Merge pull request #52753 from munnerz/sample-controller

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

sample-controller: add example CRD controller

**What this PR does / why we need it**:

Adds a sample-controller example repository

fixes #52752

**Special notes for your reviewer**:

This is currently based on the sttts:sttts-codegen-scripts branch and should not be merged until that is (ref https://github.com/kubernetes/kubernetes/pull/52186)

**Release note**:

```
Add sample-controller repository
```

/cc @sttts @nikhita @colemickens

Kubernetes-commit: 9a7800f7d2efb88b397674672ac56f898826cf7c

vendor/k8s.io/apimachinery/pkg/apis/meta/v1/labels.go

@@ -0,0 +1,75 @@
+/*
+Copyright 2016 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
+
+    http://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 v1
+
+// Clones the given selector and returns a new selector with the given key and value added.
+// Returns the given selector, if labelKey is empty.
+func CloneSelectorAndAddLabel(selector *LabelSelector, labelKey, labelValue string) *LabelSelector {
+	if labelKey == "" {
+		// Don't need to add a label.
+		return selector
+	}
+
+	// Clone.
+	newSelector := new(LabelSelector)
+
+	// TODO(madhusudancs): Check if you can use deepCopy_extensions_LabelSelector here.
+	newSelector.MatchLabels = make(map[string]string)
+	if selector.MatchLabels != nil {
+		for key, val := range selector.MatchLabels {
+			newSelector.MatchLabels[key] = val
+		}
+	}
+	newSelector.MatchLabels[labelKey] = labelValue
+
+	if selector.MatchExpressions != nil {
+		newMExps := make([]LabelSelectorRequirement, len(selector.MatchExpressions))
+		for i, me := range selector.MatchExpressions {
+			newMExps[i].Key = me.Key
+			newMExps[i].Operator = me.Operator
+			if me.Values != nil {
+				newMExps[i].Values = make([]string, len(me.Values))
+				copy(newMExps[i].Values, me.Values)
+			} else {
+				newMExps[i].Values = nil
+			}
+		}
+		newSelector.MatchExpressions = newMExps
+	} else {
+		newSelector.MatchExpressions = nil
+	}
+
+	return newSelector
+}
+
+// AddLabelToSelector returns a selector with the given key and value added to the given selector's MatchLabels.
+func AddLabelToSelector(selector *LabelSelector, labelKey, labelValue string) *LabelSelector {
+	if labelKey == "" {
+		// Don't need to add a label.
+		return selector
+	}
+	if selector.MatchLabels == nil {
+		selector.MatchLabels = make(map[string]string)
+	}
+	selector.MatchLabels[labelKey] = labelValue
+	return selector
+}
+
+// SelectorHasLabel checks if the given selector contains the given label key in its MatchLabels
+func SelectorHasLabel(selector *LabelSelector, labelKey string) bool {
+	return len(selector.MatchLabels[labelKey]) > 0
+}