[llvm] r318069 - Create a TempFile class.
Rafael Espindola via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 13 10:33:44 PST 2017
Author: rafael
Date: Mon Nov 13 10:33:44 2017
New Revision: 318069
URL: http://llvm.org/viewvc/llvm-project?rev=318069&view=rev
Log:
Create a TempFile class.
This just adds a TempFile class and replaces the use in
FileOutputBuffer with it.
The only difference for now is better error handling. Followup work includes:
- Convert other user of temporary files to it.
- Add support for automatically deleting on windows.
- Add a createUnnamed method that returns a potentially unnamed
file. It would be actually unnamed on modern linux and have a
unknown name on windows.
Modified:
llvm/trunk/include/llvm/Support/FileSystem.h
llvm/trunk/lib/Support/FileOutputBuffer.cpp
llvm/trunk/lib/Support/Path.cpp
Modified: llvm/trunk/include/llvm/Support/FileSystem.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/FileSystem.h?rev=318069&r1=318068&r2=318069&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/FileSystem.h (original)
+++ llvm/trunk/include/llvm/Support/FileSystem.h Mon Nov 13 10:33:44 2017
@@ -31,6 +31,7 @@
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/Chrono.h"
+#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/MD5.h"
@@ -694,6 +695,40 @@ std::error_code createUniqueFile(const T
std::error_code createUniqueFile(const Twine &Model,
SmallVectorImpl<char> &ResultPath);
+/// Represents a temporary file.
+///
+/// The temporary file must be eventually discarded or given a final name and
+/// kept.
+///
+/// The destructor doesn't implicitly discard because there is no way to
+/// properly handle errors in a destructor.
+class TempFile {
+ bool Done = false;
+ TempFile(StringRef Name, int FD);
+
+public:
+ /// This creates a temporary file with createUniqueFile and schedules it for
+ /// deletion with sys::RemoveFileOnSignal.
+ static Expected<TempFile> create(const Twine &Model,
+ unsigned Mode = all_read | all_write);
+ TempFile(TempFile &&Other);
+
+ // Name of the temporary file.
+ std::string TmpName;
+
+ // The open file descriptor.
+ int FD = -1;
+
+ // Keep this with the given name.
+ Error keep(const Twine &Name);
+
+ // Delete the file.
+ Error discard();
+
+ // This checks that keep or delete was called.
+ ~TempFile();
+};
+
/// @brief Create a file in the system temporary directory.
///
/// The filename is of the form prefix-random_chars.suffix. Since the directory
Modified: llvm/trunk/lib/Support/FileOutputBuffer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/FileOutputBuffer.cpp?rev=318069&r1=318068&r2=318069&view=diff
==============================================================================
--- llvm/trunk/lib/Support/FileOutputBuffer.cpp (original)
+++ llvm/trunk/lib/Support/FileOutputBuffer.cpp Mon Nov 13 10:33:44 2017
@@ -17,7 +17,6 @@
#include "llvm/Support/Errc.h"
#include "llvm/Support/Memory.h"
#include "llvm/Support/Path.h"
-#include "llvm/Support/Signals.h"
#include <system_error>
#if !defined(_MSC_VER) && !defined(__MINGW32__)
@@ -34,9 +33,9 @@ using namespace llvm::sys;
// with the temporary file on commit().
class OnDiskBuffer : public FileOutputBuffer {
public:
- OnDiskBuffer(StringRef Path, StringRef TempPath,
+ OnDiskBuffer(StringRef Path, fs::TempFile Temp,
std::unique_ptr<fs::mapped_file_region> Buf)
- : FileOutputBuffer(Path), Buffer(std::move(Buf)), TempPath(TempPath) {}
+ : FileOutputBuffer(Path), Buffer(std::move(Buf)), Temp(std::move(Temp)) {}
uint8_t *getBufferStart() const override { return (uint8_t *)Buffer->data(); }
@@ -51,21 +50,19 @@ public:
Buffer.reset();
// Atomically replace the existing file with the new one.
- auto EC = fs::rename(TempPath, FinalPath);
- sys::DontRemoveFileOnSignal(TempPath);
- return errorCodeToError(EC);
+ return Temp.keep(FinalPath);
}
~OnDiskBuffer() override {
// Close the mapping before deleting the temp file, so that the removal
// succeeds.
Buffer.reset();
- fs::remove(TempPath);
+ consumeError(Temp.discard());
}
private:
std::unique_ptr<fs::mapped_file_region> Buffer;
- std::string TempPath;
+ fs::TempFile Temp;
};
// A FileOutputBuffer which keeps data in memory and writes to the final
@@ -110,13 +107,11 @@ createInMemoryBuffer(StringRef Path, siz
static Expected<std::unique_ptr<OnDiskBuffer>>
createOnDiskBuffer(StringRef Path, size_t Size, unsigned Mode) {
- // Create new file in same directory but with random name.
