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	Clients of MemoryBuffer::getOpenFile expect it not to take ownership of the file descriptor passed in. So don't. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176995 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
			120 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			120 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
//===- FileOutputBuffer.cpp - File Output Buffer ----------------*- C++ -*-===//
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//
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//                     The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Utility for creating a in-memory buffer that will be written to a file.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/FileOutputBuffer.h"
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#include "llvm/ADT/OwningPtr.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Support/system_error.h"
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using llvm::sys::fs::mapped_file_region;
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namespace llvm {
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FileOutputBuffer::FileOutputBuffer(mapped_file_region * R,
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                                   StringRef Path, StringRef TmpPath)
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  : Region(R)
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  , FinalPath(Path)
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  , TempPath(TmpPath) {
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}
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FileOutputBuffer::~FileOutputBuffer() {
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  bool Existed;
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  sys::fs::remove(Twine(TempPath), Existed);
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}
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error_code FileOutputBuffer::create(StringRef FilePath,
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                                    size_t Size,
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                                    OwningPtr<FileOutputBuffer> &Result,
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                                    unsigned Flags) {
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  // If file already exists, it must be a regular file (to be mappable).
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  sys::fs::file_status Stat;
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  error_code EC = sys::fs::status(FilePath, Stat);
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  switch (Stat.type()) {
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    case sys::fs::file_type::file_not_found:
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      // If file does not exist, we'll create one.
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      break;
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    case sys::fs::file_type::regular_file: {
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        // If file is not currently writable, error out.
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        // FIXME: There is no sys::fs:: api for checking this.
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        // FIXME: In posix, you use the access() call to check this.
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      }
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      break;
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    default:
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      if (EC)
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        return EC;
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      else
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        return make_error_code(errc::operation_not_permitted);
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  }
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  // Delete target file.
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  bool Existed;
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  EC = sys::fs::remove(FilePath, Existed);
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  if (EC)
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    return EC;
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  // Create new file in same directory but with random name.
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  SmallString<128> TempFilePath;
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  int FD;
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  EC = sys::fs::unique_file(Twine(FilePath) + ".tmp%%%%%%%",
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                            FD, TempFilePath, false, 0644);
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  if (EC)
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    return EC;
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  OwningPtr<mapped_file_region> MappedFile(new mapped_file_region(
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      FD, true, mapped_file_region::readwrite, Size, 0, EC));
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  if (EC)
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    return EC;
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  // If requested, make the output file executable.
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  if ( Flags & F_executable ) {
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    sys::fs::file_status Stat2;
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    EC = sys::fs::status(Twine(TempFilePath), Stat2);
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    if (EC)
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      return EC;
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    sys::fs::perms new_perms = Stat2.permissions();
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    if ( new_perms & sys::fs::owner_read )
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      new_perms |= sys::fs::owner_exe;
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    if ( new_perms & sys::fs::group_read )
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      new_perms |= sys::fs::group_exe;
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    if ( new_perms & sys::fs::others_read )
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      new_perms |= sys::fs::others_exe;
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    new_perms |= sys::fs::add_perms;
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    EC = sys::fs::permissions(Twine(TempFilePath), new_perms);
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    if (EC)
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      return EC;
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  }
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  Result.reset(new FileOutputBuffer(MappedFile.get(), FilePath, TempFilePath));
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  if (Result)
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    MappedFile.take();
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  return error_code::success();
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}
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error_code FileOutputBuffer::commit(int64_t NewSmallerSize) {
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  // Unmap buffer, letting OS flush dirty pages to file on disk.
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  Region.reset(0);
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  // If requested, resize file as part of commit.
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  if ( NewSmallerSize != -1 ) {
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    error_code EC = sys::fs::resize_file(Twine(TempPath), NewSmallerSize);
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    if (EC)
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      return EC;
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  }
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  // Rename file to final name.
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  return sys::fs::rename(Twine(TempPath), Twine(FinalPath));
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}
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} // namespace
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