cardinal-sdk 0.1.0

Cardinal's SDK for building macOS file search utilities.
Documentation 
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use libc::dev_t;
use objc2_core_services::{FSEventsGetCurrentEventId, FSEventsGetLastEventIdForDeviceBeforeTime};
use std::{collections::HashMap, time::SystemTime};

pub fn current_timestamp() -> i64 {
    SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .map(|d| d.as_secs() as i64)
        .unwrap_or_default()
}

pub fn current_event_id() -> u64 {
    unsafe { FSEventsGetCurrentEventId() }
}

pub fn last_event_id_before_time(dev: dev_t, timestamp: i64) -> u64 {
    unsafe { FSEventsGetLastEventIdForDeviceBeforeTime(dev, timestamp as f64) }
}

/// Given a device id, an event id, and a cache mapping timestamps to last event ids before them,
/// perform a binary search to find the timestamp corresponding to the event id.
pub fn event_id_to_timestamp(dev: dev_t, event_id: u64, cache: &mut HashMap<i64, u64>) -> i64 {
    let mut begin = 0i64;
    let mut end = current_timestamp();
    loop {
        let mid = (begin + end) / 2;
        if mid == begin || mid == end {
            return mid;
        }
        let mid_event_id = *cache
            .entry(mid)
            .or_insert_with(|| last_event_id_before_time(dev, mid));
        if mid_event_id < event_id {
            begin = mid
        } else if mid_event_id > event_id {
            end = mid
        } else {
            return mid;
        }
    }
}