Extract libusb context to a longer living lifetime

This is due to a limitation where we can't hold a struct that has both
the context and a device handle (that internally references back to it).
The libusb context has to outlive the device handle.

Github issue:

https://github.com/dcuddeback/libusb-rs/issues/3

Example solution via IRC:

https://play.rust-lang.org/?gist=c68bda27266249c781e6335c4127f301&version=stable&mode=debug&edition=2015

1 files changed, 2 insertions, 1 deletions

diff --git a/src/main.rs b/src/main.rs
index e1dfc5d..1bdade5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,6 +6,7 @@ use lib::RtlSdr;
 
 fn main() {
     println!("Running");
-    let mut rtlsdr = RtlSdr::new();
+    let ctx = libusb::Context::new().unwrap();
+    let mut rtlsdr = RtlSdr::new(&ctx);
     rtlsdr.init();
 }