signature: Rewrite signature handling and move it into a library.

pkg/xl/bucket.go

@@ -306,7 +306,7 @@ func (b bucket) WriteObject(objectName string, objectData io.Reader, size int64,
 			//
 			// Signature mismatch occurred all temp files to be removed and all data purged.
 			CleanupWritersOnError(writers)
-			return ObjectMetadata{}, probe.NewError(signV4.SigDoesNotMatch{})
+			return ObjectMetadata{}, probe.NewError(SignDoesNotMatch{})
 		}
 	}
 	objMetadata.MD5Sum = hex.EncodeToString(dataMD5sum)

pkg/xl/errors.go

@@ -18,6 +18,13 @@ package xl
 
 import "fmt"
 
+// SignDoesNotMatch - signature does not match.
+type SignDoesNotMatch struct{}
+
+func (e SignDoesNotMatch) Error() string {
+	return "Signature does not match."
+}
+
 // InvalidArgument invalid argument
 type InvalidArgument struct{}
 

pkg/xl/multipart.go

@@ -226,7 +226,7 @@ func (xl API) createObjectPart(bucket, key, uploadID string, partID int, content
 				return "", err.Trace()
 			}
 			if !ok {
-				return "", probe.NewError(signV4.SigDoesNotMatch{})
+				return "", probe.NewError(SignDoesNotMatch{})
 			}
 		}
 	}
@@ -342,7 +342,7 @@ func (xl API) completeMultipartUploadV2(bucket, key, uploadID string, data io.Re
 			return nil, err.Trace()
 		}
 		if !ok {
-			return nil, probe.NewError(signV4.SigDoesNotMatch{})
+			return nil, probe.NewError(SignDoesNotMatch{})
 		}
 	}
 	parts := &CompleteMultipartUpload{}

pkg/xl/xl-v1.go

@@ -376,7 +376,7 @@ func (xl API) completeMultipartUpload(bucket, object, uploadID string, data io.R
 			return ObjectMetadata{}, err.Trace()
 		}
 		if !ok {
-			return ObjectMetadata{}, probe.NewError(signV4.SigDoesNotMatch{})
+			return ObjectMetadata{}, probe.NewError(SignDoesNotMatch{})
 		}
 	}
 	parts := &CompleteMultipartUpload{}

pkg/xl/xl-v2.go

@@ -392,7 +392,7 @@ func (xl API) createObject(bucket, key, contentType, expectedMD5Sum string, size
 		if !ok {
 			// Delete perhaps the object is already saved, due to the nature of append()
 			xl.objects.Delete(objectKey)
-			return ObjectMetadata{}, probe.NewError(signV4.SigDoesNotMatch{})
+			return ObjectMetadata{}, probe.NewError(SignDoesNotMatch{})
 		}
 	}
 
@@ -435,7 +435,7 @@ func (xl API) MakeBucket(bucketName, acl string, location io.Reader, signature *
 			return err.Trace()
 		}
 		if !ok {
-			return probe.NewError(signV4.SigDoesNotMatch{})
+			return probe.NewError(SignDoesNotMatch{})
 		}
 	}