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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
use inherent::inherent;
use std::sync::Arc;
use super::{CommonMetricData, MetricId};
use crate::ipc::need_ipc;
/// A string metric.
///
/// Record an Unicode string value with arbitrary content.
/// Strings are length-limited to `MAX_LENGTH_VALUE` bytes.
///
/// # Example
///
/// The following piece of code will be generated by `glean_parser`:
///
/// ```rust,ignore
/// use glean::metrics::{StringMetric, CommonMetricData, Lifetime};
/// use once_cell::sync::Lazy;
///
/// mod browser {
/// pub static search_engine: Lazy<StringMetric> = Lazy::new(|| StringMetric::new(CommonMetricData {
/// name: "search_engine".into(),
/// category: "browser".into(),
/// lifetime: Lifetime::Ping,
/// disabled: false,
/// dynamic_label: None
/// }));
/// }
/// ```
///
/// It can then be used with:
///
/// ```rust,ignore
/// browser::search_engine.set("websearch");
/// ```
#[derive(Clone)]
pub enum StringMetric {
Parent(Arc<glean::private::StringMetric>),
Child(StringMetricIpc),
}
#[derive(Clone, Debug)]
pub struct StringMetricIpc;
impl StringMetric {
/// Create a new string metric.
pub fn new(_id: MetricId, meta: CommonMetricData) -> Self {
if need_ipc() {
StringMetric::Child(StringMetricIpc)
} else {
StringMetric::Parent(Arc::new(glean::private::StringMetric::new(meta)))
}
}
#[cfg(test)]
pub(crate) fn child_metric(&self) -> Self {
match self {
StringMetric::Parent(_) => StringMetric::Child(StringMetricIpc),
StringMetric::Child(_) => panic!("Can't get a child metric from a child metric"),
}
}
}
#[inherent]
impl glean::traits::String for StringMetric {
/// Sets to the specified value.
///
/// # Arguments
///
/// * `value` - The string to set the metric to.
///
/// ## Notes
///
/// Truncates the value if it is longer than `MAX_STRING_LENGTH` bytes and logs an error.
pub fn set<S: Into<std::string::String>>(&self, value: S) {
match self {
StringMetric::Parent(p) => {
p.set(value.into());
}
StringMetric::Child(_) => {
log::error!("Unable to set string metric in non-main process. This operation will be ignored.");
// If we're in automation we can panic so the instrumentor knows they've gone wrong.
// This is a deliberate violation of Glean's "metric APIs must not throw" design.
assert!(!crate::ipc::is_in_automation(), "Attempted to set string metric in non-main process, which is forbidden. This panics in automation.");
// TODO: Record an error.
}
};
}
/// **Exported for test purposes.**
///
/// Gets the currently stored value as a string.
///
/// This doesn't clear the stored value.
///
/// # Arguments
///
/// * `ping_name` - represents the optional name of the ping to retrieve the
/// metric for. Defaults to the first value in `send_in_pings`.
pub fn test_get_value<'a, S: Into<Option<&'a str>>>(
&self,
ping_name: S,
) -> Option<std::string::String> {
let ping_name = ping_name.into().map(|s| s.to_string());
match self {
StringMetric::Parent(p) => p.test_get_value(ping_name),
StringMetric::Child(_) => {
panic!("Cannot get test value for string metric in non-main process!")
}
}
}
/// **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. Defaults to the first value in `send_in_pings`.
///
/// # Returns
///
/// The number of errors reported.
pub fn test_get_num_recorded_errors(&self, error: glean::ErrorType) -> i32 {
match self {
StringMetric::Parent(p) => p.test_get_num_recorded_errors(error),
StringMetric::Child(_) => panic!(
"Cannot get the number of recorded errors for string metric in non-main process!"
),
}
}
}
#[cfg(test)]
mod test {
use crate::{common_test::*, ipc, metrics};
#[test]
fn sets_string_value() {
let _lock = lock_test();
let metric = &metrics::test_only_ipc::a_string;
metric.set("test_string_value");
assert_eq!(
"test_string_value",
metric.test_get_value("store1").unwrap()
);
}
#[test]
fn string_ipc() {
// StringMetric doesn't support IPC.
let _lock = lock_test();
let parent_metric = &metrics::test_only_ipc::a_string;
parent_metric.set("test_parent_value");
{
let child_metric = parent_metric.child_metric();
let _raii = ipc::test_set_need_ipc(true);
// Instrumentation calls do not panic.
child_metric.set("test_string_value");
// (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!(
"test_parent_value" == parent_metric.test_get_value("store1").unwrap(),
"String metrics should only work in the parent process"
);
}
}