1 files changed, 52 insertions, 0 deletions
diff --git a/src/bg/ContentScriptOnce.js b/src/bg/ContentScriptOnce.js
new file mode 100644
index 0000000..5be602e
--- /dev/null
+++ b/src/bg/ContentScriptOnce.js
@@ -0,0 +1,52 @@
+var ContentScriptOnce = (() => {
+  "use strict";
+  
+  let requestMap = new Map();
+  
+  {
+    let cleanup = r => {
+      let {requestId} = r;
+      let scripts = requestMap.get(requestId);
+      if (scripts) {
+        window.setTimeout(() => {
+          requestMap.delete(requestId);
+          for (let s of scripts) s.unregister();
+        }, 0);
+      }
+    }
+    
+    let filter = {
+      urls: ["<all_urls>"],
+      types:  ["main_frame", "sub_frame", "object"]
+    };
+    let wr = browser.webRequest;
+    for (let event of ["onCompleted", "onErrorOccurred"]) {
+      wr[event].addListener(cleanup, filter);
+    }
+  }
+  
+  return {
+    async execute(request, options) {
+      let {requestId, url} = request; 
+      let scripts = requestMap.get(requestId);
+      if (!scripts) requestMap.set(requestId, scripts = new Set());
+      try {
+        let urlObj = new URL(url);
+        if (urlObj.port) {
+          urlObj.port = "";
+          url = urlObj.toString();
+        }
+      } catch (e) {}
+      let defOpts = {
+        runAt: "document_start",
+        matchAboutBlank: true,
+        matches: [url],
+        allFrames: true,
+      };
+      
+      scripts.add(await browser.contentScripts.register(
+        Object.assign(defOpts, options)
+      ));
+    }
+  }
+})();