Improve the CPU core count detection

See theofidry/cpu-core-counter#11 for the motivations.

The code should be sensibly the same, the notable differences are:

- fixed the deprecated usage of `hw.ncpu`
- /proc/cpuinfo is check _last_
- nproc is checked first (before was not checked at all, it's considered to be more accurate and less convoluted than cpuinfo though)
- not sure about the `return 2`, but this was not too clear [here](phpstan#514 (review)) neither. I could otherwise change the fallback value to return `1` if `proc_open` doesn't exist and 2 otherwise
- add more ways to find the CPU cores count

composer.json

@@ -10,6 +10,7 @@
 		"clue/ndjson-react": "^1.0",
 		"composer/ca-bundle": "^1.2",
 		"composer/xdebug-handler": "^3.0.3",
+		"fidry/cpu-core-counter": "^0.4.0",
 		"hoa/compiler": "3.17.08.08",
 		"hoa/exception": "^1.0",
 		"hoa/regex": "1.17.01.13",

src/Process/CpuCoreCounter.php

@@ -2,16 +2,8 @@
 
 namespace PHPStan\Process;
 
-use function count;
-use function fgets;
-use function file_get_contents;
-use function function_exists;
-use function is_file;
-use function is_resource;
-use function pclose;
-use function popen;
-use function preg_match_all;
-use const DIRECTORY_SEPARATOR;
+use Fidry\CpuCoreCounter\CpuCoreCounter as FidryCpuCoreCounter;
+use Fidry\CpuCoreCounter\NumberOfCpuCoreNotFound;
 
 class CpuCoreCounter
 {
@@ -24,42 +16,13 @@ public function getNumberOfCpuCores(): int
 			return $this->count;
 		}
 
-		if (!function_exists('proc_open')) {
-			return $this->count = 1;
+		try {
+			$this->count = (new FidryCpuCoreCounter())->getCount();
+		} catch (NumberOfCpuCoreNotFound) {
+			$this->count = 1;
 		}
 
-		// from brianium/paratest
-		if (@is_file('/proc/cpuinfo')) {
-			// Linux (and potentially Windows with linux sub systems)
-			$cpuinfo = @file_get_contents('/proc/cpuinfo');
-			if ($cpuinfo !== false) {
-				preg_match_all('/^processor/m', $cpuinfo, $matches);
-				return $this->count = count($matches[0]);
-			}
-		}
-
-		if (DIRECTORY_SEPARATOR === '\\') {
-			// Windows
-			$process = @popen('wmic cpu get NumberOfLogicalProcessors', 'rb');
-			if (is_resource($process)) {
-				fgets($process);
-				$cores = (int) fgets($process);
-				pclose($process);
-
-				return $this->count = $cores;
-			}
-		}
-
-		$process = @popen('sysctl -n hw.ncpu', 'rb');
-		if (is_resource($process)) {
-			// *nix (Linux, BSD and Mac)
-			$cores = (int) fgets($process);
-			pclose($process);
-
-			return $this->count = $cores;
-		}
-
-		return $this->count = 2;
+		return $this->count;
 	}
 
 }