WASM builds

.github/workflows/release.yml

@@ -237,3 +237,47 @@ jobs:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
           file-name: libpowersync_x64.dylib
           tag: ${{ needs.draft_release.outputs.tag }}
+
+  publish_wasm:
+    name: Publish WASM builds
+    needs: [draft_release]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          submodules: true
+
+      - name: Install Rust Nightly
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          toolchain: nightly-2024-05-18
+          components: rust-src
+
+      - name: Setup emsdk
+        uses: mymindstorm/setup-emsdk@v14
+        with:
+          version: 3.1.68
+
+      - name: Build WASM
+        run: ./tool/build_wasm.sh
+
+      - name: Upload libpowersync.wasm
+        uses: ./.github/actions/upload
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          file-name: libpowersync.wasm
+          tag: ${{ needs.draft_release.outputs.tag }}
+
+      - name: Upload libpowersync-async.wasm
+        uses: ./.github/actions/upload
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          file-name: libpowersync-async.wasm
+          tag: ${{ needs.draft_release.outputs.tag }}
+
+      - name: Upload libpowersync-wasm.a
+        uses: ./.github/actions/upload
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          file-name: libpowersync-wasm.a
+          tag: ${{ needs.draft_release.outputs.tag }}

.github/workflows/wasm.yml

@@ -1,6 +1,6 @@
 on:
   push:
-name: "linux"
+name: "wasm"
 jobs:
   build_wasm:
     name: Basic WASM build
@@ -16,5 +16,10 @@ jobs:
           toolchain: nightly-2024-05-18
           components: rust-src
 
-      - name: Build WASM bytecode
-        run: RUSTFLAGS="--emit=llvm-bc -C linker=/bin/true" cargo build -p powersync_loadable --profile wasm --no-default-features --features "powersync_core/static powersync_core/omit_load_extension sqlite_nostd/static sqlite_nostd/omit_load_extension" -Z build-std=panic_abort,core,alloc --target wasm32-unknown-emscripten
+      - name: Setup emsdk
+        uses: mymindstorm/setup-emsdk@v14
+        with:
+          version: 3.1.68
+
+      - name: Build WASM
+        run: ./tool/build_wasm.sh

Cargo.toml

@@ -19,10 +19,9 @@ lto = true
 
 [profile.wasm]
 inherits = "release"
-# Enabling LTO in WASM build gives:
-# warning: Linking globals named '__rust_alloc_error_handler': symbol multiply defined!
-# error: failed to load bitcode of module "sgnxivc9sns8d6t":
-lto = false
+
+[profile.wasm_asyncify]
+inherits = "wasm"
 
 [workspace.package]
 version = "0.3.0"

crates/core/src/kv.rs

@@ -36,7 +36,7 @@ fn powersync_client_id_impl(
 create_sqlite_text_fn!(
     powersync_client_id,
     powersync_client_id_impl,
-    "powersync_last_synced_at"
+    "powersync_client_id"
 );
 
 fn powersync_last_synced_at_impl(

crates/loadable/Cargo.toml

@@ -10,7 +10,7 @@ keywords.workspace = true
 
 [lib]
 name = "powersync"
-crate-type = ["cdylib"]
+crate-type = ["cdylib", "staticlib"]
 
 [dependencies]
 sqlite_nostd = { workspace=true }

crates/loadable/src/lib.rs

@@ -30,28 +30,3 @@ fn panic(_info: &core::panic::PanicInfo) -> ! {
 #[cfg(not(test))]
 #[lang = "eh_personality"]
 extern "C" fn eh_personality() {}
-
-#[cfg(target_family = "wasm")]
-#[no_mangle]
-pub fn __rust_alloc_error_handler(_: core::alloc::Layout) -> ! {
-    core::intrinsics::abort()
-}
-
-#[cfg(target_family = "wasm")]
-#[no_mangle]
-static __rust_alloc_error_handler_should_panic: u8 = 0;
-
-#[cfg(target_family = "wasm")]
-#[no_mangle]
-static _CLOCK_PROCESS_CPUTIME_ID: i32 = 1;
-
-#[cfg(target_family = "wasm")]
-#[no_mangle]
-static _CLOCK_THREAD_CPUTIME_ID: i32 = 1;
-
-// Not used, but must be defined in some cases. Most notably when using native sqlite3 and loading
-// the extension.
-// #[allow(non_upper_case_globals)]
-// #[no_mangle]
-// pub static mut _Unwind_Resume: *mut core::ffi::c_void = core::ptr::null_mut();
-

tool/build_wasm.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+set -e
+
+# Normal build
+# target/wasm32-unknown-emscripten/wasm/powersync.wasm
+RUSTFLAGS="-C link-arg=-sSIDE_MODULE=2" \
+  cargo build \
+    -p powersync_loadable \
+    --profile wasm \
+    --no-default-features \
+    --features "powersync_core/static powersync_core/omit_load_extension sqlite_nostd/omit_load_extension" \
+    -Z build-std=panic_abort,core,alloc \
+    --target wasm32-unknown-emscripten
+
+cp "target/wasm32-unknown-emscripten/wasm/powersync.wasm" "libpowersync.wasm"
+
+# Asyncify
+# target/wasm32-unknown-emscripten/wasm_asyncify/powersync.wasm
+RUSTFLAGS="-C link-arg=-sSIDE_MODULE=2 -C link-arg=-sASYNCIFY=1 -C link-arg=-sJSPI_IMPORTS=@wasm/asyncify_imports.json" \
+  cargo build \
+    -p powersync_loadable \
+    --profile wasm_asyncify \
+    --no-default-features \
+    --features "powersync_core/static powersync_core/omit_load_extension sqlite_nostd/omit_load_extension" \
+    -Z build-std=panic_abort,core,alloc \
+    --target wasm32-unknown-emscripten
+
+cp "target/wasm32-unknown-emscripten/wasm_asyncify/powersync.wasm" "libpowersync-async.wasm"
+
+
+# Static lib.
+# Works for both sync and asyncify builds.
+# Works for both emscripten and wasi.
+# target/wasm32-wasi/wasm/libpowersync.a
+cargo build \
+  -p powersync_loadable \
+  --profile wasm \
+  --no-default-features \
+  --features "powersync_core/static powersync_core/omit_load_extension sqlite_nostd/omit_load_extension" \
+  -Z build-std=panic_abort,core,alloc \
+  --target wasm32-wasi
+
+cp "target/wasm32-wasi/wasm/libpowersync.a" "libpowersync-wasm.a"

wasm/asyncify_imports.json

@@ -0,0 +1,14 @@
+[
+  "sqlite3_close",
+  "sqlite3_finalize",
+  "sqlite3_open_v2",
+  "sqlite3_prepare",
+  "sqlite3_prepare16",
+  "sqlite3_prepare_v2",
+  "sqlite3_prepare16_v2",
+  "sqlite3_prepare_v3",
+  "sqlite3_prepare16_v3",
+  "sqlite3_reset",
+  "sqlite3_step",
+  "sqlite3_exec"
+]