.

go/neo/internal/xsha1/xsha1.go

@@ -17,8 +17,12 @@
 // See COPYING file for full licensing terms.
 // See https://www.nexedi.com/licensing for rationale and options.
 
-// Package xsha1, similarly to crypto/sha1, provides SHA1 computation, but
-// makes it a noop if requested so from environment.
+// Package xsha1 provides NEO-flavoured SHA1 sum.
+//
+// It is the same as regular SHA1, but returns all-zeros for empty input.
+//
+// Besides, checksum computation can be switched to be a noop if requested so
+// from environment.
 package xsha1
 
 import (
@@ -27,7 +31,9 @@ import (
 	"os"
 )
 
-// XXX for benchmarking: how much sha1 computation takes time from latency
+// Skip controls and indicates whether NEOSum skips SHA1 computation.
+//
+// It is used for benchmarking to see how much sha1 computation takes time from latency.
 var Skip bool
 func init() {
 	if os.Getenv("X_NEOGO_SHA1_SKIP") == "y" {
@@ -36,23 +42,16 @@ func init() {
 	}
 }
 
-func Sum(b []byte) [sha1.Size]byte {
-	if !Skip {
-		return sha1.Sum(b)
-	}
-
-	return [sha1.Size]byte{} // all 0
-}
-
 // NEOSum returns SHA1(b) computed by NEO rules.
 //
 // it is the same as regular SHA1, but returns all-zeros for empty b.
 // https://lab.nexedi.com/nexedi/neoppod/blob/c1c26894/neo/client/app.py#L464-468
-//
-// XXX merge into Sum?
 func NEOSum(b []byte) [sha1.Size]byte {
 	if len(b) == 0 {
 		return [sha1.Size]byte{} // all 0
 	}
-	return Sum(b)
+	if !Skip {
+		return sha1.Sum(b)
+	}
+	return [sha1.Size]byte{} // all 0
 }