Add private class BMergedDirectory to storage kit

An arbitrary number of directories can be added, which the implemented BEntryList interface presents as a single merged entry list. Three different merge policies are supported which define how entries that appear in more than one directory are treated.
2013-05-07 04:43:50 +02:00
parent e387e24faa
commit 38e3973ecf
3 changed files with 310 additions and 0 deletions
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2013, Haiku, Inc. All Rights Reserved.
+ * Distributed under the terms of the MIT License.
+ *
+ * Authors:
+ *		Ingo Weinhold <[email protected]>
+ */
+#ifndef _MERGED_DIRECTORY_H
+#define _MERGED_DIRECTORY_H
+
+
+#include <EntryList.h>
+#include <ObjectList.h>
+
+
+class BDirectory;
+
+
+class BMergedDirectory : public BEntryList {
+public:
+			// policy how to handle equally named entries in different
+			// directories
+			enum BPolicy {
+				B_ALLOW_DUPLICATES,
+				B_ALWAYS_FIRST,
+				B_COMPARE
+			};
+
+public:
+								BMergedDirectory(
+									BPolicy policy = B_ALWAYS_FIRST);
+	virtual						~BMergedDirectory();
+
+			status_t			Init();
+
+			BPolicy				Policy() const;
+			void				SetPolicy(BPolicy policy);
+
+			status_t			AddDirectory(BDirectory* directory);
+			status_t			AddDirectory(const char* path);
+
+	virtual status_t			GetNextEntry(BEntry* entry,
+									bool traverse = false);
+	virtual status_t			GetNextRef(entry_ref* ref);
+	virtual int32				GetNextDirents(struct dirent* direntBuffer,
+									size_t bufferSize,
+									int32 maxEntries = INT_MAX);
+	virtual status_t			Rewind();
+	virtual int32				CountEntries();
+
+protected:
+	virtual	bool				ShallPreferFirstEntry(const entry_ref& entry1,
+									int32 index1, const entry_ref& entry2,
+									int32 index2);
+									// always invoked with index1 < index2
+
+private:
+			typedef BObjectList<BDirectory> DirectoryList;
+			struct EntryNameSet;
+
+private:
+			void				_FindBestEntry(dirent* direntBuffer);
+
+private:
+			DirectoryList		fDirectories;
+			BPolicy				fPolicy;
+			int32				fDirectoryIndex;
+			EntryNameSet*		fVisitedEntries;
+};
+
+
+#endif	// _MERGED_DIRECTORY_H