[Cmake-commits] CMake branch, next, updated. v2.8.10.2-2111-gb1caac7

[Brad King]

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The branch, next has been updated
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       via  2dc17f88dd2de900154f153f521b803ec9b7c377 (commit)
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- Log -----------------------------------------------------------------
http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=b1caac79288bae0226dbb750f0768dfa26ea90a1
commit b1caac79288bae0226dbb750f0768dfa26ea90a1
Merge: a5fc93d 2dc17f8
Author:     Brad King <brad.king at kitware.com>
AuthorDate: Tue Feb 12 13:56:35 2013 -0500
Commit:     CMake Topic Stage <kwrobot at kitware.com>
CommitDate: Tue Feb 12 13:56:35 2013 -0500

    Merge topic 'vs-atomic-generated-stamp' into next
    
    2dc17f8 VS: Replace generation timestamp file atomically


http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=2dc17f88dd2de900154f153f521b803ec9b7c377
commit 2dc17f88dd2de900154f153f521b803ec9b7c377
Author:     Brad King <brad.king at kitware.com>
AuthorDate: Tue Feb 12 10:46:22 2013 -0500
Commit:     Brad King <brad.king at kitware.com>
CommitDate: Tue Feb 12 13:55:53 2013 -0500

    VS: Replace generation timestamp file atomically
    
    Since commit 34c882a9 (Allow VS 7 project Rebuild and Solution Rebuild to
    work, 2007-11-10) we use a "CMakeFiles/generated.stamp" and some
    associated files in the build tree to avoid re-running CMake when the
    inputs have not changed but VS has cleaned the outputs it knows about.
    
    When we do not really need to re-run we restore the generated.stamp file.
    The non-re-run case can happen in multiple targets in parallel in VS >= 10
    so we must restore the file atomically to avoid races.  Write the stamp
    file to a random temporary name and then atomically rename it to the real
    stamp file.

diff --git a/Source/cmake.cxx b/Source/cmake.cxx
index d57e981..3071aeb 100644
--- a/Source/cmake.cxx
+++ b/Source/cmake.cxx
@@ -4033,10 +4033,18 @@ static bool cmakeCheckStampFile(const char* stampName)
     }
 
   // The build system is up to date.  The stamp file has been removed
-  // by the VS IDE due to a "rebuild" request.  Just restore it.
-  std::ofstream stamp(stampName);
+  // by the VS IDE due to a "rebuild" request.  Restore it atomically.
+  cmOStringStream stampTempStream;
+  stampTempStream << stampName << ".tmp" << cmSystemTools::RandomSeed();
+  std::string stampTempString = stampTempStream.str();
+  const char* stampTemp = stampTempString.c_str();
+  {
+  // TODO: Teach cmGeneratedFileStream to use a random temp file (with
+  // multiple tries in unlikely case of conflict) and use that here.
+  std::ofstream stamp(stampTemp);
   stamp << "# CMake generation timestamp file this directory.\n";
-  if(stamp)
+  }
+  if(cmSystemTools::RenameFile(stampTemp, stampName))
     {
     // Notify the user why CMake is not re-running.  It is safe to
     // just print to stdout here because this code is only reachable
@@ -4047,6 +4055,7 @@ static bool cmakeCheckStampFile(const char* stampName)
     }
   else
     {
+    cmSystemTools::RemoveFile(stampTemp);
     cmSystemTools::Error("Cannot restore timestamp ", stampName);
     return false;
     }

-----------------------------------------------------------------------

Summary of changes:
 Source/cmake.cxx |   15 ++++++++++++---
 1 files changed, 12 insertions(+), 3 deletions(-)


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