1 // Copyright (c) 2011, Google Inc.
2 // All rights reserved.
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
8 // * Redistributions of source code must retain the above copyright
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
14 // * Neither the name of Google Inc. nor the names of its
15 // contributors may be used to endorse or promote products derived from
16 // this software without specific prior written permission.
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 // memory_mapped_file.h: Define the google_breakpad::MemoryMappedFile
31 // class, which maps a file into memory for read-only access.
33 #ifndef COMMON_LINUX_MEMORY_MAPPED_FILE_H_
34 #define COMMON_LINUX_MEMORY_MAPPED_FILE_H_
37 #include "common/basictypes.h"
38 #include "common/memory_range.h"
40 namespace google_breakpad {
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 {
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);
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);
62 // Unmaps the memory for the mapped file. It's a no-op if no file is
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_; }
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(); }
74 // Returns the size in bytes of the mapped file, or zero if no file
76 size_t size() const { return content_.length(); }
79 // Mapped file content as a MemoryRange object.
82 DISALLOW_COPY_AND_ASSIGN(MemoryMappedFile);
85 } // namespace google_breakpad
87 #endif // COMMON_LINUX_MEMORY_MAPPED_FILE_H_