[experiment] add alternative wasm sqlite3 implementation available via build-tag (#2863)

This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).

1 files changed, 374 insertions, 0 deletions

diff --git a/vendor/github.com/tetratelabs/wazero/runtime.go b/vendor/github.com/tetratelabs/wazero/runtime.go
new file mode 100644
index 000000000..d1f0a1a31
--- /dev/null
+++ b/vendor/github.com/tetratelabs/wazero/runtime.go
@@ -0,0 +1,374 @@
+package wazero
+
+import (
+	"context"
+	"fmt"
+	"sync/atomic"
+
+	"github.com/tetratelabs/wazero/api"
+	experimentalapi "github.com/tetratelabs/wazero/experimental"
+	"github.com/tetratelabs/wazero/internal/expctxkeys"
+	internalsock "github.com/tetratelabs/wazero/internal/sock"
+	internalsys "github.com/tetratelabs/wazero/internal/sys"
+	"github.com/tetratelabs/wazero/internal/wasm"
+	binaryformat "github.com/tetratelabs/wazero/internal/wasm/binary"
+	"github.com/tetratelabs/wazero/sys"
+)
+
+// Runtime allows embedding of WebAssembly modules.
+//
+// The below is an example of basic initialization:
+//
+//	ctx := context.Background()
+//	r := wazero.NewRuntime(ctx)
+//	defer r.Close(ctx) // This closes everything this Runtime created.
+//
+//	mod, _ := r.Instantiate(ctx, wasm)
+//
+// # Notes
+//
+//   - This is an interface for decoupling, not third-party implementations.
+//     All implementations are in wazero.
+//   - Closing this closes any CompiledModule or Module it instantiated.
+type Runtime interface {
+	// Instantiate instantiates a module from the WebAssembly binary (%.wasm)
+	// with default configuration, which notably calls the "_start" function,
+	// if it exists.
+	//
+	// Here's an example:
+	//	ctx := context.Background()
+	//	r := wazero.NewRuntime(ctx)
+	//	defer r.Close(ctx) // This closes everything this Runtime created.
+	//
+	//	mod, _ := r.Instantiate(ctx, wasm)
+	//
+	// # Notes
+	//
+	//   - See notes on InstantiateModule for error scenarios.
+	//   - See InstantiateWithConfig for configuration overrides.
+	Instantiate(ctx context.Context, source []byte) (api.Module, error)
+
+	// InstantiateWithConfig instantiates a module from the WebAssembly binary
+	// (%.wasm) or errs for reasons including exit or validation.
+	//
+	// Here's an example:
+	//	ctx := context.Background()
+	//	r := wazero.NewRuntime(ctx)
+	//	defer r.Close(ctx) // This closes everything this Runtime created.
+	//
+	//	mod, _ := r.InstantiateWithConfig(ctx, wasm,
+	//		wazero.NewModuleConfig().WithName("rotate"))
+	//
+	// # Notes
+	//
+	//   - See notes on InstantiateModule for error scenarios.
+	//   - If you aren't overriding defaults, use Instantiate.
+	//   - This is a convenience utility that chains CompileModule with
+	//     InstantiateModule. To instantiate the same source multiple times,
+	//     use CompileModule as InstantiateModule avoids redundant decoding
+	//     and/or compilation.
+	InstantiateWithConfig(ctx context.Context, source []byte, config ModuleConfig) (api.Module, error)
+
+	// NewHostModuleBuilder lets you create modules out of functions defined in Go.
+	//
+	// Below defines and instantiates a module named "env" with one function:
+	//
+	//	ctx := context.Background()
+	//	hello := func() {
+	//		fmt.Fprintln(stdout, "hello!")
+	//	}
+	//	_, err := r.NewHostModuleBuilder("env").
+	//		NewFunctionBuilder().WithFunc(hello).Export("hello").
+	//		Instantiate(ctx, r)
+	//
+	// Note: empty `moduleName` is not allowed.
