Cleanup and fixes (#3273)

* newRequestID() (previously generateUploadID()) returns string than byte array.
* Remove unclear comments and added appropriate comments.
* SHA-256, MD5 Hash functions return Hex/Base64 encoded string than byte array.
* Remove duplicate MD5 hasher functions.
* Rename listObjectsValidateArgs() into validateListObjectsArgs()
* Remove repeated auth check code in all bucket request handlers.
* Remove abbreviated names in bucket-metadata
* Avoid nested if in bucketPolicyMatchStatement()
* Use ioutil.ReadFile() instead of os.Open() and ioutil.ReadAll()
* Set crossDomainXML as constant.

cmd/s3-peer-rpc-handlers_test.go

@@ -73,7 +73,7 @@ func (s *TestRPCS3PeerSuite) testS3PeerRPC(t *testing.T) {
 	}
 
 	// Check bucket notification call works.
-	BNPArgs := SetBNPArgs{Bucket: "bucket", NCfg: &notificationConfig{}}
+	BNPArgs := SetBucketNotificationPeerArgs{Bucket: "bucket", NCfg: &notificationConfig{}}
 	client := newAuthClient(s.testAuthConf)
 	defer client.Close()
 	err = client.Call("S3.SetBucketNotificationPeer", &BNPArgs, &GenericReply{})
@@ -82,7 +82,7 @@ func (s *TestRPCS3PeerSuite) testS3PeerRPC(t *testing.T) {
 	}
 
 	// Check bucket listener update call works.
-	BLPArgs := SetBLPArgs{Bucket: "bucket", LCfg: nil}
+	BLPArgs := SetBucketListenerPeerArgs{Bucket: "bucket", LCfg: nil}
 	err = client.Call("S3.SetBucketListenerPeer", &BLPArgs, &GenericReply{})
 	if err != nil {
 		t.Fatal(err)
@@ -94,7 +94,7 @@ func (s *TestRPCS3PeerSuite) testS3PeerRPC(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	BPPArgs := SetBPPArgs{Bucket: "bucket", PChBytes: pChBytes}
+	BPPArgs := SetBucketPolicyPeerArgs{Bucket: "bucket", PChBytes: pChBytes}
 	err = client.Call("S3.SetBucketPolicyPeer", &BPPArgs, &GenericReply{})
 	if err != nil {
 		t.Fatal(err)