fix: Add lock to prevent double consent tab (#148)

The consent tab seems to be opening twice, once for update and once for
install. This lock prevents that from happening.

Tested to make sure it probably won't have a race condition where both
gets happen before the first set. It seems to work fine.

Author: spalmurray

src/background/main.ts

@@ -13,8 +13,11 @@ import {
 } from "./dynamic_content_scripts";
 
 async function handleConsent(): Promise<void> {
-  const consent = await new Codecov().getConsent();
-  if (consent === "none") {
+  const codecov = new Codecov();
+  const consent = await codecov.getConsent();
+  const canOpenConsentTab = await codecov.canOpenConsentTab();
+
+  if (consent === "none" && canOpenConsentTab) {
     const url = browser.runtime.getURL("consent.html");
     await browser.tabs.create({ url, active: true });
   }

src/constants.ts

@@ -2,6 +2,7 @@
 // We must update the key's version to re-request consent whenever the data we collect changes.
 export const allConsentStorageKey = "codecov-consent-0.6.3";
 export const onlyEssentialConsentStorageKey = "codecov-essential-consent-0.6.3";
+export const consentTabLock = "codecov-consent-tab-lock";
 
 export const codecovApiTokenStorageKey = "self_hosted_codecov_api_token";
 export const selfHostedCodecovURLStorageKey = "self_hosted_codecov_url";

src/service.ts

@@ -11,6 +11,7 @@ import {
   cacheTtlMs,
   allConsentStorageKey,
   onlyEssentialConsentStorageKey,
+  consentTabLock,
 } from "src/constants";
 import { Consent } from "./types";
 
@@ -286,4 +287,33 @@ export class Codecov {
 
     return consent;
   }
+
+  async canOpenConsentTab(): Promise<Boolean> {
+    // Returns false if the consent tab has been opened in the last two seconds.
+    // Resolves the case where two consent tabs are opened simultaneously.
+    const locked = await browser.storage.local
+      .get([consentTabLock])
+      .then((res) => res[consentTabLock]);
+
+    if (locked) {
+      return false;
+    }
+
+    // Acquire the lock and return true
+
+    const storageObject: { [id: string]: boolean } = {};
+    storageObject[consentTabLock] = true;
+
+    await browser.storage.local.set(storageObject);
+
+    // After 2 seconds, release the lock
+    setTimeout(() => {
+      const storageObject: { [id: string]: boolean } = {};
+      storageObject[consentTabLock] = false;
+
+      browser.storage.local.set(storageObject);
+    }, 2000);
+
+    return true;
+  }
 }