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//! Monitor progress at a `Stream`.
use std::rc::Rc;
use std::cell::RefCell;
use progress::{Timestamp, Operate, Antichain};
use progress::frontier::MutableAntichain;
use progress::nested::subgraph::{Source, Target};
use progress::count_map::CountMap;
use dataflow::channels::pushers::Tee;
use dataflow::channels::pushers::Counter as PushCounter;
use dataflow::channels::pushers::buffer::Buffer as PushBuffer;
use dataflow::channels::pact::{ParallelizationContract, Pipeline};
use dataflow::channels::pullers::Counter as PullCounter;
use Data;
use dataflow::{Stream, Scope};
/// Monitors progress at a `Stream`.
pub trait Probe<G: Scope, D: Data> {
/// Constructs a progress probe which indicates which timestamps have elapsed at the operator.
///
/// #Examples
/// ```
/// use timely::*;
/// use timely::dataflow::Scope;
/// use timely::dataflow::operators::{Input, Probe, Inspect};
/// use timely::progress::timestamp::RootTimestamp;
///
/// // construct and execute a timely dataflow
/// timely::execute(Configuration::Thread, |worker| {
///
/// // add an input and base computation off of it
/// let (mut input, probe) = worker.dataflow(|scope| {
/// let (input, stream) = scope.new_input();
/// let probe = stream.inspect(|x| println!("hello {:?}", x))
/// .probe();
/// (input, probe)
/// });
///
/// // introduce input, advance computation
/// for round in 0..10 {
/// input.send(round);
/// input.advance_to(round + 1);
/// worker.step_while(|| probe.less_than(input.time()));
/// }
/// }).unwrap();
/// ```
fn probe(&self) -> Handle<G::Timestamp>;
/// Inserts a progress probe in a stream.
///
/// #Examples
/// ```
/// use timely::*;
/// use timely::dataflow::Scope;
/// use timely::dataflow::operators::{Input, Probe, Inspect};
/// use timely::dataflow::operators::probe::Handle;
/// use timely::progress::timestamp::RootTimestamp;
///
/// // construct and execute a timely dataflow
/// timely::execute(Configuration::Thread, |worker| {
///
/// // add an input and base computation off of it
/// let mut probe = Handle::new();
/// let mut input = worker.dataflow(|scope| {
/// let (input, stream) = scope.new_input();
/// stream.probe_with(&mut probe)
/// .inspect(|x| println!("hello {:?}", x));
///
/// input
/// });
///
/// // introduce input, advance computation
/// for round in 0..10 {
/// input.send(round);
/// input.advance_to(round + 1);
/// worker.step_while(|| probe.less_than(input.time()));
/// }
/// }).unwrap();
/// ```
fn probe_with(&self, handle: &mut Handle<G::Timestamp>) -> Stream<G, D>;
}
impl<G: Scope, D: Data> Probe<G, D> for Stream<G, D> {
fn probe(&self) -> Handle<G::Timestamp> {
// the frontier is shared state; scope updates, handle reads.
let handle = Handle::new();
let mut scope = self.scope(); // clones the scope
let channel_id = scope.new_identifier();
let (sender, receiver) = Pipeline.connect(&mut scope, channel_id);
let (targets, registrar) = Tee::<G::Timestamp,D>::new();
let operator = Operator {
input: PullCounter::new(receiver),
output: PushBuffer::new(PushCounter::new(targets, Rc::new(RefCell::new(CountMap::new())))),
frontier: handle.frontier.clone(),
};
let index = scope.add_operator(operator);
self.connect_to(Target { index: index, port: 0 }, sender, channel_id);
Stream::new(Source { index: index, port: 0 }, registrar, scope);
handle
}
fn probe_with(&self, handle: &mut Handle<G::Timestamp>) -> Stream<G, D> {
let mut scope = self.scope(); // clones the scope
let channel_id = scope.new_identifier();
let (sender, receiver) = Pipeline.connect(&mut scope, channel_id);
let (targets, registrar) = Tee::<G::Timestamp,D>::new();
let operator = Operator {
input: PullCounter::new(receiver),
output: PushBuffer::new(PushCounter::new(targets, Rc::new(RefCell::new(CountMap::new())))),
frontier: handle.frontier.clone(),
};
let index = scope.add_operator(operator);
self.connect_to(Target { index: index, port: 0 }, sender, channel_id);
Stream::new(Source { index: index, port: 0 }, registrar, scope)
}
}
/// Reports information about progress at the probe.
pub struct Handle<T:Timestamp> {
frontier: Rc<RefCell<MutableAntichain<T>>>
}
impl<T: Timestamp> Handle<T> {
/// returns true iff the frontier is strictly less than `time`.
