Implement the initial set of reporter events

crates/report/src/runner_event.rs

@@ -0,0 +1,147 @@
+//! The types associated with the events sent by the runner to the reporter.
+
+use std::path::PathBuf;
+
+use revive_dt_format::corpus::Corpus;
+use revive_dt_format::metadata::Metadata;
+use tokio::sync::{broadcast, oneshot};
+
+use crate::ReporterEvent;
+
+macro_rules! keep_if_doc {
+    (#[doc = $doc:expr]) => {
+        #[doc = $doc]
+    };
+    ( $($_:tt)* ) => {};
+}
+
+/// Defines the runner-event which is sent from the test runners to the report aggregator.
+///
+/// This macro defines a number of things related to the reporting infrastructure and the interface
+/// used. First of all, it defines the enum of all of the possible events that the runners can send
+/// to the aggregator. For each one of the variants it defines a separate struct for it to allow the
+/// variant field in the enum to be put in a [`Box`].
+///
+/// In addition to the above, it defines [`From`] implementations for the various event types for
+/// the [`RunnerEvent`] enum essentially allowing for events such as [`CorpusFileDiscoveryEvent`] to
+/// be converted into a [`RunnerEvent`].
+///
+/// In addition to the above, it also defines the [`RunnerEventReporter`] which is a wrapper around
+/// an [`UnboundedSender`] allowing for events to be sent to the report aggregator.
+///
+/// With the above description, we can see that this macro defines almost all of the interface of
+/// the reporting infrastructure, from the enum itself, to its associated types, and also to the
+/// reporter that's used to report events to the aggregator.
+///
+/// [`UnboundedSender`]: tokio::sync::mpsc::UnboundedSender
+macro_rules! define_event {
+    (
+        $(#[$enum_meta: meta])*
+        $vis: vis enum $ident: ident {
+            $(
+                $(#[$variant_meta: meta])*
+                $variant_ident: ident {
+                    $(
+                        $(#[$field_meta: meta])*
+                        $field_ident: ident: $field_ty: ty
+                    ),* $(,)?
+                }
+            ),* $(,)?
+        }
+    ) => {
+        paste::paste! {
+            $(#[$enum_meta])*
+            $vis enum $ident {
+                $(
+                    $(#[$variant_meta])*
+                    $variant_ident(Box<[<$variant_ident Event>]>)
+                ),*
+            }
+
+            $(
+                $(#[$variant_meta])*
+                $vis struct [<$variant_ident Event>] {
+                    $(
+                        $(#[$field_meta])*
+                        $vis $field_ident: $field_ty
+                    ),*
+                }
+            )*
+
+            $(
+                impl From<[<$variant_ident Event>]> for $ident {
+                    fn from(value: [<$variant_ident Event>]) -> Self {
+                        Self::$variant_ident(Box::new(value))
+                    }
+                }
+            )*
+
+            /// Provides a way to report events to the aggregator.
+            ///
+            /// Under the hood, this is a wrapper around an [`UnboundedSender`] which abstracts away
+            /// the fact that channels are used and that implements high-level methods for reporting
+            /// various events to the aggregator.
+            #[derive(Clone, Debug)]
+            pub struct [< $ident Reporter >]($vis tokio::sync::mpsc::UnboundedSender<$ident>);
+
+            impl From<tokio::sync::mpsc::UnboundedSender<$ident>> for [< $ident Reporter >] {
+                fn from(value: tokio::sync::mpsc::UnboundedSender<$ident>) -> Self {
+                    Self(value)
+                }
+            }
+
+            impl [< $ident Reporter >] {
+                fn report(&self, event: impl Into<$ident>) -> anyhow::Result<()> {
+                    self.0.send(event.into()).map_err(Into::into)
+                }
+
+                $(
+                    keep_if_doc!($(#[$variant_meta])*);
+                    pub fn [< report_ $variant_ident:snake _event >](&self, $($field_ident: impl Into<$field_ty>),*) -> anyhow::Result<()> {
+                        self.report([< $variant_ident Event >] {
+                            $($field_ident: $field_ident.into()),*
+                        })
+                    }
+                )*
+            }
+        }
+    };
+}
+
+define_event! {
+    /// An event type that's sent by the test runners/drivers to the report aggregator.
+    pub(crate) enum RunnerEvent {
+        /// An event emitted by the reporter when it wishes to listen to events emitted by the
+        /// aggregator.
+        SubscribeToEvents {
+            /// The channel that the aggregator is to send the receive side of the channel on.
+            tx: oneshot::Sender<broadcast::Receiver<ReporterEvent>>
+        },
+        /// An event emitted by runners when they've discovered a corpus file.
+        CorpusFileDiscovery {
+            /// The contents of the corpus file.
+            corpus: Corpus
+        },
+        /// An event emitted by runners when they've discovered a metadata file.
+        MetadataFileDiscovery {
+            /// The path of the metadata file discovered.
+            path: PathBuf,
+            /// The content of the metadata file.
+            metadata: Metadata
+        },
+        /// An event emitted by the runners when the execution is completed and the aggregator can
+        /// stop.
+        ExecutionCompleted {}
+    }
+}
+
+/// An extension to the [`Reporter`] implemented by the macro.
+impl RunnerEventReporter {
+    pub async fn subscribe(&self) -> anyhow::Result<broadcast::Receiver<ReporterEvent>> {
+        let (tx, rx) = oneshot::channel::<broadcast::Receiver<ReporterEvent>>();
+        self.report_subscribe_to_events_event(tx)?;
+        rx.await.map_err(Into::into)
+    }
+}
+
+pub type Reporter = RunnerEventReporter;