- SmallString<128> TempPath;
- int FD;
- if (auto EC = fs::createUniqueFile(Path + ".tmp%%%%%%%", FD, TempPath, Mode))
- return errorCodeToError(EC);
-
- sys::RemoveFileOnSignal(TempPath);
+ Expected<fs::TempFile> FileOrErr =
+ fs::TempFile::create(Path + ".tmp%%%%%%%", Mode);
+ if (!FileOrErr)
+ return FileOrErr.takeError();
+ fs::TempFile File = std::move(*FileOrErr);
#ifndef LLVM_ON_WIN32
// On Windows, CreateFileMapping (the mmap function on Windows)
@@ -124,18 +119,22 @@ createOnDiskBuffer(StringRef Path, size_
// extend the file beforehand. _chsize (ftruncate on Windows) is
// pretty slow just like it writes specified amount of bytes,
// so we should avoid calling that function.
- if (auto EC = fs::resize_file(FD, Size))
+ if (auto EC = fs::resize_file(File.FD, Size)) {
+ consumeError(File.discard());
return errorCodeToError(EC);
+ }
#endif
// Mmap it.
std::error_code EC;
auto MappedFile = llvm::make_unique<fs::mapped_file_region>(
- FD, fs::mapped_file_region::readwrite, Size, 0, EC);
- close(FD);
- if (EC)
+ File.FD, fs::mapped_file_region::readwrite, Size, 0, EC);
+ if (EC) {
+ consumeError(File.discard());
return errorCodeToError(EC);
- return llvm::make_unique<OnDiskBuffer>(Path, TempPath, std::move(MappedFile));
+ }
+ return llvm::make_unique<OnDiskBuffer>(Path, std::move(File),
+ std::move(MappedFile));
}
// Create an instance of FileOutputBuffer.
Modified: llvm/trunk/lib/Support/Path.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Path.cpp?rev=318069&r1=318068&r2=318069&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Path.cpp (original)
+++ llvm/trunk/lib/Support/Path.cpp Mon Nov 13 10:33:44 2017
@@ -18,6 +18,7 @@
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Process.h"
+#include "llvm/Support/Signals.h"
#include <cctype>
#include <cstring>
@@ -759,6 +760,58 @@ std::error_code createUniqueFile(const T
return createUniqueEntity(Model, Dummy, ResultPath, false, 0, FS_Name);
}
+TempFile::TempFile(StringRef Name, int FD) : TmpName(Name), FD(FD) {}
+TempFile::TempFile(TempFile &&Other) {
+ TmpName = std::move(Other.TmpName);
+ FD = Other.FD;
+ Other.Done = true;
+}
+
+TempFile::~TempFile() { assert(Done); }
+
+Error TempFile::discard() {
+ if (Done)
+ return Error::success();
+ Done = true;
+ // Always try to close and remove.
+ std::error_code RemoveEC = fs::remove(TmpName);
+ sys::DontRemoveFileOnSignal(TmpName);
+ if (close(FD) == -1) {
+ std::error_code EC = std::error_code(errno, std::generic_category());
+ return errorCodeToError(EC);
+ }
+ return errorCodeToError(RemoveEC);
+}
+
+Error TempFile::keep(const Twine &Name) {
+ assert(!Done);
+ Done = true;
+ // Always try to close and rename.
+ std::error_code RenameEC = fs::rename(TmpName, Name);
+ sys::DontRemoveFileOnSignal(TmpName);
+ if (close(FD) == -1) {
+ std::error_code EC(errno, std::generic_category());
+ return errorCodeToError(EC);
+ }
+ return errorCodeToError(RenameEC);
+}
+
+Expected<TempFile> TempFile::create(const Twine &Model, unsigned Mode) {
+ int FD;
+ SmallString<128> ResultPath;
+ if (std::error_code EC = createUniqueFile(Model, FD, ResultPath, Mode))
+ return errorCodeToError(EC);
+
+ // Make sure we delete the file when RemoveFileOnSignal fails.
+ TempFile Ret(ResultPath, FD);
+ if (sys::RemoveFileOnSignal(ResultPath)) {
+ consumeError(Ret.discard());
+ std::error_code EC(errc::operation_not_permitted);
+ return errorCodeToError(EC);
+ }
+ return std::move(Ret);
+}
+
static std::error_code
createTemporaryFile(const Twine &Model, int &ResultFD,
llvm::SmallVectorImpl<char> &ResultPath, FSEntity Type) {
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