Removed the Requirement to Install Python and NodeJS (Now Bundled with Borealis)

Dependencies/Python/Lib/test/libregrtest/win_utils.py

@@ -0,0 +1,128 @@
+import _overlapped
+import _thread
+import _winapi
+import math
+import struct
+import winreg
+
+
+# Seconds per measurement
+SAMPLING_INTERVAL = 1
+# Exponential damping factor to compute exponentially weighted moving average
+# on 1 minute (60 seconds)
+LOAD_FACTOR_1 = 1 / math.exp(SAMPLING_INTERVAL / 60)
+# Initialize the load using the arithmetic mean of the first NVALUE values
+# of the Processor Queue Length
+NVALUE = 5
+
+
+class WindowsLoadTracker():
+    """
+    This class asynchronously reads the performance counters to calculate
+    the system load on Windows.  A "raw" thread is used here to prevent
+    interference with the test suite's cases for the threading module.
+    """
+
+    def __init__(self):
+        # make __del__ not fail if pre-flight test fails
+        self._running = None
+        self._stopped = None
+
+        # Pre-flight test for access to the performance data;
+        # `PermissionError` will be raised if not allowed
+        winreg.QueryInfoKey(winreg.HKEY_PERFORMANCE_DATA)
+
+        self._values = []
+        self._load = None
+        self._running = _overlapped.CreateEvent(None, True, False, None)
+        self._stopped = _overlapped.CreateEvent(None, True, False, None)
+
+        _thread.start_new_thread(self._update_load, (), {})
+
+    def _update_load(self,
+                    # localize module access to prevent shutdown errors
+                     _wait=_winapi.WaitForSingleObject,
+                     _signal=_overlapped.SetEvent):
+        # run until signaled to stop
+        while _wait(self._running, 1000):
+            self._calculate_load()
+        # notify stopped
+        _signal(self._stopped)
+
+    def _calculate_load(self,
+                        # localize module access to prevent shutdown errors
+                        _query=winreg.QueryValueEx,
+                        _hkey=winreg.HKEY_PERFORMANCE_DATA,
+                        _unpack=struct.unpack_from):
+        # get the 'System' object
+        data, _ = _query(_hkey, '2')
+        # PERF_DATA_BLOCK {
+        #   WCHAR Signature[4]      8 +
+        #   DWOWD LittleEndian      4 +
+        #   DWORD Version           4 +
+        #   DWORD Revision          4 +
+        #   DWORD TotalByteLength   4 +
+        #   DWORD HeaderLength      = 24 byte offset
+        #   ...
+        # }
+        obj_start, = _unpack('L', data, 24)
+        # PERF_OBJECT_TYPE {
+        #   DWORD TotalByteLength
+        #   DWORD DefinitionLength
+        #   DWORD HeaderLength
+        #   ...
+        # }
+        data_start, defn_start = _unpack('4xLL', data, obj_start)
+        data_base = obj_start + data_start
+        defn_base = obj_start + defn_start
+        # find the 'Processor Queue Length' counter (index=44)
+        while defn_base < data_base:
+            # PERF_COUNTER_DEFINITION {
+            #   DWORD ByteLength
+            #   DWORD CounterNameTitleIndex
+            #   ... [7 DWORDs/28 bytes]
+            #   DWORD CounterOffset
+            # }
+            size, idx, offset = _unpack('LL28xL', data, defn_base)
+            defn_base += size
+            if idx == 44:
+                counter_offset = data_base + offset
+                # the counter is known to be PERF_COUNTER_RAWCOUNT (DWORD)
+                processor_queue_length, = _unpack('L', data, counter_offset)
+                break
+        else:
+            return
+
+        # We use an exponentially weighted moving average, imitating the
+        # load calculation on Unix systems.
+        # https://en.wikipedia.org/wiki/Load_(computing)#Unix-style_load_calculation
+        # https://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
+        if self._load is not None:
+            self._load = (self._load * LOAD_FACTOR_1
+                            + processor_queue_length  * (1.0 - LOAD_FACTOR_1))
+        elif len(self._values) < NVALUE:
+            self._values.append(processor_queue_length)
+        else:
+            self._load = sum(self._values) / len(self._values)
+
+    def close(self, kill=True):
+        self.__del__()
+        return
+
+    def __del__(self,
+                # localize module access to prevent shutdown errors
+                _wait=_winapi.WaitForSingleObject,
+                _close=_winapi.CloseHandle,
+                _signal=_overlapped.SetEvent):
+        if self._running is not None:
+            # tell the update thread to quit
+            _signal(self._running)
+            # wait for the update thread to signal done
+            _wait(self._stopped, -1)
+            # cleanup events
+            _close(self._running)
+            _close(self._stopped)
+            self._running = self._stopped = None
+
+    def getloadavg(self):
+        return self._load