There are concerns around HTML Imports that does sync or blocking loading as the default. I’d like to address these concerns. Especially I’d like to understand the actual use cases that “sync” loading hurts. This document aims to be a portal of that effort.
Before discussing use cases, let’s clarify which part of page loading process HTML Imports possibly blocks. The blocking model of HTML Imports is modeled after the one for external stylesheets. There are two main bits of the blocking:
| <!DOCTYPE> | |
| <script> | |
| window.Document.prototype.hello = function() { | |
| alert("Hello!"); | |
| } | |
| </script> | |
| <h1>Call document.hello() for me.</h1> |
| # -*- coding: utf-8 -*- | |
| import os | |
| import json | |
| import urllib | |
| import urllib2 | |
| import requests | |
| URL = "https://api.github.com/gists" | |
| #PADDING_SIZE = 1024 # This works |
| <!HTML> | |
| <html> | |
| <head></head> | |
| <body> | |
| <script> | |
| function parseProfileHeader(text) | |
| { | |
| return parseInt(text.match(/(\d+) \[/)[1]); | |
| } |
| #0 0x0000555559529d6c in WebCore::wrap (impl=0x2ebf9c071620, creationContext=..., isolate=0x7ffff7e62020) at gen/webkit/bindings/V8DocumentFragment.h:72 | |
| #1 0x0000555559a8fdac in WebCore::wrap (impl=0x2ebf9c071620, creationContext=..., isolate=0x7ffff7e62020) at ../../third_party/WebKit/Source/bindings/v8/custom/V8NodeCustom.cpp:152 | |
| #2 0x00005555594cde8f in WebCore::toV8 (impl=0x2ebf9c071620, creationContext=..., isolate=0x7ffff7e62020) at gen/webkit/bindings/V8Node.h:75 | |
| #3 0x0000555559a706a1 in WebCore::toV8 (impl=0x2ebf9c071620, creationContext=..., isolate=0x7ffff7e62020) at ../../third_party/WebKit/Source/bindings/v8/custom/V8EventTargetCustom.cpp:50 | |
| #4 0x0000555559b220bc in WebCore::V8AbstractEventListener::getReceiverObject (this=0x2ebf9b177f50, context=0x2ebf9b3390c8, event=0x2ebf9ba3ed60) at ../../third_party/WebKit/Source/bindings/v8/V8AbstractEventListener.cpp:186 | |
| #5 0x0000555559b23262 in WebCore::V8EventListener::callListenerFunction (this=0x2ebf9b177f50, context=0x2ebf9b3390c8, jsEvent=..., e |
| {"mp3":["http://video.ted.com/talks/podcast/audio/AdoraSvitak_2010.mp3","http://video.ted.com/talks/podcast/audio/AimeeMullins_2009.mp3","http://video.ted.com/talks/podcast/audio/AlGore_2006.mp3","http://video.ted.com/talks/podcast/audio/AlGore_2008.mp3","http://video.ted.com/talks/podcast/audio/AlGore_2009.mp3","http://video.ted.com/talks/podcast/audio/AlaindeBotton_2009G.mp3","http://video.ted.com/talks/podcast/audio/AlanRussell_2006.mp3","http://video.ted.com/talks/podcast/audio/AlanSiegel_2010.mp3","http://video.ted.com/talks/podcast/audio/AlexSteffen_2005.mp3","http://video.ted.com/talks/podcast/audio/AlexTabarrok_2009.mp3","http://video.ted.com/talks/podcast/audio/AmySmith_2006.mp3","http://video.ted.com/talks/podcast/audio/AmyTan_2008.mp3","http://video.ted.com/talks/podcast/audio/AndrewMwenda_2007G.mp3","http://video.ted.com/talks/podcast/audio/AnilGupta_2009I.mp3","http://video.ted.com/talks/podcast/audio/AnnaDeveareSmith_2005.mp3","http://video.ted.com/talks/podcast/audio/AnthonyAtala_2009P.mp3","ht |
| logs | |
| project/project | |
| project/target | |
| target | |
| tmp | |
| .settings |
| # install gyp. | |
| $ git clone http://git.chromium.org/external/gyp.git | |
| # checkout breakpad. | |
| $ svn checkout http://src.chromium.org/svn/trunk/src/breakpad/ | |
| $ cd breakpad | |
| $ svn co http://google-breakpad.googlecode.com/svn/trunk/src | |
| $ vi breakpad.gyp # To comment out reference to parent (..) directories. | |
| # generate xcodeproj and build it. |
| File "/usr/local/Cellar/python/2.7.2/lib/python2.7/SocketServer.py", line 284, in _handle_request_noblock | |
| self.process_request(request, client_address) | |
| File "/usr/local/Cellar/python/2.7.2/lib/python2.7/SocketServer.py", line 310, in process_request | |
| self.finish_request(request, client_address) | |
| File "/usr/local/Cellar/python/2.7.2/lib/python2.7/SocketServer.py", line 323, in finish_request | |
| self.RequestHandlerClass(request, client_address, self) | |
| File "/usr/local/Cellar/python/2.7.2/lib/python2.7/SocketServer.py", line 639, in __init__ | |
| self.handle() | |
| File "/usr/local/Cellar/python/2.7.2/lib/python2.7/BaseHTTPServer.py", line 343, in handle | |
| self.handle_one_request() |
| void ProcessManager::resume(ProcessBase* process) | |
| { | |
| ... | |
| // Now service the event. | |
| try { | |
| process->serve(*event); | |
| } catch (const std::exception& e) { | |
| std::cerr << "libprocess: " << process->pid | |
| << " terminating due to " | |
| << e.what() << std::endl; |