blob: 2ea5f8a0747cbf3b5caf802c081d29eee4c93c77 [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 (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"github.com/google/gitfs/gitiles"
git "github.com/libgit2/git2go"
)
// A TreeCache caches recursively expanded trees by their git commit and tree IDs.
type TreeCache struct {
dir string
}
// NewTreeCache constructs a new TreeCache.
func NewTreeCache(d string) (*TreeCache, error) {
if err := os.MkdirAll(d, 0700); err != nil {
return nil, err
}
return &TreeCache{dir: d}, nil
}
func (c *TreeCache) path(id *git.Oid) string {
str := id.String()
return fmt.Sprintf("%s/%s/%s", c.dir, str[:3], str[3:])
}
// Get returns a tree, if available.
func (c *TreeCache) Get(id *git.Oid) (*gitiles.Tree, error) {
content, err := ioutil.ReadFile(c.path(id))
if err != nil {
return nil, err
}
var t gitiles.Tree
if err := json.Unmarshal(content, &t); err != nil {
return nil, err
}
return &t, nil
}
// Add adds a Tree to the cache
func (c *TreeCache) Add(id *git.Oid, tree *gitiles.Tree) error {
if err := c.add(id, tree); err != nil {
return err
}
if id.String() != tree.ID {
treeID, err := git.NewOid(tree.ID)
if err != nil {
return err
}
return c.add(treeID, tree)
}
return nil
}
func (c *TreeCache) add(id *git.Oid, tree *gitiles.Tree) error {
f, err := ioutil.TempFile(c.dir, "tmp")
if err != nil {
return err
}
content, err := json.Marshal(tree)
if err != nil {
return err
}
if _, err := f.Write(content); err != nil {
return err
}
if err := f.Close(); err != nil {
return err
}
dir := filepath.Dir(c.path(id))
if err := os.MkdirAll(dir, 0700); err != nil {
return err
}
if err := os.Rename(f.Name(), c.path(id)); err != nil {
return err
}
return nil
}
// GetTree loads the Tree from an on-disk Git repository.
func GetTree(repo *git.Repository, id *git.Oid) (*gitiles.Tree, error) {
obj, err := repo.Lookup(id)
if err != nil {
return nil, err
}
obj, err = obj.Peel(git.ObjectTree)
if err != nil {
return nil, err
}
asTree, err := obj.AsTree()
if err != nil {
return nil, err
}
var tree gitiles.Tree
tree.ID = obj.Id().String()
odb, err := repo.Odb()
if err != nil {
return nil, err
}
cb := func(n string, e *git.TreeEntry) int {
t := ""
var size *int
switch e.Type {
case git.ObjectTree:
return 0
case git.ObjectCommit:
t = "commit"
case git.ObjectBlob:
t = "blob"
sz, _, rhErr := odb.ReadHeader(e.Id)
if rhErr != nil {
err = rhErr
return -1
}
size = new(int)
*size = int(sz)
default:
err = fmt.Errorf("illegal object %d for %s", e.Type, n)
}
gEntry := gitiles.TreeEntry{
Name: filepath.Join(n, e.Name),
ID: e.Id.String(),
Mode: int(e.Filemode),
Size: size,
Type: t,
}
if e.Filemode == git.FilemodeLink {
obj, lookErr := repo.Lookup(e.Id)
if err != nil {
err = lookErr
return -1
}
blob, blobErr := obj.AsBlob()
if blobErr != nil {
err = blobErr
return -1
}
target := string(blob.Contents())
gEntry.Target = &target
}
tree.Entries = append(tree.Entries, gEntry)
return 0
}
if err := asTree.Walk(cb); err != nil {
return nil, err
}
return &tree, nil
}