1 /* 2 Copyright 2016 The Kubernetes Authors. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package term 18 19 import ( 20 "time" 21 22 "k8s.io/apimachinery/pkg/util/runtime" 23 "k8s.io/client-go/tools/remotecommand" 24 ) 25 26 // monitorResizeEvents spawns a goroutine that periodically gets the terminal size and tries to send 27 // it to the resizeEvents channel if the size has changed. The goroutine stops when the stop channel 28 // is closed. 29 func monitorResizeEvents(fd uintptr, resizeEvents chan<- remotecommand.TerminalSize, stop chan struct{}) { 30 go func() { 31 defer runtime.HandleCrash() 32 33 size := GetSize(fd) 34 if size == nil { 35 return 36 } 37 lastSize := *size 38 39 for { 40 // see if we need to stop running 41 select { 42 case <-stop: 43 return 44 default: 45 } 46 47 size := GetSize(fd) 48 if size == nil { 49 return 50 } 51 52 if size.Height != lastSize.Height || size.Width != lastSize.Width { 53 lastSize.Height = size.Height 54 lastSize.Width = size.Width 55 resizeEvents <- *size 56 } 57 58 // sleep to avoid hot looping 59 time.Sleep(250 * time.Millisecond) 60 } 61 }() 62 } 63