mdl Directory Reference

Directory dependency graph for mdl:

Directories
	inc
	src

Detailed Description

apps/shared_libs/mdl

The portable core of the comic downloader: everything the product does, with nothing that knows how it was asked to do it. Following a series, the persistent library state, the page cache, the exporters, verification, progress reporting and packing all live here – and so do the site descriptors, because a descriptor is data the core reads rather than anything a particular product owns.

It is written against seams rather than against a host. The network is an injected function-pointer vtable, and storage and streams have the same shape, so the code that follows a series on a laptop is the code that follows one on the board. Only the leaf backend changes.

Why it is not inside the product

A form is a way of running the core. The host command line under apps/host/mdl is one; a loadable on-device module is the second. A core that lived inside one form would have to be reached out of the other by relative path, which is how a shared dependency turns into a copy – and two copies of a downloader are two downloaders that drift.

So the layering is a directory rule, and it is one-way: nothing under apps/shared_libs may include from apps/host, apps/board/stand_alone, or apps/board/threadx_modules. The proof is mechanical rather than a promise. This directory configures, builds and runs its own test suite on its own, with no host HTTP library named anywhere in its listfile, so a dependency belonging to a form cannot reach in without that standalone build failing.

What is deliberately absent

No main(), no argument parsing, no usage text, no host transport. A file here that named a host HTTP library, or knew that a command-line flag existed, would be a form's file sitting in the core's directory. Where the core needs a decision only a form can make, it takes it as an argument or through a seam – that is the whole of the arrangement, and it is what lets the same bytes run in both places.

The device-side transport does live here, because every form that runs on the board shares it; it is the host half that belongs to the host form.