Add CheckDataDirOption() function

Author: hebasto

src/util/system.cpp

@@ -741,8 +741,9 @@ const fs::path &GetDataDir(bool fNetSpecific)
     // this function
     if (!path.empty()) return path;
 
-    if (gArgs.IsArgSet("-datadir")) {
-        path = fs::system_complete(gArgs.GetArg("-datadir", ""));
+    std::string datadir = gArgs.GetArg("-datadir", "");
+    if (!datadir.empty()) {
+        path = fs::system_complete(datadir);
         if (!fs::is_directory(path)) {
             path = "";
             return path;
@@ -761,6 +762,12 @@ const fs::path &GetDataDir(bool fNetSpecific)
     return path;
 }
 
+bool CheckDataDirOption()
+{
+    std::string datadir = gArgs.GetArg("-datadir", "");
+    return datadir.empty() || fs::is_directory(fs::system_complete(datadir));
+}
+
 void ClearDatadirCache()
 {
     LOCK(csPathCached);

src/util/system.h

@@ -83,6 +83,8 @@ fs::path GetDefaultDataDir();
 // The blocks directory is always net specific.
 const fs::path &GetBlocksDir();
 const fs::path &GetDataDir(bool fNetSpecific = true);
+// Return true if -datadir option points to a valid directory or is not specified.
+bool CheckDataDirOption();
 /** Tests only */
 void ClearDatadirCache();
 fs::path GetConfigFile(const std::string& confPath);