llvm-for-llvmta/tools/llvm-objcopy/Buffer.cpp

80 lines
2.6 KiB
C++

//===- Buffer.cpp ---------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "Buffer.h"
#include "llvm/Support/FileOutputBuffer.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Process.h"
#include <memory>
namespace llvm {
namespace objcopy {
Buffer::~Buffer() {}
static Error createEmptyFile(StringRef FileName) {
// Create an empty tempfile and atomically swap it in place with the desired
// output file.
Expected<sys::fs::TempFile> Temp =
sys::fs::TempFile::create(FileName + ".temp-empty-%%%%%%%");
return Temp ? Temp->keep(FileName) : Temp.takeError();
}
Error FileBuffer::allocate(size_t Size) {
// When a 0-sized file is requested, skip allocation but defer file
// creation/truncation until commit() to avoid side effects if something
// happens between allocate() and commit().
if (Size == 0) {
EmptyFile = true;
return Error::success();
}
Expected<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
FileOutputBuffer::create(getName(), Size, FileOutputBuffer::F_executable);
// FileOutputBuffer::create() returns an Error that is just a wrapper around
// std::error_code. Wrap it in FileError to include the actual filename.
if (!BufferOrErr)
return createFileError(getName(), BufferOrErr.takeError());
Buf = std::move(*BufferOrErr);
return Error::success();
}
Error FileBuffer::commit() {
if (EmptyFile)
return createEmptyFile(getName());
assert(Buf && "allocate() not called before commit()!");
Error Err = Buf->commit();
// FileOutputBuffer::commit() returns an Error that is just a wrapper around
// std::error_code. Wrap it in FileError to include the actual filename.
return Err ? createFileError(getName(), std::move(Err)) : std::move(Err);
}
uint8_t *FileBuffer::getBufferStart() {
return reinterpret_cast<uint8_t *>(Buf->getBufferStart());
}
Error MemBuffer::allocate(size_t Size) {
Buf = WritableMemoryBuffer::getNewMemBuffer(Size, getName());
return Error::success();
}
Error MemBuffer::commit() { return Error::success(); }
uint8_t *MemBuffer::getBufferStart() {
return reinterpret_cast<uint8_t *>(Buf->getBufferStart());
}
std::unique_ptr<WritableMemoryBuffer> MemBuffer::releaseMemoryBuffer() {
return std::move(Buf);
}
} // end namespace objcopy
} // end namespace llvm