enhancements to code folding

README.md

@@ -25,6 +25,9 @@ MATLAB language server supports these editors by installing the corresponding ex
 
 ### Unreleased
 
+Fixed:
+* General bug fixes
+
 ### 1.2.1
 Release date: 2024-04-04
 

matlab/+matlabls/+handlers/FoldingSupportHandler.m

@@ -0,0 +1,33 @@
+classdef (Hidden) FoldingSupportHandler < matlabls.handlers.FeatureHandler
+    % FOLDINGSUPPORTHANDLER The feature handler for retrieving a document's
+    % folding ranges.
+
+    % Copyright 2024 The MathWorks, Inc.
+
+
+    properties (Access = private)
+        RequestChannel = "/matlabls/foldDocument/request"
+        ResponseChannel = "/matlabls/foldDocument/response"
+    end
+
+    methods
+        function this = FoldingSupportHandler ()
+            this = this@matlabls.handlers.FeatureHandler();
+            this.RequestSubscriptions = matlabls.internal.CommunicationManager.subscribe(this.RequestChannel, @this.handleFoldingRangeRequest);
+        end
+    end
+
+    methods (Access = private)
+        function handleFoldingRangeRequest (this, msg)
+            % Handles folding range requests
+            codeToFold = msg.code;
+
+            fRangesArray = matlabls.internal.getFoldingRanges(codeToFold);
+            response.data = fRangesArray;
+
+            % Send folding ranges
+            responseChannel = strcat(this.ResponseChannel, '/', msg.channelId);
+            matlabls.internal.CommunicationManager.publish(responseChannel, response.data)
+        end
+    end
+end

matlab/+matlabls/MatlabLanguageServerHelper.m

@@ -31,6 +31,7 @@ function initializeFeatureHandlers (this)
             this.FeatureHandlers(end + 1) = matlabls.handlers.IndexingHandler();
             this.FeatureHandlers(end + 1) = matlabls.handlers.LintingSupportHandler();
             this.FeatureHandlers(end + 1) = matlabls.handlers.NavigationSupportHandler();
+            this.FeatureHandlers(end + 1) = matlabls.handlers.FoldingSupportHandler();
         end
     end
 end

src/providers/folding/FoldingSupportProvider.ts

@@ -0,0 +1,82 @@
+// Copyright 2024 The MathWorks, Inc.
+
+import { FoldingRangeParams, TextDocuments, FoldingRange} from 'vscode-languageserver'
+import { TextDocument } from 'vscode-languageserver-textdocument'
+import { URI } from 'vscode-uri'
+import MatlabLifecycleManager from '../../lifecycle/MatlabLifecycleManager'
+import { MatlabConnection } from '../../lifecycle/MatlabCommunicationManager'
+
+
+class FoldingSupportProvider {
+    private readonly REQUEST_CHANNEL = '/matlabls/foldDocument/request'
+    private readonly RESPONSE_CHANNEL = '/matlabls/foldDocument/response'
+
+    async handleFoldingRangeRequest (params: FoldingRangeParams, documentManager: TextDocuments<TextDocument>): Promise<FoldingRange[] | null> {
+        const docToFold = documentManager.get(params.textDocument.uri)
+        if (docToFold == null) {
+            return null
+        }
+
+        const matlabConnection = await MatlabLifecycleManager.getMatlabConnection()
+        const isMatlabAvailable = (matlabConnection != null)
+        const matlabRelease = MatlabLifecycleManager.getMatlabRelease()
+
+        // check for connection and release
+        if (!isMatlabAvailable || (matlabRelease == null) || (matlabRelease < 'R2024b')) {
+            return null
+        }
+
+        const fileName = URI.parse(docToFold.uri).fsPath
+        const code = docToFold.getText()
+
+        const frArray = await this.getFoldingRangesFromMatlab(code, fileName, matlabConnection)
+
+        const foldingRanges = this.processFoldingRanges(frArray)
+
+        return foldingRanges;
+    }
+
+    /**
+     * Gets folding ranges from MATLAB.
+     *
+     * @param code The code in the file
+     * @param fileName The file's name
+     * @param matlabConnection The connection to MATLAB
+     * @returns An array of line numbers
+     */
+    private async getFoldingRangesFromMatlab (code: string, fileName: string, matlabConnection: MatlabConnection): Promise<number[]> {
+        return await new Promise<number[]>(resolve => {
+            const channelId = matlabConnection.getChannelId()
+            const channel = `${this.RESPONSE_CHANNEL}/${channelId}`
+            const responseSub = matlabConnection.subscribe(channel, message => {
+                matlabConnection.unsubscribe(responseSub)
+                resolve(message as number[])
+            })
+
+            matlabConnection.publish(this.REQUEST_CHANNEL, {
+                code,
+                fileName,
+                channelId
+            })
+        })
+    }
+
+    /**
+     * Processes folding range data from MATLAB.
+     *
+     * @param frArray An array of line numbers from MATLAB
+     * @returns An array of FoldingRanges
+     */
+    private processFoldingRanges (frArray: number[]): FoldingRange[] {
+        let fRangeArray: FoldingRange[] = []
+
+        for(let i = 0; i < frArray.length; i = i+2) {
+            let fRange = FoldingRange.create(frArray[i] - 1, frArray[i+1] - 1)
+            fRangeArray.push(fRange)
+        }
+
+        return fRangeArray
+    }
+}
+
+export default new FoldingSupportProvider()

src/server.ts

@@ -16,6 +16,8 @@ import ExecuteCommandProvider, { MatlabLSCommands } from './providers/lspCommand
 import NavigationSupportProvider, { RequestType } from './providers/navigation/NavigationSupportProvider'
 import LifecycleNotificationHelper from './lifecycle/LifecycleNotificationHelper'
 import MVM from './mvm/MVM'
+import FoldingSupportProvider from './providers/folding/FoldingSupportProvider'
+import { FoldingRange } from 'vscode-languageserver'
 
 // Create a connection for the server
 export const connection = createConnection(ProposedFeatures.all)
@@ -68,6 +70,7 @@ connection.onInitialize((params: InitializeParams) => {
             executeCommandProvider: {
                 commands: Object.values(MatlabLSCommands)
             },
+            foldingRangeProvider: true,
             referencesProvider: true,
             signatureHelpProvider: {
                 triggerCharacters: ['(', ',']
@@ -178,6 +181,14 @@ connection.onSignatureHelp(async params => {
     return await CompletionProvider.handleSignatureHelpRequest(params, documentManager)
 })
 
+/** -------------------- FOLDING SUPPORT -------------------- **/
+connection.onFoldingRanges(async params => {
+    // Retrieve the folding ranges
+    // If there are valid folding ranges, hand them back to the IDE
+    // Else, return null, so the IDE falls back to indent-based folding
+    return await FoldingSupportProvider.handleFoldingRangeRequest(params, documentManager)  
+})
+
 /** -------------------- FORMATTING SUPPORT -------------------- **/
 connection.onDocumentFormatting(async params => {
     // Gather a set of document edits required for formatting, which the IDE will execute