archive,cmd,images: clean up some code

Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com>

archive/compression/compression.go

@@ -60,7 +60,7 @@ func DetectCompression(source []byte) Compression {
 			// Len too short
 			continue
 		}
-		if bytes.Compare(m, source[:len(m)]) == 0 {
+		if bytes.Equal(m, source[:len(m)]) {
 			return compression
 		}
 	}

archive/compression/compression_test.go

@@ -53,7 +53,7 @@ func testCompressDecompress(t *testing.T, size int, compression Compression) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if bytes.Compare(orig, decompressed) != 0 {
+	if !bytes.Equal(orig, decompressed) {
 		t.Fatal("strange decompressed data")
 	}
 }

cmd/containerd/main.go

@@ -137,7 +137,7 @@ func main() {
 		// start the prometheus metrics API for containerd
 		serveMetricsAPI()
 
-		log.G(global).Infof("containerd successfully booted in %fs", time.Now().Sub(start).Seconds())
+		log.G(global).Infof("containerd successfully booted in %fs", time.Since(start).Seconds())
 		return handleSignals(signals, server)
 	}
 

cmd/dist/fetch.go

@@ -212,11 +212,7 @@ func (j *jobs) jobs() []string {
 	defer j.mu.Unlock()
 
 	var jobs []string
-	for _, j := range j.refs {
-		jobs = append(jobs, j)
-	}
-
-	return jobs
+	return append(jobs, j.refs...)
 }
 
 type statusInfo struct {

images/handlers.go

@@ -137,9 +137,7 @@ func ChildrenHandler(provider content.Provider) HandlerFunc {
 		var descs []ocispec.Descriptor
 
 		descs = append(descs, manifest.Config)
-		for _, desc := range manifest.Layers {
-			descs = append(descs, desc)
-		}
+		descs = append(descs, manifest.Layers...)
 
 		return descs, nil
 	}