update vendor

vendor/github.com/qiniu/x/reqid.v7/reqid.go

@@ -0,0 +1,52 @@
+package reqid
+
+import (
+	"encoding/binary"
+	"encoding/base64"
+	"net/http"
+	"time"
+
+	. "golang.org/x/net/context"
+)
+
+// --------------------------------------------------------------------
+
+var pid = uint32(time.Now().UnixNano() % 4294967291)
+
+func genReqId() string {
+	var b [12]byte
+	binary.LittleEndian.PutUint32(b[:], pid)
+	binary.LittleEndian.PutUint64(b[4:], uint64(time.Now().UnixNano()))
+	return base64.URLEncoding.EncodeToString(b[:])
+}
+
+// --------------------------------------------------------------------
+
+type key int // key is unexported and used for Context
+
+const (
+	reqidKey key = 0
+)
+
+func NewContext(ctx Context, reqid string) Context {
+	return WithValue(ctx, reqidKey, reqid)
+}
+
+func NewContextWith(ctx Context, w http.ResponseWriter, req *http.Request) Context {
+	reqid := req.Header.Get("X-Reqid")
+	if reqid == "" {
+		reqid = genReqId()
+		req.Header.Set("X-Reqid", reqid)
+	}
+	h := w.Header()
+	h.Set("X-Reqid", reqid)
+	return WithValue(ctx, reqidKey, reqid)
+}
+
+func FromContext(ctx Context) (reqid string, ok bool) {
+	reqid, ok = ctx.Value(reqidKey).(string)
+	return
+}
+
+// --------------------------------------------------------------------
+