1 /*
2  * Copyright 2012, The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef BCC_SUPPORT_FILE_H
18 #define BCC_SUPPORT_FILE_H
19 
20 #include "bcc/Support/FileBase.h"
21 
22 namespace bcc {
23 
24 template<enum FileBase::OpenModeEnum OpenMode>
25 struct FileAttribute {
26   // The flags to the 2nd argument in ::open().
27   enum { kOpenFlags };
28 
29   // Default value of LockMode.
30   enum { kDefaultLockMode };
31 };
32 
33 // FileAttribute for accessing read-only file
34 template<>
35 struct FileAttribute<FileBase::kReadMode> {
36   enum { kOpenFlags       = O_RDONLY };
37   enum { kDefaultLockMode = FileBase::kReadLock };
38 };
39 
40 // FileAttribute for accessing writable file
41 template<>
42 struct FileAttribute<FileBase::kWriteMode> {
43   enum { kOpenFlags       = O_RDWR | O_CREAT };
44   enum { kDefaultLockMode = FileBase::kWriteLock };
45 };
46 
47 template<enum FileBase::OpenModeEnum OpenMode>
48 class File : public FileBase {
49 public:
50   File(const std::string &pFilename, unsigned pFlags)
51     : FileBase(pFilename, FileAttribute<OpenMode>::kOpenFlags, pFlags) { }
52 
53   inline bool lock(enum LockModeEnum pMode = static_cast<enum LockModeEnum>(
54                       FileAttribute<OpenMode>::kDefaultLockMode),
55                    bool pNonblocking = true,
56                    unsigned pMaxRetry = FileBase::kDefaultMaxRetryLock,
57                    useconds_t pRetryInterval =
58                       FileBase::kDefaultRetryLockInterval) {
59     return FileBase::lock(pMode, pNonblocking, pMaxRetry, pRetryInterval);
60   }
61 
62   inline android::FileMap *createMap(off_t pOffset, size_t pLength,
63                                      bool pIsReadOnly =
64                                         (OpenMode == FileBase::kReadMode)) {
65     return FileBase::createMap(pOffset, pLength, pIsReadOnly);
66   }
67 };
68 
69 
70 } // end namespace bcc
71 
72 #endif  // BCC_SUPPORT_FILE_H
73