diff options
| -rw-r--r-- | src/lib/SyncMessage.js | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/src/lib/SyncMessage.js b/src/lib/SyncMessage.js index a644507..5b6ac6e 100644 --- a/src/lib/SyncMessage.js +++ b/src/lib/SyncMessage.js @@ -19,6 +19,7 @@ } let tabUrlCache = new Map(); + let asyncResults = new Map(); let tabRemovalListener = null; let CANCEL = {cancel: true}; let {TAB_ID_NONE} = browser.tabs; @@ -28,6 +29,9 @@ let {url, tabId} = request; let params = new URLSearchParams(url.split("?")[1]); let msgId = params.get("id"); + if (asyncResults.has(msgId)) { + return asyncRet(msgId); + } let msg = params.get("msg"); let documentUrl = params.get("url"); let sender; @@ -82,9 +86,34 @@ console.error("%o processing message %o from %o", e, msg, sender); } } - return result instanceof Promise ? (async () => ret(await result)) : ret(result); + if (result instanceof Promise) { + if (MOZILLA) { + // Firefox supports asynchronous webRequest listeners, so we can + // just defer the return + return (async () => ret(await result))(); + } else { + // On Chromium, if the promise is not resolved yet, + // we redirect the XHR to the same URL (hence same msgId) + // while the result get cached for asynchronous retrieval + result.then(r => { + asyncResults.set(msgId, result = r); + }); + return asyncResults.has(msgId) + ? asyncRet(msgId) // promise was already resolved + : {redirectUrl: url.replace( + /&redirects=(\d+)|$/, // redirects count to avoid loop detection + (all, count) => `&redirects=${parseInt(count) + 1 || 1}`)}; + } + } + return ret(result); }; + let ret = r => ({redirectUrl: `data:application/json,${JSON.stringify(r)}`}) + let asyncRet = msgId => { + let result = asyncResults.get(msgId); + asyncResults.delete(msgId); + return ret(result); + } let listeners = new Set(); browser.runtime.onSyncMessage = { |