[FAB-11294] Prover Service - List Tokens

This change-set does the following:
- Update prover.proto to support ListUnspentTokens command
- Implement ListUnspentTokens for Prover service
- Add transactor interface to reduce dependency on TMS

Change-Id: Ib8b9d8564933aadd85aacc05267f10ca3a1274b8
Signed-off-by: Wenjian Qiao <wenjianq@gmail.com>

protos/token/prover.proto

@@ -35,6 +35,28 @@ message RecipientTransferShare {
     uint64 quantity = 2;
 }
 
+// TokenOutput is used to specify a token returned by ListRequest
+message TokenOutput {
+    // ID is used to uniquely identify the token
+    bytes id = 1;
+
+    // Type is the type of the token
+    string type = 2;
+
+    // Quantity represents the number for this type of token
+    uint64 quantity = 3;
+}
+
+// UnspentTokens is used to hold the output of listRequest
+message UnspentTokens {
+    repeated TokenOutput tokens = 1;
+}
+
+// ListRequest is used to request a list of unspent tokens
+message ListRequest {
+    bytes credential = 1;
+}
+
 // ImportRequest is used to request creation of imports
 message ImportRequest {
     // Credential contains information about the party who is requesting the operation
@@ -82,6 +104,7 @@ message Command {
     oneof payload {
         ImportRequest import_request = 2;
         TransferRequest transfer_request = 3;
+        ListRequest list_request = 4;
     }
 }
 
@@ -109,7 +132,7 @@ message CommandResponseHeader {
     bytes creator = 3;
 }
 
-// Error reports an applicaton error
+// Error reports an application error
 message Error {
     // Message associated with this response.
     string message = 1;
@@ -127,6 +150,7 @@ message CommandResponse {
     oneof payload {
         Error err = 2;
         TokenTransaction token_transaction = 3;
+        UnspentTokens unspent_tokens = 4;
     }
 }
 

token/server/manager.go

@@ -21,3 +21,9 @@ type Manager struct {
 func (t *Manager) GetIssuer(channel string, privateCredential, publicCredential []byte) (Issuer, error) {
 	return &plain.Issuer{}, nil
 }
+
+// GetTransactor returns a Transactor bound to the passed channel and whose credential
+// is the tuple (privateCredential, publicCredential).
+func (t *Manager) GetTransactor(channel string, privateCredential, publicCredential []byte) (Transactor, error) {
+	panic("not implemented yet")
+}

token/server/prover.go

@@ -55,6 +55,8 @@ func (s *Prover) ProcessCommand(ctx context.Context, sc *token.SignedCommand) (*
 	switch t := command.GetPayload().(type) {
 	case *token.Command_ImportRequest:
 		payload, err = s.RequestImport(ctx, command.Header, t.ImportRequest)
+	case *token.Command_ListRequest:
+		payload, err = s.ListUnspentTokens(ctx, command.Header, t.ListRequest)
 	default:
 		err = errors.Errorf("command type not recognized: %T", t)
 	}
@@ -82,6 +84,23 @@ func (s *Prover) RequestImport(ctx context.Context, header *token.Header, reques
 	return &token.CommandResponse_TokenTransaction{TokenTransaction: tokenTransaction}, nil
 }
 
+func (s *Prover) ListUnspentTokens(ctxt context.Context, header *token.Header, listRequest *token.ListRequest) (*token.CommandResponse_UnspentTokens, error) {
+	trasactor, err := s.TMSManager.GetTransactor(header.ChannelId, listRequest.Credential, header.Creator)
+	if err != nil {
+		return nil, err
+	}
+
+	tokens, err := trasactor.ListUnspentTokens()
+	if err != nil {
+		return nil, err
+	}
+
+	return &token.CommandResponse_UnspentTokens{
+		UnspentTokens: &token.UnspentTokens{
+			Tokens: tokens,
+		}}, nil
+}
+
 func (s *Prover) ValidateHeader(header *token.Header) error {
 	if header == nil {
 		return errors.New("command header is required")