Files
oak-editor/crates/oaktimeline/README.md
T
Mike-Solar 013a175707 refactor: workspace layout — crates/, app at root, legacy C++ removed
Single mechanical restructure commit:
- root Cargo.toml = oakapp bin + workspace; one cargo build produces
  oakapp, oak-cli, oak-worker, liboakengine.dylib
- app/rust/src -> src/ (app at repo root, no rust/ nesting)
- src/<mod>/rust -> crates/oak<mod>; src/oakcore-rs -> crates/oakcore;
  src/bindings/oakotio -> crates/oakotio; src/engine/rust ->
  crates/oakengine (keeps cdylib+staticlib+rlib)
- public C headers include/<mod>/ -> crates/oakengine/include/<mod>/
- OFX SDK headers vendored into crates/oakplugin/ofx/ (HostSupport gone)
- legacy deleted: old src/ C++ modules, engine/, core/, ffmpeg_bridge/,
  app/ (Qt), cli/worker C++, root CMakeLists, third_party/KDDockWidgets
  submodule, otio-install, all build-* output (~40GB)
- oakstorage kept but excluded from the workspace (skeleton w/ todos);
  gpui excluded (own workspace)
- verified: cargo build green, cargo test --workspace 1845/0
  (with the documented OCIO_RS_* env override for the homebrew OCIO)
2026-08-10 20:24:25 +08:00

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# oaktimeline Rust crate (declaration draft, for review)
> Status: **declaration draft**. Signatures + doc comments are the
> spec; every body is `todo!()`. Not wired into any build.
> The crate template (FFI discipline, testing layers) follows
> `crates/oakplugin/README.md` and `crates/oaknode/README.md`.
## Scope
Replaces the C++ oaktimeline module (`src/timeline/src`): timeline
markers and work areas, the timeline undo-command family (add/remove
tracks, place/trim/split blocks, ripple edits, slide, gap insertion),
and the shared `Timeline` namespace / utility helpers.
Public contract: `include/timeline/*.h` (`error.h`, `displaymode.h`,
`marker.h`, `workarea.h`, `edit.h`) — frozen, implemented verbatim by
`src/ffi.rs`. The timeline value handles (`OakTimelineMarkerList`,
`OakTimelineWorkArea`) and every edit command are exported through this
ABI only; consumers (the facade/app, the oaknode crate) never see the
internal Rust types.
## Key architectural decisions (C++ → Rust mapping)
1. **Domain modules mirror the C++ header files.** The C++ module is a
flat set of headers, not a deep class hierarchy, so the Rust crate
keeps one module per C++ header family (`common`, `marker`,
`workarea`, `undocommon`, `undotrack`, `undogeneral`, `undopointer`,
`undoripple`, `undosplit`, `util`). `COVERAGE.md` maps every C++ type
to its Rust home; review that first.
2. **No C++ `UndoCommand` subclass hierarchy.** Following the oaknode
crate decision (#4), each undo command is a plain Rust struct that
exposes `prepare()` / `redo()` / `undo()` (all `todo!()` here) and
is surfaced to the world through the oakundo C ABI vtable
(`bridge::undo::oakundo_command_init`, Rust callbacks as `userdata`).
Every command struct carries a `to_command() -> CHandle` factory doc
comment describing the wiring.
3. **Value types come from `oakcore-rs`.** Markers and work areas are
built on `Rational`/`TimeRange`, so the crate depends on
`oakcore-rs` (`crates/oakcore`) exactly like oaknode does; no
pixel/sample formats are involved here.
4. **All cross-module access goes through the C ABI.** Per the project
rule (no cross-module C++ member calls), timeline commands touch the
node graph exclusively through the oaknode C ABI
(`bridge::node`), undo through the oakundo C ABI (`bridge::undo`),
and XML/config through the oakcommon C ABI (`bridge::common`). The
C++ internal helpers `oakundo_capi::make_command_handle` /
`oaknode_c_api::to_native` are **not** replicated in Rust — their
role is subsumed by vtable commands and by value handles treated as
opaque.
5. **Handles.** `handle.rs` provides the shared `RefBox`/`CHandle`
scaffolding (duplicated per crate, as in oaknode) with
`OAKTIMELINE_ABI_VERSION = 1`. Borrowed handles into node-owned
objects and owning handles created by `*_create` share one box
layout `{ctx, addref, release, abi_version}`.
## Layout
```
src/
lib.rs crate doc + module map
error.rs error codes (mirrors include/timeline/error.h)
handle.rs refcounted-handle scaffolding (same pattern as node)
common.rs Timeline namespace (MovementMode/ThumbnailMode/
WaveformMode, EditToInfo) — timelinecommon.h
marker.rs TimelineMarker/MarkerList + 5 marker commands
workarea.rs TimelineWorkArea + 2 workarea commands
undocommon.rs node/block remove helpers + CHandleCommandWrapper
undotrack.rs track ripple/prepend/insert-after/replace commands
undogeneral.rs resize/media-in/add/remove-track/transition/gap/
enable-disable/insert-gaps/default-transition commands
undopointer.rs BlockTrimCommand/TrackSlideCommand/TrackPlaceBlockCommand
undoripple.rs ripple remove-area / ripple-tool / delete-gaps commands
undosplit.rs BlockSplitCommand/BlockSplitPreservingLinksCommand/
TrackSplitAtTimeCommand
util.rs timelineutil.h inline helpers (rat_nd, same_*,
free_detached_handle, block/track queries)
bridge/ C ABI imports: node.rs, undo.rs, common.rs
ffi.rs include/timeline/*.h export layer
tests/ contract + golden tests (see README test section)
```
## Hard rules for the implementer
1. Every `extern "C"` body goes through `handle::guard*`; no panic
crosses FFI.
2. Timeline objects never outlive their owning node; borrowed handles
are created under a guard that owns the node reference.
3. Behavior parity with C++ is proven by the C ABI test-suite
(`src/timeline/tests`, unchanged) plus the golden tests in `tests/`
(XML save/load formats captured verbatim from
`src/timeline/src/timelinemarker.cpp` / `timelineworkarea.cpp`).
4. Where C++ behavior is genuinely load-bearing but ugly (e.g. marker
list kept sorted by time, ripple's compensation gap rules), port the
behavior, not the aesthetics; leave a `// CPP-PARITY:` comment with
the C++ file:line.
## Dependency policy
Prefer mature third-party crates (MIT/Apache-2.0/BSD, GPL-compatible)
over hand-rolling; register each addition (name + reason) here. Large
existing C++ libraries (OTIO, OCIO, OIIO, FFmpeg) are NEVER rewritten
— they are consumed through their C ABI / bridge layers.