1 files changed, 28 insertions, 0 deletions
diff --git a/src/profiler.rs b/src/profiler.rs
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+++ b/src/profiler.rs
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+//! This module provides an extension trait which allows in-process profilers
+//! to be hooked into the `--profile-time` argument at compile-time. Users of
+//! out-of-process profilers such as perf don't need to do anything special.
+
+use std::path::Path;
+
+/// Extension trait for external crates to implement which provides start/stop
+/// hooks when profiling (but not when benchmarking) functions.
+pub trait Profiler {
+    /// This function is called when Criterion.rs starts profiling a particular
+    /// benchmark. It provides the stringified benchmark ID and
+    /// a path to a directory where the profiler can store its data.
+    fn start_profiling(&mut self, benchmark_id: &str, benchmark_dir: &Path);
+
+    /// This function is called after Criterion.rs stops profiling a particular
+    /// benchmark. The benchmark ID and directory are the same as in the call
+    /// to `start`, provided for convenience.
+    fn stop_profiling(&mut self, benchmark_id: &str, benchmark_dir: &Path);
+}
+
+/// Dummy profiler implementation, representing cases where the profiler is
+/// an external process (eg. perftools, etc.) which do not require start/stop
+/// hooks. This implementation does nothing and is used as the default.
+pub struct ExternalProfiler;
+impl Profiler for ExternalProfiler {
+    fn start_profiling(&mut self, _benchmark_id: &str, _benchmark_dir: &Path) {}
+    fn stop_profiling(&mut self, _benchmark_id: &str, _benchmark_dir: &Path) {}
+}