feat: add MVP implementation of OpfsBackend [WPB-19426]

.editorconfig

@@ -17,3 +17,6 @@ indent_size = 2
 
 [*.toml]
 indent_size = 2
+
+[Makefile]
+indent_style = tab

.github/dependabot.yml

@@ -0,0 +1,14 @@
+version: 2
+updates:
+  - package-ecosystem: "cargo"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    open-pull-requests-limit: 10
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: "rust-toolchain"
+    schedule:
+      interval: "daily"

.github/workflows/rust.yml

@@ -28,10 +28,8 @@ jobs:
       matrix:
         command:
           - cargo fmt --all -- --check
-          - cargo check --all-targets
-          - cargo check --target wasm32-unknown-unknown
-          - cargo clippy --all-targets
-          - cargo clippy --target wasm32-unknown-unknown
+          - cargo check --target wasm32-unknown-unknown --all-targets
+          - cargo clippy --target wasm32-unknown-unknown --all-targets
     steps:
       - uses: actions/checkout@v5
       - uses: wireapp/core-crypto/.github/actions/setup-and-cache-rust@main

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+    "rust-analyzer.cargo.target": "wasm32-unknown-unknown"
+}

Cargo.toml

@@ -4,5 +4,20 @@ version = "0.1.0"
 edition = "2024"
 description = "Implements a `StorageBackend` which delegates to OPFS"
 license = "GPL-3.0-only"
+repository = "https://github.com/wireapp/redb-opfs"
+
+[lib]
+crate-type = ["lib", "cdylib"]
 
 [dependencies]
+async-lock = "3.4.1"
+derive_more = { version = "2.0.1", features = ["display", "error"] }
+futures-lite = "2.6"
+# Temporary! Should be next released version after https://github.com/cberner/redb/pull/1065 is merged
+redb = { git = "https://github.com/coriolinus/redb", branch = "prgn/feat/wasm32-unknown-unknown-support", version = "3.0" }
+tokio-fs-ext = "0.6.3"
+wasm-bindgen = "0.2.101"
+wasm-bindgen-futures = "0.4.51"
+
+[profile.release]
+lto = true

Makefile

@@ -0,0 +1,31 @@
+RUST_RS_FILES := $(shell find . -type f -name '*.rs' 2>/dev/null | LC_ALL=C sort)
+RUST_SOURCES := Cargo.toml Cargo.lock $(RUST_RS_FILES)
+WASM_OUT := ts/gen/redb-opfs_bg.wasm
+DTS_OUT := ts/gen/redb-opfs.d.ts
+JS_OUT := ts/gen/redb-opfs.js
+
+# If RELEASE is nonempty, build in release mode
+# Otherwise build in dev mode, which is much faster
+WASM_BUILD_ARGS := $(if $(RELEASE),,--dev)
+
+Cargo.lock: Cargo.toml
+	cargo check
+
+$(JS_OUT) $(DTS_OUT) $(WASM_OUT) &: $(RUST_SOURCES)
+	wasm-pack build \
+		--locked \
+		--no-pack \
+		--out-dir ts/gen \
+		--out-name redb-opfs \
+		--mode normal \
+		--target web \
+		$(WASM_BUILD_ARGS)
+
+# human name for building wasm
+.PHONY: wasm-build
+wasm-build: $(WASM_OUT)
+
+.PHONY: web-worker-example
+web-worker-example: $(WASM_OUT)
+	cd examples/web-worker && \
+	timeout 1s bun run src/index.ts

README.md

@@ -1,6 +1,6 @@
 # `redb-opfs`: Implements a `StorageBackend` which delegates to OPFS
 
-This allows compilation and deployment on `wasm32-unknown-unknown`.
+This allows deployment on `wasm32-unknown-unknown`.
 
 > [!WARNING]
 > The contents of this README are a statement of intent, not an accurate reflection of the current state of the project.
@@ -9,22 +9,67 @@ This allows compilation and deployment on `wasm32-unknown-unknown`.
 
 ## Usage
 
-- Add this dependency to your project:
+It is important to understand that Redb's [`StorageBackend` interface](https://docs.rs/redb/latest/redb/trait.StorageBackend.html) is fundamentally synchronous,
+and OPFS is fundamentally asynchronous.
+There's a simple way to tie these two things together--[`block_on`](https://docs.rs/futures-lite/latest/futures_lite/future/fn.block_on.html)--but that method
+is illegal on the main thread, in order not to block the UI.
 
-  ```sh
-  cargo add redb-opfs
-  ```
+> [!IMPORTANT]
+> The `OpfsBackend` instance **must** run on a web worker.
 
