1//
2// This file is part of the aMule Project.
3//
4// Copyright (c) 2008-2011 aMule Team ( admin@amule.org / http://www.amule.org )
5// Copyright (c) 2008-2011 Stu Redman ( sturedman@amule.org )
6//
7// Any parts of this program derived from the xMule, lMule or eMule project,
8// or contributed by third-party developers are copyrighted by their
9// respective authors.
10//
11// This program is free software; you can redistribute it and/or modify
12// it under the terms of the GNU General Public License as published by
13// the Free Software Foundation; either version 2 of the License, or
14// (at your option) any later version.
15//
16// This program is distributed in the hope that it will be useful,
17// but WITHOUT ANY WARRANTY; without even the implied warranty of
18// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19// GNU General Public License for more details.
20//
21// You should have received a copy of the GNU General Public License
22// along with this program; if not, write to the Free Software
23// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA
24//
25
26#ifndef FILEAUTOCLOSE_H
27#define FILEAUTOCLOSE_H
28
29#include "CFile.h"			// Needed for CFile
30
31/**
32 * This class encapsulates the CFile class.
33 *
34 * It allows to close the used file handle and reopen
35 * it on usage to minimize the number of used file handles.
36 *
37 */
38class CFileAutoClose
39{
40public:
41
42	/**
43	 * Creates a closed file.
44	 */
45	CFileAutoClose();
46
47	/**
48	 * Constructor, calls Open on the specified file.
49	 *
50	 * To check if the file was successfully opened, a
51	 * call to IsOpened() is required.
52	 */
53	CFileAutoClose(const CPath& path, CFile::OpenMode mode = CFile::read);
54
55	/**
56	 * Request auto closing of the file handle.
57	 *
58	 * @param now true: close immediately  false: close when timeout has expired
59	 * @return True if the file has been (or has already been) autoclosed.
60	 */
61	bool Release(bool now = false);
62
63	/**
64	 * Opens a file.
65	 *
66	 * @param path The full or relative path to the file.
67	 * @param mode The opening mode (see CFile).
68	 * @return True if the file was opened, false otherwise.
69	 */
70	bool Open(const CPath& path, CFile::OpenMode mode = CFile::read);
71
72	/**
73	 * Calling Create is equivilant of calling open with OpenMode 'write'.
74	 *
75	 * @param overwrite Specifies if the target file should be overwritten,
76	 *                  in case that it already exists.
77	 *
78	 * @see CFile::Open
79	 */
80	bool Create(const CPath& path, bool overwrite = false);
81
82	/**
83	 * Closes the file.
84	 *
85	 * Note that calling Close on an closed file
86	 * is an illegal operation.
87	 */
88	bool Close();
89
90	/**
91	 * @see CSafeFileIO::GetLength
92	 *
93	 * Note that calling GetLength on a closed file
94	 * is an illegal operation.
95	 */
96	uint64 GetLength() const;
97
98	/**
99	 * Resizes the file to the specified length.
100	 *
101	 */
102	bool SetLength(uint64 newLength);
103
104	/**
105	 * Returns the path of the currently opened file.
106	 *
107	 */
108	const CPath& GetFilePath() const;
109
110	/**
111	 * Returns true if the file is opened, false otherwise.
112	 */
113	bool IsOpened() const;
114
115	/**
116	 * Reads 'count' bytes into 'buffer'.
117	 *
118	 * @param buffer The target buffer.
119	 * @param offset The seek address in the file.
120	 * @param count The number of bytes to read.
121	 *
122	 * See CFileDataIO::Read
123	 */
124	void ReadAt(void* buffer, uint64 offset, size_t count);
125
126	/**
127	 * Write 'count' bytes from 'buffer' into the file.
128	 *
129	 * @param buffer The source-data buffer.
130	 * @param offset The seek address in the file.
131	 * @param count The number of bytes to write.
132	 *
133	 * See CFileDataIO::Write
134	 */
135	void WriteAt(const void* buffer, uint64 offset, size_t count);
136
137	/**
138	 * Returns true when the file-position is past or at the end of the file.
139	 */
140	bool Eof();
141
142	/**
143	 * Returns the file descriptior assosiated with the file.
144	 *
145	 * This breaks the purpose of this class of course.
146	 * Therefore the AutoClose mechanism is disabled when fd() is called.
147	 * It's required for FileArea's mmap stuff.
148	 * Currently FileArea objects are shortlived enough for this not being
149	 * a problem anyway, but that might change in the future.
150	 */
151	int fd();
152
153	/**
154	 * Reenables AutoClose disabled by fd() before.
155	 */
156	void Unlock();
157
158private:
159	//! A CFileAutoClose is neither copyable nor assignable.
160	//@{
161	CFileAutoClose(const CFileAutoClose&);
162	CFileAutoClose& operator=(const CFileAutoClose&);
163	//@}
164
165	/**
166	 * Check if file was autoclosed, and reopen if needed.
167	 */
168	void Reopen();
169
170	//! The wrapped CFile.
171	CFile m_file;
172
173	//! The mode used to open it.
174	CFile::OpenMode m_mode;
175
176	//! Is it temporarily closed?
177	bool m_autoClosed;
178
179	//! Autoclosing is disabled if != 0
180	uint16 m_locked;
181
182	//! Size before it was closed.
183	uint64 m_size;
184
185	//! Last access time (s)
186	uint32 m_lastAccess;
187};
188
189
190#endif // FILEAUTOCLOSE_H
191// File_checked_for_headers
192