pub fn evaluate<'a>(
    store: &'a dyn Store,
    flag: &'a Flag,
    user: &'a User,
    prerequisite_event_recorder: Option<&dyn PrerequisiteEventRecorder>,
) -> Detail<&'a FlagValue> {
    if !flag.on {
        return flag.off_value(Reason::Off);
    }

    for prereq in &flag.prerequisites {
        if let Some(prereq_flag) = store.flag(&prereq.key) {
            let prerequisite_result =
                evaluate(store, &prereq_flag, user, prerequisite_event_recorder);
            let variation_index = prerequisite_result.variation_index;

            if let Some(recorder) = prerequisite_event_recorder {
                recorder.record(PrerequisiteEvent {
                    target_flag_key: flag.key.clone(),
                    user: user.clone(),
                    prerequisite_flag: prereq_flag.clone(),
                    prerequisite_result: prerequisite_result.map(|v| v.clone()),
                });
            }

            if !prereq_flag.on || variation_index != Some(prereq.variation) {
                return flag.off_value(Reason::PrerequisiteFailed {
                    prerequisite_key: prereq.key.to_string(),
                });
            }
        } else {
            return flag.off_value(Reason::PrerequisiteFailed {
                prerequisite_key: prereq.key.to_string(),
            });
        }
    }

    for target in &flag.targets {
        for value in &target.values {
            if value == user.key() {
                return flag.variation(target.variation, Reason::TargetMatch);
            }
        }
    }

    for (rule_index, rule) in flag.rules.iter().enumerate() {
        if rule.matches(user, &*store) {
            let result = flag.resolve_variation_or_rollout(&rule.variation_or_rollout, user);
            return match result {
                Ok(BucketResult {
                    variation_index,
                    in_experiment,
                }) => {
                    let reason = Reason::RuleMatch {
                        rule_index,
                        rule_id: rule.id.clone(),
                        in_experiment,
                    };
                    flag.variation(variation_index, reason)
                }
                Err(e) => Detail::err(e),
            };
        }
    }

