fileOperation: Corrected processor counting for moving mesh cases

Also resolves bug-report https://bugs.openfoam.org/view.php?id=2774

applications/utilities/parallelProcessing/decomposePar/decomposePar.C

@@ -272,6 +272,7 @@ int main(int argc, char *argv[])
 
     #include "setRootCase.H"
 
+    bool region                  = args.optionFound("region");
     bool allRegions              = args.optionFound("allRegions");
     bool writeCellDist           = args.optionFound("cellDist");
     bool copyZero                = args.optionFound("copyZero");
@@ -403,6 +404,12 @@ int main(int argc, char *argv[])
                 Info<< "Using existing processor directories" << nl;
             }
 
+            if (region || allRegions)
+            {
+                procDirsProblem = false;
+                forceOverwrite = false;
+            }
+
             if (forceOverwrite)
             {
                 Info<< "Removing " << nProcs

src/OSspecific/POSIX/POSIX.C

@@ -827,6 +827,32 @@ bool Foam::cp(const fileName& src, const fileName& dest, const bool followLink)
             return false;
         }
 
+        char* realSrcPath = realpath(src.c_str(), nullptr);
+        char* realDestPath = realpath(destFile.c_str(), nullptr);
+        const bool samePath = strcmp(realSrcPath, realDestPath) == 0;
+
+        if (POSIX::debug && samePath)
+        {
+            InfoInFunction
+                << "Attempt to copy " << realSrcPath << " to itself" << endl;
+        }
+
+        if (realSrcPath)
+        {
+            free(realSrcPath);
+        }
+
+        if (realDestPath)
+        {
+            free(realDestPath);
+        }
+
+        // Do not copy over self when src is actually a link to dest
+        if (samePath)
+        {
+            return false;
+        }
+
         // Copy files
         fileNameList contents = readDir(src, fileName::FILE, false, followLink);
         forAll(contents, i)

src/OpenFOAM/global/fileOperations/fileOperation/fileOperation.C

@@ -591,14 +591,7 @@ Foam::label Foam::fileOperation::nProcs
     label nProcs = 0;
     while
     (
-        isDir
-        (
-            dir
-           /(word("processor") + name(nProcs))
-           /"constant"
-           /local
-           /polyMesh::meshSubDir
-        )
+        isDir(dir/(word("processor") + name(nProcs)))
     )
     {
         ++nProcs;