409 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			409 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C++
		
	
	
	
//===- ArchiveWriter.cpp - ar File Format implementation --------*- 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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// This file defines the writeArchive function.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Object/ArchiveWriter.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/Object/Archive.h"
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#include "llvm/Object/ObjectFile.h"
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#include "llvm/Object/SymbolicFile.h"
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#include "llvm/Support/EndianStream.h"
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#include "llvm/Support/Errc.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/Format.h"
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#include "llvm/Support/Path.h"
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#include "llvm/Support/ToolOutputFile.h"
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#include "llvm/Support/raw_ostream.h"
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#if !defined(_MSC_VER) && !defined(__MINGW32__)
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#include <unistd.h>
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#else
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#include <io.h>
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#endif
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using namespace llvm;
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NewArchiveMember::NewArchiveMember(MemoryBufferRef BufRef)
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    : Buf(MemoryBuffer::getMemBuffer(BufRef, false)) {}
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Expected<NewArchiveMember>
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NewArchiveMember::getOldMember(const object::Archive::Child &OldMember,
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                               bool Deterministic) {
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  ErrorOr<llvm::MemoryBufferRef> BufOrErr = OldMember.getMemoryBufferRef();
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  if (!BufOrErr)
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    return errorCodeToError(BufOrErr.getError());
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  NewArchiveMember M;
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  M.Buf = MemoryBuffer::getMemBuffer(*BufOrErr, false);
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  if (!Deterministic) {
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    M.ModTime = OldMember.getLastModified();
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    M.UID = OldMember.getUID();
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    M.GID = OldMember.getGID();
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    M.Perms = OldMember.getAccessMode();
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  }
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  return std::move(M);
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}
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Expected<NewArchiveMember> NewArchiveMember::getFile(StringRef FileName,
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                                                     bool Deterministic) {
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  sys::fs::file_status Status;
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  int FD;
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  if (auto EC = sys::fs::openFileForRead(FileName, FD))
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    return errorCodeToError(EC);
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  assert(FD != -1);
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  if (auto EC = sys::fs::status(FD, Status))
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    return errorCodeToError(EC);
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  // Opening a directory doesn't make sense. Let it fail.
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  // Linux cannot open directories with open(2), although
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  // cygwin and *bsd can.
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  if (Status.type() == sys::fs::file_type::directory_file)
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    return errorCodeToError(make_error_code(errc::is_a_directory));
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  ErrorOr<std::unique_ptr<MemoryBuffer>> MemberBufferOrErr =
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      MemoryBuffer::getOpenFile(FD, FileName, Status.getSize(), false);
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  if (!MemberBufferOrErr)
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    return errorCodeToError(MemberBufferOrErr.getError());
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  if (close(FD) != 0)
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    return errorCodeToError(std::error_code(errno, std::generic_category()));
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  NewArchiveMember M;
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  M.Buf = std::move(*MemberBufferOrErr);
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  if (!Deterministic) {
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    M.ModTime = Status.getLastModificationTime();
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    M.UID = Status.getUser();
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    M.GID = Status.getGroup();
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    M.Perms = Status.permissions();
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  }
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  return std::move(M);
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}
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template <typename T>
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static void printWithSpacePadding(raw_fd_ostream &OS, T Data, unsigned Size,
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                                  bool MayTruncate = false) {
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  uint64_t OldPos = OS.tell();
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  OS << Data;
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  unsigned SizeSoFar = OS.tell() - OldPos;
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  if (Size > SizeSoFar) {
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    OS.indent(Size - SizeSoFar);
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  } else if (Size < SizeSoFar) {
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    assert(MayTruncate && "Data doesn't fit in Size");
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    // Some of the data this is used for (like UID) can be larger than the
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    // space available in the archive format. Truncate in that case.
