llvm-6502/include/llvm/Support/FileOutputBuffer.h
Rafael Espindola 7acd886ecf Use std::error_code instead of llvm::error_code.
The idea of this patch is to turn llvm/Support/system_error.h into a
transitional header that just brings in the erorr_code api to the llvm
namespace. I will remove it shortly afterwards.

The cases where the general idea needed some tweaking:

* std::errc is a namespace in msvc, so we cannot use "using std::errc". I could
add an #ifdef, but there were not that many uses, so I just added std:: to
them in this patch.

* Template specialization had to be moved to the std namespace in this
patch set already.

* The msvc implementation of default_error_condition doesn't seem to
provide the same transformations as we need. Not too surprising since
the standard doesn't actually say what "equivalent" means. I fixed the
problem by keeping our old mapping and using it at error_code
construction time.

Despite these shortcomings I think this is still a good thing. Some reasons:

* The different implementations of system_error might improve over time.
* It removes 925 lines of code from llvm already.
* It removes 6313 bytes from the text segment of the clang binary when
it is built with gcc and 2816 bytes when building with clang and
libstdc++.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210687 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-11 19:05:50 +00:00

90 lines
3.2 KiB
C++

//=== 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 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.
error_code commit(int64_t NewSmallerSize = -1);
/// 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 &) LLVM_DELETED_FUNCTION;
FileOutputBuffer &operator=(const FileOutputBuffer &) LLVM_DELETED_FUNCTION;
FileOutputBuffer(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