+	NewHostModuleBuilder(moduleName string) HostModuleBuilder
+
+	// CompileModule decodes the WebAssembly binary (%.wasm) or errs if invalid.
+	// Any pre-compilation done after decoding wasm is dependent on RuntimeConfig.
+	//
+	// There are two main reasons to use CompileModule instead of Instantiate:
+	//   - Improve performance when the same module is instantiated multiple times under different names
+	//   - Reduce the amount of errors that can occur during InstantiateModule.
+	//
+	// # Notes
+	//
+	//   - The resulting module name defaults to what was binary from the custom name section.
+	//   - Any pre-compilation done after decoding the source is dependent on RuntimeConfig.
+	//
+	// See https://www.w3.org/TR/2019/REC-wasm-core-1-20191205/#name-section%E2%91%A0
+	CompileModule(ctx context.Context, binary []byte) (CompiledModule, error)
+
+	// InstantiateModule instantiates the module or errs for reasons including
+	// exit or validation.
+	//
+	// Here's an example:
+	//	mod, _ := n.InstantiateModule(ctx, compiled, wazero.NewModuleConfig().
+	//		WithName("prod"))
+	//
+	// # Errors
+	//
+	// While CompiledModule is pre-validated, there are a few situations which
+	// can cause an error:
+	//   - The module name is already in use.
+	//   - The module has a table element initializer that resolves to an index
+	//     outside the Table minimum size.
+	//   - The module has a start function, and it failed to execute.
+	//   - The module was compiled to WASI and exited with a non-zero exit
+	//     code, you'll receive a sys.ExitError.
+	//   - RuntimeConfig.WithCloseOnContextDone was enabled and a context
+	//     cancellation or deadline triggered before a start function returned.
+	InstantiateModule(ctx context.Context, compiled CompiledModule, config ModuleConfig) (api.Module, error)
+
+	// CloseWithExitCode closes all the modules that have been initialized in this Runtime with the provided exit code.
+	// An error is returned if any module returns an error when closed.
+	//
+	// Here's an example:
+	//	ctx := context.Background()
+	//	r := wazero.NewRuntime(ctx)
+	//	defer r.CloseWithExitCode(ctx, 2) // This closes everything this Runtime created.
+	//
+	//	// Everything below here can be closed, but will anyway due to above.
+	//	_, _ = wasi_snapshot_preview1.InstantiateSnapshotPreview1(ctx, r)
+	//	mod, _ := r.Instantiate(ctx, wasm)
+	CloseWithExitCode(ctx context.Context, exitCode uint32) error
+
+	// Module returns an instantiated module in this runtime or nil if there aren't any.
+	Module(moduleName string) api.Module
+
+	// Closer closes all compiled code by delegating to CloseWithExitCode with an exit code of zero.
+	api.Closer
+}
+
+// NewRuntime returns a runtime with a configuration assigned by NewRuntimeConfig.
+func NewRuntime(ctx context.Context) Runtime {
+	return NewRuntimeWithConfig(ctx, NewRuntimeConfig())
+}
+
+// NewRuntimeWithConfig returns a runtime with the given configuration.
+func NewRuntimeWithConfig(ctx context.Context, rConfig RuntimeConfig) Runtime {
+	config := rConfig.(*runtimeConfig)
+	var engine wasm.Engine
+	var cacheImpl *cache
+	if c := config.cache; c != nil {
+		// If the Cache is configured, we share the engine.
+		cacheImpl = c.(*cache)
+		engine = cacheImpl.initEngine(config.engineKind, config.newEngine, ctx, config.enabledFeatures)
+	} else {
+		// Otherwise, we create a new engine.
+		engine = config.newEngine(ctx, config.enabledFeatures, nil)
+	}
+	store := wasm.NewStore(config.enabledFeatures, engine)
+	return &runtime{
+		cache:                 cacheImpl,
+		store:                 store,
+		enabledFeatures:       config.enabledFeatures,
+		memoryLimitPages:      config.memoryLimitPages,
+		memoryCapacityFromMax: config.memoryCapacityFromMax,
+		dwarfDisabled:         config.dwarfDisabled,
+		storeCustomSections:   config.storeCustomSections,
+		ensureTermination:     config.ensureTermination,
+	}
+}
+
+// runtime allows decoupling of public interfaces from internal representation.
