packer-cn/vendor/github.com/aliyun/aliyun-oss-go-sdk/oss/utils.go

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2017-03-04 05:06:32 -05:00
package oss
import (
"bytes"
"errors"
"fmt"
"hash/crc64"
"net/http"
"os"
"os/exec"
"runtime"
"time"
)
// Get User Agent
// Go sdk相关信息包括sdk版本操作系统类型GO版本
var userAgent = func() string {
sys := getSysInfo()
return fmt.Sprintf("aliyun-sdk-go/%s (%s/%s/%s;%s)", Version, sys.name,
sys.release, sys.machine, runtime.Version())
}()
type sysInfo struct {
name string // 操作系统名称windows/Linux
release string // 操作系统版本 2.6.32-220.23.2.ali1089.el5.x86_64等
machine string // 机器类型amd64/x86_64
}
// Get system info
// 获取操作系统信息、机器类型
func getSysInfo() sysInfo {
name := runtime.GOOS
release := "-"
machine := runtime.GOARCH
if out, err := exec.Command("uname", "-s").CombinedOutput(); err == nil {
name = string(bytes.TrimSpace(out))
}
if out, err := exec.Command("uname", "-r").CombinedOutput(); err == nil {
release = string(bytes.TrimSpace(out))
}
if out, err := exec.Command("uname", "-m").CombinedOutput(); err == nil {
machine = string(bytes.TrimSpace(out))
}
return sysInfo{name: name, release: release, machine: machine}
}
// GetNowSec returns Unix time, the number of seconds elapsed since January 1, 1970 UTC.
// 获取当前时间从UTC开始的秒数。
func GetNowSec() int64 {
return time.Now().Unix()
}
// GetNowNanoSec returns t as a Unix time, the number of nanoseconds elapsed
// since January 1, 1970 UTC. The result is undefined if the Unix time
// in nanoseconds cannot be represented by an int64. Note that this
// means the result of calling UnixNano on the zero Time is undefined.
// 获取当前时间从UTC开始的纳秒。
func GetNowNanoSec() int64 {
return time.Now().UnixNano()
}
// GetNowGMT 获取当前时间,格式形如"Mon, 02 Jan 2006 15:04:05 GMT"HTTP中使用的时间格式
func GetNowGMT() string {
return time.Now().UTC().Format(http.TimeFormat)
}
// FileChunk 文件片定义
type FileChunk struct {
Number int // 块序号
Offset int64 // 块在文件中的偏移量
Size int64 // 块大小
}
// SplitFileByPartNum Split big file to part by the num of part
// 按指定的块数分割文件。返回值FileChunk为分割结果error为nil时有效。
func SplitFileByPartNum(fileName string, chunkNum int) ([]FileChunk, error) {
if chunkNum <= 0 || chunkNum > 10000 {
return nil, errors.New("chunkNum invalid")
}
file, err := os.Open(fileName)
if err != nil {
return nil, err
}
defer file.Close()
stat, err := file.Stat()
if err != nil {
return nil, err
}
if int64(chunkNum) > stat.Size() {
return nil, errors.New("oss: chunkNum invalid")
}
var chunks []FileChunk
var chunk = FileChunk{}
var chunkN = (int64)(chunkNum)
for i := int64(0); i < chunkN; i++ {
chunk.Number = int(i + 1)
chunk.Offset = i * (stat.Size() / chunkN)
if i == chunkN-1 {
chunk.Size = stat.Size()/chunkN + stat.Size()%chunkN
} else {
chunk.Size = stat.Size() / chunkN
}
chunks = append(chunks, chunk)
}
return chunks, nil
}
// SplitFileByPartSize Split big file to part by the size of part
// 按块大小分割文件。返回值FileChunk为分割结果error为nil时有效。
func SplitFileByPartSize(fileName string, chunkSize int64) ([]FileChunk, error) {
if chunkSize <= 0 {
return nil, errors.New("chunkSize invalid")
}
file, err := os.Open(fileName)
if err != nil {
return nil, err
}
defer file.Close()
stat, err := file.Stat()
if err != nil {
return nil, err
}
var chunkN = stat.Size() / chunkSize
if chunkN >= 10000 {
return nil, errors.New("Too many parts, please increase part size.")
}
var chunks []FileChunk
var chunk = FileChunk{}
for i := int64(0); i < chunkN; i++ {
chunk.Number = int(i + 1)
chunk.Offset = i * chunkSize
chunk.Size = chunkSize
chunks = append(chunks, chunk)
}
if stat.Size()%chunkSize > 0 {
chunk.Number = len(chunks) + 1
chunk.Offset = int64(len(chunks)) * chunkSize
chunk.Size = stat.Size() % chunkSize
chunks = append(chunks, chunk)
}
return chunks, nil
}
// GetPartEnd 计算结束位置
func GetPartEnd(begin int64, total int64, per int64) int64 {
if begin+per > total {
return total - 1
}
return begin + per - 1
}
// crcTable returns the Table constructed from the specified polynomial
var crcTable = func() *crc64.Table {
return crc64.MakeTable(crc64.ECMA)
}