From 7b1f966a6c456270004a2aec2c53057ca8efbac9 Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Wed, 12 Feb 2014 09:45:56 -0500
Subject: Windows: Make file delete/rename retry configurable

Several CMake operations need to replace files in rapid succession.
This commonly fails on Windows due to filesystem lock behavior so
we have retry loops.  No matter how many times we retry or how long
we delay there will inevitably be someone with an environment that
needs more.  Make the retry count and delay configurable in the
Windows Registry keys:

 {HKCU,HKLM}/Software/Kitware/CMake/Config

in DWORD values

 FilesystemRetryCount = Number of tries
 FilesystemRetryDelay = Delay in milliseconds between tries

Leave the feature undocumented for now to see how it goes.
---
 Source/cmCoreTryCompile.cxx | 13 +++++++++----
 Source/cmSystemTools.cxx    | 46 +++++++++++++++++++++++++++++++++++++++++----
 Source/cmSystemTools.h      |  9 +++++++++
 3 files changed, 60 insertions(+), 8 deletions(-)

diff --git a/Source/cmCoreTryCompile.cxx b/Source/cmCoreTryCompile.cxx
index bbdb3a1..7b52069 100644
--- a/Source/cmCoreTryCompile.cxx
+++ b/Source/cmCoreTryCompile.cxx
@@ -585,15 +585,20 @@ void cmCoreTryCompile::CleanupFiles(const char* binDir)
           }
         else
           {
+#ifdef _WIN32
           // Sometimes anti-virus software hangs on to new files so we
           // cannot delete them immediately.  Try a few times.
-          int tries = 5;
+          cmSystemTools::WindowsFileRetry retry =
+            cmSystemTools::GetWindowsFileRetry();
           while(!cmSystemTools::RemoveFile(fullPath.c_str()) &&
-                --tries && cmSystemTools::FileExists(fullPath.c_str()))
+                --retry.Count && cmSystemTools::FileExists(fullPath.c_str()))
             {
-            cmSystemTools::Delay(500);
+            cmSystemTools::Delay(retry.Delay);
             }
-          if(tries == 0)
+          if(retry.Count == 0)
+#else
+          if(!cmSystemTools::RemoveFile(fullPath.c_str()))
+#endif
             {
             std::string m = "Remove failed on file: " + fullPath;
             cmSystemTools::ReportLastSystemError(m.c_str());
diff --git a/Source/cmSystemTools.cxx b/Source/cmSystemTools.cxx
index 41c7509..ff05975 100644
--- a/Source/cmSystemTools.cxx
+++ b/Source/cmSystemTools.cxx
@@ -864,6 +864,44 @@ bool cmSystemTools::CopyFileIfDifferent(const char* source,
 }
 
 //----------------------------------------------------------------------------
+#ifdef _WIN32
+cmSystemTools::WindowsFileRetry cmSystemTools::GetWindowsFileRetry()
+{
+  static WindowsFileRetry retry = {0,0};
+  if(!retry.Count)
+    {
+    unsigned int data[2] = {0,0};
+    HKEY const keys[2] = {HKEY_CURRENT_USER, HKEY_LOCAL_MACHINE};
+    wchar_t const* const values[2] = {L"FilesystemRetryCount",
+                                      L"FilesystemRetryDelay"};
+    for(int k=0; k < 2; ++k)
+      {
+      HKEY hKey;
+      if(RegOpenKeyExW(keys[k], L"Software\\Kitware\\CMake\\Config",
+                       0, KEY_QUERY_VALUE, &hKey) == ERROR_SUCCESS)
+        {
+        for(int v=0; v < 2; ++v)
+          {
+          DWORD dwData, dwType, dwSize = 4;
+          if(!data[v] &&
+             RegQueryValueExW(hKey, values[v], 0, &dwType, (BYTE *)&dwData,
+                              &dwSize) == ERROR_SUCCESS &&
+             dwType == REG_DWORD && dwSize == 4)
+            {
+            data[v] = static_cast<unsigned int>(dwData);
+            }
+          }
+        RegCloseKey(hKey);
+        }
+      }
+    retry.Count = data[0]? data[0] : 5;
+    retry.Delay = data[1]? data[1] : 500;
+    }
+  return retry;
+}
+#endif
+
+//----------------------------------------------------------------------------
 bool cmSystemTools::RenameFile(const char* oldname, const char* newname)
 {
 #ifdef _WIN32
@@ -874,10 +912,10 @@ bool cmSystemTools::RenameFile(const char* oldname, const char* newname)
      fails then remove the read-only attribute from any existing destination.
      Try multiple times since we may be racing against another process
      creating/opening the destination file just before our MoveFileEx.  */
-  int tries = 5;
+  WindowsFileRetry retry = cmSystemTools::GetWindowsFileRetry();
   while(!MoveFileExW(cmsys::Encoding::ToWide(oldname).c_str(),
                      cmsys::Encoding::ToWide(newname).c_str(),
-                     MOVEFILE_REPLACE_EXISTING) && --tries)
+                     MOVEFILE_REPLACE_EXISTING) && --retry.Count)
     {
     // Try again only if failure was due to access permissions.
     if(GetLastError() != ERROR_ACCESS_DENIED)
@@ -896,10 +934,10 @@ bool cmSystemTools::RenameFile(const char* oldname, const char* newname)
     else
       {
       // The file may be temporarily in use so wait a bit.
-      cmSystemTools::Delay(100);
+      cmSystemTools::Delay(retry.Delay);
       }
     }
-  return tries > 0;
+  return retry.Count > 0;
 #else
   /* On UNIX we have an OS-provided call to do this atomically.  */
   return rename(oldname, newname) == 0;
diff --git a/Source/cmSystemTools.h b/Source/cmSystemTools.h
index 4e854c8..4a5d298 100644
--- a/Source/cmSystemTools.h
+++ b/Source/cmSystemTools.h
@@ -460,6 +460,15 @@ public:
   /** Tokenize a string */
   static std::vector<std::string> tokenize(const std::string& str,
                                            const std::string& sep);
+
+#ifdef _WIN32
+  struct WindowsFileRetry
+  {
+    unsigned int Count;
+    unsigned int Delay;
+  };
+  static WindowsFileRetry GetWindowsFileRetry();
+#endif
 private:
   static bool s_ForceUnixPaths;
   static bool s_RunCommandHideConsole;
-- 
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