deno_node 0.183.0

Node compatibility for Deno
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146

// Copyright 2018-2026 the Deno authors. MIT license.

pub use impl_::*;

#[derive(Debug, thiserror::Error, deno_error::JsError)]
pub enum PriorityError {
  #[class(inherit)]
  #[error("{0}")]
  Io(#[from] std::io::Error),
  #[cfg(windows)]
  #[class(type)]
  #[error("Invalid priority")]
  InvalidPriority,
}

#[cfg(unix)]
mod impl_ {
  use errno::Errno;
  use errno::errno;
  use errno::set_errno;
  use libc::PRIO_PROCESS;
  use libc::id_t;

  // Ref: https://github.com/libuv/libuv/blob/55376b044b74db40772e8a6e24d67a8673998e02/src/unix/core.c#L1533-L1547
  pub fn get_priority(pid: u32) -> Result<i32, super::PriorityError> {
    set_errno(Errno(0));
    match (
      // SAFETY: libc::getpriority is unsafe
      unsafe { libc::getpriority(PRIO_PROCESS, pid as id_t) },
      errno(),
    ) {
      (-1, Errno(0)) => Ok(-1),
      (-1, _) => Err(std::io::Error::last_os_error().into()),
      (priority, _) => Ok(priority),
    }
  }

  pub fn set_priority(
    pid: u32,
    priority: i32,
  ) -> Result<(), super::PriorityError> {
    // 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 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;
  use winapi::um::winnt::PROCESS_SET_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, super::PriorityError> {
    // 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<(), super::PriorityError> {
    // SAFETY: Windows API calls
    unsafe {
      let handle = if pid == 0 {
        GetCurrentProcess()
      } else {
        OpenProcess(PROCESS_SET_INFORMATION, FALSE, pid as DWORD)
      };
      if handle == NULL {
        Err(std::io::Error::last_os_error().into())
      } else {
        let priority_class =
          if !(PRIORITY_HIGHEST..=PRIORITY_LOW).contains(&priority) {
            return Err(super::PriorityError::InvalidPriority);
          } 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
      }
    }
  }
}