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    OS.seek(OldPos + Size);
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  }
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}
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static void print32(raw_ostream &Out, object::Archive::Kind Kind,
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                    uint32_t Val) {
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  if (Kind == object::Archive::K_GNU)
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    support::endian::Writer<support::big>(Out).write(Val);
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  else
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    support::endian::Writer<support::little>(Out).write(Val);
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}
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static void printRestOfMemberHeader(raw_fd_ostream &Out,
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                                    const sys::TimeValue &ModTime, unsigned UID,
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                                    unsigned GID, unsigned Perms,
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                                    unsigned Size) {
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  printWithSpacePadding(Out, ModTime.toEpochTime(), 12);
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  printWithSpacePadding(Out, UID, 6, true);
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  printWithSpacePadding(Out, GID, 6, true);
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  printWithSpacePadding(Out, format("%o", Perms), 8);
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  printWithSpacePadding(Out, Size, 10);
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  Out << "`\n";
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}
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static void printGNUSmallMemberHeader(raw_fd_ostream &Out, StringRef Name,
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                                      const sys::TimeValue &ModTime,
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                                      unsigned UID, unsigned GID,
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                                      unsigned Perms, unsigned Size) {
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  printWithSpacePadding(Out, Twine(Name) + "/", 16);
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  printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
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}
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static void printBSDMemberHeader(raw_fd_ostream &Out, StringRef Name,
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                                 const sys::TimeValue &ModTime, unsigned UID,
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                                 unsigned GID, unsigned Perms, unsigned Size) {
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  uint64_t PosAfterHeader = Out.tell() + 60 + Name.size();
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  // Pad so that even 64 bit object files are aligned.
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  unsigned Pad = OffsetToAlignment(PosAfterHeader, 8);
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  unsigned NameWithPadding = Name.size() + Pad;
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  printWithSpacePadding(Out, Twine("#1/") + Twine(NameWithPadding), 16);
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  printRestOfMemberHeader(Out, ModTime, UID, GID, Perms,
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                          NameWithPadding + Size);
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  Out << Name;
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  assert(PosAfterHeader == Out.tell());
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  while (Pad--)
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    Out.write(uint8_t(0));
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}
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static bool useStringTable(bool Thin, StringRef Name) {
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  return Thin || Name.size() >= 16;
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}
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static void
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printMemberHeader(raw_fd_ostream &Out, object::Archive::Kind Kind, bool Thin,
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                  StringRef Name,
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                  std::vector<unsigned>::iterator &StringMapIndexIter,
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                  const sys::TimeValue &ModTime, unsigned UID, unsigned GID,
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                  unsigned Perms, unsigned Size) {
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  if (Kind == object::Archive::K_BSD)
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    return printBSDMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
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  if (!useStringTable(Thin, Name))
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    return printGNUSmallMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
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  Out << '/';
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  printWithSpacePadding(Out, *StringMapIndexIter++, 15);
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  printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
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}
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// Compute the relative path from From to To.
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static std::string computeRelativePath(StringRef From, StringRef To) {
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  if (sys::path::is_absolute(From) || sys::path::is_absolute(To))
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    return To;
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  StringRef DirFrom = sys::path::parent_path(From);
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  auto FromI = sys::path::begin(DirFrom);
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  auto ToI = sys::path::begin(To);
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  while (*FromI == *ToI) {
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    ++FromI;
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    ++ToI;
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  }
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  SmallString<128> Relative;
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  for (auto FromE = sys::path::end(DirFrom); FromI != FromE; ++FromI)
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    sys::path::append(Relative, "..");
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  for (auto ToE = sys::path::end(To); ToI != ToE; ++ToI)
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    sys::path::append(Relative, *ToI);
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  return Relative.str();
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}
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static void writeStringTable(raw_fd_ostream &Out, StringRef ArcName,
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                             ArrayRef<NewArchiveMember> Members,
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                             std::vector<unsigned> &StringMapIndexes,
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                             bool Thin) {
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  unsigned StartOffset = 0;
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  for (const NewArchiveMember &M : Members) {
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    StringRef Path = M.Buf->getBufferIdentifier();
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    StringRef Name = sys::path::filename(Path);
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    if (!useStringTable(Thin, Name))
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      continue;
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    if (StartOffset == 0) {
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      printWithSpacePadding(Out, "//", 58);
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      Out << "`\n";
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      StartOffset = Out.tell();
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    }
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    StringMapIndexes.push_back(Out.tell() - StartOffset);
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    if (Thin)
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      Out << computeRelativePath(ArcName, Path);
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    else
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      Out << Name;
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    Out << "/\n";
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  }
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  if (StartOffset == 0)
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    return;
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  if (Out.tell() % 2)
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    Out << '\n';
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  int Pos = Out.tell();
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  Out.seek(StartOffset - 12);
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  printWithSpacePadding(Out, Pos - StartOffset, 10);
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  Out.seek(Pos);
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}
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static sys::TimeValue now(bool Deterministic) {
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  if (!Deterministic)
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    return sys::TimeValue::now();
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  sys::TimeValue TV;
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  TV.fromEpochTime(0);
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  return TV;
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}
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// Returns the offset of the first reference to a member offset.
