build: move e2e dependencies into e2e/go.mod

Several packages are only used while running the e2e suite. These
packages are less important to update, as the they can not influence the
final executable that is part of the Ceph-CSI container-image.

By moving these dependencies out of the main Ceph-CSI go.mod, it is
easier to identify if a reported CVE affects Ceph-CSI, or only the
testing (like most of the Kubernetes CVEs).

Signed-off-by: Niels de Vos <ndevos@ibm.com>

e2e/vendor/k8s.io/dynamic-resource-allocation/cel/cache.go

@@ -0,0 +1,79 @@
+/*
+Copyright 2024 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 cel
+
+import (
+	"sync"
+
+	"k8s.io/utils/keymutex"
+	"k8s.io/utils/lru"
+)
+
+// Cache is a thread-safe LRU cache for a compiled CEL expression.
+type Cache struct {
+	compileMutex keymutex.KeyMutex
+	cacheMutex   sync.RWMutex
+	cache        *lru.Cache
+}
+
+// NewCache creates a cache. The maximum number of entries determines
+// how many entries are cached at most before dropping the oldest
+// entry.
+func NewCache(maxCacheEntries int) *Cache {
+	return &Cache{
+		compileMutex: keymutex.NewHashed(0),
+		cache:        lru.New(maxCacheEntries),
+	}
+}
+
+// GetOrCompile checks whether the cache already has a compilation result
+// and returns that if available. Otherwise it compiles, stores successful
+// results and returns the new result.
+func (c *Cache) GetOrCompile(expression string) CompilationResult {
+	// Compiling a CEL expression is expensive enough that it is cheaper
+	// to lock a mutex than doing it several times in parallel.
+	c.compileMutex.LockKey(expression)
+	//nolint:errcheck // Only returns an error for unknown keys, which isn't the case here.
+	defer c.compileMutex.UnlockKey(expression)
+
+	cached := c.get(expression)
+	if cached != nil {
+		return *cached
+	}
+
+	expr := GetCompiler().CompileCELExpression(expression, Options{})
+	if expr.Error == nil {
+		c.add(expression, &expr)
+	}
+	return expr
+}
+
+func (c *Cache) add(expression string, expr *CompilationResult) {
+	c.cacheMutex.Lock()
+	defer c.cacheMutex.Unlock()
+	c.cache.Add(expression, expr)
+}
+
+func (c *Cache) get(expression string) *CompilationResult {
+	c.cacheMutex.RLock()
+	defer c.cacheMutex.RUnlock()
+	expr, found := c.cache.Get(expression)
+	if !found {
+		return nil
+	}
+	return expr.(*CompilationResult)
+}