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//=== FileOutputBuffer.h - File Output Buffer -------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Utility for creating a in-memory buffer that will be written to a file.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_FILEOUTPUTBUFFER_H
#define LLVM_SUPPORT_FILEOUTPUTBUFFER_H
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/FileSystem.h"
namespace llvm {
/// FileOutputBuffer - This interface provides simple way to create an in-memory
/// buffer which will be written to a file. During the lifetime of these
/// objects, the content or existence of the specified file is undefined. That
/// is, creating an OutputBuffer for a file may immediately remove the file.
/// If the FileOutputBuffer is committed, the target file's content will become
/// the buffer content at the time of the commit. If the FileOutputBuffer is
/// not committed, the file will be deleted in the FileOutputBuffer destructor.
class FileOutputBuffer {
public:
enum {
F_executable = 1 /// set the 'x' bit on the resulting file
};
/// Factory method to create an OutputBuffer object which manages a read/write
/// buffer of the specified size. When committed, the buffer will be written
/// to the file at the specified path.
static std::error_code create(StringRef FilePath, size_t Size,
std::unique_ptr<FileOutputBuffer> &Result,
unsigned Flags = 0);
/// Returns a pointer to the start of the buffer.
uint8_t *getBufferStart() {
return (uint8_t*)Region->data();
}
/// Returns a pointer to the end of the buffer.
uint8_t *getBufferEnd() {
return (uint8_t*)Region->data() + Region->size();
}
/// Returns size of the buffer.
size_t getBufferSize() const {
return Region->size();
}
/// Returns path where file will show up if buffer is committed.
StringRef getPath() const {
return FinalPath;
}
/// Flushes the content of the buffer to its file and deallocates the
/// buffer. If commit() is not called before this object's destructor
/// is called, the file is deleted in the destructor. The optional parameter
/// is used if it turns out you want the file size to be smaller than
/// initially requested.
std::error_code commit();
/// If this object was previously committed, the destructor just deletes
/// this object. If this object was not committed, the destructor
/// deallocates the buffer and the target file is never written.
~FileOutputBuffer();
private:
FileOutputBuffer(const FileOutputBuffer &) = delete;
FileOutputBuffer &operator=(const FileOutputBuffer &) = delete;
FileOutputBuffer(std::unique_ptr<llvm::sys::fs::mapped_file_region> R,
StringRef Path, StringRef TempPath);
std::unique_ptr<llvm::sys::fs::mapped_file_region> Region;
SmallString<128> FinalPath;
SmallString<128> TempPath;
};
} // end namespace llvm
#endif
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