refactor(serverHandler): refine virtual FileInfo

- use immediate data instead of pointer for virtual FileInfo
- rename `fakeFileInfo` to `placeholderFileInfo`
- add case-sesitive version for virtual FileInfo
- add a utility function to create virtual FileInfo

Author: marjune163

src/serverHandler/archive.go

@@ -63,15 +63,15 @@ func (h *handler) visitTreeNode(
 				if os.IsExist(err) {
 					return err
 				}
-				fInfo = newFakeFileInfo(path.Base(fsPath), true) // prefix path for alias
+				fInfo = createPlaceholderFileInfo(path.Base(fsPath), true) // prefix path for alias
 			} else {
 				fInfo, err = f.Stat()
 				if h.errHandler.LogError(err) {
 					return err
 				}
 			}
 		} else {
-			fInfo = newFakeFileInfo(path.Base(fsPath), true)
+			fInfo = createPlaceholderFileInfo(path.Base(fsPath), true)
 		}
 
 		if len(relPath) > 0 {

src/serverHandler/fakeFileInfo.go

@@ -0,0 +1,49 @@
+package serverHandler
+
+import (
+	"os"
+	"time"
+)
+
+var initTime = time.Now()
+
+type placeholderFileInfo struct {
+	name  string
+	isDir bool
+}
+
+func (info placeholderFileInfo) Name() string {
+	return info.name
+}
+
+func (info placeholderFileInfo) Size() int64 {
+	return 0
+}
+
+func (info placeholderFileInfo) Mode() os.FileMode {
+	return 0
+}
+
+func (info placeholderFileInfo) ModTime() time.Time {
+	return initTime
+}
+
+func (info placeholderFileInfo) IsDir() bool {
+	return info.isDir
+}
+
+func (info placeholderFileInfo) Sys() interface{} {
+	return nil
+}
+
+func createPlaceholderFileInfo(name string, isDir bool) placeholderFileInfo {
+	return placeholderFileInfo{name, isDir}
+}
+
+type placeholderFileInfoNoCase struct {
+	placeholderFileInfo
+}
+
+func createPlaceholderFileInfoNoCase(name string, isDir bool) placeholderFileInfoNoCase {
+	return placeholderFileInfoNoCase{placeholderFileInfo{name, isDir}}
+}

src/serverHandler/placeholderFileInfo.go

@@ -7,10 +7,18 @@ type renamedFileInfo struct {
 	os.FileInfo
 }
 
-func (info *renamedFileInfo) Name() string {
+func (info renamedFileInfo) Name() string {
 	return info.name
 }
 
-func newRenamedFileInfo(name string, fileInfo os.FileInfo) *renamedFileInfo {
-	return &renamedFileInfo{name, fileInfo}
+func createRenamedFileInfo(name string, fileInfo os.FileInfo) renamedFileInfo {
+	return renamedFileInfo{name, fileInfo}
+}
+
+type renamedFileInfoNoCase struct {
+	renamedFileInfo
+}
+
+func createRenamedFileInfoNoCase(name string, fileInfo os.FileInfo) renamedFileInfoNoCase {
+	return renamedFileInfoNoCase{renamedFileInfo{name, fileInfo}}
 }

src/serverHandler/renamedFileInfo.go

@@ -142,6 +142,7 @@ func (h *handler) mergeAlias(
 		if !ok {
 			continue
 		}
+		aliasCaseSensitive := alias.caseSensitive()
 
 		var fsItem os.FileInfo
 		if isChildAlias { // reached second-deepest path of alias
@@ -161,26 +162,23 @@ func (h *handler) mergeAlias(
 				continue
 			}
 			matchExisted = true
-			var aliasSubItem os.FileInfo
+			var baseItem os.FileInfo
 			if fsItem != nil {
-				aliasSubItem = newRenamedFileInfo(subItem.Name(), fsItem)
+				baseItem = fsItem
 			} else {
-				aliasSubItem = newRenamedFileInfo(subItem.Name(), subItem)
+				baseItem = subItem
 			}
+			aliasSubItem := createVirtualFileInfo(subItem.Name(), baseItem, aliasCaseSensitive)
 			aliasSubItems = append(aliasSubItems, aliasSubItem)
 			subItems[i] = aliasSubItem
-			if alias.caseSensitive() {
+			if aliasCaseSensitive {
 				break
 			}
 		}
 
 		if !matchExisted {
-			var aliasSubItem os.FileInfo
-			if fsItem != nil {
-				aliasSubItem = newRenamedFileInfo(subName, fsItem)
-			} else {
-				aliasSubItem = newFakeFileInfo(subName, true)
-			}
+			// fsItem could be nil
+			aliasSubItem := createVirtualFileInfo(subName, fsItem, aliasCaseSensitive)
 			aliasSubItems = append(aliasSubItems, aliasSubItem)
 			subItems = append(subItems, aliasSubItem)
 		}

src/serverHandler/responseData.go

@@ -69,11 +69,28 @@ func getCompressWriter(w http.ResponseWriter, r *http.Request) (wr io.WriteClose
 	return wr, encoding, true
 }
 
-func isVirtual(info os.FileInfo) bool {
-	if _, isRenamedInfo := info.(*renamedFileInfo); isRenamedInfo {
-		return true
+func createVirtualFileInfo(name string, refItem os.FileInfo, caseSensitive bool) os.FileInfo {
+	if refItem != nil {
+		if caseSensitive {
+			return createRenamedFileInfo(name, refItem)
+		} else {
+			return createRenamedFileInfoNoCase(name, refItem)
+		}
+	} else {
+		if caseSensitive {
+			return createPlaceholderFileInfo(name, true)
+		} else {
+			return createPlaceholderFileInfoNoCase(name, true)
+		}
 	}
-	if _, isFakeInfo := info.(*fakeFileInfo); isFakeInfo {
+}
+
+func isVirtual(info os.FileInfo) bool {
+	switch info.(type) {
+	case placeholderFileInfo:
+	case renamedFileInfo:
+	case placeholderFileInfoNoCase:
+	case renamedFileInfoNoCase:
 		return true
 	}
 	return false