Rename ra_prof -> profile

crates/profile/src/google_cpu_profiler.rs

@@ -0,0 +1,39 @@
+//! https://github.com/gperftools/gperftools
+
+use std::{
+    ffi::CString,
+    os::raw::c_char,
+    path::Path,
+    sync::atomic::{AtomicUsize, Ordering},
+};
+
+#[link(name = "profiler")]
+#[allow(non_snake_case)]
+extern "C" {
+    fn ProfilerStart(fname: *const c_char) -> i32;
+    fn ProfilerStop();
+}
+
+static PROFILER_STATE: AtomicUsize = AtomicUsize::new(OFF);
+const OFF: usize = 0;
+const ON: usize = 1;
+const PENDING: usize = 2;
+
+pub fn start(path: &Path) {
+    if PROFILER_STATE.compare_and_swap(OFF, PENDING, Ordering::SeqCst) != OFF {
+        panic!("profiler already started");
+    }
+    let path = CString::new(path.display().to_string()).unwrap();
+    if unsafe { ProfilerStart(path.as_ptr()) } == 0 {
+        panic!("profiler failed to start")
+    }
+    assert!(PROFILER_STATE.compare_and_swap(PENDING, ON, Ordering::SeqCst) == PENDING);
+}
+
+pub fn stop() {
+    if PROFILER_STATE.compare_and_swap(ON, PENDING, Ordering::SeqCst) != ON {
+        panic!("profiler is not started")
+    }
+    unsafe { ProfilerStop() };
+    assert!(PROFILER_STATE.compare_and_swap(PENDING, OFF, Ordering::SeqCst) == PENDING);
+}