[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, 226 insertions, 0 deletions

diff --git a/vendor/github.com/tetratelabs/wazero/internal/wasm/binary/section.go b/vendor/github.com/tetratelabs/wazero/internal/wasm/binary/section.go
new file mode 100644
index 000000000..622ee5923
--- /dev/null
+++ b/vendor/github.com/tetratelabs/wazero/internal/wasm/binary/section.go
@@ -0,0 +1,226 @@
+package binary
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+
+	"github.com/tetratelabs/wazero/api"
+	"github.com/tetratelabs/wazero/internal/leb128"
+	"github.com/tetratelabs/wazero/internal/wasm"
+)
+
+func decodeTypeSection(enabledFeatures api.CoreFeatures, r *bytes.Reader) ([]wasm.FunctionType, error) {
+	vs, _, err := leb128.DecodeUint32(r)
+	if err != nil {
+		return nil, fmt.Errorf("get size of vector: %w", err)
+	}
+
+	result := make([]wasm.FunctionType, vs)
+	for i := uint32(0); i < vs; i++ {
+		if err = decodeFunctionType(enabledFeatures, r, &result[i]); err != nil {
+			return nil, fmt.Errorf("read %d-th type: %v", i, err)
+		}
+	}
+	return result, nil
+}
+
+// decodeImportSection decodes the decoded import segments plus the count per wasm.ExternType.
+func decodeImportSection(
+	r *bytes.Reader,
+	memorySizer memorySizer,
+	memoryLimitPages uint32,
+	enabledFeatures api.CoreFeatures,
+) (result []wasm.Import,
+	perModule map[string][]*wasm.Import,
+	funcCount, globalCount, memoryCount, tableCount wasm.Index, err error,
+) {
+	vs, _, err := leb128.DecodeUint32(r)
+	if err != nil {
+		err = fmt.Errorf("get size of vector: %w", err)
+		return
+	}
+
+	perModule = make(map[string][]*wasm.Import)
+	result = make([]wasm.Import, vs)
+	for i := uint32(0); i < vs; i++ {
+		imp := &result[i]
+		if err = decodeImport(r, i, memorySizer, memoryLimitPages, enabledFeatures, imp); err != nil {
+			return
+		}
+		switch imp.Type {
+		case wasm.ExternTypeFunc:
+			imp.IndexPerType = funcCount
+			funcCount++
+		case wasm.ExternTypeGlobal:
+			imp.IndexPerType = globalCount
+			globalCount++
+		case wasm.ExternTypeMemory:
+			imp.IndexPerType = memoryCount
+			memoryCount++
+		case wasm.ExternTypeTable:
+			imp.IndexPerType = tableCount
+			tableCount++
+		}
+		perModule[imp.Module] = append(perModule[imp.Module], imp)
+	}
+	return
+}
+
+func decodeFunctionSection(r *bytes.Reader) ([]uint32, error) {
+	vs, _, err := leb128.DecodeUint32(r)
+	if err != nil {
+		return nil, fmt.Errorf("get size of vector: %w", err)
+	}
+
+	result := make([]uint32, vs)
+	for i := uint32(0); i < vs; i++ {
+		if result[i], _, err = leb128.DecodeUint32(r); err != nil {
+			return nil, fmt.Errorf("get type index: %w", err)
+		}
+	}
+	return result, err
+}
+
+func decodeTableSection(r *bytes.Reader, enabledFeatures api.CoreFeatures) ([]wasm.Table, error) {
+	vs, _, err := leb128.DecodeUint32(r)
+	if err != nil {
+		return nil, fmt.Errorf("error reading size")
+	}
+	if vs > 1 {
+		if err := enabledFeatures.RequireEnabled(api.CoreFeatureReferenceTypes); err != nil {
+			return nil, fmt.Errorf("at most one table allowed in module as %w", err)
+		}
+	}
+
+	ret := make([]wasm.Table, vs)
+	for i := range ret {
+		err = decodeTable(r, enabledFeatures, &ret[i])
+		if err != nil {
+			return nil, err
+		}
+	}
+	return ret, nil
+}
+
+func decodeMemorySection(
+	r *bytes.Reader,
+	enabledFeatures api.CoreFeatures,
+	memorySizer memorySizer,
+	memoryLimitPages uint32,
+) (*wasm.Memory, error) {
+	vs, _, err := leb128.DecodeUint32(r)
+	if err != nil {
+		return nil, fmt.Errorf("error reading size")
+	}
+	if vs > 1 {
+		return nil, fmt.Errorf("at most one memory allowed in module, but read %d", vs)
+	} else if vs == 0 {
+		// memory count can be zero.
