type LazyRepo struct {
url string
cache *gitCache
repoMu sync.Mutex
cloning bool
repo *git.Repository
}
func newLazyRepo(url string, cache *gitCache) *LazyRepo {
r := &LazyRepo{
url: url,
cache: cache,
}
return r
}
// NewLazyRepo creates a new repository. If the repository is never to
// be cloned, url should be set to empty string.
func NewLazyRepo(url string, cache *Cache) *LazyRepo {
return newLazyRepo(url, cache.Git)
}
// Repository returns a git.Repository for this repo, or nil if it
// wasn't loaded. This method is safe for concurrent use from
// multiple goroutines. The return value must not be Free'd since it
// is persisted inside LazyRepo.
func (r *LazyRepo) Repository() *git.Repository {
r.repoMu.Lock()
defer r.repoMu.Unlock()
return r.repo
}
// runClone initiates a clone. It makes sure that only one clone
// process runs at any time.
func (r *LazyRepo) runClone() {
repo, err := r.cache.Open(r.url)
r.repoMu.Lock()
defer r.repoMu.Unlock()
r.url = ""
r.cloning = false
r.repo = repo
if err != nil {
log.Printf("runClone: %v", err)
}
}
// Clone schedules the repository to be cloned. This method is safe
// for concurrent use from multiple goroutines.
func (r *LazyRepo) Clone() {
r.repoMu.Lock()
defer r.repoMu.Unlock()
if r.url == "" || r.repo != nil {
return
}
if r.cloning {
return
}
r.cloning = true
go r.runClone()
}