// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/process/process_metrics.h"

#include <stddef.h>
#include <sys/sysctl.h>
#include <sys/user.h>
#include <unistd.h>

#include "base/memory/ptr_util.h"

namespace base {

ProcessMetrics::ProcessMetrics(ProcessHandle process)
    : process_(process),
      last_cpu_(0) {}

// static
std::unique_ptr<ProcessMetrics> ProcessMetrics::CreateProcessMetrics(
    ProcessHandle process) {
  return WrapUnique(new ProcessMetrics(process));
}

base::expected<double, ProcessCPUUsageError>
ProcessMetrics::GetPlatformIndependentCPUUsage() {
  struct kinfo_proc info;
  int mib[] = {CTL_KERN, KERN_PROC, KERN_PROC_PID, process_};
  size_t length = sizeof(info);

  if (sysctl(mib, std::size(mib), &info, &length, NULL, 0) < 0)
    return base::unexpected(ProcessCPUUsageError::kSystemError);

  return base::ok(double{info.ki_pctcpu} / FSCALE * 100.0);
}

base::expected<TimeDelta, ProcessCPUUsageError>
ProcessMetrics::GetCumulativeCPUUsage() {
  NOTREACHED();
}

size_t GetSystemCommitCharge() {
  int mib[2], pagesize;
  unsigned long mem_total, mem_free, mem_inactive;
  size_t length = sizeof(mem_total);

  if (sysctl(mib, std::size(mib), &mem_total, &length, NULL, 0) < 0)
    return 0;

  length = sizeof(mem_free);
  if (sysctlbyname("vm.stats.vm.v_free_count", &mem_free, &length, NULL, 0) < 0)
    return 0;

  length = sizeof(mem_inactive);
  if (sysctlbyname("vm.stats.vm.v_inactive_count", &mem_inactive, &length,
      NULL, 0) < 0) {
    return 0;
  }

  pagesize = getpagesize();

  return mem_total - (mem_free*pagesize) - (mem_inactive*pagesize);
}

}  // namespace base