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static ErrorOr<unsigned>
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writeSymbolTable(raw_fd_ostream &Out, object::Archive::Kind Kind,
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                 ArrayRef<NewArchiveMember> Members,
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                 std::vector<unsigned> &MemberOffsetRefs, bool Deterministic) {
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  unsigned HeaderStartOffset = 0;
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  unsigned BodyStartOffset = 0;
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  SmallString<128> NameBuf;
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  raw_svector_ostream NameOS(NameBuf);
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  LLVMContext Context;
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  for (unsigned MemberNum = 0, N = Members.size(); MemberNum < N; ++MemberNum) {
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    MemoryBufferRef MemberBuffer = Members[MemberNum].Buf->getMemBufferRef();
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    Expected<std::unique_ptr<object::SymbolicFile>> ObjOrErr =
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        object::SymbolicFile::createSymbolicFile(
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            MemberBuffer, sys::fs::file_magic::unknown, &Context);
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    if (!ObjOrErr) {
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      // FIXME: check only for "not an object file" errors.
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      consumeError(ObjOrErr.takeError());
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      continue;
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    }
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    object::SymbolicFile &Obj = *ObjOrErr.get();
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    if (!HeaderStartOffset) {
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      HeaderStartOffset = Out.tell();
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      if (Kind == object::Archive::K_GNU)
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        printGNUSmallMemberHeader(Out, "", now(Deterministic), 0, 0, 0, 0);
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      else
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        printBSDMemberHeader(Out, "__.SYMDEF", now(Deterministic), 0, 0, 0, 0);
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      BodyStartOffset = Out.tell();
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      print32(Out, Kind, 0); // number of entries or bytes
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    }
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    for (const object::BasicSymbolRef &S : Obj.symbols()) {
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      uint32_t Symflags = S.getFlags();
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      if (Symflags & object::SymbolRef::SF_FormatSpecific)
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        continue;
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      if (!(Symflags & object::SymbolRef::SF_Global))
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        continue;
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      if (Symflags & object::SymbolRef::SF_Undefined)
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        continue;
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      unsigned NameOffset = NameOS.tell();
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      if (auto EC = S.printName(NameOS))
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        return EC;
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      NameOS << '\0';
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      MemberOffsetRefs.push_back(MemberNum);
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      if (Kind == object::Archive::K_BSD)
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        print32(Out, Kind, NameOffset);
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      print32(Out, Kind, 0); // member offset
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    }
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  }
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  if (HeaderStartOffset == 0)
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    return 0;
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  StringRef StringTable = NameOS.str();
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  if (Kind == object::Archive::K_BSD)
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    print32(Out, Kind, StringTable.size()); // byte count of the string table
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  Out << StringTable;
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  // ld64 requires the next member header to start at an offset that is
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  // 4 bytes aligned.
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  unsigned Pad = OffsetToAlignment(Out.tell(), 4);
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  while (Pad--)
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    Out.write(uint8_t(0));
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  // Patch up the size of the symbol table now that we know how big it is.
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  unsigned Pos = Out.tell();
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  const unsigned MemberHeaderSize = 60;
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  Out.seek(HeaderStartOffset + 48); // offset of the size field.
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  printWithSpacePadding(Out, Pos - MemberHeaderSize - HeaderStartOffset, 10);
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  // Patch up the number of symbols.
