BEGIN CONCURRENT, wal2. (#138)

.github/workflows/repro.sh

@@ -29,5 +29,10 @@ embed/build.sh
 util/vtabutil/parse/download.sh
 util/vtabutil/parse/build.sh
 
+# Download and build the bedrock branch (bcw2 patches)
+if [[ "$OSTYPE" == "linux"* ]]; then
+  embed/bcw2/build.sh
+fi
+
 # Check diffs
 git diff --exit-code 

.github/workflows/repro.yml

@@ -28,4 +28,5 @@ jobs:
       with:
         subject-path: |
           embed/sqlite3.wasm
+          embed/bcw2/bcw2.wasm
           util/vtabutil/parse/sql3parse_table.wasm

embed/bcw2/bcw2_test.go

@@ -0,0 +1,40 @@
+package bcw2_test
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3/driver"
+	_ "github.com/ncruces/go-sqlite3/embed/bcw2"
+	"github.com/ncruces/go-sqlite3/vfs"
+)
+
+func Test_bcw2(t *testing.T) {
+	if !vfs.SupportsSharedMemory {
+		t.Skip("skipping without shared memory")
+	}
+
+	tmp := filepath.ToSlash(filepath.Join(t.TempDir(), "test.db"))
+
+	db, err := driver.Open("file:" + tmp + "?_pragma=journal_mode(wal2)&_txlock=concurrent")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer tx.Rollback()
+
+	_, err = tx.Exec(`CREATE TABLE test (col)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = tx.Commit()
+	if err != nil {
+		t.Fatal(err)
+	}
+}

embed/bcw2/build.sh

@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cd -P -- "$(dirname -- "$0")"
+
+ROOT=../../
+BINARYEN="$ROOT/tools/binaryen/bin"
+WASI_SDK="$ROOT/tools/wasi-sdk/bin"
+
+trap 'rm -rf build sqlite bcw2.tmp' EXIT
+
+mkdir -p build/ext/
+cp "$ROOT"/sqlite3/*.[ch] build/
+cp "$ROOT"/sqlite3/*.patch build/
+
+curl -# https://www.sqlite.org/src/tarball/sqlite.tar.gz?r=bedrock-3.46 | tar xz
+
+cd sqlite
+sh configure
+make sqlite3.c
+cd ~-
+
+mv sqlite/sqlite3.c             build/
+mv sqlite/sqlite3.h             build/
+mv sqlite/sqlite3ext.h          build/
+mv sqlite/ext/misc/anycollseq.c build/ext/
+mv sqlite/ext/misc/base64.c     build/ext/
+mv sqlite/ext/misc/decimal.c    build/ext/
+mv sqlite/ext/misc/ieee754.c    build/ext/
+mv sqlite/ext/misc/regexp.c     build/ext/
+mv sqlite/ext/misc/series.c     build/ext/
+mv sqlite/ext/misc/uint.c       build/ext/
+
+cd build
+cat *.patch | patch --no-backup-if-mismatch
+cd ~-
+
+"$WASI_SDK/clang" --target=wasm32-wasi -std=c23 -g0 -O2 \
+	-Wall -Wextra -Wno-unused-parameter -Wno-unused-function \
+	-o bcw2.wasm "build/main.c" \
+	-I"build" \
+	-mexec-model=reactor \
+	-matomics -msimd128 -mmutable-globals \
+	-mbulk-memory -mreference-types \
+	-mnontrapping-fptoint -msign-ext \
+	-fno-stack-protector -fno-stack-clash-protection \
+	-Wl,--stack-first \
+	-Wl,--import-undefined \
+	-Wl,--initial-memory=327680 \
+	-D_HAVE_SQLITE_CONFIG_H \
+	-DSQLITE_CUSTOM_INCLUDE=sqlite_opt.h \
+	$(awk '{print "-Wl,--export="$0}' ../exports.txt)
+
+"$BINARYEN/wasm-ctor-eval" -g -c _initialize bcw2.wasm -o bcw2.tmp
+"$BINARYEN/wasm-opt" -g --strip --strip-producers -c -O3 \
+	bcw2.tmp -o bcw2.wasm \
+	--enable-simd --enable-mutable-globals --enable-multivalue \
+	--enable-bulk-memory --enable-reference-types \
+	--enable-nontrapping-float-to-int --enable-sign-ext

embed/bcw2/init.go

@@ -0,0 +1,23 @@
+// Package bcw2 embeds SQLite into your application.
+//
+// Importing package bcw2 initializes the [sqlite3.Binary] variable
+// with a build of SQLite that includes the [BEGIN CONCURRENT] and [Wal2] patches:
+//
+//	import _ "github.com/ncruces/go-sqlite3/embed/bcw2"
+//
+// [BEGIN CONCURRENT]: https://sqlite.org/src/doc/begin-concurrent/doc/begin_concurrent.md
+// [Wal2]: https://www.sqlite.org/cgi/src/doc/wal2/doc/wal2.md
+package bcw2
+
+import (
+	_ "embed"
+
+	"github.com/ncruces/go-sqlite3"
+)
+
+//go:embed bcw2.wasm
+var binary []byte
+
+func init() {
+	sqlite3.Binary = binary
+}

vfs/memdb/api.go

@@ -42,8 +42,9 @@ func Create(name string, data []byte) {
 		size: int64(len(data)),
 	}
 
-	// Convert data from WAL to rollback journal.
-	if len(data) >= 20 && data[18] == 2 && data[19] == 2 {
+	// Convert data from WAL/2 to rollback journal.
+	if len(data) >= 20 && (data[18] == 2 && data[19] == 2 ||
+		data[18] == 3 && data[19] == 3) {
 		data[18] = 1
 		data[19] = 1
 	}