Flat directory/module structure

src/timer/windows_timer.rs

@@ -0,0 +1,83 @@
+#![cfg(windows)]
+
+use super::internal::CPUTimes;
+use crate::timer::{TimerStart, TimerStop};
+use crate::units::Second;
+
+use winapi::um::processthreadsapi::GetProcessTimes;
+use winapi::um::winnt::HANDLE;
+
+use std::mem;
+use std::os::windows::io::{AsRawHandle, RawHandle};
+use std::process::Child;
+
+const HUNDRED_NS_PER_MS: i64 = 10;
+
+pub fn get_cpu_timer(process: &Child) -> Box<dyn TimerStop<Result = (Second, Second)>> {
+    Box::new(CPUTimer::start_for_process(process))
+}
+
+struct CPUTimer {
+    handle: RawHandle,
+}
+
+impl TimerStart for CPUTimer {
+    fn start() -> Self {
+        panic!()
+    }
+
+    fn start_for_process(process: &Child) -> Self {
+        CPUTimer {
+            handle: process.as_raw_handle(),
+        }
+    }
+}
+
+impl TimerStop for CPUTimer {
+    type Result = (Second, Second);
+
+    fn stop(&self) -> Self::Result {
+        let times = get_cpu_times(self.handle);
+        (
+            times.user_usec as f64 * 1e-6,
+            times.system_usec as f64 * 1e-6,
+        )
+    }
+}
+
+/// Read CPU execution times (dummy for now)
+fn get_cpu_times(handle: RawHandle) -> CPUTimes {
+    let (user_usec, system_usec) = unsafe {
+        let mut _ctime = mem::zeroed();
+        let mut _etime = mem::zeroed();
+        let mut kernel_time = mem::zeroed();
+        let mut user_time = mem::zeroed();
+        let res = GetProcessTimes(
+            handle as HANDLE,
+            &mut _ctime,
+            &mut _etime,
+            &mut kernel_time,
+            &mut user_time,
+        );
+
+        // GetProcessTimes will exit with non-zero if success as per: https://msdn.microsoft.com/en-us/library/windows/desktop/ms683223(v=vs.85).aspx
+        if res != 0 {
+            // Extract times as laid out here: https://support.microsoft.com/en-us/help/188768/info-working-with-the-filetime-structure
+            // Both user_time and kernel_time are spans that the proces spent in either.
+            let user: i64 = (((user_time.dwHighDateTime as i64) << 32)
+                + user_time.dwLowDateTime as i64)
+                / HUNDRED_NS_PER_MS;
+            let kernel: i64 = (((kernel_time.dwHighDateTime as i64) << 32)
+                + kernel_time.dwLowDateTime as i64)
+                / HUNDRED_NS_PER_MS;
+            (user, kernel)
+        } else {
+            (0, 0)
+        }
+    };
+
+    CPUTimes {
+        user_usec,
+        system_usec,
+    }
+}