r296408 - clang-format: Don't leave behind temp files in -i mode on Windows, PR26125, reloaded

[Nico Weber via cfe-commits]

Author: nico
Date: Mon Feb 27 16:59:58 2017
New Revision: 296408

URL: http://llvm.org/viewvc/llvm-project?rev=296408&view=rev
Log:
clang-format: Don't leave behind temp files in -i mode on Windows, PR26125, reloaded

Second attempt after http://llvm.org/viewvc/llvm-project?rev=296166&view=rev

In the first attempt, Code (the memory buffer backing the input file) was reset
before overwriteChangedFiles() was called, but overwriteChangedFiles() still
reads from it.  This time, load the whole input file into memory instead of
using mmap when formatting in-place.

(Since the test is identical to what was in the repo before chapuni's revert,
svn diff doesn't show it – see the above link for the test.)

https://reviews.llvm.org/D30385

Added:
    cfe/trunk/test/Format/inplace.cpp
      - copied unchanged from r296236, cfe/trunk/test/Format/inplace.cpp
Modified:
    cfe/trunk/tools/clang-format/ClangFormat.cpp

Modified: cfe/trunk/tools/clang-format/ClangFormat.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/tools/clang-format/ClangFormat.cpp?rev=296408&r1=296407&r2=296408&view=diff
==============================================================================
--- cfe/trunk/tools/clang-format/ClangFormat.cpp (original)
+++ cfe/trunk/tools/clang-format/ClangFormat.cpp Mon Feb 27 16:59:58 2017
@@ -236,8 +236,15 @@ static void outputReplacementsXML(const
 
 // Returns true on error.
 static bool format(StringRef FileName) {
+  if (!OutputXML && Inplace && FileName == "-") {
+    errs() << "error: cannot use -i when reading from stdin.\n";
+    return false;
+  }
+  // On Windows, overwriting a file with an open file mapping doesn't work,
+  // so read the whole file into memory when formatting in-place.
   ErrorOr<std::unique_ptr<MemoryBuffer>> CodeOrErr =
-      MemoryBuffer::getFileOrSTDIN(FileName);
+      !OutputXML && Inplace ? MemoryBuffer::getFileAsStream(FileName) :
+                              MemoryBuffer::getFileOrSTDIN(FileName);
   if (std::error_code EC = CodeOrErr.getError()) {
     errs() << EC.message() << "\n";
     return true;
@@ -297,9 +304,7 @@ static bool format(StringRef FileName) {
     Rewriter Rewrite(Sources, LangOptions());
     tooling::applyAllReplacements(Replaces, Rewrite);
     if (Inplace) {
-      if (FileName == "-")
-        errs() << "error: cannot use -i when reading from stdin.\n";
-      else if (Rewrite.overwriteChangedFiles())
+      if (Rewrite.overwriteChangedFiles())
         return true;
     } else {
       if (Cursor.getNumOccurrences() != 0)