1 files changed, 128 insertions, 0 deletions
diff --git a/toolkit/components/glean/api/src/private/boolean.rs b/toolkit/components/glean/api/src/private/boolean.rs
new file mode 100644
index 0000000000..8fd6dbbd0f
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+++ b/toolkit/components/glean/api/src/private/boolean.rs
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+// 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 inherent::inherent;
+
+use glean_core::traits::Boolean;
+
+use super::CommonMetricData;
+
+use crate::ipc::need_ipc;
+use crate::private::MetricId;
+
+/// A boolean metric.
+///
+/// Records a simple true or false value.
+#[derive(Clone)]
+pub enum BooleanMetric {
+    Parent(glean::private::BooleanMetric),
+    Child(BooleanMetricIpc),
+}
+#[derive(Clone, Debug)]
+pub struct BooleanMetricIpc;
+
+impl BooleanMetric {
+    /// Create a new boolean metric.
+    pub fn new(_id: MetricId, meta: CommonMetricData) -> Self {
+        if need_ipc() {
+            BooleanMetric::Child(BooleanMetricIpc)
+        } else {
+            BooleanMetric::Parent(glean::private::BooleanMetric::new(meta))
+        }
+    }
+
+    #[cfg(test)]
+    pub(crate) fn child_metric(&self) -> Self {
+        match self {
+            BooleanMetric::Parent(_) => BooleanMetric::Child(BooleanMetricIpc),
+            BooleanMetric::Child(_) => panic!("Can't get a child metric from a child metric"),
+        }
+    }
+}
+
+#[inherent(pub)]
+impl Boolean for BooleanMetric {
+    /// Set to the specified boolean value.
+    ///
+    /// ## Arguments
+    ///
+    /// * `value` - the value to set.
+    fn set(&self, value: bool) {
+        match self {
+            BooleanMetric::Parent(p) => {
+                Boolean::set(&*p, value);
+            }
+            BooleanMetric::Child(_) => {
+                log::error!("Unable to set boolean metric in non-parent process. Ignoring.");
+                // TODO: Record an error.
+            }
+        }
+    }
+
+    /// **Test-only API.**
+    ///
+    /// Get the currently stored value as a boolean.
+    /// This doesn't clear the stored value.
+    ///
+    /// ## Arguments
+    ///
+    /// * `ping_name` - the storage name to look into.
+    ///
+    /// ## Return value
+    ///
+    /// Returns the stored value or `None` if nothing stored.
+    fn test_get_value<'a, S: Into<Option<&'a str>>>(&self, ping_name: S) -> Option<bool> {
+        match self {
+            BooleanMetric::Parent(p) => p.test_get_value(ping_name),
+            BooleanMetric::Child(_) => {
+                panic!("Cannot get test value for boolean metric in non-parent process!",)
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::{common_test::*, ipc, metrics};
+
+    #[test]
+    fn sets_boolean_value() {
+        let _lock = lock_test();
+
+        let metric = &metrics::test_only_ipc::a_bool;
+        metric.set(true);
+
+        assert!(metric.test_get_value("store1").unwrap());
+    }
+
+    #[test]
+    fn boolean_ipc() {
+        // BooleanMetric doesn't support IPC.
+        let _lock = lock_test();
+
+        let parent_metric = &metrics::test_only_ipc::a_bool;
+
+        parent_metric.set(false);
+
+        {
+            let child_metric = parent_metric.child_metric();
+
+            // scope for need_ipc RAII
+            let _raii = ipc::test_set_need_ipc(true);
+
+            // Instrumentation calls do not panic.
+            child_metric.set(true);
+
+            // (They also shouldn't do anything,
+            // but that's not something we can inspect in this test)
+        }
+
+        assert!(ipc::replay_from_buf(&ipc::take_buf().unwrap()).is_ok());
+
+        assert!(
+            false == parent_metric.test_get_value("store1").unwrap(),
+            "Boolean metrics should only work in the parent process"
+        );
+    }
+}