From 15c3e8eb9cb44e9333dd120e533f9f07e737c256 Mon Sep 17 00:00:00 2001
From: Jan Korous <jkorous@apple.com>
Date: Fri, 13 Sep 2019 20:08:27 +0000
Subject: [PATCH] [Support] Add overload writeFileAtomically(std::function
 Writer)

Differential Revision: https://reviews.llvm.org/D67424

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@371890 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Frontend/ASTUnit.cpp                | 24 ++++++----------
 lib/Serialization/GlobalModuleIndex.cpp | 37 ++++---------------------
 2 files changed, 14 insertions(+), 47 deletions(-)

diff --git a/lib/Frontend/ASTUnit.cpp b/lib/Frontend/ASTUnit.cpp
index 35348ffe13..f5e291b7fe 100644
--- a/lib/Frontend/ASTUnit.cpp
+++ b/lib/Frontend/ASTUnit.cpp
@@ -84,6 +84,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FileUtilities.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/VirtualFileSystem.h"
@@ -2301,26 +2302,19 @@ bool ASTUnit::Save(StringRef File) {
   SmallString<128> TempPath;
   TempPath = File;
   TempPath += "-%%%%%%%%";
-  int fd;
-  if (llvm::sys::fs::createUniqueFile(TempPath, fd, TempPath))
-    return true;
-
   // FIXME: Can we somehow regenerate the stat cache here, or do we need to
   // unconditionally create a stat cache when we parse the file?
-  llvm::raw_fd_ostream Out(fd, /*shouldClose=*/true);
-
-  serialize(Out);
-  Out.close();
-  if (Out.has_error()) {
-    Out.clear_error();
-    return true;
-  }
 
-  if (llvm::sys::fs::rename(TempPath, File)) {
-    llvm::sys::fs::remove(TempPath);
+  if (llvm::Error Err = llvm::writeFileAtomically(
+          TempPath, File, [this](llvm::raw_ostream &Out) {
+            return serialize(Out) ? llvm::make_error<llvm::StringError>(
+                                        "ASTUnit serialization failed",
+                                        llvm::inconvertibleErrorCode())
+                                  : llvm::Error::success();
+          })) {
+    consumeError(std::move(Err));
     return true;
   }
-
   return false;
 }
 
diff --git a/lib/Serialization/GlobalModuleIndex.cpp b/lib/Serialization/GlobalModuleIndex.cpp
index 1833ebbdc8..54ab17681e 100644
--- a/lib/Serialization/GlobalModuleIndex.cpp
+++ b/lib/Serialization/GlobalModuleIndex.cpp
@@ -10,7 +10,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-
 #include "ASTReaderInternals.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Lex/HeaderSearch.h"
@@ -21,10 +20,12 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/Bitstream/BitstreamReader.h"
 #include "llvm/Bitstream/BitstreamWriter.h"
 #include "llvm/Support/DJB.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FileUtilities.h"
 #include "llvm/Support/LockFileManager.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/OnDiskHashTable.h"
@@ -912,37 +913,9 @@ GlobalModuleIndex::writeIndex(FileManager &FileMgr,
                                      "failed writing index");
   }
 
-  // Write the global index file to a temporary file.
-  llvm::SmallString<128> IndexTmpPath;
-  int TmpFD;
-  if (llvm::sys::fs::createUniqueFile(IndexPath + "-%%%%%%%%", TmpFD,
-                                      IndexTmpPath))
-    return llvm::createStringError(std::errc::io_error,
-                                   "failed creating unique file");
-
-  // Open the temporary global index file for output.
-  llvm::raw_fd_ostream Out(TmpFD, true);
-  if (Out.has_error())
-    return llvm::createStringError(Out.error(), "failed outputting to stream");
-
-  // Write the index.
-  Out.write(OutputBuffer.data(), OutputBuffer.size());
-  Out.close();
-  if (Out.has_error())
-    return llvm::createStringError(Out.error(), "failed writing to stream");
-
-  // Remove the old index file. It isn't relevant any more.
-  llvm::sys::fs::remove(IndexPath);
-
-  // Rename the newly-written index file to the proper name.
-  if (std::error_code Err = llvm::sys::fs::rename(IndexTmpPath, IndexPath)) {
-    // Remove the file on failure, don't check whether removal succeeded.
-    llvm::sys::fs::remove(IndexTmpPath);
-    return llvm::createStringError(Err, "failed renaming file \"%s\" to \"%s\"",
-                                   IndexTmpPath.c_str(), IndexPath.c_str());
-  }
-
-  return llvm::Error::success();
+  return llvm::writeFileAtomically(
+      (IndexPath + "-%%%%%%%%").str(), IndexPath,
+      llvm::StringRef(OutputBuffer.data(), OutputBuffer.size()));
 }
 
 namespace {
-- 
2.40.0