1 files changed, 171 insertions, 0 deletions
diff --git a/third_party/rust/glean-core/src/metrics/counter.rs b/third_party/rust/glean-core/src/metrics/counter.rs
new file mode 100644
index 0000000000..8f0a01cc3e
--- /dev/null
+++ b/third_party/rust/glean-core/src/metrics/counter.rs
@@ -0,0 +1,171 @@
+// 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::cmp::Ordering;
+use std::sync::Arc;
+
+use crate::common_metric_data::CommonMetricDataInternal;
+use crate::error_recording::{record_error, test_get_num_recorded_errors, ErrorType};
+use crate::metrics::Metric;
+use crate::metrics::MetricType;
+use crate::storage::StorageManager;
+use crate::CommonMetricData;
+use crate::Glean;
+
+/// A counter metric.
+///
+/// Used to count things.
+/// The value can only be incremented, not decremented.
+#[derive(Clone, Debug)]
+pub struct CounterMetric {
+    meta: Arc<CommonMetricDataInternal>,
+}
+
+impl MetricType for CounterMetric {
+    fn meta(&self) -> &CommonMetricDataInternal {
+        &self.meta
+    }
+
+    fn with_name(&self, name: String) -> Self {
+        let mut meta = (*self.meta).clone();
+        meta.inner.name = name;
+        Self {
+            meta: Arc::new(meta),
+        }
+    }
+
+    fn with_dynamic_label(&self, label: String) -> Self {
+        let mut meta = (*self.meta).clone();
+        meta.inner.dynamic_label = Some(label);
+        Self {
+            meta: Arc::new(meta),
+        }
+    }
+}
+
+// IMPORTANT:
+//
+// When changing this implementation, make sure all the operations are
+// also declared in the related trait in `../traits/`.
+impl CounterMetric {
+    /// Creates a new counter metric.
+    pub fn new(meta: CommonMetricData) -> Self {
+        Self {
+            meta: Arc::new(meta.into()),
+        }
+    }
+
+    /// Increases the counter by `amount` synchronously.
+    #[doc(hidden)]
+    pub fn add_sync(&self, glean: &Glean, amount: i32) {
+        if !self.should_record(glean) {
+            return;
+        }
+
+        match amount.cmp(&0) {
+            Ordering::Less => {
+                record_error(
+                    glean,
+                    &self.meta,
+                    ErrorType::InvalidValue,
+                    format!("Added negative value {}", amount),
+                    None,
+                );
+                return;
+            }
+            Ordering::Equal => {
+                // Silently ignore.
+                return;
+            }
+            Ordering::Greater => (),
+        };
+
+        // Let's be defensive here:
+        // The uploader tries to store a counter metric,
+        // but in tests that storage might be gone already.
+        // Let's just ignore those.
+        // This should never happen in real app usage.
+        if let Some(storage) = glean.storage_opt() {
+            storage.record_with(glean, &self.meta, |old_value| match old_value {
+                Some(Metric::Counter(old_value)) => {
+                    Metric::Counter(old_value.saturating_add(amount))
+                }
+                _ => Metric::Counter(amount),
+            })
+        } else {
+            log::warn!(
+                "Couldn't get storage. Can't record counter '{}'.",
+                self.meta.base_identifier()
+            );
+        }
+    }
+
+    /// Increases the counter by `amount`.
+    ///
+    /// # Arguments
+    ///
+    /// * `glean` - The Glean instance this metric belongs to.
+    /// * `amount` - The amount to increase by. Should be positive.
+    ///
+    /// ## Notes
+    ///
+    /// Logs an error if the `amount` is 0 or negative.
+    pub fn add(&self, amount: i32) {
+        let metric = self.clone();
+        crate::launch_with_glean(move |glean| metric.add_sync(glean, amount))
+    }
+
+    /// Get current value
+    #[doc(hidden)]
+    pub fn get_value<'a, S: Into<Option<&'a str>>>(
+        &self,
+        glean: &Glean,
+        ping_name: S,
+    ) -> Option<i32> {
+        let queried_ping_name = ping_name
+            .into()
+            .unwrap_or_else(|| &self.meta().inner.send_in_pings[0]);
+
+        match StorageManager.snapshot_metric_for_test(
+            glean.storage(),
+            queried_ping_name,
+            &self.meta.identifier(glean),
+            self.meta.inner.lifetime,
+        ) {
+            Some(Metric::Counter(i)) => Some(i),
+            _ => None,
+        }
+    }
+
+    /// **Test-only API (exported for FFI purposes).**
+    ///
+    /// Gets the currently stored value as an integer.
+    ///
+    /// This doesn't clear the stored value.
+    pub fn test_get_value(&self, ping_name: Option<String>) -> Option<i32> {
+        crate::block_on_dispatcher();
+        crate::core::with_glean(|glean| self.get_value(glean, ping_name.as_deref()))
+    }
+
+    /// **Exported for test purposes.**
+    ///
+    /// Gets the number of recorded errors for the given metric and error type.
+    ///
+    /// # Arguments
+    ///
+    /// * `error` - The type of error
+    /// * `ping_name` - represents the optional name of the ping to retrieve the
+    ///   metric for. inner to the first value in `send_in_pings`.
+    ///
+    /// # Returns
+    ///
+    /// The number of errors reported.
+    pub fn test_get_num_recorded_errors(&self, error: ErrorType) -> i32 {
+        crate::block_on_dispatcher();
+
+        crate::core::with_glean(|glean| {
+            test_get_num_recorded_errors(glean, self.meta(), error).unwrap_or(0)
+        })
+    }
+}