func NewCache(path string, client *http.Client) Reader {
return &driveCache{
path: path,
client: client,
chunkSize: *chunkSize,
lru: lru.New(int(*numChunks)),
pending: make(map[chunk]*readRequest),
}
}
// NewDriveDB creates a new DriveDB and starts syncing metadata.
func NewDriveDB(client *http.Client, dbPath, cachePath string, pollInterval time.Duration, rootId string) (*DriveDB, error) {
svc, _ := gdrive.New(client)
_, err := svc.About.Get().Do()
if err != nil {
log.Fatalf("drive.service.About.Get().Do: %v\n", err)
}
if *debugDriveDB {
debug = true
}
ldbPath := path.Join(dbPath, "meta")
log.Printf("using db path: %q", ldbPath)
err = os.MkdirAll(ldbPath, 0700)
if err != nil {
return nil, fmt.Errorf("could not create directory %q", ldbPath)
}
log.Printf("using cache path: %q", cachePath)
err = os.MkdirAll(cachePath, 0700)
if err != nil {
return nil, fmt.Errorf("could not create directory %q", cachePath)
}
db, err := openLevelDB(ldbPath)
if err != nil {
return nil, err
}
d := &DriveDB{
client: client,
service: svc,
db: db,
dbpath: ldbPath,
data: cachePath,
lruCache: lru.New(*inodeCacheSize),
changes: make(chan *gdrive.ChangeList, 200),
pollInterval: pollInterval,
rootId: rootId,
driveSize: (*driveCacheChunk) * (*driveCacheChunks), // ensure drive reads are always a multiple of cache size
cacheBlocks: (*cacheSize) * ((*driveCacheChunks) * (*prefetchMultiplier)), // enough blocks for readahead
pfetchq: make(chan DownloadSpec, 20000),
pfetchmap: make(map[string]bool),
}
log.Printf("%d cache blocks of %d bytes", d.cacheBlocks, *driveCacheChunk)
// Get saved checkpoint.
err = d.get(internalKey("checkpoint"), &d.cpt)
if err != nil {
log.Printf("error reading checkpoint: %v", err)
d.cpt = NewCheckpoint()
}
if d.cpt.Version != checkpointVersion {
log.Printf("checkpoint version invalid, require %v but found %v", checkpointVersion, d.cpt.Version)
err = d.reinit()
if err != nil {
log.Printf("Failed to reinitialize the database: %v", err)
log.Fatal("You should probably run: rm -rf %v", ldbPath)
}
}
err = d.writeCheckpoint(nil)
if err != nil {
return nil, fmt.Errorf("could not write checkpoint: %v", err)
}
debug.Printf("Recovered from checkpoint: %+v", d.cpt)
if err := d.createRoot(); err != nil {
return nil, fmt.Errorf("could not create root inode entry: %v", err)
}
d.synced = sync.NewCond(&d.syncmu)
go d.sync()
go d.pollForChanges()
if debug {
registerDebugHandles(*d) // in http_handlers.go
}
for i := 0; i < *prefetchWorkers; i++ {
go d.prefetcher()
}
return d, nil
}