1 | // Copyright (c) 2011, Google Inc. |
2 | // All rights reserved. |
3 | // |
4 | // Redistribution and use in source and binary forms, with or without |
5 | // modification, are permitted provided that the following conditions are |
6 | // met: |
7 | // |
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9 | // notice, this list of conditions and the following disclaimer. |
10 | // * Redistributions in binary form must reproduce the above |
11 | // copyright notice, this list of conditions and the following disclaimer |
12 | // in the documentation and/or other materials provided with the |
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15 | // contributors may be used to endorse or promote products derived from |
16 | // this software without specific prior written permission. |
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18 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
19 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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29 | |
30 | // memory_mapped_file.h: Define the google_breakpad::MemoryMappedFile |
31 | // class, which maps a file into memory for read-only access. |
32 | |
33 | #ifndef COMMON_LINUX_MEMORY_MAPPED_FILE_H_ |
34 | #define COMMON_LINUX_MEMORY_MAPPED_FILE_H_ |
35 | |
36 | #include <stddef.h> |
37 | #include "common/basictypes.h" |
38 | #include "common/memory_range.h" |
39 | |
40 | namespace google_breakpad { |
41 | |
42 | // A utility class for mapping a file into memory for read-only access of |
43 | // the file content. Its implementation avoids calling into libc functions |
44 | // by directly making system calls for open, close, mmap, and munmap. |
45 | class MemoryMappedFile { |
46 | public: |
47 | MemoryMappedFile(); |
48 | |
49 | // Constructor that calls Map() to map a file at |path| into memory. |
50 | // If Map() fails, the object behaves as if it is default constructed. |
51 | MemoryMappedFile(const char* path, size_t offset); |
52 | |
53 | ~MemoryMappedFile(); |
54 | |
55 | // Maps a file at |path| into memory, which can then be accessed via |
56 | // content() as a MemoryRange object or via data(), and returns true on |
57 | // success. Mapping an empty file will succeed but with data() and size() |
58 | // returning NULL and 0, respectively. An existing mapping is unmapped |
59 | // before a new mapping is created. |
60 | bool Map(const char* path, size_t offset); |
61 | |
62 | // Unmaps the memory for the mapped file. It's a no-op if no file is |
63 | // mapped. |
64 | void Unmap(); |
65 | |
66 | // Returns a MemoryRange object that covers the memory for the mapped |
67 | // file. The MemoryRange object is empty if no file is mapped. |
68 | const MemoryRange& content() const { return content_; } |
69 | |
70 | // Returns a pointer to the beginning of the memory for the mapped file. |
71 | // or NULL if no file is mapped or the mapped file is empty. |
72 | const void* data() const { return content_.data(); } |
73 | |
74 | // Returns the size in bytes of the mapped file, or zero if no file |
75 | // is mapped. |
76 | size_t size() const { return content_.length(); } |
77 | |
78 | private: |
79 | // Mapped file content as a MemoryRange object. |
80 | MemoryRange content_; |
81 | |
82 | DISALLOW_COPY_AND_ASSIGN(MemoryMappedFile); |
83 | }; |
84 | |
85 | } // namespace google_breakpad |
86 | |
87 | #endif // COMMON_LINUX_MEMORY_MAPPED_FILE_H_ |
88 | |