Use MoveFileEx to rename files on Windows (not rename)

diff --git a/src/filesys.cpp b/src/filesys.cpp
index 501f9ad6ca53f721f4d117b2a199bb6b2e251af9..b4c52ab793b8bb1bb5331285767b159e7bd917c9 100644 (file)
--- a/src/filesys.cpp
+++ b/src/filesys.cpp
@@ -26,6 +26,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <fstream>
 #include "log.h"
 #include "config.h"
+#include "porting.h"
 
 namespace fs
 {
@@ -698,22 +699,37 @@ bool safeWriteToFile(const std::string &path, const std::string &content)
                return false;
        }
 
+       bool rename_success = false;
+
        // Move the finished temporary file over the real file
 #ifdef _WIN32
+       // When creating the file, it can cause Windows Search indexer, virus scanners and other apps
+       // to query the file. This can make the move file call below fail.
+       // We retry up to 5 times, with a 1ms sleep between, before we consider the whole operation failed
+       int number_attempts = 0;
+       while (number_attempts < 5) {
+               rename_success = MoveFileEx(tmp_file.c_str(), path.c_str(),
+                               MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH);
+               if (rename_success)
+                       break;
+               sleep_ms(1);
+               ++number_attempts;
+       }
+#else
        // On POSIX compliant systems rename() is specified to be able to swap the
        // file in place of the destination file, making this a truly error-proof
        // transaction.
-       // However, on Windows, the target file has to be removed first.
-       remove(path.c_str());
+       rename_success = rename(tmp_file.c_str(), path.c_str()) == 0;
 #endif
-       if(rename(tmp_file.c_str(), path.c_str())) {
+       if (!rename_success) {
+               warningstream << "Failed to write to file: " << path.c_str() << std::endl;
                // Remove the temporary file because moving it over the target file
                // failed.
                remove(tmp_file.c_str());
                return false;
-       } else {
-               return true;
        }
+
+       return true;
 }
 
 bool Rename(const std::string &from, const std::string &to)