Files
oak-editor/crates/oaknode/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

106 lines
5.1 KiB
Markdown

# oaknode Rust crate (implementation)
> Status: **all FFI headers implemented**. Phase 1 (core engine: graph
> arena, values, keyframes, project, factory, ~55 FFI exports), Phase 2
> (sequence/track/block/footage/colormanager + traverser + serializer,
> the folder/group/keyframe/dragger FFI families, the undo/XML bridges
> with test stubs, and the contract tests) and Phase 3 (the multicam
> grid family and the deferred bridge exports: markers/work-area/frame
> cache accessors, viewer params, sequence/footage stream params via
> the videoparams/audioparams C ABIs, and the colormanager compliant
> transform) are complete; `cargo test --features test-stubs` is green
> (84 tests, 1 ignored byte-exact golden). The remaining `todo!()`s are
> the concrete node-type behaviors under `src/nodes/` (registered in
> the factory, bodies deferred) — the multicam node behavior and the
> effect/generator nodes. The crate template (FFI discipline, testing
> layers) follows `crates/oakplugin/README.md`.
## Scope
Replaces the C++ oaknode module (`src/node/src`, ~40k lines):
the node graph engine, project/folder/sequence/track/block hierarchy,
footage, color manager, keyframes, evaluation (traverser), project
serialization, and the undo bridge.
Public contract: `include/node/*.h` (14 headers, ~280 functions) —
frozen, implemented verbatim by `src/ffi.rs`.
## Key architectural decisions (C++ → Rust mapping)
1. **Inheritance → arena + trait objects.** The C++ design is deep
inheritance (`Node``ViewerOutput`/`Track`/`Block`/… and ~50
effect nodes). Rust: a slab-allocated `Graph` arena of
`NodeEntry { core: NodeCore, behavior: Box<dyn NodeBehavior> }`,
addressed by generational `NodeId`. No reference cycles exist by
construction (edges are IDs, not pointers).
2. **Cross-module inheritance disappears.** C++ `RenderProcessor :
NodeTraverser` (render subclassing a node class) becomes a plain
evaluation API: `traverser::evaluate(...) -> NodeValueTable` is a
function, and oakrender supplies backend hooks via a trait
(`RenderHooks`) instead of overriding virtuals.
3. **Value system.** `olive::Variant`/type-erasure becomes a closed
`NodeValue` enum (`value.rs`). C ABI marshalling lives only in
`ffi.rs`.
4. **Undo.** Commands are created through the oakundo C ABI
(`bridge::undo`); the C++ `UndoCommand` subclass hierarchy becomes
vtable commands whose userdata is a Rust closure.
5. **Serialization.** XML read/write goes through the oakcommon C ABI
(`bridge::common`) until oakcommon itself is rewritten.
6. **Threading.** The C++ code relied on Qt's event thread +
`called_on_owner_thread()` assertions. Rust replaces this with
`Mutex<Graph>` interior mutability plus explicit
`&mut Graph` phases for structural edits; the threading contract is
documented per function.
## Layout
`COVERAGE.md` maps every method of the C++ `olive::Node` (260
declaration lines, ~150 unique methods) to its Rust home — trait /
core / graph / ops / bridge / drop-with-reason. Review that first.
```
src/
lib.rs crate doc + module map
error.rs error codes (mirrors include/node/error.h)
handle.rs refcounted-handle scaffolding (same pattern as plugin)
value.rs NodeValue / NodeValueTable / ValueHint
id.rs NodeId, generational arena ids
node.rs NodeCore + NodeBehavior trait (the virtual surface)
graph.rs Graph arena, edges, topological order
input.rs Input descriptors, flags, array inputs, hints
keyframe.rs NodeKeyframe + track interpolation
project.rs Project, settings, folder tree
sequence.rs Sequence (ViewerOutput equivalent)
track.rs Track, TrackList
block.rs Block/ClipBlock/GapBlock/TransitionBlock
footage.rs Footage (probe via oakcodec C ABI)
colormanager.rs ColorManager (OCIO via oakrender C ABI for now)
traverser.rs Evaluation engine (iterative, hook-based)
serializer.rs XML project load/save (bridge::common)
factory.rs Node type registry (id -> constructor)
nodes/ The concrete built-in node types
bridge/ C ABI imports: common.rs, undo.rs, render.rs, codec.rs
ffi.rs include/node/*.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. `Graph` is the only owner of nodes; the public API never hands out
references into the arena, only `NodeId`-carrying handles.
3. Behavior parity with C++ is proven by the C ABI test-suite
(`src/node/tests`, unchanged) plus the golden tests in `tests/`.
4. Where C++ behavior is genuinely load-bearing but ugly (e.g.
`Block` length-change side effects on `Track`), 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.