1
0
forked from sm/vain
vain/storage.go
stephen mcquay 5de44ba4d6 tighter constraints on allowed paths.
Change-Id: Ie6b121e4733e45288a36dbc2426f556fd5e2832d
2016-03-02 22:06:17 -08:00

127 lines
2.4 KiB
Go

package vain
import (
"encoding/json"
"errors"
"fmt"
"os"
"strings"
"sync"
)
// Valid checks that p will not confuse the go tool if added to packages.
func Valid(p string, packages []Package) bool {
for _, pkg := range packages {
if strings.HasPrefix(pkg.path, p) || strings.HasPrefix(p, pkg.path) {
return false
}
}
return true
}
// Storage is a shim to allow for alternate storage types.
type Storage interface {
Contains(name string) bool
Add(p Package) error
Remove(path string) error
All() []Package
}
// SimpleStore implements a simple json on-disk storage.
type SimpleStore struct {
l sync.RWMutex
p map[string]Package
dbl sync.Mutex
path string
}
// NewSimpleStore returns a ready-to-use SimpleStore storing json at path.
func NewSimpleStore(path string) *SimpleStore {
return &SimpleStore{
path: path,
p: make(map[string]Package),
}
}
func (ms *SimpleStore) Contains(name string) bool {
_, contains := ms.p[name]
return contains
}
// Add adds p to the SimpleStore.
func (ss *SimpleStore) Add(p Package) error {
ss.l.Lock()
ss.p[p.path] = p
ss.l.Unlock()
m := ""
if err := ss.Save(); err != nil {
m = fmt.Sprintf("unable to store db: %v", err)
if err := ss.Remove(p.path); err != nil {
m = fmt.Sprintf("%s\nto add insult to injury, could not delete package: %v\n", m, err)
}
return errors.New(m)
}
return nil
}
// Remove removes p from the SimpleStore.
func (ss *SimpleStore) Remove(path string) error {
ss.l.Lock()
delete(ss.p, path)
ss.l.Unlock()
return nil
}
// All returns all current packages.
func (ss *SimpleStore) All() []Package {
r := []Package{}
ss.l.RLock()
for _, p := range ss.p {
r = append(r, p)
}
ss.l.RUnlock()
return r
}
// Save writes the db to disk.
func (ss *SimpleStore) Save() error {
// running in-memory only
if ss.path == "" {
return nil
}
ss.dbl.Lock()
defer ss.dbl.Unlock()
f, err := os.Create(ss.path)
if err != nil {
return err
}
defer f.Close()
return json.NewEncoder(f).Encode(ss.p)
}
// Load reads the db from disk and populates ss.
func (ss *SimpleStore) Load() error {
// running in-memory only
if ss.path == "" {
return nil
}
ss.dbl.Lock()
defer ss.dbl.Unlock()
f, err := os.Open(ss.path)
if err != nil {
return err
}
defer f.Close()
in := map[string]Package{}
if err := json.NewDecoder(f).Decode(&in); err != nil {
return err
}
for k, v := range in {
v.path = k
ss.p[k] = v
}
return nil
}