feat(schema): indexing API (#20647)

schema/decoding/resolver.go

@@ -0,0 +1,66 @@
+package decoding
+
+import (
+	"sort"
+
+	"cosmossdk.io/schema"
+)
+
+// DecoderResolver is an interface that allows indexers to discover and use module decoders.
+type DecoderResolver interface {
+	// IterateAll iterates over all available module decoders.
+	IterateAll(func(moduleName string, cdc schema.ModuleCodec) error) error
+
+	// LookupDecoder looks up a specific module decoder.
+	LookupDecoder(moduleName string) (decoder schema.ModuleCodec, found bool, err error)
+}
+
+// ModuleSetDecoderResolver returns DecoderResolver that will discover modules implementing
+// DecodeableModule in the provided module set.
+func ModuleSetDecoderResolver(moduleSet map[string]interface{}) DecoderResolver {
+	return &moduleSetDecoderResolver{
+		moduleSet: moduleSet,
+	}
+}
+
+type moduleSetDecoderResolver struct {
+	moduleSet map[string]interface{}
+}
+
+func (a moduleSetDecoderResolver) IterateAll(f func(string, schema.ModuleCodec) error) error {
+	keys := make([]string, 0, len(a.moduleSet))
+	for k := range a.moduleSet {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	for _, k := range keys {
+		module := a.moduleSet[k]
+		dm, ok := module.(schema.HasModuleCodec)
+		if ok {
+			decoder, err := dm.ModuleCodec()
+			if err != nil {
+				return err
+			}
+			err = f(k, decoder)
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
+func (a moduleSetDecoderResolver) LookupDecoder(moduleName string) (schema.ModuleCodec, bool, error) {
+	mod, ok := a.moduleSet[moduleName]
+	if !ok {
+		return schema.ModuleCodec{}, false, nil
+	}
+
+	dm, ok := mod.(schema.HasModuleCodec)
+	if !ok {
+		return schema.ModuleCodec{}, false, nil
+	}
+
+	decoder, err := dm.ModuleCodec()
+	return decoder, true, err
+}