Soroban add meta and contract spec sections for add

addsec.go

package main

import (
	"bytes"
	"fmt"
	"log"
	"os"

	"github.com/tetratelabs/wabin/binary"
	"github.com/tetratelabs/wabin/wasm"
	"soneso.com/xdr"
)

const META_SECTION_NAME = "contractenvmetav0"
const SPEC_SECTION_NAME = "contractspecv0"

func main() {
	if len(os.Args) < 2 {
		log.Println("usage: wasmprepare <wasm file>")
		return
	}
	filename := os.Args[1]

	bin, err := os.ReadFile(filename)
	if err != nil {
		log.Panicln(err)
	}

	mod, err := binary.DecodeModule(bin, wasm.CoreFeaturesV2)
	if err != nil {
		log.Panicln(err)
	}

	xdrMeta := xdr.ScEnvMetaEntry{}
	xdrMeta.Kind = xdr.ScEnvMetaKind(xdr.ScEnvMetaKindScEnvMetaKindInterfaceVersion)
	var v xdr.Uint64 = 27
	xdrMeta.InterfaceVersion = &v
	var metaBytes bytes.Buffer

	_, err = xdr.Marshal(&metaBytes, xdrMeta)
	if err != nil {
		fmt.Println("error generating meta xdr")
	}

	xdrArg1 := xdr.ScSpecFunctionInputV0{}
	xdrArg1.Name = "x"
	xdrArg1.Type = xdr.ScSpecTypeDef{}
	xdrArg1.Type.Type = xdr.ScSpecTypeScSpecTypeU32

	xdrArg2 := xdr.ScSpecFunctionInputV0{}
	xdrArg2.Name = "y"
	xdrArg2.Type = xdr.ScSpecTypeDef{}
	xdrArg2.Type.Type = xdr.ScSpecTypeScSpecTypeU32

	xdrRet := xdr.ScSpecTypeDef{}
	xdrRet.Type = xdr.ScSpecTypeScSpecTypeU32

	xdrFunc := xdr.ScSpecFunctionV0{}
	xdrFunc.Name = xdr.ScSymbol("add")
	xdrFunc.Inputs = []xdr.ScSpecFunctionInputV0{xdrArg1, xdrArg2}
	xdrFunc.Outputs = []xdr.ScSpecTypeDef{xdrRet}

	xdrFuncEntry := xdr.ScSpecEntry{}
	xdrFuncEntry.Kind = xdr.ScSpecEntryKind(xdr.ScSpecEntryKindScSpecEntryFunctionV0)
	xdrFuncEntry.FunctionV0 = &xdrFunc

	var specBytes bytes.Buffer
	_, err = xdr.Marshal(&specBytes, xdrFuncEntry)
	if err != nil {
		fmt.Println("error generating spec xdr")
	}

	var meta *wasm.CustomSection
	var spec *wasm.CustomSection
	for _, custom := range mod.CustomSections {
		if custom.Name == META_SECTION_NAME {
			meta = custom
		} else if custom.Name == SPEC_SECTION_NAME {
			spec = custom
		}
	}
	changed := false

	if meta == nil {
		meta = &wasm.CustomSection{
			Name: META_SECTION_NAME,
			Data: metaBytes.Bytes(),
		}
		mod.CustomSections = append(mod.CustomSections, meta)
		changed = true
		fmt.Printf("Added %s section\n", META_SECTION_NAME)
	} else {
		fmt.Println("meta already present")
	}

	if spec == nil {
		spec = &wasm.CustomSection{
			Name: SPEC_SECTION_NAME,
			Data: specBytes.Bytes(),
		}
		mod.CustomSections = append(mod.CustomSections, spec)
		changed = true
		fmt.Printf("Added %s section\n", SPEC_SECTION_NAME)
	} else {
		fmt.Println("spec already present")
	}

	if changed {
		bin = binary.EncodeModule(mod)
		if err = os.WriteFile(filename, bin, 0644); err != nil {
			log.Panicln(err)
		}
	}
	fmt.Println("")
}