Files
vdm/core/include/vdm/README.md
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samiandClaude Sonnet 5 d6cf1fe7dc core: post the engine API for DAEMON review (pre-stage-7)
The download entry point the AGENT-CORE brief asked for on day one and
that slipped. DAEMON has an RPC surface and a store and, until this is
agreed, nothing in velox::core to call.

vdm/task/download.hpp — DownloadSpec (the resolved subset DAEMON hands in:
absolute save_path, verbatim browser headers, requested segments/buffer,
optional probe_hint / checksum / auth, allow_resume), EngineState (the
CORE-owned subset of the wire TaskState), Progress / SegmentProgress,
DownloadCallbacks (on_progress <=4 Hz, on_state for every transition
incl. auto-pauses, on_auth_required, on_decision_needed, on_finished
last), DownloadHandle (pause/resume/cancel — idempotent per the ADR 0013
signature — plus provide_auth / decide / refresh_url, and synchronous
state()/progress() snapshots).

vdm/engine.hpp — Engine: start(spec, callbacks) -> handle, segment_budget()
(DAEMON's sched/ admission surface, ADR 0011), live connection.* setters,
a standalone probe() on the pool outside the segment budget.

core/docs/engine-api-m1.md — the review doc: field semantics, the state
machine, threading/lifetime rules (which thread callbacks arrive on, what
is legal from inside one, handle/engine lifetime), the shared-`paused`
idempotency contract as a signature, and five open questions for DAEMON.

Value types compile and are covered by api_compiles_test; Engine /
DownloadHandle bodies land in stage 8, built against whatever DAEMON
signs off here.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01HPPSGhiArbvQgwC2DNiURS
2026-09-10 15:39:25 +04:00

3.8 KiB

libveloxcore — public API

Status: M1 in progress. util/, net/ (http_client, probe, url, content_disposition), io/ (sparse_file, write_buffer), meta/veloxpart, and segment/ (segmenter, budget) are landed. The download entry pointvdm::Engine, vdm::task::DownloadSpec / DownloadHandle / DownloadCallbacks — is sketched in vdm/engine.hpp and vdm/task/download.hpp and out for DAEMON review: see core/docs/engine-api-m1.md. Bodies land in CORE stage 8; build against the value types now.

Layering (CLAUDE.md §3): this library knows nothing about JSON, SQL, Qt, or RPC. Input is a spec value; output is bytes on disk plus typed callbacks. DAEMON projects engine state onto the wire contract's TaskSummary / TaskDetail / events — see core/docs/proto-requests-m1.md for the shapes that projection needs frozen.

Every header under core/include/vdm/ compiles standalone (-Wall -Wextra -Wpedantic -Werror, C++23). Clean under ASan/UBSan and TSan.


util/ — foundations

vdm/util/error.hpp

enum class Error — the engine-wide failure taxonomy (network / HTTP / content / local I/O / metadata / probe / retry / internal). This is CORE's own vocabulary; it is not a wire type. error_name(Error) gives a stable snake_case string; is_retryable(Error) is the advisory retry hint the task policy consults.

struct ErrorInfo { Error code; std::string context; int http_status; bool retryable; Error cause; } — the payload carried by every failed Result. .to_string() renders "<name>: <context> (HTTP <n>)".

vdm/util/result.hpp

Result<T> — return-based error channel, a thin wrapper over std::expected<T, ErrorInfo>. Errors are returned, never thrown, on anything that runs during a transfer.

  • Result<int> r = 42; / Result<int> r = Err{Error::timeout, "..."}; / Result<T> r = Error::not_found;
  • r.has_value(), explicit operator bool, r.value() / *r / r->, r.error(), r.code(), r.value_or(x)
  • monadic and_then / transform / transform_error (forward to std::expected)
  • Result<void> specialization; vdm::ok() success sentinel
  • VDM_TRY(expr) — return the error if expr failed
  • VDM_TRY_ASSIGN(auto x, expr) — bind the value or return the error

vdm/util/bytes.hpp

Byte / ByteSpan / ConstByteSpan aliases; as_bytes(string_view) / as_chars(span). Little-endian fixed-width codec load_le<T> / store_le<T> and a bounds-checked sequential ByteReader (.u8/.u16/.u32/.u64, .raw(n), .lp_string(), .overran()). Built for the .veloxpart.meta reader and the 4-byte NM framing; every read is bounds-checked and latches on overrun (reader-first, fuzz-ready).

vdm/util/event_bus.hpp

EventBus — typed, thread-safe in-process pub/sub. subscribe<E>(fn) -> Token, publish<E>(ev) (synchronous, calling thread, registration order), unsubscribe(Token), and RAII subscribe_scoped<E> returning a Subscription. Handlers may (un)subscribe or publish during dispatch. Handlers must not throw. Not a hot-path structure — progress is coalesced to ≤4 Hz upstream.

vdm/util/thread_pool.hpp

ThreadPool — fixed-size std::jthread pool for bounded off-loop work (hashing, fsync batches, DNS pre-resolve). submit(fn, args...) -> std::future<R>; propagates exceptions through the future; drains already-queued tasks on destruction. Not the transfer loop — net/ will own one curl_multi per dedicated worker.

vdm/util/log.hpp

Sink interface — core does no I/O itself. LogSink abstract base; DAEMON installs one via set_log_sink(), default discards. CallbackSink adapter (with a min-level filter). VDM_LOG_{TRACE,DEBUG,INFO,WARN,ERROR}(category, fmt, args...)std::format syntax, only formatted when a sink is installed and wants the level.