/
cache.go
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/
cache.go
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//
// Propolis: Amazon S3 <--> local file system synchronizer
// Copyright © 2011 Russ Ross <russ@russross.com>
//
// This file is part of Propolis
//
// Propolis is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// Propolis is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Propolis. If not, see <http://www.gnu.org/licenses/>.
//
// Cache of file metadata
package main
import (
"gosqlite.googlecode.com/hg/sqlite"
"os"
"strings"
)
type Cache struct {
*sqlite.Conn
}
func Connect(filename string) (db Cache, err os.Error) {
var c *sqlite.Conn
if c, err = sqlite.Open(filename); err != nil {
return
}
db = Cache{c}
err = db.Exec("CREATE TABLE IF NOT EXISTS cache (\n" +
" path TEXT NOT NULL,\n" +
" md5 TEXT NOT NULL,\n" +
" uid INTEGER,\n" +
" gid INTEGER,\n" +
" mode INTEGER,\n" +
" mtime INTEGER,\n" +
" size INTEGER,\n" +
" PRIMARY KEY (path)\n" +
")\n")
if err != nil {
db.Close()
return
}
err = db.Exec("CREATE INDEX IF NOT EXISTS idx_md5 ON cache (md5)\n")
if err != nil {
db.Close()
return
}
return
}
func (p *Propolis) GetFileInfo(elt *File) (err os.Error) {
var stmt *sqlite.Stmt
stmt, err = p.Db.Prepare("SELECT md5, uid, gid, mode, mtime, size " +
"FROM cache WHERE path = ?")
if err != nil {
return
}
defer stmt.Finalize()
if err = stmt.Exec(elt.ServerPath); err != nil || !stmt.Next() {
return
}
elt.CacheInfo = new(os.FileInfo)
elt.CacheInfo.Name = elt.ServerPath
var mode int64
err = stmt.Scan(
&elt.CacheHashHex,
&elt.CacheInfo.Uid,
&elt.CacheInfo.Gid,
&mode,
&elt.CacheInfo.Mtime_ns,
&elt.CacheInfo.Size)
elt.CacheInfo.Mode = uint32(mode)
return
}
func (p *Propolis) GetPathFromMd5(elt *File) (path string, err os.Error) {
var stmt1, stmt2 *sqlite.Stmt
stmt1, err = p.Db.Prepare("SELECT path FROM cache WHERE md5 = ? AND path = ?")
if err != nil {
return
}
defer stmt1.Finalize()
if err = stmt1.Exec(elt.LocalHashHex, elt.ServerPath); err != nil {
return
}
if stmt1.Next() {
// this path has the desired md5 hash
return elt.ServerPath, nil
}
stmt2, err = p.Db.Prepare("SELECT path FROM cache WHERE md5 = ? LIMIT 1")
if err != nil {
return
}
defer stmt2.Finalize()
if err = stmt2.Exec(elt.LocalHashHex); err != nil || !stmt2.Next() {
return
}
err = stmt2.Scan(&path)
return
}
func (p *Propolis) SetFileInfo(elt *File, uselocal bool) (err os.Error) {
// clear old entry if it exists
if err = p.DeleteFileInfo(elt); err != nil {
return
}
// insert new entry
info := elt.LocalInfo
hash := elt.LocalHashHex
if !uselocal {
info = elt.CacheInfo
hash = elt.ServerHashHex
}
err = p.Db.Exec("INSERT INTO cache VALUES (?, ?, ?, ?, ?, ?, ?)",
elt.ServerPath,
hash,
info.Uid,
info.Gid,
info.Mode,
info.Mtime_ns,
info.Size)
return
}
func (p *Propolis) DeleteFileInfo(elt *File) (err os.Error) {
// delete entry if it exists
err = p.Db.Exec("DELETE FROM cache WHERE path = ?", elt.ServerPath)
return
}
func (p *Propolis) ResetCache() (err os.Error) {
// clear all cache entries
err = p.Db.Exec("DELETE FROM cache")
return
}
func (p *Propolis) ScanCache(push bool) (err os.Error) {
// scan the entire cache
var stmt *sqlite.Stmt
prefix := p.BucketRoot
if prefix != "" {
prefix = strings.Replace(prefix, "\\", "\\\\", -1)
prefix = strings.Replace(prefix, "_", "\\_", -1)
prefix = strings.Replace(prefix, "%", "\\%", -1)
prefix += "/%"
stmt, err = p.Db.Prepare("SELECT * FROM cache WHERE path LIKE ? ESCAPE '\\'")
} else {
stmt, err = p.Db.Prepare("SELECT * FROM cache")
}
if err != nil {
return
}
defer stmt.Finalize()
if prefix != "" {
if err = stmt.Exec(prefix); err != nil {
return
}
} else {
if err = stmt.Exec(); err != nil {
return
}
}
// read the results
for stmt.Next() {
info := new(os.FileInfo)
var mode int64
var hashHex string
err = stmt.Scan(
&info.Name,
&hashHex,
&info.Uid,
&info.Gid,
&mode,
&info.Mtime_ns,
&info.Size)
if err != nil {
return
}
info.Mode = uint32(mode)
// see if we have a matching entry already
var elt *File
var present bool
if elt, present = p.Catalog[info.Name]; !present {
elt = p.NewFileServer(info.Name, push)
}
elt.CacheInfo = info
elt.CacheHashHex = hashHex
// store the result (if it's not already there)
p.Catalog[info.Name] = elt
}
return
}
func (p *Propolis) AuditCache() (err os.Error) {
// gather entries where the cache does not match the server
var deathrow []*File
for _, elt := range p.Catalog {
if elt.CacheInfo != nil &&
(elt.ServerHashHex == "" ||
elt.ServerHashHex != elt.CacheHashHex ||
elt.ServerSize != elt.CacheInfo.Size) {
deathrow = append(deathrow, elt)
}
}
if len(deathrow) == 0 {
return
}
// wrap all the deletes in a single transaction
if err = p.Db.Exec("BEGIN TRANSACTION"); err != nil {
return
}
for _, elt := range deathrow {
if err = p.Db.Exec("DELETE FROM cache WHERE path = ?", elt.ServerPath); err != nil {
return
}
p.Catalog[elt.ServerPath] = nil, false
}
if err = p.Db.Exec("COMMIT"); err != nil {
return
}
return
}