+		return nil, nil
+	}
+
+	return decodeMemory(r, enabledFeatures, memorySizer, memoryLimitPages)
+}
+
+func decodeGlobalSection(r *bytes.Reader, enabledFeatures api.CoreFeatures) ([]wasm.Global, error) {
+	vs, _, err := leb128.DecodeUint32(r)
+	if err != nil {
+		return nil, fmt.Errorf("get size of vector: %w", err)
+	}
+
+	result := make([]wasm.Global, vs)
+	for i := uint32(0); i < vs; i++ {
+		if err = decodeGlobal(r, enabledFeatures, &result[i]); err != nil {
+			return nil, fmt.Errorf("global[%d]: %w", i, err)
+		}
+	}
+	return result, nil
+}
+
+func decodeExportSection(r *bytes.Reader) ([]wasm.Export, map[string]*wasm.Export, error) {
+	vs, _, sizeErr := leb128.DecodeUint32(r)
+	if sizeErr != nil {
+		return nil, nil, fmt.Errorf("get size of vector: %v", sizeErr)
+	}
+
+	exportMap := make(map[string]*wasm.Export, vs)
+	exportSection := make([]wasm.Export, vs)
+	for i := wasm.Index(0); i < vs; i++ {
+		export := &exportSection[i]
+		err := decodeExport(r, export)
+		if err != nil {
+			return nil, nil, fmt.Errorf("read export: %w", err)
+		}
+		if _, ok := exportMap[export.Name]; ok {
+			return nil, nil, fmt.Errorf("export[%d] duplicates name %q", i, export.Name)
+		} else {
+			exportMap[export.Name] = export
+		}
+	}
+	return exportSection, exportMap, nil
+}
+
+func decodeStartSection(r *bytes.Reader) (*wasm.Index, error) {
+	vs, _, err := leb128.DecodeUint32(r)
+	if err != nil {
+		return nil, fmt.Errorf("get function index: %w", err)
+	}
+	return &vs, nil
+}
+
+func decodeElementSection(r *bytes.Reader, enabledFeatures api.CoreFeatures) ([]wasm.ElementSegment, error) {
+	vs, _, err := leb128.DecodeUint32(r)
+	if err != nil {
+		return nil, fmt.Errorf("get size of vector: %w", err)
+	}
+
+	result := make([]wasm.ElementSegment, vs)
+	for i := uint32(0); i < vs; i++ {
+		if err = decodeElementSegment(r, enabledFeatures, &result[i]); err != nil {
+			return nil, fmt.Errorf("read element: %w", err)
+		}
+	}
+	return result, nil
+}
+
+func decodeCodeSection(r *bytes.Reader) ([]wasm.Code, error) {
+	codeSectionStart := uint64(r.Len())
+	vs, _, err := leb128.DecodeUint32(r)
+	if err != nil {
+		return nil, fmt.Errorf("get size of vector: %w", err)
+	}
+
+	result := make([]wasm.Code, vs)
+	for i := uint32(0); i < vs; i++ {
+		err = decodeCode(r, codeSectionStart, &result[i])
+		if err != nil {
+			return nil, fmt.Errorf("read %d-th code segment: %v", i, err)
+		}
+	}
+	return result, nil
+}
+
+func decodeDataSection(r *bytes.Reader, enabledFeatures api.CoreFeatures) ([]wasm.DataSegment, error) {
+	vs, _, err := leb128.DecodeUint32(r)
+	if err != nil {
+		return nil, fmt.Errorf("get size of vector: %w", err)
+	}
+
+	result := make([]wasm.DataSegment, vs)
+	for i := uint32(0); i < vs; i++ {
+		if err = decodeDataSegment(r, enabledFeatures, &result[i]); err != nil {
+			return nil, fmt.Errorf("read data segment: %w", err)
+		}
+	}
+	return result, nil
+}
+
+func decodeDataCountSection(r *bytes.Reader) (count *uint32, err error) {
+	v, _, err := leb128.DecodeUint32(r)
+	if err != nil && err != io.EOF {
+		// data count is optional, so EOF is fine.
+		return nil, err
+	}
+	return &v, nil
+}