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  Out.seek(BodyStartOffset);
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  unsigned NumSyms = MemberOffsetRefs.size();
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  if (Kind == object::Archive::K_GNU)
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    print32(Out, Kind, NumSyms);
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  else
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    print32(Out, Kind, NumSyms * 8);
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  Out.seek(Pos);
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  return BodyStartOffset + 4;
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}
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std::pair<StringRef, std::error_code>
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llvm::writeArchive(StringRef ArcName,
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                   std::vector<NewArchiveMember> &NewMembers,
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                   bool WriteSymtab, object::Archive::Kind Kind,
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                   bool Deterministic, bool Thin,
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                   std::unique_ptr<MemoryBuffer> OldArchiveBuf) {
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  assert((!Thin || Kind == object::Archive::K_GNU) &&
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         "Only the gnu format has a thin mode");
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  SmallString<128> TmpArchive;
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  int TmpArchiveFD;
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  if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
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                                          TmpArchiveFD, TmpArchive))
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    return std::make_pair(ArcName, EC);
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  tool_output_file Output(TmpArchive, TmpArchiveFD);
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  raw_fd_ostream &Out = Output.os();
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  if (Thin)
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    Out << "!<thin>\n";
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  else
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    Out << "!<arch>\n";
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  std::vector<unsigned> MemberOffsetRefs;
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  std::vector<std::unique_ptr<MemoryBuffer>> Buffers;
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  std::vector<MemoryBufferRef> Members;
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  std::vector<sys::fs::file_status> NewMemberStatus;
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  unsigned MemberReferenceOffset = 0;
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  if (WriteSymtab) {
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    ErrorOr<unsigned> MemberReferenceOffsetOrErr = writeSymbolTable(
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        Out, Kind, NewMembers, MemberOffsetRefs, Deterministic);
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    if (auto EC = MemberReferenceOffsetOrErr.getError())
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      return std::make_pair(ArcName, EC);
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    MemberReferenceOffset = MemberReferenceOffsetOrErr.get();
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  }
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  std::vector<unsigned> StringMapIndexes;
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  if (Kind != object::Archive::K_BSD)
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    writeStringTable(Out, ArcName, NewMembers, StringMapIndexes, Thin);
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  std::vector<unsigned>::iterator StringMapIndexIter = StringMapIndexes.begin();
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  std::vector<unsigned> MemberOffset;
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  for (const NewArchiveMember &M : NewMembers) {
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    MemoryBufferRef File = M.Buf->getMemBufferRef();
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    unsigned Pos = Out.tell();
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    MemberOffset.push_back(Pos);
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    printMemberHeader(Out, Kind, Thin,
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                      sys::path::filename(M.Buf->getBufferIdentifier()),
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                      StringMapIndexIter, M.ModTime, M.UID, M.GID, M.Perms,
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                      M.Buf->getBufferSize());
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    if (!Thin)
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      Out << File.getBuffer();
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    if (Out.tell() % 2)
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      Out << '\n';
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  }
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  if (MemberReferenceOffset) {
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    Out.seek(MemberReferenceOffset);
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    for (unsigned MemberNum : MemberOffsetRefs) {
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      if (Kind == object::Archive::K_BSD)
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        Out.seek(Out.tell() + 4); // skip over the string offset
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      print32(Out, Kind, MemberOffset[MemberNum]);
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    }
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  }
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  Output.keep();
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  Out.close();
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  // At this point, we no longer need whatever backing memory
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  // was used to generate the NewMembers. On Windows, this buffer
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  // could be a mapped view of the file we want to replace (if
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  // we're updating an existing archive, say). In that case, the
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  // rename would still succeed, but it would leave behind a
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  // temporary file (actually the original file renamed) because
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  // a file cannot be deleted while there's a handle open on it,
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  // only renamed. So by freeing this buffer, this ensures that
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  // the last open handle on the destination file, if any, is
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  // closed before we attempt to rename.
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  OldArchiveBuf.reset();
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  sys::fs::rename(TmpArchive, ArcName);
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  return std::make_pair("", std::error_code());
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}
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