- Shall i implement it?
- No ...
futures-rs is the library which will hopefully become a shared foundation for everything async in Rust. However it's already become renowned for having a steep learning curve, even for experienced Rustaceans.
I think one of the best ways to get comfortable with using a library is to look at how it works internally: often API design can seem bizarre or impenetrable and it's only when you put yourself in the shoes of the library author that you can really understand why it was designed that way.
In this post I'll try to put down on "paper" my understanding of how futures work and I'll aim to do it in a visual way. I'm going to assume you're already somewhat familiar with Rust and why futures are a useful tool to have at one's disposal.
For most of this post I'll be talking about how things work today (as of September 2017). At the end I'll touch on what's being proposed next and also make a case for some of the changes I'd like to see.
If you're interested in learning more ab
Hacking CORS restriction to enable in-browser XHR to any server.
Say you are running an web app at localhost, and you want to send XHR to http://remote-server:80, but the CORS restriction forbids access because you are sending requests from an origin that remote-server:80 does not allow.
Run:
Updated: Just use qutebrowser (and disable javascript). The web is done for.
L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns
Compress 1K bytes with Zippy ............. 3,000 ns = 3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns = 20 µs
SSD random read ........................ 150,000 ns = 150 µs
Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs
| Latency Comparison Numbers (~2012) | |
| ---------------------------------- | |
| L1 cache reference 0.5 ns | |
| Branch mispredict 5 ns | |
| L2 cache reference 7 ns 14x L1 cache | |
| Mutex lock/unlock 25 ns | |
| Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
| Compress 1K bytes with Zippy 3,000 ns 3 us | |
| Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
| Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |
| (function() { | |
| /* == GLOBAL DECLERATIONS == */ | |
| TouchMouseEvent = { | |
| DOWN: "touchmousedown", | |
| UP: "touchmouseup", | |
| MOVE: "touchmousemove" | |
| } | |
| /* == EVENT LISTENERS == */ |