+type runtime struct {
+	store                 *wasm.Store
+	cache                 *cache
+	enabledFeatures       api.CoreFeatures
+	memoryLimitPages      uint32
+	memoryCapacityFromMax bool
+	dwarfDisabled         bool
+	storeCustomSections   bool
+
+	// closed is the pointer used both to guard moduleEngine.CloseWithExitCode and to store the exit code.
+	//
+	// The update value is 1 + exitCode << 32. This ensures an exit code of zero isn't mistaken for never closed.
+	//
+	// Note: Exclusively reading and updating this with atomics guarantees cross-goroutine observations.
+	// See /RATIONALE.md
+	closed atomic.Uint64
+
+	ensureTermination bool
+}
+
+// Module implements Runtime.Module.
+func (r *runtime) Module(moduleName string) api.Module {
+	if len(moduleName) == 0 {
+		return nil
+	}
+	return r.store.Module(moduleName)
+}
+
+// CompileModule implements Runtime.CompileModule
+func (r *runtime) CompileModule(ctx context.Context, binary []byte) (CompiledModule, error) {
+	if err := r.failIfClosed(); err != nil {
+		return nil, err
+	}
+
+	internal, err := binaryformat.DecodeModule(binary, r.enabledFeatures,
+		r.memoryLimitPages, r.memoryCapacityFromMax, !r.dwarfDisabled, r.storeCustomSections)
+	if err != nil {
+		return nil, err
+	} else if err = internal.Validate(r.enabledFeatures); err != nil {
+		// TODO: decoders should validate before returning, as that allows
+		// them to err with the correct position in the wasm binary.
+		return nil, err
+	}
+
+	// Now that the module is validated, cache the memory definitions.
+	// TODO: lazy initialization of memory definition.
+	internal.BuildMemoryDefinitions()
+
+	c := &compiledModule{module: internal, compiledEngine: r.store.Engine}
+
+	// typeIDs are static and compile-time known.
+	typeIDs, err := r.store.GetFunctionTypeIDs(internal.TypeSection)
+	if err != nil {
+		return nil, err
+	}
+	c.typeIDs = typeIDs
+
+	listeners, err := buildFunctionListeners(ctx, internal)
+	if err != nil {
+		return nil, err
+	}
+	internal.AssignModuleID(binary, listeners, r.ensureTermination)
+	if err = r.store.Engine.CompileModule(ctx, internal, listeners, r.ensureTermination); err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+func buildFunctionListeners(ctx context.Context, internal *wasm.Module) ([]experimentalapi.FunctionListener, error) {
+	// Test to see if internal code are using an experimental feature.
+	fnlf := ctx.Value(expctxkeys.FunctionListenerFactoryKey{})
+	if fnlf == nil {
+		return nil, nil
+	}
+	factory := fnlf.(experimentalapi.FunctionListenerFactory)
+	importCount := internal.ImportFunctionCount
+	listeners := make([]experimentalapi.FunctionListener, len(internal.FunctionSection))
+	for i := 0; i < len(listeners); i++ {
+		listeners[i] = factory.NewFunctionListener(internal.FunctionDefinition(uint32(i) + importCount))
+	}
+	return listeners, nil
+}
+
+// failIfClosed returns an error if CloseWithExitCode was called implicitly (by Close) or explicitly.
