87 lines
3.5 KiB
C++
87 lines
3.5 KiB
C++
// Copyright (c) 2011, Google Inc.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// memory_mapped_file.h: Define the google_breakpad::MemoryMappedFile
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// class, which maps a file into memory for read-only access.
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#ifndef COMMON_LINUX_MEMORY_MAPPED_FILE_H_
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#define COMMON_LINUX_MEMORY_MAPPED_FILE_H_
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#include "common/basictypes.h"
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#include "common/memory_range.h"
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namespace google_breakpad {
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// A utility class for mapping a file into memory for read-only access of
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// the file content. Its implementation avoids calling into libc functions
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// by directly making system calls for open, close, mmap, and munmap.
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class MemoryMappedFile {
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public:
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MemoryMappedFile();
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// Constructor that calls Map() to map a file at |path| into memory.
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// If Map() fails, the object behaves as if it is default constructed.
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explicit MemoryMappedFile(const char* path);
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~MemoryMappedFile();
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// Maps a file at |path| into memory, which can then be accessed via
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// content() as a MemoryRange object or via data(), and returns true on
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// success. Mapping an empty file will succeed but with data() and size()
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// returning NULL and 0, respectively. An existing mapping is unmapped
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// before a new mapping is created.
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bool Map(const char* path);
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// Unmaps the memory for the mapped file. It's a no-op if no file is
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// mapped.
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void Unmap();
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// Returns a MemoryRange object that covers the memory for the mapped
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// file. The MemoryRange object is empty if no file is mapped.
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const MemoryRange& content() const { return content_; }
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// Returns a pointer to the beginning of the memory for the mapped file.
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// or NULL if no file is mapped or the mapped file is empty.
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const void* data() const { return content_.data(); }
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// Returns the size in bytes of the mapped file, or zero if no file
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// is mapped.
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size_t size() const { return content_.length(); }
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private:
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// Mapped file content as a MemoryRange object.
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MemoryRange content_;
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DISALLOW_COPY_AND_ASSIGN(MemoryMappedFile);
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};
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} // namespace google_breakpad
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#endif // COMMON_LINUX_MEMORY_MAPPED_FILE_H_
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