    let result = flag.resolve_variation_or_rollout(&flag.fallthrough, user);
    return match result {
        Ok(BucketResult {
            variation_index,
            in_experiment,
        }) => {
            let reason = Reason::Fallthrough { in_experiment };
            flag.variation(variation_index, reason)
        }
        Err(e) => Detail::err(e),
    };
}
/// Evaluate a feature flag for the specified user.
///
/// The evaluator does not know anything about analytics events; generating any appropriate
/// analytics events is the responsibility of the caller. The caller can provide an optional
/// [PrerequisiteEventRecorder] which will be notified if any additional evaluations were done due
/// to prerequisites.
Evaluate a feature flag for the specified user.
The evaluator does not know anything about analytics events; generating any appropriate
analytics events is the responsibility of the caller. The caller can provide an optional
[PrerequisiteEventRecorder] which will be notified if any additional evaluations were done due
to prerequisites.
Evaluate a feature flag for the specified user . The evaluator does not know anything about analytics events ; generating any appropriate analytics events is the responsibility of the caller . The caller can provide an optional [ PrerequisiteEventRecorder ] which will be notified if any additional evaluations were done due to prerequisites .
pub fn evaluate<'a>(
    store: &'a dyn Store,
    flag: &'a Flag,
    user: &'a User,
    prerequisite_event_recorder: Option<&dyn PrerequisiteEventRecorder>,
) -> Detail<&'a FlagValue> {
    if !flag.on {
        return flag.off_value(Reason::Off);
    }
    for prereq in &flag.prerequisites {
        if let Some(prereq_flag) = store.flag(&prereq.key) {
            let prerequisite_result =
                evaluate(store, &prereq_flag, user, prerequisite_event_recorder);
            let variation_index = prerequisite_result.variation_index;
            if let Some(recorder) = prerequisite_event_recorder {
                recorder.record(PrerequisiteEvent {
                    target_flag_key: flag.key.clone(),
                    user: user.clone(),
                    prerequisite_flag: prereq_flag.clone(),
                    prerequisite_result: prerequisite_result.map(|v| v.clone()),
                });
            }
            if !prereq_flag.on || variation_index != Some(prereq.variation) {
                return flag.off_value(Reason::PrerequisiteFailed {
                    prerequisite_key: prereq.key.to_string(),
                });
            }
        } else {
            return flag.off_value(Reason::PrerequisiteFailed {
                prerequisite_key: prereq.key.to_string(),
            });
        }
    }
    for target in &flag.targets {
        for value in &target.values {
            if value == user.key() {
                return flag.variation(target.variation, Reason::TargetMatch);
            }
        }
    }
    for (rule_index, rule) in flag.rules.iter().enumerate() {
        if rule.matches(user, &*store) {
            let result = flag.resolve_variation_or_rollout(&rule.variation_or_rollout, user);
            return match result {
                Ok(BucketResult {
                    variation_index,
                    in_experiment,
                }) => {
                    let reason = Reason::RuleMatch {
                        rule_index,
                        rule_id: rule.id.clone(),
                        in_experiment,
                    };
                    flag.variation(variation_index, reason)
                }
                Err(e) => Detail::err(e),
            };
        }
    }
    let result = flag.resolve_variation_or_rollout(&flag.fallthrough, user);
    return match result {
        Ok(BucketResult {
            variation_index,
            in_experiment,
        }) => {
            let reason = Reason::Fallthrough { in_experiment };
            flag.variation(variation_index, reason)
        }
        Err(e) => Detail::err(e),
    };
}
pub fn evaluate < ' a > ( store : & ' a dyn Store , flag : & ' a Flag , user : & ' a User , prerequisite_event_recorder : Option < & dyn PrerequisiteEventRecorder > , ) -> Detail < & ' a FlagValue > { if ! flag . on { return flag . off_value ( Reason :: Off ) ; } for prereq in & flag . prerequisites { if let Some ( prereq_flag ) = store . flag ( & prereq . key ) { let prerequisite_result = evaluate ( store , & prereq_flag , user , prerequisite_event_recorder ) ; let variation_index = prerequisite_result . variation_index ; if let Some ( recorder ) = prerequisite_event_recorder { recorder . record ( PrerequisiteEvent { target_flag_key : flag . key . clone ( ) , user : user . clone ( ) , prerequisite_flag : prereq_flag . clone ( ) , prerequisite_result : prerequisite_result . map ( | v | v . clone ( ) ) , } ) ; } if ! prereq_flag . on || variation_index != Some ( prereq . variation ) { return flag . off_value ( Reason :: PrerequisiteFailed { prerequisite_key : prereq . key . to_string ( ) , } ) ; } } else { return flag . off_value ( Reason :: PrerequisiteFailed { prerequisite_key : prereq . key . to_string ( ) , } ) ; } } for target in & flag . targets { for value in & target . values { if value == user . key ( ) { return flag . variation ( target . variation , Reason :: TargetMatch ) ; } } } for ( rule_index , rule ) in flag . rules . iter ( ) . enumerate ( ) { if rule . matches ( user , & * store ) { let result = flag . resolve_variation_or_rollout ( & rule . variation_or_rollout , user ) ; return match result { Ok ( BucketResult { variation_index , in_experiment , } ) => { let reason = Reason :: RuleMatch { rule_index , rule_id : rule . id . clone ( ) , in_experiment , } ; flag . variation ( variation_index , reason ) } Err ( e ) => Detail :: err ( e ) , } ; } } let result = flag . resolve_variation_or_rollout ( & flag . fallthrough , user ) ; return match result { Ok ( BucketResult { variation_index , in_experiment , } ) => { let reason = Reason :: Fallthrough { in_experiment } ; flag . variation ( variation_index , reason ) } Err ( e ) => Detail :: err ( e ) , } ; }
Evaluate a feature flag for the specified user.
Evaluate a feature flag for the specified user .
store
&'a dyn Store
flag
&'a Flag
user
&'a User
prerequisite_event_recorder
Option<&dyn PrerequisiteEventRecorder>
store
&'a dyn Store
flag
&'a Flag
user
&'a User
prerequisite_event_recorder
Option<&dyn PrerequisiteEventRecorder>