format: add interrupt callback support

src/format/mod.rs

@@ -1,5 +1,6 @@
 pub use ::util::format::{sample, Sample};
 pub use ::util::format::{pixel, Pixel};
+use ::util::interrupt;
 
 pub mod stream;
 
@@ -155,7 +156,7 @@ pub fn input<P: AsRef<Path>>(path: &P) -> Result<context::Input, Error> {
 	}
 }
 
-pub fn input_with<P: AsRef<Path>>(path: &P, options: Dictionary) -> Result<context::Input, Error> {
+pub fn input_with_dictionary<P: AsRef<Path>>(path: &P, options: Dictionary) -> Result<context::Input, Error> {
 	unsafe {
 		let mut ps   = ptr::null_mut();
 		let     path = from_path(path);
@@ -171,7 +172,27 @@ pub fn input_with<P: AsRef<Path>>(path: &P, options: Dictionary) -> Result<conte
 					e           => Err(Error::from(e)),
 				}
 			}
-			
+
+			e => Err(Error::from(e))
+		}
+	}
+}
+
+pub fn input_with_interrupt<P: AsRef<Path>, F>(path: &P, closure: F) -> Result<context::Input, Error>
+	where F: FnMut() -> bool {
+	unsafe {
+		let mut ps   = context::Input::wrap(avformat_alloc_context());
+		let     path = from_path(path);
+		(*ps.as_mut_ptr()).interrupt_callback = interrupt::new(Box::new(closure)).interrupt;
+
+		match avformat_open_input(&mut ps.as_mut_ptr(), path.as_ptr(), ptr::null_mut(), ptr::null_mut()) {
+			0 => {
+				match avformat_find_stream_info(ps.as_mut_ptr(), ptr::null_mut()) {
+					r if r >= 0 => Ok(ps),
+					e           => Err(Error::from(e)),
+				}
+			}
+
 			e => Err(Error::from(e))
 		}
 	}

src/util/interrupt.rs

@@ -0,0 +1,28 @@
+use std::panic;
+use std::process;
+
+use ffi::*;
+use libc::{c_void, c_int};
+
+pub struct Interrupt {
+    pub interrupt: AVIOInterruptCB,
+}
+
+extern "C" fn callback<F>(opaque: *mut c_void) -> c_int
+    where F: FnMut() -> bool
+{
+    match panic::catch_unwind(|| (unsafe { &mut *(opaque as *mut F) })()) {
+        Ok(ret) => ret as c_int,
+        Err(_) => process::abort(),
+    }
+}
+
+pub fn new<F>(opaque: Box<F>) -> Interrupt
+    where F: FnMut() -> bool
+{
+    let interrupt_cb = AVIOInterruptCB {
+        callback: Some(callback::<F>),
+        opaque: Box::into_raw(opaque) as *mut c_void,
+    };
+    Interrupt { interrupt: interrupt_cb }
+}

src/util/mod.rs

@@ -13,6 +13,7 @@ pub mod channel_layout;
 pub mod option;
 pub mod range;
 pub mod mathematics;
+pub mod interrupt;
 
 use std::ffi::CStr;
 use std::str::from_utf8_unchecked;