Add a `task_info` crate and a `task_basic_info` module within it.

The crate provides an interface to the Mac-specific `task_info()`
function in general, and the module provides an interface to the
TASK_BASIC_INFO flavor.  Currently only the `virtual_size` and
`resident_size` values of the `task_basic_info` struct are exposed, but
there's obvious room for expansion.

This is used to implement the -m measurements on Mac.

1 files changed, 55 insertions, 0 deletions

diff --git a/src/platform/macos/rust-task_info/task_basic_info.rs b/src/platform/macos/rust-task_info/task_basic_info.rs
new file mode 100644
index 00000000000..9d87ac7bc20
--- /dev/null
+++ b/src/platform/macos/rust-task_info/task_basic_info.rs
@@ -0,0 +1,55 @@
+// Copyright 2014 The Servo Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Interface to the measurements in the task_basic_info struct, gathered by
+//! invoking `task_info()` with the `TASK_BASIC_INFO` flavor.
+
+use libc::{c_int,uint64_t};
+
+/// Obtains task_basic_info::virtual_size.
+pub fn virtual_size() -> Option<u64> {
+    let mut virtual_size: u64 = 0;
+    let mut rv;
+    unsafe {
+        rv = TaskBasicInfoVirtualSize(&mut virtual_size);
+    }
+    if rv == 0 { Some(virtual_size) } else { None }
+}
+
+/// Obtains task_basic_info::resident_size.
+pub fn resident_size() -> Option<u64> {
+    let mut resident_size: u64 = 0;
+    let mut rv;
+    unsafe {
+        rv = TaskBasicInfoResidentSize(&mut resident_size);
+    }
+    if rv == 0 { Some(resident_size) } else { None }
+}
+
+#[link(name = "task_info")]
+extern {
+    fn TaskBasicInfoVirtualSize(virtual_size: *mut uint64_t) -> c_int;
+    fn TaskBasicInfoResidentSize(resident_size: *mut uint64_t) -> c_int;
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_stuff() {
+        // In theory these can fail to return a value, but in practice they
+        // don't unless something really bizarre has happened with the OS. So
+        // assume they succeed. The returned values are non-deterministic, but
+        // check they're non-zero as a basic sanity test.
+        assert!(virtual_size().unwrap() > 0);
+        assert!(resident_size().unwrap() > 0);
+    }
+}
+