change get_special_folder for consistency & safety

third-party/rsutils/src/special-folder.cpp

@@ -23,41 +23,43 @@ namespace rsutils {
 namespace os {
 
 
-std::string get_folder_path( special_folder f )
+std::string get_special_folder( special_folder f )
 {
     std::string res;
+
 #ifdef _WIN32
 
 
     if( f == special_folder::temp_folder )
     {
-        TCHAR buf[MAX_PATH];
-        if( GetTempPath( MAX_PATH, buf ) != 0 )
-        {
-            char str[1024];
-            wcstombs( str, buf, 1023 );
-            res = str;
-        }
+        char buf[MAX_PATH+2];  // "The maximum possible return value is MAX_PATH+1"
+        auto len = GetTempPathA( sizeof( buf ), buf );  // "return the length of the string, not including the terminating null character"
+        if( len > 0 )  // zero on failure
+            res.assign( buf, len );
+        else
+            throw std::runtime_error( "failed to get temp folder" );
+    }
+    else if( f == special_folder::user_documents )
+    {
+        // The user's Documents folder location may get overridden, as we know OneDrive does in certain
+        // circumstances. In such cases, the new function, SHGetKnownFolderPath, does not always return the new
+        // path, while the deprecated function does.
+        CHAR path[MAX_PATH];
+        CHECK_HR( SHGetFolderPathA( NULL, CSIDL_PERSONAL, NULL, 0, path ) );
+        res = path;
+        res += "\\";
     }
     else
     {
         GUID folder;
-        HRESULT hr;
         switch( f )
         {
         case special_folder::user_desktop:
             folder = FOLDERID_Desktop;
             break;
         case special_folder::user_documents:
             folder = FOLDERID_Documents;
-            // The user's Documents folder location may get overridden, as we know OneDrive does in certain
-            // circumstances. In such cases, the new function, SHGetKnownFolderPath, does not always return the new
-            // path, while the deprecated function does.
-            CHAR path[MAX_PATH];
-            CHECK_HR( SHGetFolderPathA( NULL, CSIDL_PERSONAL, NULL, 0, path ) );
-            res = path;
-            res += "\\";
-            return res;
+            break;
         case special_folder::user_pictures:
             folder = FOLDERID_Pictures;
             break;
@@ -68,29 +70,26 @@ std::string get_folder_path( special_folder f )
             folder = FOLDERID_RoamingAppData;
             break;
         default:
-            throw std::invalid_argument( std::string( "Value of f (" ) + std::to_string( (int)f )
-                                         + std::string( ") is not supported" ) );
+            throw std::invalid_argument( "special_folder value (" + std::to_string( (int)f ) + ") is not supported" );
         }
 
-        PWSTR folder_path = NULL;
-        hr = SHGetKnownFolderPath( folder, KF_FLAG_DEFAULT_PATH, NULL, &folder_path );
-        if( SUCCEEDED( hr ) )
-        {
-            char str[1024];
-            wcstombs( str, folder_path, 1023 );
-            CoTaskMemFree( folder_path );
-            res = str;
-            res += "\\";
-        }
-        else
-        {
-            throw std::runtime_error( "Failed to get requested special folder" );
-        }
+        PWSTR path = NULL;
+        HRESULT hr = SHGetKnownFolderPath( folder, KF_FLAG_DEFAULT_PATH, NULL, &path );
+        CHECK_HR_STR( "SHGetKnownFolderPath", hr );  // throws runtime_error
+        char str[1024];
+        size_t len;
+        auto error = wcstombs_s( &len, str, path, 1023 );
+        CoTaskMemFree( path );
+        if( error )
+            throw std::runtime_error( "failed to convert special folder: errno=" + std::to_string( error ) );
+        res = str;
+        res += "\\";
     }
 
 
-#endif  //_WIN32
-#if defined __linux__ || defined __APPLE__
+#elif defined __linux__ || defined __APPLE__
+
+
     if( f == special_folder::temp_folder )
     {
         const char * tmp_dir = getenv( "TMPDIR" );
@@ -102,7 +101,10 @@ std::string get_folder_path( special_folder f )
         if( ! home_dir )
         {
             struct passwd * pw = getpwuid( getuid() );
-            home_dir = ( pw && pw->pw_dir ) ? pw->pw_dir : "";
+            if( pw && pw->pw_dir )
+                home_dir = pw->pw_dir;
+            else
+                throw std::runtime_error( "failed to get special folder " + std::to_string( (int)f ) );
         }
         if( home_dir )
         {
@@ -125,8 +127,7 @@ std::string get_folder_path( special_folder f )
                 res += "/.";
                 break;
             default:
-                throw std::invalid_argument( std::string( "Value of f (" ) + std::to_string( (int)f )
-                                             + std::string( ") is not supported" ) );
+                throw std::invalid_argument( "special_folder value (" + std::to_string( (int) f ) + ") is not supported" );
             }
         }
     }