168913 2017-02-27 08:44:37 -0800 Optimize checkWebRTCAvailability 2017-03-03 14:00:42 -0800 1 1 1 Unclassified WebKit New Bugs WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED https://bugs.webkit.org/show_bug.cgi?id=169147 P2 Normal --- 1 achristensen achristensen darin jonlee mitz oldest_to_newest 1281384 0 achristensen 2017-02-27 08:44:37 -0800 Optimize checkWebRTCAvailability 1281387 1 302843 achristensen 2017-02-27 08:47:03 -0800 Created attachment 302843 Patch 1281399 2 302843 darin 2017-02-27 09:20:02 -0800 Comment on attachment 302843 Patch View in context: https://bugs.webkit.org/attachment.cgi?id=302843&action=review > Source/WebKit2/UIProcess/WebPreferences.cpp:213 > + static bool available = false; > + static std::once_flag once; > + std::call_once(once, [&]() { > + void* libwebrtcLibrary = dlopen("libwebrtc.dylib", RTLD_LAZY); > + if (!libwebrtcLibrary) { > + available = false; > + return; > + } > + dlclose(libwebrtcLibrary); > + available = true; > + }); > + return available; Does this need to be called from arbitrary threads? If not, then I suggest just using global variable initialization rather than call_once. static bool available = [] { auto library = dlopen("libwebrtc.dylib", RTLD_LAZY); if (!library) return false; dlclose(library); return true; }(); return available; Fewer lines of code, also slightly more efficient. 1281402 3 achristensen 2017-02-27 09:23:57 -0800 http://trac.webkit.org/r213074 1281404 4 mitz 2017-02-27 09:33:45 -0800 This check can be implemented by null-checking any of the symbols known to be exported from the dylib, which is a single branch. An implementation that involves a function call still seems unoptimal. 1282059 5 darin 2017-02-28 16:59:12 -0800 (In reply to comment #4) > This check can be implemented by null-checking any of the symbols known to > be exported from the dylib, which is a single branch. An implementation that > involves a function call still seems unoptimal. We should do that instead! 1283243 6 jonlee 2017-03-03 14:00:29 -0800 Filed follow-up bug 169147. 