Adding Delete and Reset as public Cache methods (bazelbuild#133)

go/pkg/filemetadata/cache.go

@@ -81,6 +81,11 @@ func (c *fmCache) Delete(filename string) error {
 	return c.Backend.Delete(namespace, abs)
 }
 
+// Reset clears the cache.
+func (c *fmCache) Reset() {
+	c.Backend.Reset()
+}
+
 func (c *fmCache) check() error {
 	if c.Backend == nil {
 		return fmt.Errorf("no backend found for store")

go/pkg/filemetadata/filemetadata.go

@@ -56,6 +56,8 @@ func Compute(filename string) *Metadata {
 // Cache is a cache for file contents->Metadata.
 type Cache interface {
 	Get(path string) *Metadata
+	Delete(filename string) error
+	Reset()
 }
 
 type noopCache struct{}
@@ -66,6 +68,14 @@ func (c *noopCache) Get(path string) *Metadata {
 	return Compute(path)
 }
 
+// Delete removes an entry from the cache. It is a noop for the Noop cache.
+func (c *noopCache) Delete(string) error {
+	return nil
+}
+
+// Reset clears the cache. It is a noop for the Noop cache.
+func (c *noopCache) Reset() {}
+
 // NewNoopCache returns a cache that doesn't cache (evaluates on every Get).
 func NewNoopCache() Cache {
 	return &noopCache{}

go/pkg/tree/tree_test.go

@@ -112,6 +112,21 @@ func (c *callCountingMetadataCache) Get(path string) *filemetadata.Metadata {
 	return c.cache.Get(path)
 }
 
+func (c *callCountingMetadataCache) Delete(path string) error {
+	c.t.Helper()
+	p, err := filepath.Rel(c.execRoot, path)
+	if err != nil {
+		c.t.Errorf("expected %v to be under %v", path, c.execRoot)
+	}
+	c.calls[p]++
+	return c.cache.Delete(path)
+}
+
+func (c *callCountingMetadataCache) Reset() {
+	c.t.Helper()
+	c.cache.Reset()
+}
+
 func TestComputeMerkleTreeEmptySubdirs(t *testing.T) {
 	fileBlob := []byte("bla")
 	fileDg := digest.NewFromBlob(fileBlob)