Add SentinelTypeNode (#204)

.changeset/thick-deers-applaud.md

@@ -0,0 +1,5 @@
+---
+"@metaplex-foundation/kinobi": minor
+---
+
+Add SentinelTypeNode

src/nodes/typeNodes/NestedTypeNode.ts

@@ -1,15 +1,17 @@
 import { Node, isNode } from '../Node';
-import { FixedSizeTypeNode } from './FixedSizeTypeNode';
-import { PostOffsetTypeNode } from './PostOffsetTypeNode';
-import { PreOffsetTypeNode } from './PreOffsetTypeNode';
-import { SizePrefixTypeNode } from './SizePrefixTypeNode';
+import type { FixedSizeTypeNode } from './FixedSizeTypeNode';
+import type { PostOffsetTypeNode } from './PostOffsetTypeNode';
+import type { PreOffsetTypeNode } from './PreOffsetTypeNode';
+import type { SentinelTypeNode } from './SentinelTypeNode';
+import type { SizePrefixTypeNode } from './SizePrefixTypeNode';
 import { TYPE_NODES, TypeNode } from './TypeNode';
 
 export type NestedTypeNode<TType extends TypeNode> =
   | TType
   | FixedSizeTypeNode<NestedTypeNode<TType>>
   | PostOffsetTypeNode<NestedTypeNode<TType>>
   | PreOffsetTypeNode<NestedTypeNode<TType>>
+  | SentinelTypeNode<NestedTypeNode<TType>>
   | SizePrefixTypeNode<NestedTypeNode<TType>>;
 
 export function resolveNestedTypeNode<TType extends TypeNode>(
@@ -19,6 +21,7 @@ export function resolveNestedTypeNode<TType extends TypeNode>(
     case 'fixedSizeTypeNode':
     case 'postOffsetTypeNode':
     case 'preOffsetTypeNode':
+    case 'sentinelTypeNode':
     case 'sizePrefixTypeNode':
       return resolveNestedTypeNode<TType>(
         typeNode.type as NestedTypeNode<TType>
@@ -39,6 +42,7 @@ export function transformNestedTypeNode<
     case 'fixedSizeTypeNode':
     case 'postOffsetTypeNode':
     case 'preOffsetTypeNode':
+    case 'sentinelTypeNode':
     case 'sizePrefixTypeNode':
       return {
         ...typeNode,

src/nodes/typeNodes/SentinelTypeNode.ts

@@ -0,0 +1,20 @@
+import { ConstantValueNode } from '../valueNodes';
+import { TypeNode } from './TypeNode';
+
+export interface SentinelTypeNode<
+  TType extends TypeNode = TypeNode,
+  TSentinel extends ConstantValueNode = ConstantValueNode,
+> {
+  readonly kind: 'sentinelTypeNode';
+
+  // Children.
+  readonly type: TType;
+  readonly sentinel: TSentinel;
+}
+
+export function sentinelTypeNode<
+  TType extends TypeNode,
+  TSentinel extends ConstantValueNode,
+>(type: TType, sentinel: TSentinel): SentinelTypeNode<TType, TSentinel> {
+  return { kind: 'sentinelTypeNode', type, sentinel };
+}

src/nodes/typeNodes/TypeNode.ts

@@ -19,6 +19,7 @@ import { OptionTypeNode, optionTypeNodeFromIdl } from './OptionTypeNode';
 import { PostOffsetTypeNode } from './PostOffsetTypeNode';
 import { PreOffsetTypeNode } from './PreOffsetTypeNode';
 import { PublicKeyTypeNode, publicKeyTypeNode } from './PublicKeyTypeNode';
+import { SentinelTypeNode } from './SentinelTypeNode';
 import { SetTypeNode, setTypeNodeFromIdl } from './SetTypeNode';
 import { SizePrefixTypeNode, sizePrefixTypeNode } from './SizePrefixTypeNode';
 import { SolAmountTypeNode } from './SolAmountTypeNode';
@@ -42,6 +43,7 @@ export type StandaloneTypeNode =
   | PostOffsetTypeNode
   | PreOffsetTypeNode
   | PublicKeyTypeNode
+  | SentinelTypeNode
   | SetTypeNode
   | SizePrefixTypeNode
   | SolAmountTypeNode
@@ -62,6 +64,7 @@ export const STANDALONE_TYPE_NODE_KINDS = [
   'postOffsetTypeNode',
   'preOffsetTypeNode',
   'publicKeyTypeNode',
+  'sentinelTypeNode',
   'setTypeNode',
   'sizePrefixTypeNode',
   'solAmountTypeNode',

