msime-windows/engine/contracts

Product contracts

These headers are independently consumable C++17 contracts. Including them does not link the input engine, start threads, access dictionaries, or require any third-party code. The TSF text service consumes only these headers; the server consumes the same source by linking the engine. Both live in this repository — windows/ and server/ — and so does the engine, so one commit covers all three and there is no pin to keep in step.

windows_ipc.h owns the wire layouts, pipe names and opcodes. voice_composition_pipe.h owns voice framing. uiless_page.h owns the candidate-page payload for UI-less (host-drawn) clients. Consumers may wrap these headers but must not duplicate their definitions.

punctuation/policy.json is the source of truth for the ASCII punctuation keys and their Chinese translations. Its generated policy.h is consumed by the engine and included directly by the hosts that route punctuation keys. Stateful quote alternation and nested book-title marks remain part of the same contract, rather than being re-created in each host.

product_lock.py contains the shared product-lock primitives used by the three platform locks. See product_lock.md for the vendoring and byte-equality rule.

Main handshake

Reverse endpoints retain their 16-byte hello and PipeReady acknowledgement. Once both endpoints are registered, the new client sends the existing 304-byte ClientHello with:

Field	Meaning
keycode	MSIP magic
wch	Major wire protocol version
point[0]	Minor additive version
modifiers_down	Supported capability bits
point[1]	Required capability bits
request_id	Nonzero registration correlation ID

The Server sends ProtocolReady or ProtocolMismatch on the registered reply endpoint before activating the main route. The reply echoes the correlation ID and contains major/minor, negotiated capabilities and magic in the first six UTF-16 units. These packets are consumed only during registration and are never text commits.

Existing DLLs with unversioned hello remain accepted by the new Server using the established v1 semantics; they receive no new opcode. New DLLs require an acknowledgement from the new Server within the existing bounded handshake budget. Against an old or incompatible Server they remain disconnected and use the existing raw-input fallback, rather than interpreting unnegotiated frames. A late acknowledgement from an old registration cannot authorize another one.

Append opcodes; never change released values or reuse them. An incompatible layout needs a new major protocol and an explicit migration, not another copy of a header. Minor additions must be optional capabilities.

CharacterSetShortcut is optional and is not included in the default capability set. Windows implementations that support it pass Capabilities | CharacterSetShortcut to Hello / Negotiate. Only after negotiating this bit may a Chinese-mode client consume Ctrl+Shift+F (no Alt or Windows modifier) and send the existing KeyEvent with keycode F and Shift/Control modifier bits. The server toggles the persisted character set without clearing composition, and refreshes the current candidate page and toolbar. It sends no key reply. Clients suppress auto-repeat and must not replay an ambiguously delivered toggle; older peers simply omit the optional bit.

tests/windows_ipc_contract.cpp executes wire-layout/upgrade/framing cases on all Engine CI platforms and both Windows TSF architectures.

TrilingualCycle is optional. A supporting client advertises its capability and consumes the existing configured language hotkeys only while the Server's TrilingualCycleChanged setting ([keybindings] trilingual_cycle) is enabled. After matching a hotkey through the existing shortcut handler, the client sends a normalized VK_SHIFT whose modifiers_down carries FanyImeTrilingualInput::EncodeCycleRequest(ime_open, japanese): an explicit request bit plus the client's own OPENCLOSE and native-language state. A plain VK_SHIFT is still the binary toggle and is never treated as a cycle, and raw Shift key-down events never request one. The Server computes the destination from the request's state with FanyImeTrilingualInput::Destination; if its setting was turned off while the request was in flight, it still answers, with the binary-toggle destination. The Server retains any already selected word prefix and commits the remaining raw spelling, matching the existing language toggle. It replies with TrilingualCycle: destination (0 Chinese, 1 Japanese, 2 English), a tab separator, and the exact text to commit. The client commits and ends composition before applying the destination compartment in the same edit session. The Server must not also send a worker candidate commit or compartment switch for that key, and leaves the requester out of the InputModeChanged broadcast: the reply is that client's language update. Clients that did not negotiate the capability retain their existing language toggle.

backend/protocol.json 定义 MSIME-Backend 的可选共通 HTTP 服务 API，详见后端协议与兼容性。

Temporary Japanese long vowels

TemporaryJapaneseLongVowel (bit 8) is optional. Only clients that negotiate it receive Worker TemporaryJapanesePolicyChanged (opcode 36). Its payload is one UTF-16 character 0 through 3: bit 0 allows Shift+R for the underlying Chinese scheme (quanpin/shuangpin and utility.r_mode enabled); bit 1 indicates dedicated English candidates. Full Japanese mode retains its existing behavior.

With bit 0 set and bit 1 clear, a composition beginning with uppercase R uses the Japanese minus/equal key policy: ASCII - extends romaji with a long vowel; _, = and + use the existing Japanese punctuation path. The visible R prefix is excluded from engine input. Shared classification is in temporary_japanese_input.h; both normal and deferred TSF classifiers use it. Policy is sent on activation before FocusSessionReady, on Worker registration, and when configuration or dedicated English mode changes. A TIP keeps policy per bound service, clears it on disconnect, and ignores replaced-pipe frames. Older clients and older Servers retain temporary R mode's previous key policy.