refactor ObjectLayer PutObject and PutObjectPart (#4925)

This change refactor the ObjectLayer PutObject and PutObjectPart
functions. Instead of passing an io.Reader and a size to PUT operations
ObejectLayer expects an HashReader.
A HashReader verifies the MD5 sum (and SHA256 sum if required) of the object.
This change updates all all PutObject(Part) calls and removes unnecessary code
in all ObjectLayer implementations.

Fixes #4923

cmd/gateway-s3_test.go

@@ -1,58 +0,0 @@
-/*
- * Minio Cloud Storage, (C) 2017 Minio, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package cmd
-
-import (
-	"testing"
-)
-
-// Tests extracting md5/sha256 bytes.
-func TestGetMD5AndSha256Bytes(t *testing.T) {
-	testCases := []struct {
-		md5Hex    string
-		sha256Hex string
-		success   bool
-	}{
-		// Test 1: Hex encoding failure.
-		{
-			md5Hex:    "a",
-			sha256Hex: "b",
-			success:   false,
-		},
-		// Test 2: Hex encoding success.
-		{
-			md5Hex:    "91be0b892e47ede9de06aac14ca0369e",
-			sha256Hex: "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
-			success:   true,
-		},
-		// Test 3: hex values are empty should return success.
-		{
-			md5Hex:    "",
-			sha256Hex: "",
-			success:   true,
-		},
-	}
-	for i, testCase := range testCases {
-		_, _, err := getMD5AndSha256SumBytes(testCase.md5Hex, testCase.sha256Hex)
-		if err != nil && testCase.success {
-			t.Errorf("Test %d: Expected success, but got failure %s", i+1, err)
-		}
-		if err == nil && !testCase.success {
-			t.Errorf("Test %d: Expected failure, but got success", i+1)
-		}
-	}
-}