llvm-project/llvm/lib/System/Win32/MappedFile.inc

132 lines
3.8 KiB
C++

//===- Win32/MappedFile.cpp - Win32 MappedFile Implementation ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Jeff Cohen and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file provides the Win32 implementation of the MappedFile concept.
//
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only Win32 code.
//===----------------------------------------------------------------------===//
#include "Win32.h"
#include "llvm/System/Process.h"
namespace llvm {
using namespace sys;
struct sys::MappedFileInfo {
HANDLE hFile;
HANDLE hMapping;
size_t size;
};
void MappedFile::initialize() {
assert(!info_);
info_ = new MappedFileInfo;
info_->hFile = INVALID_HANDLE_VALUE;
info_->hMapping = NULL;
DWORD mode = options_ & WRITE_ACCESS ? GENERIC_WRITE : GENERIC_READ;
DWORD disposition = options_ & WRITE_ACCESS ? OPEN_ALWAYS : OPEN_EXISTING;
DWORD share = options_ & WRITE_ACCESS ? FILE_SHARE_WRITE : FILE_SHARE_READ;
share = options_ & SHARED_MAPPING ? share : 0;
info_->hFile = CreateFile(path_.c_str(), mode, share, NULL, disposition,
FILE_ATTRIBUTE_NORMAL, NULL);
if (info_->hFile == INVALID_HANDLE_VALUE) {
delete info_;
info_ = NULL;
ThrowError(std::string("Can't open file: ") + path_.toString());
}
LARGE_INTEGER size;
if (!GetFileSizeEx(info_->hFile, &size) ||
(info_->size = size_t(size.QuadPart), info_->size != size.QuadPart)) {
CloseHandle(info_->hFile);
delete info_;
info_ = NULL;
ThrowError(std::string("Can't get size of file: ") + path_.toString());
}
}
void MappedFile::terminate() {
unmap();
if (info_->hFile != INVALID_HANDLE_VALUE)
CloseHandle(info_->hFile);
delete info_;
info_ = NULL;
}
void MappedFile::unmap() {
assert(info_ && "MappedFile not initialized");
if (isMapped()) {
UnmapViewOfFile(base_);
base_ = NULL;
}
if (info_->hMapping != INVALID_HANDLE_VALUE) {
CloseHandle(info_->hMapping);
info_->hMapping = NULL;
}
}
void* MappedFile::map() {
if (!isMapped()) {
DWORD prot = PAGE_READONLY;
if (options_ & EXEC_ACCESS)
prot = SEC_IMAGE;
else if (options_ & WRITE_ACCESS)
prot = PAGE_READWRITE;
info_->hMapping = CreateFileMapping(info_->hFile, NULL, prot, 0, 0, NULL);
if (info_->hMapping == NULL)
ThrowError(std::string("Can't map file: ") + path_.toString());
prot = (options_ & WRITE_ACCESS) ? FILE_MAP_WRITE : FILE_MAP_READ;
base_ = MapViewOfFileEx(info_->hMapping, prot, 0, 0, 0, NULL);
if (base_ == NULL) {
CloseHandle(info_->hMapping);
info_->hMapping = NULL;
ThrowError(std::string("Can't map file: ") + path_.toString());
}
}
return base_;
}
size_t MappedFile::size() const {
assert(info_ && "MappedFile not initialized");
return info_->size;
}
void MappedFile::size(size_t new_size) {
assert(info_ && "MappedFile not initialized");
// Take the mapping out of memory.
unmap();
// Adjust the new_size to a page boundary.
size_t pagesizem1 = Process::GetPageSize() - 1;
new_size = (new_size + pagesizem1) & ~pagesizem1;
// If the file needs to be extended, do so.
if (new_size > info_->size) {
LARGE_INTEGER eof;
eof.QuadPart = new_size;
if (!SetFilePointerEx(info_->hFile, eof, NULL, FILE_BEGIN))
ThrowError(std::string("Can't set end of file: ") + path_.toString());
if (!SetEndOfFile(info_->hFile))
ThrowError(std::string("Can't set end of file: ") + path_.toString());
info_->size = new_size;
}
// Remap the file.
map();
}
}