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This function is complementary to createTemporaryFile. It handles the case were the unique file is *not* temporary: we will rename it in the end. Since we will rename it, the file has to be in the same filesystem as the final destination and we don't prepend the system temporary directory. This has a small semantic difference from unique_file: the default mode is 0666. This matches the behavior of most unix tools. For example, with this change lld now produces files with the same permissions as ld. I will add a test of this change when I port clang over to createUniqueFile (next commit). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185726 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::createUniqueFile(Twine(FilePath) + ".tmp%%%%%%%",
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FD, TempFilePath);
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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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