1 files changed, 82 insertions, 0 deletions
diff --git a/toolkit/components/glean/api/src/ffi/custom_distribution.rs b/toolkit/components/glean/api/src/ffi/custom_distribution.rs
new file mode 100644
index 0000000000..853a6e9845
--- /dev/null
+++ b/toolkit/components/glean/api/src/ffi/custom_distribution.rs
@@ -0,0 +1,82 @@
+// 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/.
+
+#![cfg(feature = "with_gecko")]
+
+use nsstring::nsACString;
+use thin_vec::ThinVec;
+
+#[no_mangle]
+pub extern "C" fn fog_custom_distribution_test_has_value(id: u32, ping_name: &nsACString) -> bool {
+    with_metric!(
+        CUSTOM_DISTRIBUTION_MAP,
+        id,
+        metric,
+        test_has!(metric, ping_name)
+    )
+}
+
+#[no_mangle]
+pub extern "C" fn fog_custom_distribution_test_get_value(
+    id: u32,
+    ping_name: &nsACString,
+    sum: &mut u64,
+    buckets: &mut ThinVec<u64>,
+    counts: &mut ThinVec<u64>,
+) {
+    let val = with_metric!(
+        CUSTOM_DISTRIBUTION_MAP,
+        id,
+        metric,
+        test_get!(metric, ping_name)
+    );
+    // FIXME(bug 1771885): Glean should use `u64` where it can.
+    *sum = val.sum as _;
+    for (&bucket, &count) in val.values.iter() {
+        buckets.push(bucket as _);
+        counts.push(count as _);
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn fog_custom_distribution_accumulate_samples(id: u32, samples: &ThinVec<u64>) {
+    // N.B.: Avoid reallocation here by making the underlying type take a slice.
+    let samples = samples.into_iter().map(|&i| i as i64).collect();
+    with_metric!(
+        CUSTOM_DISTRIBUTION_MAP,
+        id,
+        metric,
+        metric.accumulate_samples_signed(samples)
+    );
+}
+
+#[no_mangle]
+pub extern "C" fn fog_custom_distribution_accumulate_samples_signed(
+    id: u32,
+    samples: &ThinVec<i64>,
+) {
+    // N.B.: Avoid reallocation here by making the underlying type take a slice.
+    let samples = samples.to_vec();
+    with_metric!(
+        CUSTOM_DISTRIBUTION_MAP,
+        id,
+        metric,
+        metric.accumulate_samples_signed(samples)
+    );
+}
+
+#[no_mangle]
+pub extern "C" fn fog_custom_distribution_test_get_error(
+    id: u32,
+
+    error_str: &mut nsACString,
+) -> bool {
+    let err = with_metric!(
+        CUSTOM_DISTRIBUTION_MAP,
+        id,
+        metric,
+        test_get_errors!(metric)
+    );
+    err.map(|err_str| error_str.assign(&err_str)).is_some()
+}