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🖥️ Terminal (executable) ​

The terminal executable provides a graphical terminal window exposed as a character device and uses it to host the command-line shell.

Role ​

  • Bridges GUI events and text I/O semantics through a mounted /devices/terminal device.
  • Launches /binaries/command_line_shell with terminal-backed stdin/stdout/stderr.

Startup and lifecycle ​

  1. Creates Terminal UI object (window, label display, text input).
  2. Mounts terminal object as /devices/terminal character device.
  3. Opens Standard streams on that path.
  4. Executes command-line shell executable.
  5. Runs event loop until terminal window close/delete event.

Runtime integration points ​

  • virtual_file_system::mount_static for runtime device registration.
  • xila::executable::execute to start command-line shell child process.
  • graphics and LVGL for window/input rendering.
  • shared::utf8_chunks for buffered output write handling.

Data and control flow / VFS touchpoints ​

  • Write path: shell output -> /devices/terminal -> DirectBaseOperations::write -> UI display append.
  • Read path: UI enter key -> validated input queue -> /devices/terminal read by shell.
  • Control flow: parent terminal loop keeps processing events while child shell uses same device streams.

Concurrency and event-loop model ​

  • Terminal executable runs a periodic loop with sleep(20 ms) while polling handle_events.
  • Device read/write paths use lock-protected terminal inner state (RwLock<CriticalSectionRawMutex, Inner>).

Failure semantics ​

  • Device mount/open/execute failures return executable error and are logged + printed.
  • Resource contention on terminal locks maps to RessourceBusy / file_system::Error::RessourceBusy.

Contract vs implementation ​

  • Contract: terminal executable exposes a character-device-backed text console and runs shell inside it.
  • Current implementation: LVGL window + textarea, mounted static device node /devices/terminal, and shell child execution via executable runtime.

Operational limitations ​

  • Input is newline-validated; no advanced terminal emulation (PTY, ANSI parser state machine) is implemented here.
  • UI/event loop cadence is fixed and may affect responsiveness under heavy output.

References ​