ENH: improve robustness of fileStat class (issue #794)

- quick ignore of empty filenames.

- relocated some implementation details from POSIX.C to the
  fileStat class, where they make more sense.

src/OSspecific/POSIX/POSIX.C

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2016-2017 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2016-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -59,7 +59,12 @@ Description
 #include <netdb.h>
 #include <netinet/in.h>
 #include <dlfcn.h>
-#include <link.h>
+
+#ifdef darwin
+    #include <mach-o/dyld.h>
+#else
+    #include <link.h>
+#endif
 
 #ifdef USE_RANDOM
     #include <climits>
@@ -652,16 +657,7 @@ time_t Foam::lastModified(const fileName& name, const bool followLink)
     }
 
     // Ignore an empty name
-    if (!name.empty())
-    {
-        fileStat fileStatus(name, followLink);
-        if (fileStatus.isValid())
-        {
-            return fileStatus.status().st_mtime;
-        }
-    }
-
-    return 0;
+    return name.empty() ? 0 : fileStat(name, followLink).modTime();
 }
 
 
@@ -677,18 +673,7 @@ double Foam::highResLastModified(const fileName& name, const bool followLink)
     }
 
     // Ignore an empty name
-    if (!name.empty())
-    {
-        fileStat fileStatus(name, followLink);
-        if (fileStatus.isValid())
-        {
-            return
-                fileStatus.status().st_mtime
-              + 1e-9*fileStatus.status().st_mtim.tv_nsec;
-        }
-    }
-
-    return 0;
+    return name.empty() ? 0 : fileStat(name, followLink).dmodTime();
 }
 
 

src/OSspecific/POSIX/fileStat.C

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2016 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2016-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -29,7 +29,9 @@ License
 
 #include <signal.h>
 #include <unistd.h>
-#include <sys/sysmacros.h>
+#ifndef darwin
+    #include <sys/sysmacros.h>
+#endif
 
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
@@ -48,6 +50,11 @@ Foam::fileStat::fileStat
 :
     isValid_(false)
 {
+    if (fName.empty())
+    {
+        return;
+    }
+
     // Work on volatile
     volatile bool locIsValid = false;
 
@@ -84,20 +91,42 @@ Foam::label Foam::fileStat::size() const
 }
 
 
-bool Foam::fileStat::sameDevice(const fileStat& stat2) const
+time_t Foam::fileStat::modTime() const
+{
+    return isValid_ ? status_.st_mtime : 0;
+}
+
+
+double Foam::fileStat::dmodTime() const
+{
+    return
+    (
+        isValid_
+      ?
+        #ifdef darwin
+        (status_.st_mtime + 1e-9*status_.st_mtimespec.tv_nsec)
+        #else
+        (status_.st_mtime + 1e-9*status_.st_mtim.tv_nsec)
+        #endif
+      : 0
+    );
+}
+
+
+bool Foam::fileStat::sameDevice(const fileStat& other) const
 {
     return
         isValid_
      && (
-            major(status_.st_dev) == major(stat2.status().st_dev)
-         && minor(status_.st_dev) == minor(stat2.status().st_dev)
+            major(status_.st_dev) == major(other.status_.st_dev)
+         && minor(status_.st_dev) == minor(other.status_.st_dev)
         );
 }
 
 
-bool Foam::fileStat::sameINode(const fileStat& stat2) const
+bool Foam::fileStat::sameINode(const fileStat& other) const
 {
-    return isValid_ && (status_.st_ino == stat2.status().st_ino);
+    return isValid_ && (status_.st_ino == other.status_.st_ino);
 }
 
 

src/OSspecific/POSIX/fileStat.H

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2016 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2016-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -51,8 +51,7 @@ SourceFiles
 namespace Foam
 {
 
-// Forward declaration of friend functions and operators
-
+// Forward declarations
 class fileStat;
 
 Istream& operator>>(Istream& is, fileStat& fStat);
@@ -88,6 +87,8 @@ public:
         //
         // \param maxTime \n
         // The timeout value.
+        //
+        // \note an empty filename is a no-op.
         fileStat
         (
             const fileName& fName,
@@ -101,34 +102,42 @@ public:
 
     // Member Functions
 
-        // Access
+    // Access
 
-            //- Raw status
-            const struct stat& status() const
-            {
-                return status_;
-            }
+        //- Raw status
+        const struct stat& status() const
+        {
+            return status_;
+        }
 
-            //- Was file-stat successful?
-            bool isValid() const
-            {
-                return isValid_;
-            }
+        //- Was file-stat successful?
+        bool isValid() const
+        {
+            return isValid_;
+        }
 
-            //- Size in bytes. Zero for invalid file-stat.
-            label size() const;
+        //- Size in bytes. Zero for an invalid file-stat.
+        label size() const;
+
+        //- Return the modification time in seconds.
+        //  Zero for an invalid file-stat.
+        time_t modTime() const;
+
+        //- Return the modification time in seconds (nanosecond resolution)
+        //  Zero for an invalid file-stat.
+        double dmodTime() const;
 
 
-        // Check
+    // Check
 
-            //- Compare two fileStats for same device
-            bool sameDevice(const fileStat& stat2) const;
+        //- Compare two fileStats for same device
+        bool sameDevice(const fileStat& other) const;
 
-            //- Compare two fileStats for same Inode
-            bool sameINode(const fileStat& stat2) const;
+        //- Compare two fileStats for same Inode
+        bool sameINode(const fileStat& other) const;
 
-            //- Compare state against inode
-            bool sameINode(const label iNode) const;
+        //- Compare state against inode
+        bool sameINode(const label iNode) const;
 
 
     // IOstream Operators

src/OSspecific/POSIX/printStack.C

@@ -86,9 +86,9 @@ string pOpen(const string& cmd, label line=0)
 
 inline word addressToWord(const uintptr_t addr)
 {
-    OStringStream nStream;
-    nStream << "0x" << hex << addr;
-    return nStream.str();
+    OStringStream os;
+    os << "0x" << hex << addr;
+    return os.str();
 }
 
 
@@ -122,7 +122,7 @@ void printSourceFileAndLine
             1
         );
 
-        if (line == "")
+        if (line.empty())
         {
             os  << " addr2line failed";
         }
@@ -161,7 +161,6 @@ fileName absolutePath(const char* fn)
 
 word demangleSymbol(const char* sn)
 {
-    word res;
     int st;
     char* cxx_sname = abi::__cxa_demangle
     (
@@ -173,15 +172,13 @@ word demangleSymbol(const char* sn)
 
     if (st == 0 && cxx_sname)
     {
-        res = word(cxx_sname);
+        word demangled(cxx_sname);
         free(cxx_sname);
-    }
-    else
-    {
-        res = word(sn);
+
+        return demangled;
     }
 
-    return res;
+    return sn;
 }
 
 
@@ -189,8 +186,8 @@ word demangleSymbol(const char* sn)
 
 } // End namespace Foam
 
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 void Foam::error::safePrintStack(std::ostream& os)
 {