lib/cache: add Delete and DeletePrefix methods #4811

lib/cache/cache.go

@@ -3,6 +3,7 @@
 package cache
 
 import (
+	"strings"
 	"sync"
 	"time"
 )
@@ -119,6 +120,32 @@ func (c *Cache) GetMaybe(key string) (value interface{}, found bool) {
 	return entry.value, found
 }
 
+// Delete the entry passed in
+//
+// Returns true if the entry was found
+func (c *Cache) Delete(key string) bool {
+	c.mu.Lock()
+	_, found := c.cache[key]
+	delete(c.cache, key)
+	c.mu.Unlock()
+	return found
+}
+
+// DeletePrefix deletes all entries with the given prefix
+//
+// Returns number of entries deleted
+func (c *Cache) DeletePrefix(prefix string) (deleted int) {
+	c.mu.Lock()
+	for k := range c.cache {
+		if strings.HasPrefix(k, prefix) {
+			delete(c.cache, k)
+			deleted++
+		}
+	}
+	c.mu.Unlock()
+	return deleted
+}
+
 // Rename renames the item at oldKey to newKey.
 //
 // If there was an existing item at newKey then it takes precedence

lib/cache/cache_test.go

@@ -28,6 +28,8 @@ func setup(t *testing.T) (*Cache, CreateFunc) {
 			return "/file.txt", true, errCached
 		case "/error":
 			return nil, false, errSentinel
+		case "/err":
+			return nil, false, errSentinel
 		}
 		panic(fmt.Sprintf("Unknown path %q", path))
 	}
@@ -225,6 +227,53 @@ func TestGetMaybe(t *testing.T) {
 	assert.Nil(t, value)
 }
 
+func TestDelete(t *testing.T) {
+	c, create := setup(t)
+
+	assert.Equal(t, 0, len(c.cache))
+
+	_, err := c.Get("/", create)
+	require.NoError(t, err)
+
+	assert.Equal(t, 1, len(c.cache))
+
+	assert.Equal(t, false, c.Delete("notfound"))
+	assert.Equal(t, 1, len(c.cache))
+
+	assert.Equal(t, true, c.Delete("/"))
+	assert.Equal(t, 0, len(c.cache))
+
+	assert.Equal(t, false, c.Delete("/"))
+	assert.Equal(t, 0, len(c.cache))
+}
+
+func TestDeletePrefix(t *testing.T) {
+	create := func(path string) (interface{}, bool, error) {
+		return path, true, nil
+	}
+	c := New()
+
+	_, err := c.Get("remote:path", create)
+	require.NoError(t, err)
+	_, err = c.Get("remote:path2", create)
+	require.NoError(t, err)
+	_, err = c.Get("remote:", create)
+	require.NoError(t, err)
+	_, err = c.Get("remote", create)
+	require.NoError(t, err)
+
+	assert.Equal(t, 4, len(c.cache))
+
+	assert.Equal(t, 3, c.DeletePrefix("remote:"))
+	assert.Equal(t, 1, len(c.cache))
+
+	assert.Equal(t, 1, c.DeletePrefix(""))
+	assert.Equal(t, 0, len(c.cache))
+
+	assert.Equal(t, 0, c.DeletePrefix(""))
+	assert.Equal(t, 0, len(c.cache))
+}
+
 func TestCacheRename(t *testing.T) {
 	c := New()
 	create := func(path string) (interface{}, bool, error) {