1 /*
2  * Copyright (C) 2021 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 CPP_CAR_BINDER_LIB_LARGEPARCELABLE_INCLUDE_MAPPEDFILE_H_
18 #define CPP_CAR_BINDER_LIB_LARGEPARCELABLE_INCLUDE_MAPPEDFILE_H_
19 
20 #include <utils/Errors.h>
21 
22 #include <assert.h>
23 #include <sys/mman.h>
24 
25 namespace android {
26 namespace automotive {
27 namespace car_binder_lib {
28 
29 using ::android::status_t;
30 
31 // MappedFile represents a memory area mapped from a file. This class owns this area and would
32 // unmap it during destruction.
33 class MappedFile {
34 public:
35     // Create a new mapped memory area from 'memoryFd' with size 'fileSize'. If 'write' is true, the
36     // area would be mapped with read/write permission, otherwise, read only. Caller should use
37     // isValid() to check whether the initialization succeed and use getErr() to read err if
38     // isValid() is not true.
39     MappedFile(int memoryFd, int32_t fileSize, bool writtable);
40 
isValid()41     inline bool isValid() const { return (mAddr != MAP_FAILED); }
42 
getErr()43     inline status_t getErr() const { return -mErrno; }
44 
getAddr()45     inline const void* getAddr() const { return mAddr; }
46 
getWriteAddr()47     inline void* getWriteAddr() const {
48         assert(!mReadOnly);
49         return mAddr;
50     }
51 
getSize()52     inline size_t getSize() const { return mSize; }
53 
54     void sync() const;
55 
56     ~MappedFile();
57 
58 private:
59     size_t mSize = 0;
60     void* mAddr = MAP_FAILED;
61     int mErrno = 0;
62     bool mReadOnly;
63 };
64 
65 }  // namespace car_binder_lib
66 }  // namespace automotive
67 }  // namespace android
68 
69 #endif  // CPP_CAR_BINDER_LIB_LARGEPARCELABLE_INCLUDE_MAPPEDFILE_H_
70