mvp working

src/background/main.ts

@@ -0,0 +1,132 @@
+declare const browser: typeof chrome;
+
+// tabSwitches is a stack of all tab activations. every time a tab becomes
+// active it is prepended (unshift) to the front of the array. this means that
+// there will be duplicate IDs in the array.
+//
+// this is handled in 2 ways:
+// 1. when the popup opens and asks for a list of tabs, we will only insert the tab
+// in the result when it is _first_ seen and ignored thereafter. however, over
+// time this will lead to a lot of wasted work since most of the iteration will
+// be just skipping elements in this array.
+//
+// 2. the array is periodically "compacted" by simply running it through a uniq()
+// operation, therefore reducing most wasted work most of the time.
+let tabSwitches: number[] = [];
+
+function uniq<T = any>(array: T[]): T[] {
+  if (array.length <= 1) {
+    return array;
+  }
+  const seen = new Set<T>();
+  const result = [];
+  for (let ele of array) {
+    if (seen.has(ele)) {
+      continue;
+    }
+    seen.add(ele);
+    result.push(ele);
+  }
+  return result;
+}
+
+setInterval(() => {
+  // periodically compact tabSwitches
+  tabSwitches = uniq(tabSwitches);
+}, 1000);
+
+try {
+  browser.runtime.onConnect.addListener((port) => {
+    port.onMessage.addListener((message) => {
+      switch (message.rpc) {
+        case "listTabs":
+          console.time(`rpc:listTabs:${message.id}`);
+          browser.tabs
+            .query({})
+            .then((tabs) => {
+              // filter out file:///... things, safari does not really have
+              // safari://... things like chrome
+              tabs = tabs.filter((t) => t.url || t.title);
+
+              const hit = new Map<number, boolean>(
+                tabs.filter((t) => !!t.id).map((t) => [t.id!, false])
+              );
+              const tabsById = new Map<number, chrome.tabs.Tab>(
+                tabs.filter((t) => !!t.id).map((t) => [t.id!, t])
+              );
+              const resultTabs = [];
+              for (let tabId of tabSwitches.slice(1)) {
+                if (hit.get(tabId)) {
+                  continue;
+                }
+                hit.set(tabId, true);
+                const tab = tabsById.get(tabId);
+                if (!tab) {
+                  continue;
+                }
+                resultTabs.push(tab);
+              }
+              for (let [tabId, didHit] of hit.entries()) {
+                if (didHit) {
+                  continue;
+                }
+                const tab = tabsById.get(tabId);
+                if (!tab) {
+                  continue;
+                }
+                resultTabs.push(tab);
+              }
+              port.postMessage({
+                result: resultTabs,
+                id: message.id,
+              });
+            })
+            .finally(() => {
+              console.timeEnd(`rpc:listTabs:${message.id}`);
+            });
+          return;
+        default:
+          port.postMessage({
+            error: `unknown rpc method: ${message.rpc}`,
+            id: message.id,
+          });
+      }
+    });
+  });
+
+  type Command = () => Promise<void> | void;
+
+  browser.tabs.onActivated.addListener((activeInfo) => {
+    if (activeInfo.tabId) {
+      tabSwitches.unshift(activeInfo.tabId);
+    }
+  });
+
+  const commands = new Map<string, Command>([
+    [
+      "openTabSwitcher",
+      async () => {
+        console.log("open that tab switcher!");
+        await (browser as any).browserAction.openPopup();
+        // await browser.action.openPopup();
+      },
+    ],
+  ]);
+
+  browser.commands.onCommand.addListener(async (command) => {
+    console.log(`received keyboard shortcut: ${command}`);
+    const fn = commands.get(command);
+    if (!fn) {
+      throw new Error(`unmapped command: ${command}`);
+    }
+    try {
+      await Promise.resolve(fn());
+    } catch (e) {
+      console.error(`command function failed: ${e}`);
+    }
+  });
+} catch (e) {
+  // wrapping everything in a try/catch because F-ING SAFARI refuses to
+  // help you understand why background scripts fail. (https://developer.apple.com/forums/thread/705321)
+  console.error(`background startup failure: ${e}`);
+}