create pkg/resize

conmon-rs currently depends on podmans pkg/kubeutils. Since podman wants
to import conmon-rs go code this can cause many problems.

To fix this we move the shared code to c/common so both projects can use
it without trouble. Also rename the package to pkg/resize from kubeutils
since this contains really only one function and the name is much more
clear.

see containers/conmon-rs#504

Signed-off-by: Paul Holzinger <[email protected]>

pkg/resize/resize.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    https://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package resize
+
+// TerminalSize represents the width and height of a terminal.
+type TerminalSize struct {
+	Width  uint16
+	Height uint16
+}
+
+// HandleResizing spawns a goroutine that processes the resize channel, calling resizeFunc for each
+// TerminalSize received from the channel. The resize channel must be closed elsewhere to stop the
+// goroutine.
+func HandleResizing(resize <-chan TerminalSize, resizeFunc func(size TerminalSize)) {
+	if resize == nil {
+		return
+	}
+
+	go func() {
+		for {
+			size, ok := <-resize
+			if !ok {
+				return
+			}
+			if size.Height < 1 || size.Width < 1 {
+				continue
+			}
+			resizeFunc(size)
+		}
+	}()
+}