os: add os.{get,set}Priority()

PR-URL: https://github.com/nodejs/node/pull/22407
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>

1 files changed, 131 insertions, 0 deletions

diff --git a/test/parallel/test-os-process-priority.js b/test/parallel/test-os-process-priority.js
new file mode 100644
index 0000000000..9d66cfc49b
--- /dev/null
+++ b/test/parallel/test-os-process-priority.js
@@ -0,0 +1,131 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const os = require('os');
+const {
+  PRIORITY_LOW,
+  PRIORITY_BELOW_NORMAL,
+  PRIORITY_NORMAL,
+  PRIORITY_ABOVE_NORMAL,
+  PRIORITY_HIGH,
+  PRIORITY_HIGHEST
+} = os.constants.priority;
+
+// Validate priority constants.
+assert.strictEqual(typeof PRIORITY_LOW, 'number');
+assert.strictEqual(typeof PRIORITY_BELOW_NORMAL, 'number');
+assert.strictEqual(typeof PRIORITY_NORMAL, 'number');
+assert.strictEqual(typeof PRIORITY_ABOVE_NORMAL, 'number');
+assert.strictEqual(typeof PRIORITY_HIGH, 'number');
+assert.strictEqual(typeof PRIORITY_HIGHEST, 'number');
+
+// Test pid type validation.
+[null, true, false, 'foo', {}, [], /x/].forEach((pid) => {
+  const errObj = {
+    code: 'ERR_INVALID_ARG_TYPE',
+    message: /The "pid" argument must be of type number\./
+  };
+
+  common.expectsError(() => {
+    os.setPriority(pid, PRIORITY_NORMAL);
+  }, errObj);
+
+  common.expectsError(() => {
+    os.getPriority(pid);
+  }, errObj);
+});
+
+// Test pid range validation.
+[NaN, Infinity, -Infinity, 3.14, 2 ** 32].forEach((pid) => {
+  const errObj = {
+    code: 'ERR_OUT_OF_RANGE',
+    message: /The value of "pid" is out of range\./
+  };
+
+  common.expectsError(() => {
+    os.setPriority(pid, PRIORITY_NORMAL);
+  }, errObj);
+
+  common.expectsError(() => {
+    os.getPriority(pid);
+  }, errObj);
+});
+
+// Test priority type validation.
+[null, true, false, 'foo', {}, [], /x/].forEach((priority) => {
+  common.expectsError(() => {
+    os.setPriority(0, priority);
+  }, {
+    code: 'ERR_INVALID_ARG_TYPE',
+    message: /The "priority" argument must be of type number\./
+  });
+});
+
+// Test priority range validation.
+[
+  NaN,
+  Infinity,
+  -Infinity,
+  3.14,
+  2 ** 32,
+  PRIORITY_HIGHEST - 1,
+  PRIORITY_LOW + 1
+].forEach((priority) => {
+  common.expectsError(() => {
+    os.setPriority(0, priority);
+  }, {
+    code: 'ERR_OUT_OF_RANGE',
+    message: /The value of "priority" is out of range\./
+  });
+});
+
+// Verify that valid values work.
+for (let i = PRIORITY_HIGHEST; i <= PRIORITY_LOW; i++) {
+  // A pid of 0 corresponds to the current process.
+  try {
+    os.setPriority(0, i);
+  } catch (err) {
+    // The current user might not have sufficient permissions to set this
+    // specific priority level. Skip this priority, but keep trying lower
+    // priorities.
+    if (err.info.code === 'EACCES')
+      continue;
+
+    assert(err);
+  }
+
+  checkPriority(0, i);
+
+  // An undefined pid corresponds to the current process.
+  os.setPriority(i);
+  checkPriority(undefined, i);
+
+  // Specifying the actual pid works.
+  os.setPriority(process.pid, i);
+  checkPriority(process.pid, i);
+}
+
+
+function checkPriority(pid, expected) {
+  const priority = os.getPriority(pid);
+
+  // Verify that the priority values match on Unix, and are range mapped on
+  // Windows.
+  if (!common.isWindows) {
+    assert.strictEqual(priority, expected);
+    return;
+  }
+
+  if (expected < PRIORITY_HIGH)
+    assert.strictEqual(priority, PRIORITY_HIGHEST);
+  else if (expected < PRIORITY_ABOVE_NORMAL)
+    assert.strictEqual(priority, PRIORITY_HIGH);
+  else if (expected < PRIORITY_NORMAL)
+    assert.strictEqual(priority, PRIORITY_ABOVE_NORMAL);
+  else if (expected < PRIORITY_BELOW_NORMAL)
+    assert.strictEqual(priority, PRIORITY_NORMAL);
+  else if (expected < PRIORITY_LOW)
+    assert.strictEqual(priority, PRIORITY_BELOW_NORMAL);
+  else
+    assert.strictEqual(priority, PRIORITY_LOW);
+}