LibWebView: Add process statistics calculations for macOS

Userland/Libraries/LibWebView/Platform/ProcessStatisticsMach.cpp

@@ -11,13 +11,67 @@
 #endif
 
 #include <AK/ByteString.h>
+#include <AK/Time.h>
 #include <LibCore/MachPort.h>
 #include <LibWebView/Platform/ProcessStatisticsMach.h>
 
 namespace WebView {
 
-ErrorOr<void> update_process_statistics(ProcessStatistics&)
+static auto user_hz = sysconf(_SC_CLK_TCK);
+
+ErrorOr<void> update_process_statistics(ProcessStatistics& statistics)
 {
+    host_cpu_load_info_data_t cpu_info {};
+    mach_msg_type_number_t count = HOST_CPU_LOAD_INFO_COUNT;
+    auto res = host_statistics(mach_host_self(), HOST_CPU_LOAD_INFO, reinterpret_cast<host_info_t>(&cpu_info), &count);
+    if (res != KERN_SUCCESS) {
+        dbgln("Failed to get host statistics: {}", mach_error_string(res));
+        return Core::mach_error_to_error(res);
+    }
+
+    u64 total_cpu_ticks = 0;
+    total_cpu_ticks += cpu_info.cpu_ticks[CPU_STATE_USER];
+    total_cpu_ticks += cpu_info.cpu_ticks[CPU_STATE_SYSTEM];
+    total_cpu_ticks += cpu_info.cpu_ticks[CPU_STATE_NICE];
+    total_cpu_ticks += cpu_info.cpu_ticks[CPU_STATE_IDLE];
+
+    auto const total_cpu_ticks_diff = total_cpu_ticks - statistics.total_time_scheduled;
+    auto const total_cpu_seconds_diff = total_cpu_ticks_diff / (static_cast<float>(user_hz));
+    auto const total_cpu_micro_diff = total_cpu_seconds_diff * 1'000'000;
+    statistics.total_time_scheduled = total_cpu_ticks;
+
+    for (auto& process : statistics.processes) {
+        mach_task_basic_info_data_t basic_info {};
+        count = MACH_TASK_BASIC_INFO_COUNT;
+        res = task_info(process.child_task_port.port(), MACH_TASK_BASIC_INFO, reinterpret_cast<task_info_t>(&basic_info), &count);
+        if (res != KERN_SUCCESS) {
+            dbgln("Failed to get task info for pid {}: {}", process.pid, mach_error_string(res));
+            return Core::mach_error_to_error(res);
+        }
+
+        process.memory_usage_bytes = basic_info.resident_size;
+
+        task_thread_times_info_data_t time_info {};
+        count = TASK_THREAD_TIMES_INFO_COUNT;
+        res = task_info(process.child_task_port.port(), TASK_THREAD_TIMES_INFO, reinterpret_cast<task_info_t>(&time_info), &count);
+        if (res != KERN_SUCCESS) {
+            dbgln("Failed to get thread times info for pid {}: {}", process.pid, mach_error_string(res));
+            return Core::mach_error_to_error(res);
+        }
+
+        timeval scratch_timeval = { static_cast<time_t>(time_info.user_time.seconds), static_cast<suseconds_t>(time_info.user_time.microseconds) };
+        auto time_in_process = Duration::from_timeval(scratch_timeval);
+        scratch_timeval = { static_cast<time_t>(time_info.system_time.seconds), static_cast<suseconds_t>(time_info.system_time.microseconds) };
+        time_in_process += Duration::from_timeval(scratch_timeval);
+
+        auto time_diff_process = time_in_process - Duration::from_microseconds(process.time_spent_in_process);
+        process.time_spent_in_process = time_in_process.to_microseconds();
+
+        process.cpu_percent = 0.0f;
+        if (time_diff_process > Duration::zero())
+            process.cpu_percent = 100.0f * static_cast<float>(time_diff_process.to_microseconds()) / total_cpu_micro_diff;
+    }
+
     return {};
 }