pub fn dequeue(&mut self) -> Option<(N, V)> {
        // Look at all our crates and find everything that's ready to build (no
        // deps). After we've got that candidate set select the one which has
        // the maximum priority in the dependency graph. This way we should
        // hopefully keep CPUs hottest the longest by ensuring that long
        // dependency chains are scheduled early on in the build process and the
        // leafs higher in the tree can fill in the cracks later.
        //
        // TODO: it'd be best here to throw in a heuristic of crate size as
        //       well. For example how long did this crate historically take to
        //       compile? How large is its source code? etc.
        let next = self
            .dep_map
            .iter()
            .filter(|(_, (deps, _))| deps.is_empty())
            .map(|(key, _)| key.clone())
            .max_by_key(|k| self.priority[k]);
        let key = match next {
            Some(key) => key,
            None => return None,
        };
        let (_, data) = self.dep_map.remove(&key).unwrap();
        Some((key, data))
    }
/// Dequeues a package that is ready to be built.
///
/// A package is ready to be built when it has 0 un-built dependencies. If
/// `None` is returned then no packages are ready to be built.
Dequeues a package that is ready to be built.
A package is ready to be built when it has 0 un-built dependencies. If
`None` is returned then no packages are ready to be built.
Dequeues a package that is ready to be built . A package is ready to be built when it has 0 un - built dependencies . If ` None ` is returned then no packages are ready to be built .
pub fn dequeue(&mut self) -> Option<(N, V)> {
        // Look at all our crates and find everything that's ready to build (no
        // deps). After we've got that candidate set select the one which has
        // the maximum priority in the dependency graph. This way we should
        // hopefully keep CPUs hottest the longest by ensuring that long
        // dependency chains are scheduled early on in the build process and the
        // leafs higher in the tree can fill in the cracks later.
        //
        // TODO: it'd be best here to throw in a heuristic of crate size as
        //       well. For example how long did this crate historically take to
        //       compile? How large is its source code? etc.
        let next = self
            .dep_map
            .iter()
            .filter(|(_, (deps, _))| deps.is_empty())
            .map(|(key, _)| key.clone())
            .max_by_key(|k| self.priority[k]);
        let key = match next {
            Some(key) => key,
            None => return None,
        };
        let (_, data) = self.dep_map.remove(&key).unwrap();
        Some((key, data))
    }
pub fn dequeue ( & mut self ) -> Option < ( N , V ) > { // Look at all our crates and find everything that's ready to build (no // deps). After we've got that candidate set select the one which has // the maximum priority in the dependency graph. This way we should // hopefully keep CPUs hottest the longest by ensuring that long // dependency chains are scheduled early on in the build process and the // leafs higher in the tree can fill in the cracks later. // // TODO: it'd be best here to throw in a heuristic of crate size as //       well. For example how long did this crate historically take to //       compile? How large is its source code? etc. let next = self . dep_map . iter ( ) . filter ( | ( _ , ( deps , _ ) ) | deps . is_empty ( ) ) . map ( | ( key , _ ) | key . clone ( ) ) . max_by_key ( | k | self . priority [ k ] ) ; let key = match next { Some ( key ) => key , None => return None , } ; let ( _ , data ) = self . dep_map . remove ( & key ) . unwrap ( ) ; Some ( ( key , data ) ) }
Dequeues a package that is ready to be built.
Dequeues a package that is ready to be built .
&mut self
&mut self