- EGLSurfaceRegistry owns the display, the surface records, the active surface, each thread's binding and the one recursive lock; BackendObject holds one and is its hooks, so the EGL virtuals keep their signatures and their defaults
- the backends reach it through EGLRegistry(): lookups return copies, and the steps they compose (adopting an already-bound surface, a window's surfaces, a window's new extent) are named operations instead of writes to protected fields
- WindowBackend and WindowHandle move with it
- BackendObjectEglStateTest only re-points its accessors; the same 235 mutants, carried over, get the same verdicts except three that need a kind-None record, which no call can make, and one that cannot be written against the registry
- comments that cited BackendObject.cpp line numbers name the function
Breaks the one process = one server = one session = one context equation
that the whole stack's correctness used to rest on. Design and per-slice
shape: docs/Disaggregated/design/11-state-ownership.md.
S1 wire: bind_context ring record (opcode 84) announces the current
context at the make-current edge; CreateContext/DestroyContext join the
SurfaceOp control frames; control revision 5 -> 6; the server keeps a
per-session token table and refuses unknown tokens by name.
S2 server: SessionRuntime per session with thread-scoped resolution
(singletons become fallbacks), per-thread gPipeInputs, per-session latch
domains, per-thread segment resolvers; the in-process unix supervisor
serves up to MOBILEGL_IPC_INPROC_MAX_SESSIONS (16) concurrent sessions;
surface mode is declared per session and the display lease refuses a
second on-screen session by name.
S3 frontend: ShareGroupState owns the shared object stores and name
generators (buffer/texture/renderbuffer/sampler/program), GLContext keeps
per-context bindings/errors/container objects; pGLContext becomes
thread-local with a process default context preserving the single-context
world verbatim; eglCreateContext builds a real GLContext and joins the
sharing context's group.
S4 backend: native EGL tuples keyed by (session, context token);
InitDisplayAndContext's unconditional teardown is gone - creating a
second context or surface no longer destroys the first; eglCreateContext
sharing is wired to the native driver; bind_context is the native switch
point.
S5 applier: MGPipeApplierState splits into MGPipeObjectRecords (per
share group) and MGPipeWorkingState (per context), resolved through a
{session, token} registry with a thread-local cached fast path.
Tests: MultiSessionTest (incl. two sessions x two contexts interleaved
with real clear/readback witnesses), ApplierOwnershipTest (with a
null-resolver negative control), ContextStateOwnershipTest,
ServerLoopEglTest native-context liveness; 99/99 of the acceptance set
green on the host build.
Known debts (documented in the design doc): twin registries still keyed
by handle alone, no per-record ContextSlot, process-global backend
generations, MakeCurrent dedup per current binding.
Step two of CONTRACT-P6 5.2. The ~90 scattered `MGLOG_F("...Fatal{...}"); std::abort();`
pairs under MG_Remote/ become one call each to SessionFail(MGFatalFamily, fmt, ...),
which logs, echoes to stderr, counts, and aborts in one place. a6's census
found no single chokepoint existed; now there is one, and step three hangs the
SessionFault-to-peer publish off it.
THE MESSAGE STRING IS PASSED VERBATIM. The contract requires the log lines, the
CI greps and every red-once byte-identical, so SessionFail does not compose the
line from the family - it takes the SAME string the site handed MGLOG_F and
forwards it unchanged. The family enum rides alongside, redundantly, so the
funnel has the coarse wire FatalCode without parsing the string. The census now
checks that redundancy the way it checks WireLogFatal: every SessionFail call's
string must carry a Fatal{ word, so the enum and the string cannot silently
disagree.
The conversion was mechanical - 89 sites by a transform that injects the family
as MGLOG_F's new first argument and drops the trailing abort - with three sites
fixed by hand that the transform would have broken: a stub macro, and two
if/else-then-shared-abort blocks (PersistentMapTracker's adopt-tier and
SurfaceOpCodec's three surface-error branches) where a naive rewrite stole the
abort from the earlier branches and would have let them fall through. The
death tests are the safety net for byte-identity, and every one stayed green.
Four std::abort() remain under MG_Remote/, all inside the two funnels
(WireLog.cpp, FatalFunnel.cpp); the census exempts both files because their
callers carry the family word, and its baseline drops from 93 aborts to 4.
SessionFaultCount() is the one telemetry point S8 will assert zero over a good
run.
G1 re-measured: 0 symbol diff, .text unchanged at 0xa52203 (FatalFunnel and
FatalFamily live under MG_Remote/, compiled only in the disaggregated build).
Unit 2358 (one pre-existing environmental failure), integration-split 186/186,
integration-spawn 102/102, retrace 6/6, census 0 unmarked.
OpenRA.DirectGLES.SPAWN is green: ssim=1.000000, mismatchPixels=0, zero
Fatal{ lines, against a server in a process the client started by name. The
inproc SPLIT arm stays beside it as the control, so "did the transport break
it" and "did the phase break it" remain separately answerable.
Five defects stood between the handshake and that picture. Each one was
silent in its own way, and none of them looked like what it was.
1. THE DOORBELL COULD NOT WAKE ITSELF. SocketDoorbell's one-fd form sends on
the end it polls, so a write is delivered to the PEER - correct for waking
the other process, useless for waking a thread in this one. The server's
control pump posts into the apply thread's mailbox and must ring the bell
that thread parks on. Symptom: every eglInitialize crossed, landed in the
mailbox, and timed out at 5 s. The two-fd form (park on [0], notify on [1])
is restored here, and the bell handover goes from two descriptors to THREE
- the client needs the same split for the same reason. Seven offers now.
