Upgrade to ndk 0.9 and delete unused ndk-sys/context dependencies

The `ndk` crate received some marginal API upgrades, besides fixing
soundness issues.  Specifcally, `ForeignLooper::add_fd_with_callback()`
now signifies that the incoming file descriptor is a `BorrowedFd` and
the callback is executed on a different thread (where the looper is
polled on the `ThreadLooper`) and must hence be `Send.`.

It appears the `ndk-sys` and `ndk-context` crates are not used directly,
hence they are removed from `Cargo.toml` here.

Cargo.toml

@@ -104,9 +104,7 @@ kuchiki = { package = "kuchikiki", version = "0.8" }
 sha2 = "0.10"
 base64 = "0.22"
 jni = "0.21"
-ndk = "0.7"
-ndk-sys = "0.4"
-ndk-context = "0.1"
+ndk = "0.9"
 tao-macros = "0.1"
 libc = "0.2"
 

src/android/main_pipe.rs

@@ -15,10 +15,10 @@ use std::{os::unix::prelude::*, sync::atomic::Ordering};
 use super::{find_class, EvalCallback, EVAL_CALLBACKS, EVAL_ID_GENERATOR, PACKAGE};
 
 static CHANNEL: Lazy<(Sender<WebViewMessage>, Receiver<WebViewMessage>)> = Lazy::new(|| bounded(8));
-pub static MAIN_PIPE: Lazy<[RawFd; 2]> = Lazy::new(|| {
+pub static MAIN_PIPE: Lazy<[OwnedFd; 2]> = Lazy::new(|| {
   let mut pipe: [RawFd; 2] = Default::default();
   unsafe { libc::pipe(pipe.as_mut_ptr()) };
-  pipe
+  unsafe { pipe.map(|fd| OwnedFd::from_raw_fd(fd)) }
 });
 
 pub struct MainPipe<'a> {
@@ -32,7 +32,13 @@ impl<'a> MainPipe<'a> {
   pub(crate) fn send(message: WebViewMessage) {
     let size = std::mem::size_of::<bool>();
     if let Ok(()) = CHANNEL.0.send(message) {
-      unsafe { libc::write(MAIN_PIPE[1], &true as *const _ as *const _, size) };
+      unsafe {
+        libc::write(
+          MAIN_PIPE[1].as_raw_fd(),
+          &true as *const _ as *const _,
+          size,
+        )
+      };
     }
   }
 

src/android/mod.rs

@@ -24,6 +24,7 @@ use sha2::{Digest, Sha256};
 use std::{
   borrow::Cow,
   collections::HashMap,
+  os::fd::{AsFd as _, AsRawFd as _},
   sync::{atomic::AtomicI32, mpsc::channel, Mutex},
 };
 
@@ -108,10 +109,10 @@ pub unsafe fn android_setup(
   };
 
   looper
-    .add_fd_with_callback(MAIN_PIPE[0], FdEvent::INPUT, move |_| {
+    .add_fd_with_callback(MAIN_PIPE[0].as_fd(), FdEvent::INPUT, move |fd, _event| {
       let size = std::mem::size_of::<bool>();
       let mut wake = false;
-      if libc::read(MAIN_PIPE[0], &mut wake as *mut _ as *mut _, size) == size as libc::ssize_t {
+      if libc::read(fd.as_raw_fd(), &mut wake as *mut _ as *mut _, size) == size as libc::ssize_t {
         main_pipe.recv().is_ok()
       } else {
         false