distribution/docs/storage/driver/azure/blockid.go
Ahmet Alp Balkan 5c372ded1b storage/driver/azure: Update vendored Azure SDK
This change refreshes the updated version of Azure SDK
for Go that has the latest changes.

I manually vendored the new SDK (github.com/Azure/azure-sdk-for-go)
and I removed `management/` `core/` packages manually simply because
they're not used here and they have a fork of `net/http` and `crypto/tls`
for a particular reason. It was introducing a 44k SLOC change otherwise...

This also undoes the `include_azure` flag (actually Steven removed the
driver from imports but forgot to add the build flag apparently, so the
flag wasn't really including azure. 😄 ). This also must be obsolete
now.

Fixes #620, #175.

Signed-off-by: Ahmet Alp Balkan <ahmetalpbalkan@gmail.com>
2015-06-16 17:13:44 -07:00

60 lines
1.2 KiB
Go

package azure
import (
"encoding/base64"
"fmt"
"math/rand"
"sync"
"time"
azure "github.com/Azure/azure-sdk-for-go/storage"
)
type blockIDGenerator struct {
pool map[string]bool
r *rand.Rand
m sync.Mutex
}
// Generate returns an unused random block id and adds the generated ID
// to list of used IDs so that the same block name is not used again.
func (b *blockIDGenerator) Generate() string {
b.m.Lock()
defer b.m.Unlock()
var id string
for {
id = toBlockID(int(b.r.Int()))
if !b.exists(id) {
break
}
}
b.pool[id] = true
return id
}
func (b *blockIDGenerator) exists(id string) bool {
_, used := b.pool[id]
return used
}
func (b *blockIDGenerator) Feed(blocks azure.BlockListResponse) {
b.m.Lock()
defer b.m.Unlock()
for _, bl := range append(blocks.CommittedBlocks, blocks.UncommittedBlocks...) {
b.pool[bl.Name] = true
}
}
func newBlockIDGenerator() *blockIDGenerator {
return &blockIDGenerator{
pool: make(map[string]bool),
r: rand.New(rand.NewSource(time.Now().UnixNano()))}
}
// toBlockId converts given integer to base64-encoded block ID of a fixed length.
func toBlockID(i int) string {
s := fmt.Sprintf("%029d", i) // add zero padding for same length-blobs
return base64.StdEncoding.EncodeToString([]byte(s))
}