[sdk/kde-builder] /: Use os.cpu_count() instead of running subprocess

[Andrew Shark]

Git commit 4f769b8417b23d27a037aede0baf5d99ad78025f by Andrew Shark, on behalf of Christoph Cullmann.
Committed on 09/03/2024 at 17:55.
Pushed by ashark into branch 'master'.

Use os.cpu_count() instead of running subprocess

This also unifies the code, so we do not need to distinct between linux/freebsd/macos specific command to get number of threads.

M  +1    -3    doc/conf-options-table.docbook
M  +2    -4    ksblib/BuildSystem/BuildSystem.py
M  +1    -6    ksblib/FirstRun.py
M  +5    -2    tests/unit/build-system/test_empty-num-cores.py

https://invent.kde.org/sdk/kde-builder/-/commit/4f769b8417b23d27a037aede0baf5d99ad78025f

diff --git a/doc/conf-options-table.docbook b/doc/conf-options-table.docbook
index b35d520c..a0008112 100644
--- a/doc/conf-options-table.docbook
+++ b/doc/conf-options-table.docbook
@@ -258,9 +258,7 @@ number, the "nicer" the program is.</para>
 <member>Available since</member><member>20.07</member>
 </simplelist>
 <para>This option is defined by &kdesrc-build; (when using <command>kdesrc-build --generate-config</command>), set to be the number of
-available CPUs (as indicated by the external application
-<application>nproc</application>). If &kdesrc-build; cannot detect the
-number of CPUs, this value is set to 4.</para>
+available CPUs. If &kdesrc-build; cannot detect the number of CPUs, this value is set to 4.</para>
 
 <para>See <xref linkend="make-options-example"/> for an example of this
 option's usage.</para>
diff --git a/ksblib/BuildSystem/BuildSystem.py b/ksblib/BuildSystem/BuildSystem.py
index 3fe13b77..6523bf20 100644
--- a/ksblib/BuildSystem/BuildSystem.py
+++ b/ksblib/BuildSystem/BuildSystem.py
@@ -97,10 +97,8 @@ class BuildSystem:
         if self.supportsAutoParallelism() and cores == "auto":
             return {}
         
-        try:
-            out = [line.removesuffix("\n") for line in Util.filter_program_output(None, "nproc")]
-            max_cores = max(1, int(out[0]))
-        except BuildException:
+        max_cores = os.cpu_count()
+        if not max_cores:
             max_cores = 1
         
         if cores == "auto" and max_cores > 1:
diff --git a/ksblib/FirstRun.py b/ksblib/FirstRun.py
index 95ea6204..356aea77 100644
--- a/ksblib/FirstRun.py
+++ b/ksblib/FirstRun.py
@@ -194,12 +194,7 @@ class FirstRun:
         with open(os.path.dirname(os.path.realpath(__file__)) + "/../data/kdesrc-buildrc.in", "r") as data_file:
             sampleRc = data_file.read()
         
-        numCores = None
-        if self.oss.vendorID() in [*self.supportedDistros, "linux"]:
-            numCores = int(subprocess.run(["nproc"], shell=False, capture_output=True, check=True).stdout.decode("utf-8").removesuffix("\n"))
-        elif self.oss.vendorID() == "freebsd":
-            numCores = int(subprocess.run(["sysctl", "-n", "hw.ncpu"], shell=False, capture_output=True, check=True).stdout.decode("utf-8").removesuffix("\n"))
-        
+        numCores = os.cpu_count()
         if not numCores:
             numCores = 4
         
diff --git a/tests/unit/build-system/test_empty-num-cores.py b/tests/unit/build-system/test_empty-num-cores.py
index b2ad9a03..a2c2f334 100644
--- a/tests/unit/build-system/test_empty-num-cores.py
+++ b/tests/unit/build-system/test_empty-num-cores.py
@@ -1,3 +1,4 @@
+import os
 import pytest
 import subprocess
 from ksblib.Module.Module import Module
@@ -29,8 +30,10 @@ def test_empty_numcores(mock_buildsystem):
     
     # The -j logic will take off one CPU if you ask for too many so try to ensure
     # test cases don't ask for too many.
-    max_cores = int(subprocess.run(["nproc"], shell=True, capture_output=True, check=True).stdout.decode("utf-8").removesuffix("\n"))
-    max_cores = int(max_cores // 2)
+    max_cores = os.cpu_count()
+    if max_cores is None:
+        max_cores = 2
+    
     if max_cores < 2:
         max_cores = 2