-- Explicitly choose this backend when initializing your `Database`:
+This gives rise to two use cases.
 
-  ```rust
-  use redb_opfs::OpfsStorageBackend;
+### Your Rust code is already running in a web worker
 
-  let database = redb::Builder::new()
-    .create_with_backend(OpfsStorageBackend::new("my-db"))?;
-  ```
+This case is nice and simple; everything stays within Rust. Just explicitly choose this backend when initializing your `Database`:
+
+```rust
+use redb_opfs::OpfsBackend;
+
+let database = redb::Builder::new()
+  .create_with_backend(OpfsBackend::new("my-db")?)?;
+```
+
+### Your Rust code is running in the main thread
+
+> [!NOTE]
+> Running in this configuration introduces unavoidable performance penalties;
+> when possible, you should prefer to run all your Rust code within a web worker to avoid these.
+
+In this case we need to instantiate the `OpfsBackend` on a web worker and then instantiate the handle on the main thread.
+
+You'll want to use the `worker-shim.js` worker file to initialize the worker, and then hand that worker to the `OpfsBackendHandle`
+
+```js
+import { WorkerHandle } from "./redb-opfs";
+
+const redbOpfsWorker = new Worker("worker-shim.js");
+const workerHandle = WorkerHandle(redbOpfsWorker);
+
+// now pass that handle to your rust code, using a mechanism of your choice.
+```
+
+As you're writing your own Rust anyway, you have your own means of getting the handle into your code from there.
+To keep life simple, there exists `impl TryFrom<JsValue> for WorkerHandle`.
+
+Once you have that, usage is fairly simple:
+
+```rust
+use redb_opfs::WorkerHandle;
+
+let worker_handle = WorkerHandle::try_from(my_js_value)?;
+let database = redb::Builder::new()
+  .create_with_backend(worker_hanndle)?;
+```
+
+## Building
+
+### Prerequisites for WASM
+
+- [`wasm-bindgen` cli](https://github.com/wasm-bindgen/wasm-bindgen?tab=readme-ov-file#install-wasm-bindgen-cli)
+- [wasm-pack](https://github.com/drager/wasm-pack)
+- [GNU Make](https://www.gnu.org/software/make/)
 
-- Go nuts!
 
 ## License
 

examples/web-worker/.gitignore

@@ -0,0 +1,175 @@
+# Based on https://raw.githubusercontent.com/github/gitignore/main/Node.gitignore
+
+# Logs
+
+logs
+_.log
+npm-debug.log_
+yarn-debug.log*
+yarn-error.log*
+lerna-debug.log*
+.pnpm-debug.log*
+
+# Caches
+
+.cache
+
+# Diagnostic reports (https://nodejs.org/api/report.html)
+
+report.[0-9]_.[0-9]_.[0-9]_.[0-9]_.json
+
+# Runtime data
+
+pids
+_.pid
+_.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+
+lib-cov
+
+# Coverage directory used by tools like istanbul
+
+coverage
+*.lcov
+
+# nyc test coverage
+
+.nyc_output
+
+# Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files)
+
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+
+bower_components
+
+# node-waf configuration
+
+.lock-wscript
+
+# Compiled binary addons (https://nodejs.org/api/addons.html)
+
+build/Release
+
+# Dependency directories
+
+node_modules/
+jspm_packages/
+
+# Snowpack dependency directory (https://snowpack.dev/)
+
+web_modules/
+
+# TypeScript cache
+
+*.tsbuildinfo
+
+# Optional npm cache directory
+
+.npm
+
+# Optional eslint cache
+
+.eslintcache
+
+# Optional stylelint cache
+
+.stylelintcache
+
+# Microbundle cache
+
+.rpt2_cache/
+.rts2_cache_cjs/
+.rts2_cache_es/
+.rts2_cache_umd/
+
+# Optional REPL history
+
+.node_repl_history
+
+# Output of 'npm pack'
+
+*.tgz
+
+# Yarn Integrity file
+
+.yarn-integrity
+
+# dotenv environment variable files
+
+.env
+.env.development.local
+.env.test.local
+.env.production.local
+.env.local
+
+# parcel-bundler cache (https://parceljs.org/)
+
+.parcel-cache
+
+# Next.js build output
+
+.next
+out
+
+# Nuxt.js build / generate output
+
+.nuxt
+dist
+
+# Gatsby files
+
+# Comment in the public line in if your project uses Gatsby and not Next.js
+
+# https://nextjs.org/blog/next-9-1#public-directory-support
+
+# public
+
+# vuepress build output
+
+.vuepress/dist
+
+# vuepress v2.x temp and cache directory
+
+.temp
+
+# Docusaurus cache and generated files
+
+.docusaurus
+
+# Serverless directories
+
+.serverless/
+
+# FuseBox cache
+
+.fusebox/
+
+# DynamoDB Local files
+
+.dynamodb/
+
+# TernJS port file
+
+.tern-port
+
+# Stores VSCode versions used for testing VSCode extensions
+
+.vscode-test
+
+# yarn v2
+
+.yarn/cache
+.yarn/unplugged
+.yarn/build-state.yml
+.yarn/install-state.gz
+.pnp.*
+
+# IntelliJ based IDEs
+.idea
+
+# Finder (MacOS) folder config
+.DS_Store

examples/web-worker/README.md

@@ -0,0 +1,19 @@
+# run-as-web-worker
+
+Demonstrate simple usage of the OPFS functionality within a web worker.
+
+## Setup
+
+To install dependencies:
+
+```bash
+bun install
+```
+
+To run:
+
+```bash
+bun run index.ts
+```
+
+This project was created using `bun init` in bun v1.2.1. [Bun](https://bun.sh) is a fast all-in-one JavaScript runtime.