Dario Gabriel LipicarandClaude Opus 5
7f75f69fda
A module can now learn which module is calling it. Not via the LIDL — this
is not part of any module's interface, and the callee already has the
identity from the token the call carried; the only question was surfacing
it. So it is ambient: logos::currentCaller(), no declared parameter, no
contract change, no per-method opt-in.
WHAT THIS PR CONTAINS
* LogosCaller — Unknown | HostAnchor | Module{name, instance?} |
Derived{parent, leaf} | Operator{name} — std-typed and Qt-free.
* CallerScope, an RAII save/restore around a thread-local STACK. Not a
slot: A calling B calling back into A on one thread must nest, and an
exception thrown from a handler must still pop.
* resolveCaller, replacing the bool fold in ModuleProxy. It reads the
INBOUND store #69 made direction-pure — the only store that may
legitimately name a caller.
* logos_module_set_call_caller DECLARED, and MINOR 5 -> 6.
WHY AMBIENT, AND WHY IT MUST CROSS AN IMAGE BOUNDARY
LogosProviderObject::callMethod is a vtable slot, and this codebase avoids
vtable changes on purpose. But the deeper reason is measured, not stylistic:
nm on real binaries shows the host and the module plugin EACH define
ModuleProxy::callRemoteMethod and TokenManager::instance, each with its own
function-local static at a distinct address, and neither with a single
undefined reference to the other's. Mach-O is TWOLEVEL; PE has no
interposition. A thread_local opened host-side is NOT the one a handler
reads. Since --backend qt is now refused outright, every module is a cdylib
and the C ABI push is the only path, not a fallback.
The pull is only safe through QMetaObject::invokeMethod on the host's
LogosAPI, because metaObject()/qt_metacall are virtual and the vptr was
written by the host's constructor — LogosAPI is duplicated across images
too, meta-object included, so a direct call would bind to the plugin's copy
and read the plugin's TLS, silently empty forever. A dynamic property
cannot carry it either: one process-global slot, so two overlapping
concurrency:"multi" calls from different callers would clobber each other.
Nothing here is spelled "verified". capability_module checks only that an
asserted name EXISTS as a key, so the strongest honest word is token-bound.
HostAnchor carries no name because core and capability_module hold one
token VALUE under two keys by construction. Unknown is the fail-closed
value and is always in-band, never spelled by absence.
The constant-time fold survives: the matched key is accumulated into a
fixed-width buffer with no data-dependent branch, verified at the
instruction level (csel, not a branch) with the comparison count invariant.
THE BUMP IS SAFE BECAUSE THE BACKENDS WENT FIRST
logos-protocol only DECLARES this ABI; every backend owes the definition,
and that gap shipped twice. logos-cpp-sdk#147 and logos-rust-sdk#47 already
define logos_module_set_call_caller, gated on >= 0.6 and therefore inert
until this lands. Verified on x86_64-linux: with this tree as the protocol,
BOTH backends at master pass their ABI checks and define the export;
manifest reports 0.6.0 with 11 exports. No repo is red at any point.
Rule 6 is now normative on a point the two backends had silently diverged
on — a present-but-unreadable "instance" is dropped and the module still
identified — each having pinned its own answer with a passing test.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
logos-protocol
The Logos protocol layer: transports, token exchange, and the
language-neutral lp_* C ABI (cpp/logos_protocol.h) that every Logos
SDK builds on.
Extracted from logos-cpp-sdk so that non-C++ SDKs (Rust, …) consume the
same transports, capability/token flow and wire behavior through one stable,
versioned boundary instead of re-wrapping the C++/Qt SDK.
What lives here
- Public C ABI —
cpp/logos_protocol.h: consumer surface (lp_client_*,lp_invoke[_async],lp_subscribe, tokens,lp_get_methods), provider groundwork (lp_provider_*), the trust-root surface (lp_grant_host_servicesand the two functions it gates), per-identity token stores (lp_token_isolate_identity,lp_token_get_for,lp_token_save_for,lp_token_reset_identity,lp_token_identity_is_isolated), and the protocol version (LOGOS_PROTOCOL_VERSION_*,lp_protocol_version(),lp_protocol_abi_major()). JSON-in-strings data model; bytes cross the boundary as{"_bytes":"<base64url>"}(lossless, NUL-safe). - Transports — plain TCP / TCP+TLS (Boost.Asio + OpenSSL + nlohmann,
Qt-free),
qt_local, in-memory mock, and Qt Remote Objects (qt_remote— the only Qt-bearing transport). - Consumer core —
LogosAPIClient/LogosAPIConsumerincluding the automaticcapability_module.requestModuletoken-fetch flow (behind the protocol boundary: every language gets it for free). - Provider-side plumbing —
ModuleProxy(auth gate the transports publish) and the abstractLogosProviderObjectinterface (logos_provider_interface.h). - Token manager, transport/registry factories, mode config (remote/local/mock), and the canonical QVariant↔JSON conversion used at the QRO boundary.
Per-identity token stores
TokenManager::instance() is the image's store. In a host that loads
several modules in one image it is also an ambient ring: the host writes
name -> that module's root auth token for every module it loads, and a client
presents a cached token before it ever mints one — so any module in that image
can reach any other with authority it was never granted, and no requestModule
appears in the log. Per-module origin strings do not change that, because
origin was never consulted on the path taken.
TokenManager::forIdentity(origin) makes origin select the store instead of
merely labelling the caller, and isolateIdentity(origin) is how a host opts a
name in (lp_token_isolate_identity and friends from C). Both are additive and
inert by default: until a name is isolated, forIdentity() returns the same
object instance() returns, so a host that knows nothing about this is
unchanged. A private store is seeded with the trust-root bootstrap (core,
capability_module) so first-call requestModule still works, and with nothing
else.
This is a second axis, not a replacement for the per-image split: a module
cdylib links its own copy of this library and therefore has its own
instance(), which stays correct as-is.
logos-cpp-sdk layers the typed C++ developer API (LogosAPI, module
context, code generator, provider base classes) on top of this repo.
Versioning
This repo carries the logos-protocol semver — the single number that governs Logos load/call compatibility. Two participants (modules, hosts, SDKs in any language) interoperate iff they share the same MAJOR. MINOR is additive/back-compatible; PATCH never affects compatibility. SDKs must re-expose the version of the protocol they linked (never mint their own).
Building
# Via workspace
ws build logos-protocol
# Standalone
nix build
# Tests
nix build .#tests
Layering invariant
logos-protocol depends only on Qt / Boost / OpenSSL / nlohmann_json — it
must NEVER depend on logos-cpp-sdk, logos-qt-sdk, logos-rust-sdk, liblogos
or logos-lidl. Everything points inward.