counter.rs

// 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
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

use std::ffi::CString;
use std::os::raw::c_char;

/// A counter metric.
///
/// Used to count things.
/// The value can only be incremented, not decremented.
#[derive(Clone, Debug)]
pub struct CounterMetric(u64);

extern "C" {
    fn glean_new_counter_metric(
        category: *const c_char,
        name: *const c_char,
        send_in_pings: *const *const c_char,
        lifetime: u32,
        disabled: u8,
    ) -> u64;
    fn glean_counter_add(glean_handle: u64, metric_id: u64, amount: u32);
}

impl CounterMetric {
    pub fn new(
        category: String,
        name: String,
        _send_in_pings: Vec<String>,
        lifetime: u32,
        disabled: bool,
    ) -> CounterMetric {
        unsafe {
            let category = CString::new(category).unwrap();
            let name = CString::new(name).unwrap();
            let handle = glean_new_counter_metric(
                category.as_ptr(),
                name.as_ptr(),
                std::ptr::null(),
                lifetime,
                disabled as u8,
            );
            CounterMetric(handle)
        }
    }

    pub fn add(&self, amount: u32) {
        unsafe { glean_counter_add(0, self.0, amount) }
    }
}