Velox Download Manager (VDM)

An IDM-class download manager for Ubuntu 26.04 LTS: multi-segment accelerated HTTP(S) downloading, resume, categories and automatic file distribution, queues and scheduler, speed limiter, a Firefox extension that captures downloads automatically, and clipboard link capture.

Name is a placeholder. Binaries are veloxd, velox-gui, velox, velox-nmhost. Rename before first release if you want something else — do it in M0, never later.

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Status

Phase M0 — scaffolding. No implementation code exists yet. This repository currently contains the architecture, the wire contract, the roadmap, and one brief per build lane so that several agents can work in parallel without colliding.

Start here:

Document	What it answers
docs/01-architecture.md	Process model, why four binaries, framework choices and why
docs/02-roadmap.md	Milestones M0–M7, what runs in parallel, exit gates
docs/03-gui-spec.md	IDM-parity UI: every window, dialog, column, menu
docs/04-engine-design.md	Segmentation, resume, buffers, rate limiting, disk I/O
docs/05-extension-spec.md	Firefox capture, transports, pairing, media grabber
docs/06-risks-and-spikes.md	Snap Firefox, Wayland clipboard, and the other landmines
docs/07-packaging.md	.deb/PPA, Flatpak, AMO signing, install layout
contracts/README.md	The interface. Both sides build against this
CLAUDE.md	Rules of engagement for agents working in this repo

Per-lane briefs live in docs/agents/ — one per agent, each with an owned directory list, a definition of done, and the files it must never touch. To dispatch the agents, use docs/agents/PROMPTS.md — six copy-paste prompts plus the worktree commands and the wave order.

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Architecture in one picture

  ┌────────────────────┐   native messaging (stdio JSON)   ┌──────────────┐
  │  Firefox extension │◄─────────────  or  ──────────────►│ velox-nmhost │
  │       (MV3, TS)    │   loopback WS 127.0.0.1 + token   └──────┬───────┘
  └────────────────────┘                                          │
                                                                  │
  ┌────────────────────┐                                          ▼
  │  velox-gui (Qt 6)  │◄──── JSON-RPC 2.0 over Unix socket ──► ┌─────────────┐
  └────────────────────┘      $XDG_RUNTIME_DIR/velox/velox.sock │   veloxd    │
                                                                │  (daemon)   │
  ┌────────────────────┐                                        │             │
  │   velox (CLI)      │◄───────────────────────────────────────┤ libveloxcore│
  └────────────────────┘                                        └──────┬──────┘
                                                                       │
                                                              SQLite + sparse files

The daemon owns all state and all sockets. The GUI is a view — closing it does not stop a download. The extension never touches the disk; it hands URL + headers + cookies to the daemon and gets a task id back.

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Repository layout

vdm/
├── contracts/          ⭐ Wire contract: JSON Schema, fixtures, codegen. Frozen per version.
├── core/               C++23  libveloxcore — engine. No UI, no RPC, no SQL.
├── daemon/             C++23  veloxd — RPC server, scheduler, queues, SQLite store.
├── gui/                C++23  velox-gui — Qt 6 Widgets, IDM-parity UI.
├── cli/                C++23  velox — scriptable client.
├── nmhost/             C++23  velox-nmhost — Firefox native-messaging bridge (thin pipe).
├── extension/          TS     Firefox MV3 WebExtension.
├── tools/
│   ├── mockd/          TS mock daemon — lets GUI + extension work before veloxd exists.
│   ├── testserver/     Deliberately hostile HTTP server (no Range, flaky, redirects, auth).
│   ├── bench/          Throughput and CPU benchmarks.
│   └── fuzz/           libFuzzer targets for parsers.
├── tests/
│   ├── conformance/    Protocol suite. Every lane must pass it. Gate for merging.
│   ├── integration/    veloxd + testserver.
│   └── e2e/            Playwright: real Firefox + real daemon + real file on disk.
├── packaging/          debian/, flatpak/, appimage/, native-host manifests.
└── docs/               Everything above, plus adr/ and agents/.

Toolchain bootstrap

Surveyed on this machine 2026-09-09 — most of it is already installed:

Present	Version
git · cmake · ninja · g++ · gdb	2.53.0 · 4.2.3 · — · 15.2.0 (C++23 ready)
qt6-base-dev · qt6-tools-dev · qt6-tools-dev-tools	✓
libcurl4-openssl-dev · libsqlite3-dev · nlohmann-json3-dev · libssl-dev	✓
libavformat-dev · libavcodec-dev · ffmpeg	✓
clang-format · clang-tidy · python3 · pkg-config	✓
python3-jsonschema · python3-referencing (conformance static runner)	✓

Only these four are missing:

sudo apt update && sudo apt install -y \
  libqt6svg6-dev \    # GUI: SVG icon rendering
  libsecret-1-dev \   # DAEMON: Secret Service for site logins
  nodejs npm \        # EXT + PROTO: extension build, mockd, conformance runner
  clang               # optional: libFuzzer targets in M7

Node in the 26.04 archive may lag; if the extension toolchain needs 22+, use nvm.

Verify with cmake --preset dev && cmake --build --preset dev once lane CORE lands its first target. Note CMake 4.2.3 is installed — newer than the 3.28 floor in CMakeLists.txt, and it hard-errors on cmake_minimum_required below 3.5, so no dependency may ship a pre-3.5 CMake file.