On Sun, Jun 24, 2012 at 12:48 PM, Ted Young <[email protected]> wrote:
> Out of curiosity, when running a UIWebView on iOS, is it running full > WebKit with JIT enabled, etc, or is there something dumbed down about it? > My understanding is the webviews get only non-jit mode for their javascript engine. Only Safari gets full jit enabled JSC. There are several articles about this when this restriction was discovered in 4.3. > > Ted > > On Jun 23, 2012, at 10:35 PM, Tim Caswell wrote: > > The difference between V8 and most other scripting languages is that V8 > does not have an interpreter. It is JIT only. That means it works by 1. > writing machine code to memory, 2. executing the code. JIT is very fast > and most of the modern scripting engines do it (V8, JSC, SpiderMonkey, > LuaJit, ...). All of these engines (except for V8) also have an > interpreter mode where the machine code is fixed at compile time and it > walks over your script code interpreting it. State is kept using various > data structures like one big state machine simulating a CPU that knows how > to run JavaScript natively. This is slower, but doesn't require using the > same region of memory as both writable and executable. > > On Sat, Jun 23, 2012 at 9:09 PM, Ryan Schmidt > <[email protected]>wrote: > >> >> On Jun 23, 2012, at 17:13, Jorge wrote: >> >> > On 23/06/2012, at 19:03, Ryan Schmidt wrote: >> >> >> >> On Jun 23, 2012, at 02:37, Jorge wrote: >> >> >> >>> I don't know the answer to your question, but my guess is that many >> of the things that node does won't run/can't be done in a sandbox. I >> believe the experiments with node on iOS so far have always been in >> jailbroken devices. But I may be wrong. >> >> >> >> Certainly, being able to run in a sandbox will be necessary, since >> Apple will not approve apps anymore that don't. I haven't tried it yet, but >> why do you think node won't run in a sandbox? >> > >> > iOS wont't let user code jump into a block of writable (from your app's >> point of view) memory -for security reasons- >> >> That seems reasonable. >> >> >> > and it seems that v8's JIT compiler requires that: >> http://code.google.com/p/v8/issues/detail?id=1312 >> >> Thank you for the link, but I think the discussion goes over my head. It >> talks about mapping executable memory pages, which are concepts I'm pleased >> as a JavaScript developer not to have to know anything about. On the >> surface, I don't understand why the block of memory containing my program >> code should need to be writable. I'm not wanting to change my program code >> as it's running. I'm just wanting to run it. Or are you saying that by >> virtue of being an interpreted language it must be writable? Also, that >> issue was started over a year ago, and has not been touched in six months. >> There is a patch attached to implement some improvement, and there's no >> indication whether it was committed. Maybe something has already changed? >> Or if not, maybe it's time to remind the v8 devs about it? >> >> >> > The Nitro JIT in JavaScriptCore in mobile Safari requires that too, but >> the security measure has been conveniently lifted for that particular app >> :-P >> >> The second article I linked to in my original post mentioned Apple >> relaxing its restrictions on interpreted languages, in recognition of the >> fact that many games use scripting languages like lua. Does lua also run >> code in writable memory? If so, how are they bypassing Apple's requirement? >> And if not, is there something we can learn from how lua is doing that that >> could be applied to improve node / v8? >> >> >> > Also it seems that quite a bunch of the usual posix APIs simply aren't >> there... until you jailbreak it and install the things yourself. >> >> I'm not interested in jailbreaking devices; I'm interesting in creating >> apps users on everyday iOS and OS X devices can install. I'm not familiar >> with how sandboxing works in OS X or iOS. I haven't found out yet how I >> could build a sample sandboxed application to play around with it either. >> What specific POSIX APIs that node needs will be unavailable? >> >> >> > Apple wants you to develop your apps using their cocoa APIs not >> anything else. Soon we are going to suffer similar constraints (sandboxes >> etc) in Mountain Lion too. And finally a day will come when nothing but >> Apple's approved apps (that is: from the mac app store) will run in a >> Mac... "for your security". >> >> I can't speculate on what direction Apple might go with future versions >> of OS X, but concerns like these are precisely why I started this thread. >> In light of the current and potential future security restrictions, how can >> we use node and NodObjC to develop an OS X or iOS app? It's no use to spend >> time developing an app if it can't be distributed to end users. >> >> >> On Jun 23, 2012, at 19:43, Tim Caswell wrote: >> >> > I don't think there is a way to get nodejs using V8 running in an >> app-store friendly format. >> >> Again, why? Is it the same concerns Jorge expressed above? >> >> >> > But I would love to get libuv and some scripting engine running there. >> I may try my luvit project first (luajit + libuv) or luvmonkey >> (spidermonkey + libuv). Another combination would be JSC + libuv. >> >> I'm interested in getting node and NodObjC usable for making OS X and iOS >> apps. The promise of using JavaScript for both server side and client side >> (web and app) programming is very appealing. I simply want nothing less >> than what the NodObjC homepage advertises: "So you can write entire Cocoa >> or iOS GUI applications entirely in NodeJS JavaScript!" >> >> >> >> >> -- >> Job Board: http://jobs.nodejs.org/ >> Posting guidelines: >> https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines >> You received this message because you are subscribed to the Google >> Groups "nodejs" group. >> To post to this group, send email to [email protected] >> To unsubscribe from this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/nodejs?hl=en?hl=en >> > > > -- > Job Board: http://jobs.nodejs.org/ > Posting guidelines: > https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines > You received this message because you are subscribed to the Google > Groups "nodejs" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/nodejs?hl=en?hl=en > > > -- > Job Board: http://jobs.nodejs.org/ > Posting guidelines: > https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines > You received this message because you are subscribed to the Google > Groups "nodejs" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/nodejs?hl=en?hl=en > -- Job Board: http://jobs.nodejs.org/ Posting guidelines: https://github.com/joyent/node/wiki/Mailing-List-Posting-Guidelines You received this message because you are subscribed to the Google Groups "nodejs" group. 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