Implement watch list management.

Author: whitequark

example/.vscode/settings.json

@@ -1,3 +1,6 @@
 {
-    "rtlDebugger.command": ["${workspaceFolder}/design_sim"]
-}
+    "rtlDebugger.command": [
+        "${workspaceFolder}/design_sim"
+    ],
+    "rtlDebugger.watchList": []
+}

package.json

@@ -23,9 +23,7 @@
       "$comment": "UPSTREAM: Unfortunately there is no way to control the formatting of the extension name within the setting title. See microsoft/vscode#103592",
       "properties": {
         "rtlDebugger.command": {
-          "type": [
-            "array"
-          ],
+          "type": "array",
           "items": {
             "type": "string"
           },
@@ -60,6 +58,20 @@
           ],
           "default": "Verilog",
           "markdownDescription": "Specifies the display format for variables."
+        },
+        "rtlDebugger.watchList": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "properties": {
+              "id": {"type": "string"},
+              "row": {"type": "integer"},
+              "bit": {"type": "integer"}
+            },
+            "required": ["id"],
+            "additionalProperties": false
+          },
+          "description": "Specifies the list of variables being watched separately."
         }
       }
     },
@@ -104,6 +116,18 @@
         "category": "RTL Debugger",
         "title": "Step Backward",
         "icon": "$(debug-step-back)"
+      },
+      {
+        "command": "rtlDebugger.watchVariable",
+        "category": "RTL Debugger",
+        "title": "Watch Variable",
+        "icon": "$(eye-watch)"
+      },
+      {
+        "command": "rtlDebugger.unWatchVariable",
+        "category": "RTL Debugger",
+        "title": "Stop Watching",
+        "icon": "$(remove)"
       }
     ],
     "viewsContainers": {
@@ -197,6 +221,18 @@
           "when": "view == rtlDebugger.sidebar && rtlDebugger.sessionStatus == running",
           "group": "navigation@5"
         }
+      ],
+      "view/item/context": [
+        {
+          "command": "rtlDebugger.watchVariable",
+          "when": "view == rtlDebugger.sidebar && viewItem == canWatch",
+          "group": "inline"
+        },
+        {
+          "command": "rtlDebugger.unWatchVariable",
+          "when": "view == rtlDebugger.sidebar && viewItem == inWatchList",
+          "group": "inline"
+        }
       ]
     }
   },

src/debug/session.ts

@@ -116,6 +116,17 @@ export class Session {
         );
     }
 
+    async getVariable(variableIdentifier: string): Promise<Variable | null> {
+        const identifierParts = variableIdentifier.split(' ');
+        const scopeIdentifier = identifierParts.slice(0, identifierParts.length - 1).join(' ');
+        const items = await this.listItemsInScope(scopeIdentifier);
+        if (variableIdentifier in items) {
+            return Variable.fromCXXRTL(variableIdentifier, items[variableIdentifier]);
+        } else {
+            return null;
+        }
+    }
+
     // ======================================== Querying the database
 
     private referenceEpochs: Map<string, number> = new Map();

src/debug/watch.ts

@@ -0,0 +1,44 @@
+import * as vscode from 'vscode';
+
+export interface IWatchItem {
+    id: string;
+    row?: number;
+    bit?: number;
+}
+
+export interface IWatchList {
+    get(): IWatchItem[];
+    set(items: IWatchItem[]): void;
+    append(item: IWatchItem): void;
+    remove(index: number): void;
+
+    onDidChange(callback: (items: IWatchItem[]) => any): vscode.Disposable;
+}
+
+export const watchList: IWatchList = {
+    get(): IWatchItem[] {
+        return vscode.workspace.getConfiguration('rtlDebugger').get('watchList') || [];
+    },
+
+    set(items: IWatchItem[]): void {
+        vscode.workspace.getConfiguration('rtlDebugger').update('watchList', items);
+    },
+
+    append(item: IWatchItem): void {
+        this.set(this.get().concat(item));
+    },
+
+    remove(index: number): void {
+        const items = this.get();
+        items.splice(index, 1);
+        this.set(items);
+    },
+
+    onDidChange(callback: (items: IWatchItem[]) => any): vscode.Disposable {
+        return vscode.workspace.onDidChangeConfiguration((event) => {
+            if (event.affectsConfiguration('rtlDebugger.watchList')) {
+                callback(watchList.get());
+            }
+        });
+    },
+};

src/extension.ts

@@ -1,15 +1,17 @@
 import * as vscode from 'vscode';
+import { watchList } from './debug/watch';
 import { CXXRTLDebugger } from './debugger';
 import * as sidebar from './ui/sidebar';
 import { inputTime } from './ui/input';
 
 export function activate(context: vscode.ExtensionContext) {
     const rtlDebugger = new CXXRTLDebugger();
-    const sidebarTreeDataProvider = new sidebar.TreeDataProvider(rtlDebugger);
 
-    context.subscriptions.push(vscode.window.createTreeView('rtlDebugger.sidebar', {
+    const sidebarTreeDataProvider = new sidebar.TreeDataProvider(rtlDebugger);
+    const sidebarTreeView = vscode.window.createTreeView('rtlDebugger.sidebar', {
         treeDataProvider: sidebarTreeDataProvider
-    }));
+    });
+    context.subscriptions.push(sidebarTreeView);
 
     vscode.commands.executeCommand('setContext', 'rtlDebugger.sessionStatus', rtlDebugger.sessionStatus);
     context.subscriptions.push(rtlDebugger.onDidChangeSessionStatus((state) =>
@@ -48,6 +50,11 @@ export function activate(context: vscode.ExtensionContext) {
     context.subscriptions.push(vscode.commands.registerCommand('rtlDebugger.stepForward', () =>
         rtlDebugger.session!.stepForward()));
 
+    context.subscriptions.push(vscode.commands.registerCommand('rtlDebugger.watchVariable', (treeItem) =>
+        watchList.append(treeItem.getWatchItem())));
+    context.subscriptions.push(vscode.commands.registerCommand('rtlDebugger.unWatchVariable', (treeItem) =>
+        watchList.remove(treeItem.metadata.index)));
+
     // For an unknown reason, the `vscode.open` command (which does the exact same thing) ignores the options.
     context.subscriptions.push(vscode.commands.registerCommand('rtlDebugger.openDocument',
         (uri: vscode.Uri, options: vscode.TextDocumentShowOptions) => {