STYLE: adjust internal coding for handing IOobject filename (related to #482)

- make the purpose of various parts clearer

src/OpenFOAM/db/IOobject/IOobject.C

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2016 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2016-2017 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -95,6 +95,17 @@ namespace Foam
 }
 
 
+// file-scope
+//
+// A file is 'outside' of the case if it has been specified using an
+// absolute path (starts with '/')
+//
+static inline bool isOutsideOfCase(const std::string& file)
+{
+    return !file.empty() && file[0] == '/';
+}
+
+
 // * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * * //
 
 // Return components following the IOobject requirements
@@ -104,10 +115,10 @@ namespace Foam
 //    -----               ------
 //    "foo"               ("", "", "foo")
 //    "foo/bar"           ("foo", "", "bar")
-//    "/XXX/bar"          ("/XXX", "", "bar")
 //    "foo/bar/"          ERROR - no name
 //    "foo/xxx/bar"       ("foo", "xxx", "bar")
 //    "foo/xxx/yyy/bar"   ("foo", "xxx/yyy", "bar")
+//    "/xxx/yyy/bar"      ("/xxx/yyy", "", "bar")
 bool Foam::IOobject::fileNameComponents
 (
     const fileName& path,
@@ -120,7 +131,7 @@ bool Foam::IOobject::fileNameComponents
     local.clear();
     name.clear();
 
-    // called with directory
+    // Called with directory
     if (isDir(path))
     {
         WarningInFunction
@@ -129,44 +140,49 @@ bool Foam::IOobject::fileNameComponents
         return false;
     }
 
-    if (path.isAbsolute())
+    const auto first = path.find('/');
+    const auto last  = path.rfind('/');
+
+    // The raw length of name (without validating for word chars)
+    auto nameLen = path.size();
+
+    if (first == std::string::npos)
     {
-        string::size_type last = path.rfind('/');
+        // No '/' found (or empty entirely)
+        // => no instance or local
+
+        name = word::validated(path, false);
+    }
+    else if (first == 0)
+    {
+        // Absolute path (starts with '/')
+        // => no local
+
         instance = path.substr(0, last);
 
-        // Check afterwards
+        const std::string ending = path.substr(last+1);
-        name.string::operator=(path.substr(last+1));
+        nameLen = ending.size();  // The raw length of name
+        name = word::validated(ending, false);
     }
     else
     {
-        string::size_type first = path.find('/');
+        // Normal case.
+        // First part is instance, remainder is local
+        instance = path.substr(0, first);
 
-        if (first == string::npos)
+        if (last > first)
         {
-            // no '/' found - no instance or local
+            // With local
-
+            local = path.substr(first+1, last-first-1);
-            // check afterwards
-            name.string::operator=(path);
         }
-        else
-        {
-            instance = path.substr(0, first);
 
-            string::size_type last = path.rfind('/');
+        const std::string ending = path.substr(last+1);
-            if (last > first)
+        nameLen = ending.size();  // The raw length of name
-            {
+        name = word::validated(ending, false);
-                // with local
-                local = path.substr(first+1, last-first-1);
-            }
-
-            // check afterwards
-            name.string::operator=(path.substr(last+1));
-        }
     }
 
-
     // Check for valid (and stripped) name, regardless of the debug level
-    if (name.empty() || string::stripInvalid<word>(name))
+    if (!nameLen || nameLen != name.size())
     {
         WarningInFunction
             << "has invalid word for name: \"" << name
@@ -360,24 +376,24 @@ const Foam::fileName& Foam::IOobject::caseName() const
 
 Foam::word Foam::IOobject::group() const
 {
-    word::size_type i = name_.find_last_of('.');
+    const auto i = name_.rfind('.');
 
-    if (i == word::npos || i == 0)
+    if (i == std::string::npos || i == 0)
     {
         return word::null;
     }
     else
     {
-        return name_.substr(i+1, word::npos);
+        return name_.substr(i+1);
     }
 }
 
 
 Foam::word Foam::IOobject::member() const
 {
-    word::size_type i = name_.find_last_of('.');
+    const auto i = name_.rfind('.');
 
-    if (i == word::npos || i == 0)
+    if (i == std::string::npos || i == 0)
     {
         return name_;
     }
@@ -390,7 +406,7 @@ Foam::word Foam::IOobject::member() const
 
 Foam::fileName Foam::IOobject::path() const
 {
-    if (instance().isAbsolute())
+    if (isOutsideOfCase(instance()))
     {
         return instance();
     }
@@ -414,9 +430,9 @@ Foam::fileName Foam::IOobject::path
 
 Foam::fileName Foam::IOobject::localFilePath(const bool search) const
 {
-    if (instance().isAbsolute())
+    if (isOutsideOfCase(instance()))
     {
-        fileName objectPath = instance()/name();
+        const fileName objectPath = instance()/name();
 
         if (isFile(objectPath))
         {
@@ -429,8 +445,8 @@ Foam::fileName Foam::IOobject::localFilePath(const bool search) const
     }
     else
     {
-        fileName path = this->path();
+        const fileName path = this->path();
-        fileName objectPath = path/name();
+        const fileName objectPath = path/name();
 
         if (isFile(objectPath))
         {
@@ -440,14 +456,14 @@ Foam::fileName Foam::IOobject::localFilePath(const bool search) const
         {
             if (!isDir(path) && search)
             {
-                word newInstancePath = time().findInstancePath
+                const word newInstancePath = time().findInstancePath
                 (
                     instant(instance())
                 );
 
                 if (newInstancePath.size())
                 {
-                    fileName fName
+                    const fileName fName
                     (
                         rootPath()/caseName()
                        /newInstancePath/db_.dbDir()/local()/name()
@@ -468,9 +484,9 @@ Foam::fileName Foam::IOobject::localFilePath(const bool search) const
 
 Foam::fileName Foam::IOobject::globalFilePath(const bool search) const
 {
-    if (instance().isAbsolute())
+    if (isOutsideOfCase(instance()))
     {
-        fileName objectPath = instance()/name();
+        const fileName objectPath = instance()/name();
         if (isFile(objectPath))
         {
             if (objectRegistry::debug)
@@ -492,8 +508,8 @@ Foam::fileName Foam::IOobject::globalFilePath(const bool search) const
     }
     else
     {
-        fileName path = this->path();
+        const fileName path = this->path();
-        fileName objectPath = path/name();
+        const fileName objectPath = path/name();
 
         if (isFile(objectPath))
         {
@@ -516,7 +532,7 @@ Foam::fileName Foam::IOobject::globalFilePath(const bool search) const
             {
                 // Constant & system can come from global case
 
-                fileName parentObjectPath =
+                const fileName parentObjectPath =
                     rootPath()/time().globalCaseName()
                    /instance()/db().dbDir()/local()/name();
 
@@ -534,14 +550,14 @@ Foam::fileName Foam::IOobject::globalFilePath(const bool search) const
             // Check for approximately same (local) time
             if (!isDir(path) && search)
             {
-                word newInstancePath = time().findInstancePath
+                const word newInstancePath = time().findInstancePath
                 (
                     instant(instance())
                 );
 
                 if (newInstancePath.size())
                 {
-                    fileName fName
+                    const fileName fName
                     (
                         rootPath()/caseName()
                        /newInstancePath/db().dbDir()/local()/name()
@@ -586,10 +602,8 @@ Foam::Istream* Foam::IOobject::objectStream(const fileName& fName)
             return nullptr;
         }
     }
-    else
+
-    {
+    return nullptr;
-        return nullptr;
-    }
 }