+func (r *runtime) failIfClosed() error {
+	if closed := r.closed.Load(); closed != 0 {
+		return fmt.Errorf("runtime closed with exit_code(%d)", uint32(closed>>32))
+	}
+	return nil
+}
+
+// Instantiate implements Runtime.Instantiate
+func (r *runtime) Instantiate(ctx context.Context, binary []byte) (api.Module, error) {
+	return r.InstantiateWithConfig(ctx, binary, NewModuleConfig())
+}
+
+// InstantiateWithConfig implements Runtime.InstantiateWithConfig
+func (r *runtime) InstantiateWithConfig(ctx context.Context, binary []byte, config ModuleConfig) (api.Module, error) {
+	if compiled, err := r.CompileModule(ctx, binary); err != nil {
+		return nil, err
+	} else {
+		compiled.(*compiledModule).closeWithModule = true
+		return r.InstantiateModule(ctx, compiled, config)
+	}
+}
+
+// InstantiateModule implements Runtime.InstantiateModule.
+func (r *runtime) InstantiateModule(
+	ctx context.Context,
+	compiled CompiledModule,
+	mConfig ModuleConfig,
+) (mod api.Module, err error) {
+	if err = r.failIfClosed(); err != nil {
+		return nil, err
+	}
+
+	code := compiled.(*compiledModule)
+	config := mConfig.(*moduleConfig)
+
+	// Only add guest module configuration to guests.
+	if !code.module.IsHostModule {
+		if sockConfig, ok := ctx.Value(internalsock.ConfigKey{}).(*internalsock.Config); ok {
+			config.sockConfig = sockConfig
+		}
+	}
+
+	var sysCtx *internalsys.Context
+	if sysCtx, err = config.toSysContext(); err != nil {
+		return
+	}
+
+	name := config.name
+	if !config.nameSet && code.module.NameSection != nil && code.module.NameSection.ModuleName != "" {
+		name = code.module.NameSection.ModuleName
+	}
+
+	// Instantiate the module.
+	mod, err = r.store.Instantiate(ctx, code.module, name, sysCtx, code.typeIDs)
+	if err != nil {
+		// If there was an error, don't leak the compiled module.
+		if code.closeWithModule {
+			_ = code.Close(ctx) // don't overwrite the error
+		}
+		return
+	}
+
+	if closeNotifier, ok := ctx.Value(expctxkeys.CloseNotifierKey{}).(experimentalapi.CloseNotifier); ok {
+		mod.(*wasm.ModuleInstance).CloseNotifier = closeNotifier
+	}
+
+	// Attach the code closer so that anything afterward closes the compiled
+	// code when closing the module.
+	if code.closeWithModule {
+		mod.(*wasm.ModuleInstance).CodeCloser = code
+	}
+
+	// Now, invoke any start functions, failing at first error.
+	for _, fn := range config.startFunctions {
+		start := mod.ExportedFunction(fn)
+		if start == nil {
+			continue
+		}
+		if _, err = start.Call(ctx); err != nil {
+			_ = mod.Close(ctx) // Don't leak the module on error.
+
+			if se, ok := err.(*sys.ExitError); ok {
+				if se.ExitCode() == 0 { // Don't err on success.
+					err = nil
+				}
+				return // Don't wrap an exit error
+			}
+			err = fmt.Errorf("module[%s] function[%s] failed: %w", name, fn, err)
+			return
+		}
+	}
+	return
+}
+
+// Close implements api.Closer embedded in Runtime.
+func (r *runtime) Close(ctx context.Context) error {
+	return r.CloseWithExitCode(ctx, 0)
+}
+
+// CloseWithExitCode implements Runtime.CloseWithExitCode
+//
+// Note: it also marks the internal `closed` field
+func (r *runtime) CloseWithExitCode(ctx context.Context, exitCode uint32) error {
+	closed := uint64(1) + uint64(exitCode)<<32 // Store exitCode as high-order bits.
+	if !r.closed.CompareAndSwap(0, closed) {
+		return nil
+	}
+	err := r.store.CloseWithExitCode(ctx, exitCode)
+	if r.cache == nil {
+		// Close the engine if the cache is not configured, which means that this engine is scoped in this runtime.
+		if errCloseEngine := r.store.Engine.Close(); errCloseEngine != nil {
+			return errCloseEngine
+		}
+	}
+	return err
+}