Wrap create_directory calls in try...catch blocks.

Ignores any exceptions thrown if directory exists, otherwise re-throws exception.

Rebased-By: Wladimir J. van der Laan <laanwj@gmail.com>

src/db.cpp

@@ -72,7 +72,7 @@ bool CDBEnv::Open(const boost::filesystem::path& pathIn)
 
     path = pathIn;
     filesystem::path pathLogDir = path / "database";
-    filesystem::create_directory(pathLogDir);
+    TryCreateDirectory(pathLogDir);
     filesystem::path pathErrorFile = path / "db.log";
     LogPrintf("dbenv.open LogDir=%s ErrorFile=%s\n", pathLogDir.string(), pathErrorFile.string());
 

src/leveldbwrapper.cpp

@@ -51,7 +51,7 @@ CLevelDBWrapper::CLevelDBWrapper(const boost::filesystem::path &path, size_t nCa
             LogPrintf("Wiping LevelDB in %s\n", path.string());
             leveldb::DestroyDB(path.string(), options);
         }
-        boost::filesystem::create_directory(path);
+        TryCreateDirectory(path);
         LogPrintf("Opening LevelDB in %s\n", path.string());
     }
     leveldb::Status status = leveldb::DB::Open(options, path.string(), &pdb);

src/qt/intro.cpp

@@ -178,7 +178,7 @@ void Intro::pickDataDirectory()
             }
             dataDir = intro.getDataDirectory();
             try {
-                fs::create_directory(GUIUtil::qstringToBoostPath(dataDir));
+                TryCreateDirectory(GUIUtil::qstringToBoostPath(dataDir));
                 break;
             } catch(fs::filesystem_error &e) {
                 QMessageBox::critical(0, tr("Bitcoin"),

src/util.cpp

@@ -976,7 +976,7 @@ boost::filesystem::path GetDefaultDataDir()
 #ifdef MAC_OSX
     // Mac
     pathRet /= "Library/Application Support";
-    fs::create_directory(pathRet);
+    TryCreateDirectory(pathRet);
     return pathRet / "Bitcoin";
 #else
     // Unix
@@ -1090,6 +1090,23 @@ bool RenameOver(boost::filesystem::path src, boost::filesystem::path dest)
 #endif /* WIN32 */
 }
 
+
+// Ignores exceptions thrown by boost's create_directory if the requested directory exists.
+//   Specifically handles case where path p exists, but it wasn't possible for the user to write to the parent directory.
+bool TryCreateDirectory(const boost::filesystem::path& p)
+{
+    try
+    {
+        return boost::filesystem::create_directory(p);
+    } catch (boost::filesystem::filesystem_error) {
+        if (!boost::filesystem::exists(p) || !boost::filesystem::is_directory(p))
+            throw;
+    }
+
+    // create_directory didn't create the directory, it had to have existed already
+    return false;
+}
+
 void FileCommit(FILE *fileout)
 {
     fflush(fileout); // harmless if redundantly called

src/util.h

@@ -189,6 +189,7 @@ bool TruncateFile(FILE *file, unsigned int length);
 int RaiseFileDescriptorLimit(int nMinFD);
 void AllocateFileRange(FILE *file, unsigned int offset, unsigned int length);
 bool RenameOver(boost::filesystem::path src, boost::filesystem::path dest);
+bool TryCreateDirectory(const boost::filesystem::path& p);
 boost::filesystem::path GetDefaultDataDir();
 const boost::filesystem::path &GetDataDir(bool fNetSpecific = true);
 boost::filesystem::path GetConfigFile();