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Change the validation code to always discard any pending requests for validation, and focus on the latest request. This works well for our purposes and avoids us queueing up a validation request and then having it somehow come in later than a more up-to-date request that may pertain to a different window or tab.

This commit is contained in:
Daniel Jalkut 2018-08-19 17:55:46 -04:00
parent 6caf85b598
commit ab810e9f1c
1 changed files with 21 additions and 9 deletions
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30
Safari Extension/SafariExtensionHandler.swift
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@ -18,7 +18,7 @@ class SafariExtensionHandler: SFSafariExtensionHandler {
// to verify whether our code is installed.
// I tried to use a NSMapTable from String to the closure directly, but Swift
// complains that the object as to be a class type.
// complains that the object has to be a class type.
typealias ValidationHandler = (Bool, String) -> Void
class ValidationWrapper {
let validationHandler: ValidationHandler
@ -30,6 +30,7 @@ class SafariExtensionHandler: SFSafariExtensionHandler {
// Maps from UUID to a validation wrapper
static var gPingPongMap = Dictionary<String, ValidationWrapper>()
static var validationQueue = DispatchQueue(label: "Toolbar Validation")
// Bottleneck for calling through to a validation handler we have saved, and removing it from the list.
static func callValidationHandler(forHandlerID handlerID: String, withShouldValidate shouldValidate: Bool) {
@ -39,8 +40,6 @@ class SafariExtensionHandler: SFSafariExtensionHandler {
}
}
var validationQueue = DispatchQueue(label: "Toolbar Validation")
override func messageReceived(withName messageName: String, from page: SFSafariPage, userInfo: [String : Any]?) {
if (messageName == "subscribeToFeed") {
if let feedURLString = userInfo?["url"] as? String {
@ -73,12 +72,25 @@ class SafariExtensionHandler: SFSafariExtensionHandler {
let uniqueValidationID = NSUUID().uuidString
// Save it right away to eliminate any doubt of whether the handler gets deallocated while
// we are waiting for a callback from the getActiveTab or getActivatePage methods below.
let validationWrapper = ValidationWrapper(validationHandler: validationHandler)
SafariExtensionHandler.gPingPongMap[uniqueValidationID] = validationWrapper
SafariExtensionHandler.validationQueue.sync {
// Save it right away to eliminate any doubt of whether the handler gets deallocated while
// we are waiting for a callback from the getActiveTab or getActivatePage methods below.
let validationWrapper = ValidationWrapper(validationHandler: validationHandler)
SafariExtensionHandler.gPingPongMap[uniqueValidationID] = validationWrapper
// To avoid problems with validation handlers dispatched after we've, for example,
// switched to a new tab, we aggressively clear out the map of any pending validations,
// and focus only on the newest validation request we've been asked for.
for thisValidationID in SafariExtensionHandler.gPingPongMap.keys {
if thisValidationID != uniqueValidationID {
// Default to valid ... we'll know soon enough whether the latest state
// is actually still valid or not...
SafariExtensionHandler.callValidationHandler(forHandlerID: thisValidationID, withShouldValidate: true);
}
}
validationQueue.sync {
// See comments above where gPingPongMap is declared. Upon being asked to validate the
// toolbar icon for a specific page, we save the validationHandler and postpone calling
// it until we have either received a response from our installed JavaScript, or until
@ -101,7 +113,7 @@ class SafariExtensionHandler: SFSafariExtensionHandler {
// Capture the uniqueValidationID to ensure it doesn't change out from under us on a future call
activePage.dispatchMessageToScript(withName: "ping", userInfo: ["validationID": uniqueValidationID])
let pongTimeoutInNanoseconds = Int(NSEC_PER_SEC * UInt64(1))
let pongTimeoutInNanoseconds = Int(Double(NSEC_PER_SEC) * 0.5)
let timeoutDeadline = DispatchTime.now() + DispatchTimeInterval.nanoseconds(pongTimeoutInNanoseconds)
DispatchQueue.main.asyncAfter(deadline: timeoutDeadline, execute: { [timedOutValidationID = uniqueValidationID] in
SafariExtensionHandler.callValidationHandler(forHandlerID: timedOutValidationID, withShouldValidate:false)