File Operation Utilities

The utilities library provides a collection of file and directory manipulation tools for data I/O operations with HOPS4 objects.

MHO_BinaryFileInterface

Class	MHO_BinaryFileInterface
Category	File Operations
Template Parameters	Templated by serializable object types
Configuration Parameters	Optional .index file collection (stores object file keys/offfsets)
Primary Functionality	High-level binary file I/O with object serialization
Key Features	Automatic object key generation and validation Optional .index file creation for faster access UUID-based type/object identification

The MHO_BinaryFileInterface class provides read/write functionality on binary files. These operations handle object serialization, key generation, and optional .index file creation for (later) efficient data access.

MHO_BinaryFileStreamer

Class	MHO_BinaryFileStreamer
Category	File Operations
Template Parameters	Variadic template for supported data types
Primary Functionality	Low-level binary streaming for POD and JSON types
Key Features	Support for POD types, strings, and JSON objects Byte count tracking for written data CBOR encoding for JSON data

The MHO_BinaryFileStreamer class provides low-level binary streaming capabilities with support for plain-old-data types, strings, and JSON objects (using CBOR encoding). It is used by MHO_BinaryFileInterface.

MHO_DirectoryInterface

Class	MHO_DirectoryInterface
Category	File Operations
Primary Functionality	Directory and file system operations
Key Features	Directory traversal and file listing File filtering by extension and prefix Legacy MK4 file format identification Path manipulation utilities

The MHO_DirectoryInterface class provides several directory and file system operations. Primarily it is responsible for directory traversal, file listing, filtering, and identification. Identification of legacy MK4 file formats is alos supported.

MHO_FileStreamer

Class	MHO_FileStreamer
Category	File Operations
Primary Functionality	Base class for file streaming operations
Key Features	Abstract interface for file I/O operations File state management (readable/writable/closed) Buffered I/O (2MB buffer size) Object state tracking for error handling

The MHO_FileStreamer class provides a base interface for file streaming operations with state management and buffered I/O capabilities.

MHO_LockFileHandler

Class	MHO_LockFileHandler
Category	File Operations
Configuration Parameters	Legacy mode support (enabled by default)
Primary Functionality	File locking mechanism for concurrent access control
Key Features	Singleton pattern implementation Legacy type_2xx file naming convention support Signal handling for cleanup on termination Process priority-based lock resolution

The MHO_LockFileHandler class implements a file locking mechanism to prevent concurrent nameing conflicts during write operations. This mechanism supports both legacy (Mk4) and HOPS4 (fringe) file naming conventions.

MHO_FileKey

Class	MHO_FileKey
Category	File Operations
Primary Functionality	Object description and file location
Key Features	64 byte file object key

The MHO_FileKey class stores object type and UUID information, as well as object size and shortname meta-data. For every HOPS4 object serialized to file it precedes the object binary data. This provides a quick indexing method into binary file data, and allows the file I/O mechanism to skip over unrecognized objects.

MHO_Serializable

Class	MHO_Serializable
Category	File Operations
Primary Functionality	Base class for all serializable objects
Key Features	Mechanisms for object version control and identification

The MHO_Serializable class provides an interface required by the file serialization library to read/write objects to disk. It provides a mechanism to identify objects and switch behavior based on object version. Classes which inherit from MHO_Serializable must provide a method to calculate the size (in bytes) of their serialized data.