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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
use std::collections::HashMap;
use std::hash::Hash;
use crate::event_database::RecordedEvent;
use crate::ErrorType;
/// Extra keys for events.
///
/// Extra keys need to be pre-defined and map to a string representation.
///
/// For user-defined `EventMetric`s these will be defined as `struct`s.
/// Each extra key will be a field in that struct.
/// Each field will correspond to an entry in the `ALLOWED_KEYS` list.
/// The Glean SDK requires the keys as strings for submission in pings,
/// whereas in code we want to provide users a type to work with
/// (e.g. to avoid typos or misuse of the API).
pub trait ExtraKeys {
/// List of allowed extra keys as strings.
const ALLOWED_KEYS: &'static [&'static str];
/// Convert the event extras into 2 lists:
///
/// 1. The list of extra key indices.
/// Unset keys will be skipped.
/// 2. The list of extra values.
fn into_ffi_extra(self) -> HashMap<String, String>;
}
/// Default of no extra keys for events.
///
/// An enum with no values for convenient use as the default set of extra keys
/// that an [`EventMetric`](crate::metrics::EventMetric) can accept.
///
/// *Note*: There exist no values for this enum, it can never exist.
/// It its equivalent to the [`never / !` type](https://doc.rust-lang.org/std/primitive.never.html).
#[derive(Clone, Copy, Debug, Hash, Eq, PartialEq)]
pub enum NoExtraKeys {}
impl ExtraKeys for NoExtraKeys {
const ALLOWED_KEYS: &'static [&'static str] = &[];
fn into_ffi_extra(self) -> HashMap<String, String> {
unimplemented!("non-existing extra keys can't be turned into a list")
}
}
/// The possible errors when parsing to an extra key.
pub enum EventRecordingError {
/// The id doesn't correspond to a valid extra key
InvalidId,
/// The value doesn't correspond to a valid extra key
InvalidExtraKey,
}
impl TryFrom<i32> for NoExtraKeys {
type Error = EventRecordingError;
fn try_from(_value: i32) -> Result<Self, Self::Error> {
Err(EventRecordingError::InvalidExtraKey)
}
}
impl TryFrom<&str> for NoExtraKeys {
type Error = EventRecordingError;
fn try_from(_value: &str) -> Result<Self, Self::Error> {
Err(EventRecordingError::InvalidExtraKey)
}
}
/// A description for the [`EventMetric`](crate::metrics::EventMetric) type.
///
/// When changing this trait, make sure all the operations are
/// implemented in the related type in `../metrics/`.
pub trait Event {
/// The type of the allowed extra keys for this event.
type Extra: ExtraKeys;
/// Records an event.
///
/// # Arguments
///
/// * `extra` - (optional) An object for the extra keys.
fn record<M: Into<Option<Self::Extra>>>(&self, extra: M);
/// **Exported for test purposes.**
///
/// Get the vector of currently stored events for this event metric.
///
/// This doesn't clear the stored value.
///
/// # Arguments
///
/// * `ping_name` - represents the optional name of the ping to retrieve the
/// metric for. Defaults to the first value in `send_in_pings`.
fn test_get_value<'a, S: Into<Option<&'a str>>>(
&self,
ping_name: S,
) -> Option<Vec<RecordedEvent>>;
/// **Exported for test purposes.**
///
/// Gets the number of recorded errors for the given metric and error type.
///
/// # Arguments
///
/// * `error` - The type of error
///
/// # Returns
///
/// The number of errors reported.
fn test_get_num_recorded_errors(&self, error: ErrorType) -> i32;
}