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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 crate::error_recording::{record_error, ErrorType};
use crate::metrics::Metric;
use crate::metrics::MetricType;
use crate::storage::StorageManager;
use crate::util::truncate_string_at_boundary_with_error;
use crate::CommonMetricData;
use crate::Glean;
// Maximum length of any list
const MAX_LIST_LENGTH: usize = 20;
// Maximum length of any string in the list
const MAX_STRING_LENGTH: usize = 50;
/// A string list metric.
///
/// This allows appending a string value with arbitrary content to a list.
#[derive(Clone, Debug)]
pub struct StringListMetric {
meta: CommonMetricData,
}
impl MetricType for StringListMetric {
fn meta(&self) -> &CommonMetricData {
&self.meta
}
fn meta_mut(&mut self) -> &mut CommonMetricData {
&mut self.meta
}
}
impl StringListMetric {
/// Create a new string list metric.
pub fn new(meta: CommonMetricData) -> Self {
Self { meta }
}
/// Add a new string to the list.
///
/// ## Arguments
///
/// * `glean` - The Glean instance this metric belongs to.
/// * `value` - The string to add.
///
/// ## Notes
///
/// Truncates the value if it is longer than `MAX_STRING_LENGTH` bytes and logs an error.
pub fn add<S: Into<String>>(&self, glean: &Glean, value: S) {
if !self.should_record(glean) {
return;
}
let value =
truncate_string_at_boundary_with_error(glean, &self.meta, value, MAX_STRING_LENGTH);
let mut error = None;
glean
.storage()
.record_with(glean, &self.meta, |old_value| match old_value {
Some(Metric::StringList(mut old_value)) => {
if old_value.len() == MAX_LIST_LENGTH {
let msg = format!(
"String list length of {} exceeds maximum of {}",
old_value.len() + 1,
MAX_LIST_LENGTH
);
error = Some(msg);
} else {
old_value.push(value.clone());
}
Metric::StringList(old_value)
}
_ => Metric::StringList(vec![value.clone()]),
});
if let Some(msg) = error {
record_error(glean, &self.meta, ErrorType::InvalidValue, msg, None);
}
}
/// Set to a specific list of strings.
///
/// ## Arguments
///
/// * `glean` - The Glean instance this metric belongs to.
/// * `value` - The list of string to set the metric to.
///
/// ## Notes
///
/// If passed an empty list, records an error and returns.
/// Truncates the list if it is longer than `MAX_LIST_LENGTH` and logs an error.
/// Truncates any value in the list if it is longer than `MAX_STRING_LENGTH` and logs an error.
pub fn set(&self, glean: &Glean, value: Vec<String>) {
if !self.should_record(glean) {
return;
}
let value = if value.len() > MAX_LIST_LENGTH {
let msg = format!(
"StringList length {} exceeds maximum of {}",
value.len(),
MAX_LIST_LENGTH
);
record_error(glean, &self.meta, ErrorType::InvalidValue, msg, None);
value[0..MAX_LIST_LENGTH].to_vec()
} else {
value
};
let value = value
.into_iter()
.map(|elem| {
truncate_string_at_boundary_with_error(glean, &self.meta, elem, MAX_STRING_LENGTH)
})
.collect();
let value = Metric::StringList(value);
glean.storage().record(glean, &self.meta, &value);
}
/// **Test-only API (exported for FFI purposes).**
///
/// Get the currently-stored values.
///
/// This doesn't clear the stored value.
pub fn test_get_value(&self, glean: &Glean, storage_name: &str) -> Option<Vec<String>> {
match StorageManager.snapshot_metric(
glean.storage(),
storage_name,
&self.meta.identifier(glean),
) {
Some(Metric::StringList(values)) => Some(values),
_ => None,
}
}
/// **Test-only API (exported for FFI purposes).**
///
/// Get the currently-stored values as a JSON String of the format
/// ["string1", "string2", ...]
///
/// This doesn't clear the stored value.
pub fn test_get_value_as_json_string(
&self,
glean: &Glean,
storage_name: &str,
) -> Option<String> {
self.test_get_value(glean, storage_name)
.map(|values| serde_json::to_string(&values).unwrap())
}
}