Support querydb blocked notifications

Author: jacobdufault

package.json

@@ -7,7 +7,7 @@
   "publisher": "cquery-project",
   "preview": true,
   "engines": {
-    "vscode": "^1.18.0"
+    "vscode": "^1.22.0"
   },
   "categories": [
     "Programming Languages"
@@ -166,6 +166,11 @@
           "default": "",
           "description": "Absolute path to the directory that the cached index will be stored in. Try to have this directory on an SSD. If not explicitly set, this will be automatically populated with the extension cache directory.\n\n${workspaceFolder} will be replaced by the folder where .vscode/settings.json resides.\n\nCache directories are project-wide, so this should be configured in the workspace settings so multiple indexes do not clash.\n\nExample value: \"/work/cquery-cache/chrome/\""
         },
+        "cquery.developer.emitQueryDbBlocked": {
+          "type": "boolean",
+          "default": false,
+          "description": "If true, a notification will be shown whenever the querydb thread is busy."
+        },
         "cquery.highlighting.enabled.types": {
           "type": "boolean",
           "default": false,

src/extension.ts

@@ -84,6 +84,7 @@ function getClientConfig(context: ExtensionContext) {
     ['launchCommand', 'launch.command'],
     ['launchArgs', 'launch.args'],
     ['cacheDirectory', kCacheDirPrefName],
+    ['emitQueryDbBlocked', 'cquery.developer.emitQueryDbBlocked'],
     ['index.whitelist', 'index.whitelist'],
     ['index.blacklist', 'index.blacklist'],
     ['index.logSkippedPaths', 'log.skippedPathsForIndex'],
@@ -517,6 +518,42 @@ export function activate(context: ExtensionContext) {
     }
   })();
 
+  // QueryDb busy
+  (() => {
+    // Notifications have a minimum time to live. If the status changes multiple
+    // times within that interface, we will show multiple notifications. Try to
+    // avoid that.
+    const kGracePeriodMs = 250;
+
+    var timeout: NodeJS.Timer
+    var resolvePromise: any
+    languageClient.onReady().then(() => {
+      languageClient.onNotification('$cquery/queryDbStatus', (args) => {
+        let isActive: boolean = args.isActive;
+        if (isActive) {
+          if (timeout) {
+            clearTimeout(timeout);
+            timeout = undefined;
+          }
+          else {
+            window.withProgress({location: ProgressLocation.Notification, title: 'querydb is busy'}, (p) => {
+              p.report({increment: 100})
+              return new Promise((resolve, reject) => {
+                resolvePromise = resolve;
+              });
+            });
+          }
+        } else if (resolvePromise) {
+          timeout = setTimeout(() => {
+            resolvePromise();
+            resolvePromise = undefined;
+            timeout = undefined;
+          }, kGracePeriodMs);
+        }
+      });
+    });
+  })();
+
   // Inheritance hierarchy.
   (() => {
     const inheritanceHierarchyProvider =