#[inline] pub fn less_than(&self, time: &T) -> bool { self.frontier.borrow().less_than(time) }
/// returns true iff the frontier is less than or equal to `time`.
#[inline] pub fn less_equal(&self, time: &T) -> bool { self.frontier.borrow().less_equal(time) }
/// returns true iff the frontier is empty.
#[inline] pub fn done(&self) -> bool { self.frontier.borrow().elements().len() == 0 }
/// Allocates a new handle.
#[inline] pub fn new() -> Self { Handle { frontier: Rc::new(RefCell::new(MutableAntichain::new())) } }
/// Invokes a method on the frontier, returning its result.
///
/// This method allows inspection of the frontier, which cannot be returned by reference as
/// it is on the other side of a `RefCell`.
///
/// #Examples
///
/// ```
/// use timely::dataflow::operators::probe::Handle;
///
/// let handle = Handle::<usize>::new();
/// let frontier = handle.with_frontier(|frontier| frontier.to_vec());
/// ```
#[inline]
pub fn with_frontier<R, F: Fn(&[T])->R>(&self, function: F) -> R {
function(self.frontier.borrow().elements())
}
}
impl<T: Timestamp> Clone for Handle<T> {
fn clone(&self) -> Self {
Handle {
frontier: self.frontier.clone()
}
}
}
struct Operator<T:Timestamp, D: Data> {
input: PullCounter<T, D>,
output: PushBuffer<T, D, PushCounter<T, D, Tee<T, D>>>,
frontier: Rc<RefCell<MutableAntichain<T>>>
}
impl<T:Timestamp, D: Data> Operate<T> for Operator<T, D> {
fn name(&self) -> String { "Probe".to_owned() }
fn inputs(&self) -> usize { 1 }
fn outputs(&self) -> usize { 1 }
// we need to set the initial value of the frontier
fn set_external_summary(&mut self, _: Vec<Vec<Antichain<T::Summary>>>, counts: &mut [CountMap<T>]) {
let mut borrow = self.frontier.borrow_mut();
while let Some((time, delta)) = counts[0].pop() {
borrow.update(&time, delta);
}
}
// each change to the frontier should be shared
fn push_external_progress(&mut self, counts: &mut [CountMap<T>]) {
let mut borrow = self.frontier.borrow_mut();
while let Some((time, delta)) = counts[0].pop() {
borrow.update(&time, delta);
}
}
// the scope does nothing. this is actually a problem, because "reachability" assumes all messages on each edge.
fn pull_internal_progress(&mut self, consumed: &mut [CountMap<T>], _: &mut [CountMap<T>], produced: &mut [CountMap<T>]) -> bool {
while let Some((time, data)) = self.input.next() {
self.output.session(time).give_content(data);
}
self.output.cease();
// extract what we know about progress from the input and output adapters.
self.input.pull_progress(&mut consumed[0]);
self.output.inner().pull_progress(&mut produced[0]);
false
}
}
#[cfg(test)]
mod tests {
use ::Configuration;
use ::progress::timestamp::RootTimestamp;
use dataflow::operators::{Input, Probe};
#[test]
fn probe() {
// initializes and runs a timely dataflow computation
::execute(Configuration::Thread, |worker| {
// create a new input, and inspect its output
let (mut input, probe) = worker.dataflow(move |scope| {
let (input, stream) = scope.new_input::<String>();
(input, stream.probe())
});
// introduce data and watch!
for round in 0..10 {
assert!(!probe.done());
assert!(probe.less_equal(&RootTimestamp::new(round)));
assert!(!probe.less_than(&RootTimestamp::new(round)));
assert!(probe.less_than(&RootTimestamp::new(round + 1)));
input.advance_to(round + 1);
worker.step();
}
// seal the input
input.close();
// finish off any remaining work
worker.step();
assert!(probe.done());
}).unwrap();
}
}