samiandClaude Sonnet 5 5d81b4cdae core: segment/segmenter + segment/budget (stage 6)
vdm/ids.hpp — TaskId, an opaque engine handle (DAEMON keeps the wire
UUID <-> TaskId map; the engine never sees the UUID).

segment/segmenter — per-download range management (docs/04 §3). Initial
lazy split; assign_slot() splits the largest remaining range when the
budget grants a slot; on_complete(may_steal) either *steals* the second
half of the largest remaining range for the same worker (slot-neutral) or
returns nullopt so the caller *yields* the slot (ADR 0011 A1); on_failed()
returns requeue only on the 3rd consecutive connection error with a mirror
present — the remaining range is orphaned and re-split. Non-resumable or
unknown-size => exactly 1 segment; never split below min_segment_bytes
(1 MiB). Resume ctor rebuilds from a persisted table (falls back to a
fresh layout if it doesn't tile [0,total)). One mutex == "the task lock";
segment fields are std::atomic and the store is a std::deque so a steal's
append never moves a worker's record.

segment/budget — the global allocator (ADR 0011). Owns exactly one
ceiling (maxActiveSegments) and min-1-before-seconds fairness: a two-pass
allocation (guarantee pass gives every wanting task 1 slot in DAEMON's
priority order, then a growth pass round-robins the rest up to each
task's effective cap = min(per_task_cap, host cap, 1 if non-resumable)),
recomputed from scratch on every edge so a live set_max_active_segments
cut naturally yields the excess lowest-priority-first, never a
mid-segment kill. DAEMON-facing surface exactly as promised in
daemon/docs/core-requests-m1.md / ADR 0011: budget(), segments_active(),
starved_tasks(), starved_since(), set_max_active_segments (drain),
set_host_segment_cap, set_task_order, on_budget_changed (a jthread
coalesces at <=4 Hz; the tasks_starved 0<->nonzero edge fires
immediately). Callbacks are copied out and run after the lock is
dropped.

Tests: segmenter split/steal/requeue/resume math + a concurrent
steal-and-advance run; budget min-1 under a tight budget, round-robin
growth, host-cap and non-resumable clamps, live-lower shedding
lowest-priority-first, starvation below the task count, starved-edge
notification, and a concurrent set_want hammer. Green under ASan/UBSan;
the steal path and the budget green under TSan.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01HPPSGhiArbvQgwC2DNiURS
2026-09-10 15:14:14 +04:00

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.


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 M0M7, 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.


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.


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.

S
Description
a download manager for ubuntu
Readme
1.4 MiB
Languages
C++ 69.9%
TypeScript 20.5%
Python 6.1%
CMake 1.9%
Shell 1.1%
Other 0.4%