QDirFilters

QDirFilters is a modular filtering system designed for Qt-based applications to refine directory listings. It provides a programmable set of rules to include or exclude files and subdirectories when enumerating a directory, improving accuracy and performance for file managers, search tools, and batch processors.

The component is designed to work with Qt's standard directory APIs such as QDir and QDirIterator. It defines a FilterSet that aggregates multiple filter rules and a common interface Filter that can be implemented by concrete filters such as NamePatternFilter, ExtensionFilter, SizeFilter, DateModifiedFilter, TypeFilter, and AttributeFilter. Filters can be combined with logical operators and can be configured to be case-sensitive or not. The system supports glob patterns, regular expressions, and native Qt string matching. It can include or exclude hidden files and optionally honor dot entries like . and ...

Performance and integration are central goals. Filters can be evaluated during directory iteration to minimize unnecessary I/O, and caching can be employed for repeated queries. The API is designed to be lightweight and compatible with Qt’s event-driven paradigm, supporting straightforward integration with models and views that present directory content.

Usage typically involves constructing a FilterSet, adding one or more filters (for example, a name pattern to include only .txt files and an exclusion rule for temporary files), and applying the set to a QDir or QDirIterator-based workflow. Changes to filter configuration can be propagated through Qt’s signals and slots to update UI components in real time.

See also: QDir, QDirIterator, and Qt’s file system model abstractions.