src/nodes/typeNodes/index.ts

@@ -16,6 +16,7 @@ export * from './OptionTypeNode';
 export * from './PostOffsetTypeNode';
 export * from './PreOffsetTypeNode';
 export * from './PublicKeyTypeNode';
+export * from './SentinelTypeNode';
 export * from './SetTypeNode';
 export * from './SizePrefixTypeNode';
 export * from './SolAmountTypeNode';

src/visitors/identityVisitor.ts

@@ -48,6 +48,7 @@ import {
   removeNullAndAssertIsNodeFilter,
   resolverValueNode,
   rootNode,
+  sentinelTypeNode,
   setTypeNode,
   setValueNode,
   sizePrefixTypeNode,
@@ -643,6 +644,18 @@ export function identityVisitor<TNodeKind extends NodeKind = NodeKind>(
     };
   }
 
+  if (castedNodeKeys.includes('sentinelTypeNode')) {
+    visitor.visitSentinelType = function visitSentinelType(node) {
+      const sentinel = visit(this)(node.sentinel);
+      if (sentinel === null) return null;
+      assertIsNode(sentinel, 'constantValueNode');
+      const type = visit(this)(node.type);
+      if (type === null) return null;
+      assertIsNode(type, TYPE_NODES);
+      return sentinelTypeNode(type, sentinel);
+    };
+  }
+
   if (castedNodeKeys.includes('constantDiscriminatorNode')) {
     visitor.visitConstantDiscriminator = function visitConstantDiscriminator(
       node

src/visitors/mergeVisitor.ts

@@ -356,6 +356,15 @@ export function mergeVisitor<TReturn, TNodeKind extends NodeKind = NodeKind>(
     };
   }
 
+  if (castedNodeKeys.includes('sentinelTypeNode')) {
+    visitor.visitSentinelType = function visitSentinelType(node) {
+      return merge(node, [
+        ...visit(this)(node.sentinel),
+        ...visit(this)(node.type),
+      ]);
+    };
+  }
+
   if (castedNodeKeys.includes('constantDiscriminatorNode')) {
     visitor.visitConstantDiscriminator = function visitConstantDiscriminator(
       node

test/visitors/nodes/typeNodes/SentinelTypeNode.test.ts

@@ -0,0 +1,34 @@
+import test from 'ava';
+import {
+  constantValueNodeFromBytes,
+  sentinelTypeNode,
+  stringTypeNode,
+} from '../../../../src';
+import {
+  deleteNodesVisitorMacro,
+  getDebugStringVisitorMacro,
+  identityVisitorMacro,
+  mergeVisitorMacro,
+} from '../_setup';
+
+const node = sentinelTypeNode(
+  stringTypeNode('utf8'),
+  constantValueNodeFromBytes('base16', 'ffff')
+);
+
+test(mergeVisitorMacro, node, 5);
+test(identityVisitorMacro, node);
+test(deleteNodesVisitorMacro, node, '[sentinelTypeNode]', null);
+test(deleteNodesVisitorMacro, node, '[stringTypeNode]', null);
+test(deleteNodesVisitorMacro, node, '[constantValueNode]', null);
+test(
+  getDebugStringVisitorMacro,
+  node,
+  `
+sentinelTypeNode
+|   constantValueNode
+|   |   bytesTypeNode
+|   |   bytesValueNode [base16.ffff]
+|   stringTypeNode [utf8]
+`
+);