Consolidate best effort policy fetching.

src/content/staticNS.js

@@ -95,42 +95,49 @@
       }
 
       if (!this.syncFetchPolicy) {
-
-        let msg = {id: "fetchChildPolicy", url};
-
-        let asyncFetch = (async () => {
-          let policy = null;
-          for (let attempts = 10; !(policy || this.policy) && attempts-- > 0;) {
-            try {
-              debug(`Retrieving policy asynchronously (${attempts} attempts left).`);
-              policy = await Messages.send(msg.id, msg) || this.domPolicy;
-              debug("Asynchronous policy", policy);
-            } catch (e) {
-              error(e, "(Asynchronous policy fetch)");
-            }
-          }
-          this.setup(policy);
-        });
-        debug(`Synchronously fetching policy for ${url}.`);
-        let policy = null;
-        let attempts = 100;
-        let refetch = () => {
-          policy = browser.runtime.sendSyncMessage(msg) || this.domPolicy;
-          if (policy) {
-            this.setup(policy);
-          } else if (attempts-- > 0) {
-            debug(`Couldn't retrieve policy synchronously (${attempts} attempts left).`);
-            if (asyncFetch) {
-              asyncFetch();
-              asyncFetch = null;
-            }
-            queueMicrotask(refetch);
-          }
-        };
-        refetch();
+        this.fetchLikeNoTomorrow(url);
       }
     },
 
+    fetchLikeNoTomorrow(url, setup = this.setup.bind(this)) {
+      let msg = {id: "fetchChildPolicy", url};
+
+      let asyncFetch = (async () => {
+        let policy = null;
+        for (let attempts = 10; !(policy || this.policy) && attempts-- > 0;) {
+          try {
+            debug(`Retrieving policy asynchronously (${attempts} attempts left).`);
+            policy = await Messages.send(msg.id, msg) || this.domPolicy;
+            debug("Asynchronous policy", policy);
+          } catch (e) {
+            error(e, "(Asynchronous policy fetch)");
+          }
+        }
+        setup(policy);
+      });
+      debug(`Synchronously fetching policy for ${url}.`);
+      let policy = null;
+      let attempts = 100;
+      let refetch = () => {
+        try {
+          policy = browser.runtime.sendSyncMessage(msg) || this.domPolicy;
+        } catch (e) {
+          error(e);
+        }
+        if (policy) {
+          setup(policy);
+        } else if (attempts-- > 0) {
+          debug(`Couldn't retrieve policy synchronously (${attempts} attempts left).`);
+          if (asyncFetch) {
+            asyncFetch();
+            asyncFetch = null;
+          }
+          queueMicrotask(refetch);
+        }
+      };
+      refetch();
+    },
+
     setup(policy) {
       if (this.policy) return false;
       debug("%s, %s, fetched %o", document.URL, document.readyState, policy, new Error().stack); // DEV_ONLY

src/content/syncFetchPolicy.js

@@ -31,12 +31,12 @@
   // injected in the DOM as soon as possible.
   debug("No CSP yet for non-HTTP document load: fetching policy synchronously...", ns);
 
-  ns.syncSetup = ns.setup.bind(ns);
+  let syncSetup = ns.setup.bind(ns);
 
   if (window.wrappedJSObject) {
     if (top === window) {
       let persistentPolicy = null;
-      ns.syncSetup = policy => {
+      syncSetup = policy => {
         if (persistentPolicy) return;
         ns.setup(policy);
         persistentPolicy = JSON.stringify(policy);
@@ -58,18 +58,14 @@
         }
       }
     } catch (e) {
-      // cross-origin accesss violation, ignore
+      // cross-origin access violation, ignore
     }
   }
   if (ns.domPolicy) {
-    ns.syncSetup(ns.domPolicy);
+    syncSetup(ns.domPolicy);
     return;
   }
-  let syncFetch = callback => {
-    browser.runtime.sendSyncMessage(
-      {id: "fetchPolicy", url},
-      callback);
-  };
+
   debug("Initial readyState and body", document.readyState, document.body);
 
   let mustFreeze = UA.isMozilla
@@ -225,19 +221,7 @@
     }
   }
 
-  for (let attempts = 3; attempts-- > 0;) {
-    try {
-      if (ns.policy) break;
-      syncFetch(ns.syncSetup);
-      break;
-    } catch (e) {
-      if (!Messages.isMissingEndpoint(e) || document.readyState === "complete") {
-        error(e);
-        break;
-      }
-      error("Background page not ready yet, retrying to fetch policy...")
-    }
-  }
+  ns.fetchLikeNoTomorrow(url, syncSetup);
 };
 
 if (ns.pendingSyncFetchPolicy) {