302843 2017-02-27 08:47:03 -0800 2017-02-27 09:20:02 -0800 Patch bug-168913-20170227084409.patch text/plain 2011 achristensen SW5kZXg6IFNvdXJjZS9XZWJLaXQyL0NoYW5nZUxvZwo9PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09Ci0tLSBTb3VyY2UvV2Vi S2l0Mi9DaGFuZ2VMb2cJKHJldmlzaW9uIDIxMzA2NikKKysrIFNvdXJjZS9XZWJLaXQyL0NoYW5n ZUxvZwkod29ya2luZyBjb3B5KQpAQCAtMSwzICsxLDE4IEBACisyMDE3LTAyLTI3ICBBbGV4IENo cmlzdGVuc2VuICA8YWNocmlzdGVuc2VuQHdlYmtpdC5vcmc+CisKKyAgICAgICAgT3B0aW1pemUg Y2hlY2tXZWJSVENBdmFpbGFiaWxpdHkKKyAgICAgICAgaHR0cHM6Ly9idWdzLndlYmtpdC5vcmcv c2hvd19idWcuY2dpP2lkPTE2ODkxMworCisgICAgICAgIFJldmlld2VkIGJ5IE5PQk9EWSAoT09Q UyEpLgorCisgICAgICAgIFdlIGNhbiBvcHRpbWl6ZSBzdGFydHVwIHRpbWUgYnkgdXNpbmcgUlRM RF9MQVpZIGluc3RlYWQgb2YgUlRMRF9OT1cgYmVjYXVzZSB3ZSBkb24ndCBuZWVkIHRvIGxvYWQg YWxsIHRoZSBzeW1ib2xzLgorICAgICAgICBXZSBqdXN0IG5lZWQgdG8gY2hlY2sgd2hldGhlciBs aWJ3ZWJydGMuZHlsaWIgY2FuIGJlIGZvdW5kIGFuZCBpcyBhIHZhbGlkIGR5bGliIGZvciB0aGUg Y3VycmVudCBhcmNoaXRlY3R1cmUuCisgICAgICAgIEFsc28sIHdyYXAgdGhlIGNoZWNrIGluc2lk ZSBhIHN0ZDo6Y2FsbF9vbmNlLiAgUmlnaHQgbm93IGl0J3Mgb25seSB1c2VkIHdoZW4gaW5pdGlh bGl6aW5nIHNldHRpbmdzLAorICAgICAgICBidXQgaWYgd2UgdXNlIGl0IGZvciBvdGhlciB0aGlu Z3MgaW4gdGhlIGZ1dHVyZSB0aGVyZSB3aWxsIGJlIG5vIG5lZWQgdG8gcmVvcGVuIHRoZSBkeWxp Yi4KKworICAgICAgICAqIFVJUHJvY2Vzcy9XZWJQcmVmZXJlbmNlcy5jcHA6CisgICAgICAgIChX ZWJLaXQ6OmNoZWNrV2ViUlRDQXZhaWxhYmlsaXR5KToKKwogMjAxNy0wMi0yNiAgV2Vuc29uIEhz aWVoICA8d2Vuc29uX2hzaWVoQGFwcGxlLmNvbT4KIAogICAgICAgICBVbnJldmlld2VkLCByZXZl cnQgYWxsIHRlbXBvcmFyeSBidWlsZCBmaXhlcyBmb3IgZGF0YSBpbnRlcmFjdGlvbgpJbmRleDog U291cmNlL1dlYktpdDIvVUlQcm9jZXNzL1dlYlByZWZlcmVuY2VzLmNwcAo9PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09Ci0t LSBTb3VyY2UvV2ViS2l0Mi9VSVByb2Nlc3MvV2ViUHJlZmVyZW5jZXMuY3BwCShyZXZpc2lvbiAy MTMwNjApCisrKyBTb3VyY2UvV2ViS2l0Mi9VSVByb2Nlc3MvV2ViUHJlZmVyZW5jZXMuY3BwCSh3 b3JraW5nIGNvcHkpCkBAIC0xOTksMTEgKzE5OSwxOCBAQCBGT1JfRUFDSF9XRUJLSVRfREVCVUdf UFJFRkVSRU5DRShERUZJTkVfCiBib29sIGNoZWNrV2ViUlRDQXZhaWxhYmlsaXR5KCkKIHsKICNp ZiBVU0UoTElCV0VCUlRDKQotICAgIHZvaWQqIGxpYndlYnJ0Y0xpYnJhcnkgPSBkbG9wZW4oImxp YndlYnJ0Yy5keWxpYiIsIFJUTERfTk9XKTsKLSAgICBpZiAoIWxpYndlYnJ0Y0xpYnJhcnkpCi0g ICAgICAgIHJldHVybiBmYWxzZTsKLSAgICBkbGNsb3NlKGxpYndlYnJ0Y0xpYnJhcnkpOwotICAg IHJldHVybiB0cnVlOworICAgIHN0YXRpYyBib29sIGF2YWlsYWJsZSA9IGZhbHNlOworICAgIHN0 YXRpYyBzdGQ6Om9uY2VfZmxhZyBvbmNlOworICAgIHN0ZDo6Y2FsbF9vbmNlKG9uY2UsIFsmXSgp IHsKKyAgICAgICAgdm9pZCogbGlid2VicnRjTGlicmFyeSA9IGRsb3BlbigibGlid2VicnRjLmR5 bGliIiwgUlRMRF9MQVpZKTsKKyAgICAgICAgaWYgKCFsaWJ3ZWJydGNMaWJyYXJ5KSB7CisgICAg ICAgICAgICBhdmFpbGFibGUgPSBmYWxzZTsKKyAgICAgICAgICAgIHJldHVybjsKKyAgICAgICAg fQorICAgICAgICBkbGNsb3NlKGxpYndlYnJ0Y0xpYnJhcnkpOworICAgICAgICBhdmFpbGFibGUg PSB0cnVlOworICAgIH0pOworICAgIHJldHVybiBhdmFpbGFibGU7CiAjZWxzZQogICAgIHJldHVy biB0cnVlOwogI2VuZGlmCg==