// getExecConfig looks up the exec instance by name. If the container associated
// with the exec instance is stopped or paused, it will return an error.
func (d *Daemon) getExecConfig(name string) (*exec.Config, error) {
	ec := d.execCommands.Get(name)

	// If the exec is found but its container is not in the daemon's list of
	// containers then it must have been deleted, in which case instead of
	// saying the container isn't running, we should return a 404 so that
	// the user sees the same error now that they will after the
	// 5 minute clean-up loop is run which erases old/dead execs.

	if ec != nil {
		if container := d.containers.Get(ec.ContainerID); container != nil {
			if !container.IsRunning() {
				return nil, fmt.Errorf("Container %s is not running: %s", container.ID, container.State.String())
			}
			if container.IsPaused() {
				return nil, errExecPaused(container.ID)
			}
			if container.IsRestarting() {
				return nil, errContainerIsRestarting(container.ID)
			}
			return ec, nil
		}
	}

	return nil, errExecNotFound(name)
}

func (d *Daemon) getActiveContainer(name string) (*container.Container, error) {
	container, err := d.GetContainer(name)
	if err != nil {
		return nil, err
	}

	if !container.IsRunning() {
		return nil, errNotRunning{container.ID}
	}
	if container.IsPaused() {
		return nil, errExecPaused(name)
	}
	if container.IsRestarting() {
		return nil, errContainerIsRestarting(container.ID)
	}
	return container, nil
}

func (d *Daemon) getActiveContainer(name string) (*container.Container, error) {
	container, err := d.GetContainer(name)
	if err != nil {
		return nil, err
	}

	if !container.IsRunning() {
		return nil, derr.ErrorCodeNotRunning.WithArgs(name)
	}
	if container.IsPaused() {
		return nil, derr.ErrorCodeExecPaused.WithArgs(name)
	}
	if container.IsRestarting() {
		return nil, derr.ErrorCodeContainerRestarting.WithArgs(name)
	}
	return container, nil
}

// ContainerStats writes information about the container to the stream
// given in the config object.
func (daemon *Daemon) ContainerStats(ctx context.Context, prefixOrName string, config *backend.ContainerStatsConfig) error {
	if runtime.GOOS == "solaris" {
		return fmt.Errorf("%+v does not support stats", runtime.GOOS)
	}
	// Remote API version (used for backwards compatibility)
	apiVersion := config.Version

	container, err := daemon.GetContainer(prefixOrName)
	if err != nil {
		return err
	}

	// If the container is either not running or restarting and requires no stream, return an empty stats.
	if (!container.IsRunning() || container.IsRestarting()) && !config.Stream {
		return json.NewEncoder(config.OutStream).Encode(&types.Stats{})
	}

	outStream := config.OutStream
	if config.Stream {
		wf := ioutils.NewWriteFlusher(outStream)
		defer wf.Close()
		wf.Flush()
		outStream = wf
	}

	var preCPUStats types.CPUStats
	var preRead time.Time
	getStatJSON := func(v interface{}) *types.StatsJSON {
		ss := v.(types.StatsJSON)
		ss.Name = container.Name
		ss.ID = container.ID
		ss.PreCPUStats = preCPUStats
		ss.PreRead = preRead
		preCPUStats = ss.CPUStats
		preRead = ss.Read
		return &ss
	}

	enc := json.NewEncoder(outStream)

	updates := daemon.subscribeToContainerStats(container)
	defer daemon.unsubscribeToContainerStats(container, updates)

	noStreamFirstFrame := true
	for {
		select {
		case v, ok := <-updates:
			if !ok {
				return nil
			}

			var statsJSON interface{}
			statsJSONPost120 := getStatJSON(v)
			if versions.LessThan(apiVersion, "1.21") {
				if runtime.GOOS == "windows" {
					return errors.New("API versions pre v1.21 do not support stats on Windows")
				}
				var (
					rxBytes   uint64
					rxPackets uint64
					rxErrors  uint64
					rxDropped uint64
					txBytes   uint64
					txPackets uint64
					txErrors  uint64
					txDropped uint64
				)
				for _, v := range statsJSONPost120.Networks {
					rxBytes += v.RxBytes
					rxPackets += v.RxPackets
					rxErrors += v.RxErrors
					rxDropped += v.RxDropped
					txBytes += v.TxBytes
					txPackets += v.TxPackets
					txErrors += v.TxErrors
					txDropped += v.TxDropped
				}
				statsJSON = &v1p20.StatsJSON{
					Stats: statsJSONPost120.Stats,
					Network: types.NetworkStats{
						RxBytes:   rxBytes,
						RxPackets: rxPackets,
						RxErrors:  rxErrors,
						RxDropped: rxDropped,
						TxBytes:   txBytes,
						TxPackets: txPackets,
						TxErrors:  txErrors,
						TxDropped: txDropped,
					},
				}
			} else {
				statsJSON = statsJSONPost120
			}

			if !config.Stream && noStreamFirstFrame {
				// prime the cpu stats so they aren't 0 in the final output
				noStreamFirstFrame = false
				continue
//.........这里部分代码省略.........