1 files changed, 136 insertions, 0 deletions
diff --git a/ext/node/ops/os/priority.rs b/ext/node/ops/os/priority.rs
new file mode 100644
index 000000000..2d5994705
--- /dev/null
+++ b/ext/node/ops/os/priority.rs
@@ -0,0 +1,136 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+use deno_core::error::AnyError;
+
+pub use impl_::*;
+
+#[cfg(unix)]
+mod impl_ {
+  use super::*;
+  use errno::errno;
+  use errno::set_errno;
+  use errno::Errno;
+  use libc::id_t;
+  use libc::PRIO_PROCESS;
+
+  const PRIORITY_HIGH: i32 = -14;
+
+  // Ref: https://github.com/libuv/libuv/blob/55376b044b74db40772e8a6e24d67a8673998e02/src/unix/core.c#L1533-L1547
+  pub fn get_priority(pid: u32) -> Result<i32, AnyError> {
+    set_errno(Errno(0));
+    match (
+      // SAFETY: libc::getpriority is unsafe
+      unsafe { libc::getpriority(PRIO_PROCESS, pid as id_t) },
+      errno(),
+    ) {
+      (-1, Errno(0)) => Ok(PRIORITY_HIGH),
+      (-1, _) => Err(std::io::Error::last_os_error().into()),
+      (priority, _) => Ok(priority),
+    }
+  }
+
+  pub fn set_priority(pid: u32, priority: i32) -> Result<(), AnyError> {
+    // SAFETY: libc::setpriority is unsafe
+    match unsafe { libc::setpriority(PRIO_PROCESS, pid as id_t, priority) } {
+      -1 => Err(std::io::Error::last_os_error().into()),
+      _ => Ok(()),
+    }
+  }
+}
+
+#[cfg(windows)]
+mod impl_ {
+  use super::*;
+  use deno_core::error::type_error;
+  use winapi::shared::minwindef::DWORD;
+  use winapi::shared::minwindef::FALSE;
+  use winapi::shared::ntdef::NULL;
+  use winapi::um::handleapi::CloseHandle;
+  use winapi::um::processthreadsapi::GetCurrentProcess;
+  use winapi::um::processthreadsapi::GetPriorityClass;
+  use winapi::um::processthreadsapi::OpenProcess;
+  use winapi::um::processthreadsapi::SetPriorityClass;
+  use winapi::um::winbase::ABOVE_NORMAL_PRIORITY_CLASS;
+  use winapi::um::winbase::BELOW_NORMAL_PRIORITY_CLASS;
+  use winapi::um::winbase::HIGH_PRIORITY_CLASS;
+  use winapi::um::winbase::IDLE_PRIORITY_CLASS;
+  use winapi::um::winbase::NORMAL_PRIORITY_CLASS;
+  use winapi::um::winbase::REALTIME_PRIORITY_CLASS;
+  use winapi::um::winnt::PROCESS_QUERY_LIMITED_INFORMATION;
+
+  // Taken from: https://github.com/libuv/libuv/blob/a877ca2435134ef86315326ef4ef0c16bdbabf17/include/uv.h#L1318-L1323
+  const PRIORITY_LOW: i32 = 19;
+  const PRIORITY_BELOW_NORMAL: i32 = 10;
+  const PRIORITY_NORMAL: i32 = 0;
+  const PRIORITY_ABOVE_NORMAL: i32 = -7;
+  const PRIORITY_HIGH: i32 = -14;
+  const PRIORITY_HIGHEST: i32 = -20;
+
+  // Ported from: https://github.com/libuv/libuv/blob/a877ca2435134ef86315326ef4ef0c16bdbabf17/src/win/util.c#L1649-L1685
+  pub fn get_priority(pid: u32) -> Result<i32, AnyError> {
+    // SAFETY: Windows API calls
+    unsafe {
+      let handle = if pid == 0 {
+        GetCurrentProcess()
+      } else {
+        OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, FALSE, pid as DWORD)
+      };
+      if handle == NULL {
+        Err(std::io::Error::last_os_error().into())
+      } else {
+        let result = match GetPriorityClass(handle) {
+          0 => Err(std::io::Error::last_os_error().into()),
+          REALTIME_PRIORITY_CLASS => Ok(PRIORITY_HIGHEST),
+          HIGH_PRIORITY_CLASS => Ok(PRIORITY_HIGH),
+          ABOVE_NORMAL_PRIORITY_CLASS => Ok(PRIORITY_ABOVE_NORMAL),
+          NORMAL_PRIORITY_CLASS => Ok(PRIORITY_NORMAL),
+          BELOW_NORMAL_PRIORITY_CLASS => Ok(PRIORITY_BELOW_NORMAL),
+          IDLE_PRIORITY_CLASS => Ok(PRIORITY_LOW),
+          _ => Ok(PRIORITY_LOW),
+        };
+        CloseHandle(handle);
+        result
+      }
+    }
+  }
+
+  // Ported from: https://github.com/libuv/libuv/blob/a877ca2435134ef86315326ef4ef0c16bdbabf17/src/win/util.c#L1688-L1719
+  pub fn set_priority(pid: u32, priority: i32) -> Result<(), AnyError> {
+    // SAFETY: Windows API calls
+    unsafe {
+      let handle = if pid == 0 {
+        GetCurrentProcess()
+      } else {
+        OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, FALSE, pid as DWORD)
+      };
+      if handle == NULL {
+        Err(std::io::Error::last_os_error().into())
+      } else {
+        #[allow(clippy::manual_range_contains)]
+        let priority_class =
+          if priority < PRIORITY_HIGHEST || priority > PRIORITY_LOW {
+            return Err(type_error("Invalid priority"));
+          } else if priority < PRIORITY_HIGH {
+            REALTIME_PRIORITY_CLASS
+          } else if priority < PRIORITY_ABOVE_NORMAL {
+            HIGH_PRIORITY_CLASS
+          } else if priority < PRIORITY_NORMAL {
+            ABOVE_NORMAL_PRIORITY_CLASS
+          } else if priority < PRIORITY_BELOW_NORMAL {
+            NORMAL_PRIORITY_CLASS
+          } else if priority < PRIORITY_LOW {
+            BELOW_NORMAL_PRIORITY_CLASS
+          } else {
+            IDLE_PRIORITY_CLASS
+          };
+
+        let result = match SetPriorityClass(handle, priority_class) {
+          FALSE => Err(std::io::Error::last_os_error().into()),
+          _ => Ok(()),
+        };
+        CloseHandle(handle);
+        result
+      }
+    }
+  }
+}