From dd1ace12f79b421b72ae54ade3d89f2035f9ece2 Mon Sep 17 00:00:00 2001
From: Alex Vanin <alexey@nspcc.ru>
Date: Tue, 20 Apr 2021 18:11:35 +0300
Subject: [PATCH] [#486] morph/client: Add option to setup custom alphabet
 source in notary

To enable notary support in main chain, notary subsystem should not get
alphabet keys from (main chain) committee. This key fetcher is now
separated and may be overwritten by `WithAlphabetSource` option.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>
---
 pkg/morph/client/notary.go | 45 ++++++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 14 deletions(-)

diff --git a/pkg/morph/client/notary.go b/pkg/morph/client/notary.go
index ea551890..cbc290f7 100644
--- a/pkg/morph/client/notary.go
+++ b/pkg/morph/client/notary.go
@@ -23,14 +23,19 @@ type (
 		roundTime    uint32 // extra amount of blocks to synchronize sidechain height diff of inner ring nodes
 		fallbackTime uint32 // amount of blocks before fallbackTx will be sent
 
+		alphabetSource AlphabetKeys // source of alphabet node keys to prepare witness
+
 		notary util.Uint160
 		proxy  util.Uint160
 	}
 
 	notaryCfg struct {
 		txValidTime, roundTime, fallbackTime uint32
+
+		alphabetSource AlphabetKeys
 	}
 
+	AlphabetKeys func() (keys.PublicKeys, error)
 	NotaryOption func(*notaryCfg)
 )
 
@@ -48,19 +53,20 @@ const (
 
 var errUnexpectedItems = errors.New("invalid number of NEO VM arguments on stack")
 
-func defaultNotaryConfig() *notaryCfg {
+func defaultNotaryConfig(c *Client) *notaryCfg {
 	return &notaryCfg{
-		txValidTime:  defaultNotaryValidTime,
-		roundTime:    defaultNotaryRoundTime,
-		fallbackTime: defaultNotaryFallbackTime,
+		txValidTime:    defaultNotaryValidTime,
+		roundTime:      defaultNotaryRoundTime,
+		fallbackTime:   defaultNotaryFallbackTime,
+		alphabetSource: c.Committee,
 	}
 }
 
 // EnableNotarySupport creates notary structure in client that provides
-// ability for client to get inner ring list from netmap contract and
-// use proxy contract script hash to create tx for notary contract.
-func (c *Client) EnableNotarySupport(proxy, netmap util.Uint160, opts ...NotaryOption) error {
-	cfg := defaultNotaryConfig()
+// ability for client to get alphabet keys from committee or provided source
+// and use proxy contract script hash to create tx for notary contract.
+func (c *Client) EnableNotarySupport(proxy util.Uint160, opts ...NotaryOption) error {
+	cfg := defaultNotaryConfig(c)
 
 	for _, opt := range opts {
 		opt(cfg)
@@ -72,11 +78,12 @@ func (c *Client) EnableNotarySupport(proxy, netmap util.Uint160, opts ...NotaryO
 	}
 
 	c.notary = &notary{
-		notary:       notaryContract,
-		proxy:        proxy,
-		txValidTime:  cfg.txValidTime,
-		roundTime:    cfg.roundTime,
-		fallbackTime: cfg.fallbackTime,
+		notary:         notaryContract,
+		proxy:          proxy,
+		txValidTime:    cfg.txValidTime,
+		roundTime:      cfg.roundTime,
+		fallbackTime:   cfg.fallbackTime,
+		alphabetSource: cfg.alphabetSource,
 	}
 
 	return nil
@@ -203,7 +210,7 @@ func (c *Client) notaryInvokeAsCommittee(contract util.Uint160, method string, a
 }
 
 func (c *Client) notaryInvoke(committee bool, contract util.Uint160, method string, args ...interface{}) error {
-	alphabetList, err := c.Committee() // prepare arguments for test invocation
+	alphabetList, err := c.notary.alphabetSource() // prepare arguments for test invocation
 	if err != nil {
 		return err
 	}
@@ -472,6 +479,16 @@ func WithFallbackTime(t uint32) NotaryOption {
 	}
 }
 
+// WithAlphabetSource returns a notary support option for client
+// that specifies function to return list of alphabet node keys.
+// By default notary subsystem uses committee as a source. This is
+// valid for side chain but notary in main chain should override it.
+func WithAlphabetSource(t AlphabetKeys) NotaryOption {
+	return func(c *notaryCfg) {
+		c.alphabetSource = t
+	}
+}
+
 const alreadyOnChainErrorMessage = "already on chain"
 
 // Neo RPC node can return `core.ErrInvalidAttribute` error with