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authorhackademix2019-10-19 19:55:26 +0200
committerhackademix2019-10-19 19:55:26 +0200
commit314784079c96124334df0589a0fc5b1c63893b61 (patch)
treee76225bb998192b0e4fd5dfcbef9520bd7d826ae /src/lib
parent726392f5eee94c676360c64d7876896f476a0471 (diff)
downloadnoscript-314784079c96124334df0589a0fc5b1c63893b61.tar.gz
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More robust SyncMessage implementation coping with XHR suspension inconsistencies on Firefox.
Diffstat (limited to 'src/lib')
-rw-r--r--src/lib/SyncMessage.js39
1 files changed, 34 insertions, 5 deletions
diff --git a/src/lib/SyncMessage.js b/src/lib/SyncMessage.js
index 5b6ac6e..1df9411 100644
--- a/src/lib/SyncMessage.js
+++ b/src/lib/SyncMessage.js
@@ -34,12 +34,23 @@
}
let msg = params.get("msg");
let documentUrl = params.get("url");
+ let suspension = !!params.get("suspend");
let sender;
- if (tabId === TAB_ID_NONE) {
+ if (tabId === TAB_ID_NONE || suspension) {
// Firefox sends privileged content script XHR without valid tab ids
// so we cache sender info from unprivileged XHR correlated by msgId
if (pending.has(msgId)) {
sender = pending.get(msgId);
+ if (suspension) { // we hold any script execution / DOM modification on this promise
+ return new Promise(resolve => {
+ sender.unsuspend = resolve;
+ });
+ }
+ if (sender.unsuspend) {
+ let {unsuspend} = sender;
+ delete sender.unsuspend;
+ setTimeout(unsuspend(ret("unsuspend")), 0);
+ }
pending.delete(msgId);
} else {
throw new Error(`sendSyncMessage: cannot correlate sender info for ${msgId}.`);
@@ -141,9 +152,7 @@
}
} else if (typeof browser.runtime.sendSyncMessage !== "function") {
// Content Script side
- if (typeof uuid !== "function") {
- let uuid = () => (Math.random() * Date.now()).toString(16);
- }
+ let uuid = () => (Math.random() * Date.now()).toString(16);
let docUrl = document.URL;
browser.runtime.sendSyncMessage = msg => {
let msgId = `${uuid()},${docUrl}`;
@@ -154,12 +163,30 @@
// about frameAncestors
url += "&top=true";
}
-
+ let finalizers = [];
if (MOZILLA) {
// on Firefox we first need to send an async message telling the
// background script about the tab ID, which does not get sent
// with "privileged" XHR
browser.runtime.sendMessage({___syncMessageId: msgId});
+
+ // In order to cope with inconsistencies in XHR synchronicity,
+ // allowing DOM element to be inserted and script to be executed
+ // (seen with file:// and ftp:// loads) we additionally suspend on
+ // Mutation notifications and beforescriptexecute events
+ let suspendURL = url + "&suspend";
+ let suspend = () => {
+ let r = new XMLHttpRequest();
+ r.open("GET", url, false);
+ r.send(null);
+ };
+ let domSuspender = new MutationObserver(suspend);
+ domSuspender.observe(document.documentElement, {childList: true});
+ addEventListener("beforescriptexecute", suspend, true);
+ finalizers.push(() => {
+ removeEventListener("beforescriptexecute", suspend, true);
+ domSuspender.disconnect();
+ });
}
// then we send the payload using a privileged XHR, which is not subject
// to CORS but unfortunately doesn't carry any tab id except on Chromium
@@ -172,6 +199,8 @@
return JSON.parse(r.responseText);
} catch(e) {
console.error(`syncMessage error in ${document.URL}: ${e.message} (response ${r.responseText})`);
+ } finally {
+ for (let f of finalizers) try { f(); } catch(e) { console.error(e); }
}
return null;
};