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// Copyright 2018 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef BAZEL_SRC_TOOLS_SINGLEJAR_MAPPED_FILE_WINDOWS_H_
#define BAZEL_SRC_TOOLS_SINGLEJAR_MAPPED_FILE_WINDOWS_H_ 1
#if !defined(_WIN64)
#error This code is for 64 bit Windows.
#endif
#include "src/main/cpp/util/path_platform.h"
#include "src/tools/singlejar/diag.h"
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#include <windows.h>
#include <string>
MappedFile::MappedFile()
: mapped_start_(nullptr),
mapped_end_(nullptr),
hFile_(INVALID_HANDLE_VALUE),
hMapFile_(INVALID_HANDLE_VALUE) {}
bool MappedFile::is_open() const { return hFile_ != INVALID_HANDLE_VALUE; }
bool MappedFile::Open(const std::string& path) {
if (is_open()) {
diag_errx(1, "%s:%d: This instance is already open", __FILE__, __LINE__);
}
std::wstring wpath;
std::string error;
if (!blaze_util::AsAbsoluteWindowsPath(path, &wpath, &error)) {
diag_warn("%s:%d: AsAbsoluteWindowsPath failed: %s", __FILE__, __LINE__,
error.c_str());
return false;
}
hFile_ = CreateFileW(wpath.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL,
OPEN_EXISTING, 0, NULL);
if (hFile_ == INVALID_HANDLE_VALUE) {
diag_warn("%s:%d: CreateFileW failed for %S", __FILE__, __LINE__,
wpath.c_str());
return false;
}
LARGE_INTEGER temp;
::GetFileSizeEx(hFile_, &temp);
size_t fileSize = temp.QuadPart;
if (fileSize == 0) {
// Handle empty files specially, because CreateFileMapping cannot map them:
//
// From
// https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-createfilemappinga
//
// An attempt to map a file with a length of 0 (zero) fails with an error
// code of ERROR_FILE_INVALID. Applications should test for files with a
// length of 0 (zero) and reject those files.
mapped_start_ = nullptr;
mapped_end_ = nullptr;
hMapFile_ = INVALID_HANDLE_VALUE;
return true;
}
hMapFile_ = ::CreateFileMapping(
hFile_,
nullptr, // default security
PAGE_READONLY, // read-only permission
static_cast<DWORD>(fileSize >> 32), // size of mapping object, high
static_cast<DWORD>(fileSize), // size of mapping object, low
nullptr); // name of mapping object
if (hMapFile_ == nullptr) {
diag_warn("%s:%d: CreateFileMapping for %s failed", __FILE__, __LINE__,
path.c_str());
::CloseHandle(hFile_);
hFile_ = INVALID_HANDLE_VALUE;
return false;
}
mapped_start_ = static_cast<unsigned char*>(
MapViewOfFile(hMapFile_,
FILE_MAP_READ | FILE_MAP_COPY, // PROT_READ | MAP_PRIVATE
0, // file offset, high
0, // file offset, low
fileSize)); // file size
if (mapped_start_ == nullptr) {
diag_warn("%s:%d: MapViewOfFile for %s failed", __FILE__, __LINE__,
path.c_str());
::CloseHandle(hMapFile_);
::CloseHandle(hFile_);
hFile_ = INVALID_HANDLE_VALUE;
hMapFile_ = INVALID_HANDLE_VALUE;
return false;
}
mapped_end_ = mapped_start_ + fileSize;
return true;
}
void MappedFile::Close() {
if (is_open()) {
if (mapped_start_) {
::UnmapViewOfFile(mapped_start_);
}
if (hMapFile_ != INVALID_HANDLE_VALUE) {
::CloseHandle(hMapFile_);
hMapFile_ = INVALID_HANDLE_VALUE;
}
::CloseHandle(hFile_);
hFile_ = INVALID_HANDLE_VALUE;
mapped_start_ = mapped_end_ = nullptr;
}
}
#endif // BAZEL_SRC_TOOLS_SINGLEJAR_MAPPED_FILE_WINDOWS_H_