2. InitCapabilities HAD NO WIRE KIND. CONTRACT-P6 §2 predicted this exactly
("the request has a live client caller and the codec refuses to encode
it"). SurfaceOpKind gains 11, append-only; the decode range's upper bound
moves with it, or the new tag reads as out-of-range and surfaces as
Fatal{ProtocolCorruption} rather than the missing row it is. The op's name
loses its InprocOnly suffix, which stopped being true here.
3. THE CHILD LOADED NO CONFIG AT ALL. mobilegl_server_main calls
InitServerRoleForSpawn directly, and MG_ConfigLoader::Init is a step of
MobileGL::Initialize - so every MG_Config value in the server was its
static default. MOBILEGL_BACKEND_TYPE survives the launcher's scrub on
purpose and was read by nobody: a DirectVulkan session would have brought
up a DirectGLES server and then disagreed with its client about which
backend the capability mask describes.
4. AND THEREFORE Transport READ AS Monolith, which CONTRACT-P6 §3.1 (D1)
forbids in as many words. a6 measured the cost: 226 live lines test
`Transport != Monolith` to select the SERVER arm, 148 in MG_Backend.
Monolith flips all of them to frontend glue in the one process with no
frontend. Observed precisely as predicted - UnitTexturesByHandle() answered
false, Clear took the legacy arm that dereferences borrowed FRONTEND slot
pointers, and the apply thread took a SIGSEGV inside SyncNeccessaryTextures
on the first Clear record of the trace. It is pinned in-process rather than
through the environment because the environment is where it must NOT be:
LooksLikeAClientEnvironment exits 65 on a surviving MOBILEGL_TRANSPORT, and
that check is anti-recursion catch (b). Dial, not Transport, is that axis.
5. THE LOG WAS CORRUPT, NOT MERELY INTERLEAVED. Two processes opened the same
MOBILEGL_LOG_FILE_PATH with "w" and each carried its OWN file offset, so
they overwrote each other's bytes - half-lines like `ote client: CapsMirror
generation 1 adopted`, and the server's whole startup block vanishing under
the client's later writes. This cost real diagnosis time twice, because a
missing line read as a code path not taken. O_APPEND now; the client still
truncates once so a fresh run is not a pile of old ones, and the server
never does - it would delete the very startup lines a failed session needs.
run_trace_case.cmake's Fatal{ census reads exactly this file, so it was
also reading a lie.
The retrace runner's split assertions become transport-aware: one row per
transport it admits, and a transport with no row is a FATAL rather than a
fall-through, because the fall-through is the accident the block exists to
prevent. The spawn row carries a SECOND sentence and it is the stronger half
- ConfigLoader's marker proves the value RESOLVED, while `spawn ARMED - the
server role runs in pid N` is written only after the launch, the connect and
the handshake all succeeded, and carries a pid that is not this process's.
inproc resolves its own marker while running the server role on a thread
here; nothing on that path can write this one.
G14: one test name added (TheEleventhFramedOpIsInitCapabilitiesAndItCrosses-
TheWire), none removed. The ten-op table keeps its name and its scope rather
than being renamed to eleven.
Two unit failures predate this change and are environmental in this tree:
PipeCatalogue.FrontendNeverTakesAnApplierAddress (the frontend source root
resolves empty) and SessionHandshakeTest.TheAbiFingerprintChangesWhenAnyOf-
ItsInputsDoes (GIT_COMMIT_HASH_SHORT is empty here, which a6 already recorded
as red in this configuration).
The twelve Server* forwarders' one-slot mailbox carried a raw function
pointer plus a void* to a stack-local Args struct (P5c audit row G4);
neither means anything across a process boundary. The slot now carries
one SurfaceControlFrame by value: kind is the op, scalars are the
arguments, and ok/eglMajor/eglMinor come back in the same value. The
blocking handshake, the shadow, the doorbell order and the C2 exit
block are unchanged.
- protocol.fbs: append-only - SurfaceOpKind gains SetSwapInterval=8,
ReleaseResources=9, SetWindowHandle=10; WindowKind gains MetalLayer=6;
SurfaceOp gains readSurface and context (the MakeCurrent four-tuple).
protocol_generated.h regenerated with the pinned flatc.
- Server/SurfaceControlFrame.{h,cpp}: the frame (trivially copyable by
static_assert) and the op enum - ten wire kinds plus four inproc-only
kinds (InitCapabilities is answered by CapsSnapshot on the wire,
SwapBuffers/InitWindowSurface have no production caller - f0-egl F8,
kept for the inproc test lane).
- Protocol/SurfaceOpCodec.{h,cpp}: the frame <-> SurfaceOp/SurfaceReply
codec, the explicit WindowBackend <-> WindowKind table, and the wire
entry ServerApplyWireSurfaceOp whose refusals are named:
Fatal{UnmigratedSurface, "AndroidNativeWindow@P12"} and
Fatal{ProtocolCorruption, "SurfaceOp"}.
- ServerLoop: RunOnApplyThread(fn, void*) -> RunSurfaceControlFrame(frame)
plus the dispatch ApplySurfaceControlFrame; the old per-forwarder Args
bodies moved into the dispatch unchanged (C7/ID-54, N-3, R-12 included).
RunProbeOnApplyThreadForTesting is the test seam through the same
channel (the hook lives in a member, never in the slot).
- Tests: RemoteClientTest/ServerLoopTest migrated to the probe seam; new
SurfaceControlFrameTest suite (mapping tables, wire round-trips, the
two named refusals) plus ServerLoopTest's AVoidForwarderCrossesAsOne-
DispatchedFrame (the frame channel's red-once handle) and
ServerLoopEglTest's TheInitializeDisplayReplyArrivesThroughTheFrame.
swung0x48