Change diff command properly to send messages over channels

diff.go

@@ -0,0 +1,182 @@
+/*
+ * Minio Client (C) 2015 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 main
+
+import (
+	"path/filepath"
+
+	"github.com/minio/mc/pkg/client"
+	"github.com/minio/minio/pkg/iodine"
+)
+
+type diff struct {
+	message string
+	err     error
+}
+
+// urlJoinPath Join a path to existing URL
+func urlJoinPath(urlStr, path string) (newURLStr string, err error) {
+	u, err := client.Parse(urlStr)
+	if err != nil {
+		return "", iodine.New(err, nil)
+	}
+
+	u.Path = filepath.Join(u.Path, path)
+	newURLStr = u.String()
+	return newURLStr, nil
+}
+
+// doDiffObjects - Diff two object URLs
+func doDiffObjects(firstURL, secondURL string, ch chan diff) {
+	if firstURL == secondURL {
+		return
+	}
+	_, firstContent, err := url2Stat(firstURL)
+	if err != nil {
+		ch <- diff{
+			message: "Failed to stat ‘" + firstURL + "’ " + "Reason: [" + iodine.ToError(err).Error() + "].\n",
+			err:     iodine.New(err, nil),
+		}
+		return
+	}
+
+	_, secondContent, err := url2Stat(secondURL)
+	if err != nil {
+		ch <- diff{
+			message: "Failed to stat ‘" + secondURL + "’ " + "Reason: [" + iodine.ToError(err).Error() + "].\n",
+			err:     iodine.New(err, nil),
+		}
+		return
+	}
+
+	switch {
+	case firstContent.Type.IsRegular():
+		if !secondContent.Type.IsRegular() {
+			ch <- diff{
+				message: firstURL + " and " + secondURL + " differs in type.\n",
+				err:     nil,
+			}
+		}
+	default:
+		ch <- diff{
+			message: "‘" + firstURL + "’ is not an object. Please report this bug with ‘--debug’ option\n.",
+			err:     iodine.New(errNotAnObject{url: firstURL}, nil),
+		}
+	}
+
+	if firstContent.Size != secondContent.Size {
+		ch <- diff{
+			message: firstURL + " and " + secondURL + " differs in size.\n",
+			err:     nil,
+		}
+	}
+}
+
+// doDiffDirs - Diff two Dir URLs
+func doDiffDirs(firstURL, secondURL string, ch chan diff) {
+	firstClnt, firstContent, err := url2Stat(firstURL)
+	if err != nil {
+		ch <- diff{
+			message: "Failed to stat ‘" + firstURL + "’ ." + "Reason: [" + iodine.ToError(err).Error() + "].\n",
+			err:     iodine.New(err, nil),
+		}
+		return
+	}
+	_, secondContent, err := url2Stat(secondURL)
+	if err != nil {
+		ch <- diff{
+			message: "Failed to stat ‘" + secondURL + "’ ." + "Reason: [" + iodine.ToError(err).Error() + "].\n",
+			err:     iodine.New(err, nil),
+		}
+		return
+	}
+	switch {
+	case firstContent.Type.IsDir():
+		if !secondContent.Type.IsDir() {
+			ch <- diff{
+				message: firstURL + " and " + secondURL + " differs in type.\n",
+				err:     nil,
+			}
+		}
+	default:
+		ch <- diff{
+			message: "‘" + firstURL + "’ is not an object. Please report this bug with ‘--debug’ option\n.",
+			err:     iodine.New(errNotAnObject{url: firstURL}, nil),
+		}
+	}
+	for contentCh := range firstClnt.List() {
+		if contentCh.Err != nil {
+			ch <- diff{
+				message: "Failed to list ‘" + firstURL + "’. Reason: [" + iodine.ToError(contentCh.Err).Error() + "].\n",
+				err:     iodine.New(contentCh.Err, nil),
+			}
+			return
+		}
+		newFirstURL, err := urlJoinPath(firstURL, contentCh.Content.Name)
+		if err != nil {
+			ch <- diff{
+				message: "Unable to construct new URL from ‘" + firstURL + "’ using ‘" + contentCh.Content.Name + "’. Reason: [" + iodine.ToError(err).Error() + "].\n",
+				err:     iodine.New(err, nil),
+			}
+			return
+		}
+		newSecondURL, err := urlJoinPath(secondURL, contentCh.Content.Name)
+		if err != nil {
+			ch <- diff{
+				message: "Unable to construct new URL from ‘" + secondURL + "’ using ‘" + contentCh.Content.Name + "’. Reason: [" + iodine.ToError(err).Error() + "].\n",
+				err:     iodine.New(err, nil),
+			}
+			return
+		}
+		_, newFirstContent, err := url2Stat(newFirstURL)
+		if err != nil {
+			ch <- diff{
+				message: "Failed to stat ‘" + newFirstURL + "’. Reason: [" + iodine.ToError(err).Error() + "].\n",
+				err:     iodine.New(err, nil),
+			}
+			return
+
+		}
+		_, newSecondContent, err := url2Stat(newSecondURL)
+		if err != nil {
+			ch <- diff{
+				message: "‘" + filepath.Base(newFirstContent.Name) + "’ only in ‘" + firstURL + "’.\n",
+				err:     nil,
+			}
+			continue
+		}
+		switch {
+		case newFirstContent.Type.IsDir():
+			if !newSecondContent.Type.IsDir() {
+				ch <- diff{
+					message: newFirstURL + " and " + newSecondURL + " differs in type.\n",
+					err:     nil,
+				}
+				continue
+			}
+		case newFirstContent.Type.IsRegular():
+			if !newSecondContent.Type.IsRegular() {
+				ch <- diff{
+					message: newFirstURL + " and " + newSecondURL + " differs in type.\n",
+					err:     nil,
+				}
+				continue
+			}
+			doDiffObjects(newFirstURL, newSecondURL, ch)
+		}
+	} // End of for-loop
+}