add DocumentLink support

language-server/src/build-server.ts

@@ -11,6 +11,7 @@ import { Completion } from "./features/Completion.ts";
 import { FoldingRanges } from "./features/FoldingRanges.ts";
 import { DocumentSymbols } from "./features/DocumentSymbols.ts";
 import { SelectionRanges } from "./features/SelectionRanges.ts";
+import { DocumentLinks } from "./features/DocumentLinks.ts";
 
 import "@hyperjump/json-schema/draft-2020-12";
 import "@hyperjump/json-schema/draft-2019-09";
@@ -43,6 +44,7 @@ export const buildServer = (connection: Connection): Server => {
   new FoldingRanges(server, documents);
   new DocumentSymbols(server, documents);
   new SelectionRanges(server, documents);
+  new DocumentLinks(server, documents, workspace);
 
   return server;
 };

language-server/src/features/DocumentLinks.test.ts

@@ -0,0 +1,95 @@
+import { describe, test, expect, beforeEach, afterEach } from "vitest";
+import { DocumentLinkRequest } from "vscode-languageserver";
+import { TestClient } from "../test/TestClient.ts";
+
+describe("DocumentLinks", () => {
+  let client: TestClient;
+
+  beforeEach(async () => {
+    client = new TestClient();
+    await client.start();
+  });
+
+  afterEach(async () => {
+    await client.stop();
+  });
+
+  test("should return a link for a $schema that resolves to a schema file in the workspace", async () => {
+    const schemaUri = await client.writeDocument("schema.json", `{
+      "type": "object"
+    }`);
+
+    const instanceUri = await client.writeDocument("instance.json", `{
+      "$schema": "./schema.json"
+    }`);
+    const uri = await client.openDocument("instance.json");
+
+    const result = await client.sendRequest(DocumentLinkRequest.type, {
+      textDocument: { uri }
+    });
+
+    expect(uri).toBe(instanceUri);
+    expect(result).toEqual([
+      {
+        target: schemaUri,
+        tooltip: "Click to open schema file",
+        range: {
+          start: { line: 1, character: 18 },
+          end: { line: 1, character: 31 }
+        }
+      }
+    ]);
+  });
+
+  test("should not return a link for a $schema resolved from SchemaStore.org", async () => {
+    await client.writeDocument("instance.json", `{
+      "$schema": "https://json.schemastore.org/package.json"
+    }`);
+    const uri = await client.openDocument("instance.json");
+
+    const result = await client.sendRequest(DocumentLinkRequest.type, {
+      textDocument: { uri }
+    });
+
+    expect(result).toEqual([]);
+  });
+
+  test("should not return a link when $schema resolves outside the workspace", async () => {
+    await client.writeDocument("instance.json", `{
+      "$schema": "../../schema.json"
+    }`);
+    const uri = await client.openDocument("instance.json");
+
+    const result = await client.sendRequest(DocumentLinkRequest.type, {
+      textDocument: { uri }
+    });
+
+    expect(result).toEqual([]);
+  });
+
+  test("should return an empty array when the document has no $schema", async () => {
+    await client.writeDocument("instance.json", `{"type": "string"}`);
+    const uri = await client.openDocument("instance.json");
+
+    const result = await client.sendRequest(DocumentLinkRequest.type, {
+      textDocument: { uri }
+    });
+
+    expect(result).toEqual([]);
+  });
+
+  test("should not treat a nested $schema property as the document's dialect schema", async () => {
+    await client.writeDocument("instance.json", `{
+      "properties": {
+        "$schema": { "type": "string" }
+      }
+    }`);
+    const uri = await client.openDocument("instance.json");
+
+    const result = await client.sendRequest(DocumentLinkRequest.type, {
+      textDocument: { uri }
+    });
+
+    expect(result).toEqual([]);
+  });
+});

language-server/src/features/DocumentLinks.ts

@@ -0,0 +1,62 @@
+import { normalizeIri, resolveIri } from "@hyperjump/uri";
+
+import type { DocumentLink, ServerCapabilities } from "vscode-languageserver";
+import type { Server } from "../services/Server.ts";
+import type { JsonDocuments } from "../services/JsonDocuments.ts";
+import type { Workspace } from "../services/Workspace.ts";
+
+export class DocumentLinks {
+  private jsonDocuments: JsonDocuments;
+  private workspace: Workspace;
+
+  constructor(server: Server, jsonDocuments: JsonDocuments, workspace: Workspace) {
+    this.jsonDocuments = jsonDocuments;
+    this.workspace = workspace;
+
+    server.onInitialize(() => {
+      const serverCapabilities: ServerCapabilities = {
+        documentLinkProvider: {}
+      };
+
+      return {
+        capabilities: serverCapabilities
+      };
+    });
+
+    server.onDocumentLinks((params) => {
+      const jsonDocument = this.jsonDocuments.get(params.textDocument.uri)!;
+
+      const schemaNode = jsonDocument.findNodeAtPointer("/$schema");
+      if (schemaNode?.type !== "string") {
+        return [];
+      }
+
+      let schemaUri: string;
+      try {
+        schemaUri = resolveIri(schemaNode.value as string, jsonDocument.uri);
+      } catch {
+        return [];
+      }
+
+      const isWorkspaceSchema = [...this.workspace.workspaceFolders].some((workspaceFolderUri) => {
+        const normalized = normalizeIri(workspaceFolderUri);
+        const prefix = normalized.endsWith("/") ? normalized : `${normalized}/`;
+        return schemaUri.startsWith(prefix);
+      });
+      if (!isWorkspaceSchema) {
+        return [];
+      }
+
+      const link: DocumentLink = {
+        target: schemaUri,
+        tooltip: "Click to open schema file",
+        range: {
+          start: jsonDocument.positionAt(schemaNode.offset + 1),
+          end: jsonDocument.positionAt(schemaNode.offset + schemaNode.length - 1)
+        }
+      };
+
+      return [link];
+    });
+  }
+}