Completion.cc

/*
 * Copyright (c) 2026, Pedigree Developers
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted.
 */
 
#include "pedigree/kernel/Log.h"
#include "pedigree/kernel/process/Completion.h"
#include "pedigree/kernel/process/Thread.h"
 
Completion::Completion() : m_Waiters(), m_Completed(false), m_WaitClaimed(false) {}
 
Completion::~Completion() = default;
 
bool Completion::wait(WaitQueue::StackDiscardCleanup onStackDiscard, void* stackDiscardContext) {
  Thread::StackDiscardScope discardScope(onStackDiscard, stackDiscardContext);
  bool claimed = false;
  while (true) {
    auto guard = m_Waiters.acquire();
    if (!claimed) {
      if (m_WaitClaimed) {
        FATAL("Completion waited more than once");
      }
      m_WaitClaimed = true;
      claimed = true;
    }
 
    if (m_Completed) {
      return true;
    }
 
    WaitQueue::WakeReason reason =
        guard.wait(WaitQueue::Channel(), Thread::SemWait,
                   reinterpret_cast<uintptr_t>(__builtin_return_address(0)));
    if (reason == WaitQueue::WakeReason::Unwinding ||
        reason == WaitQueue::WakeReason::Terminating) {
      return false;
    }
  }
}
 
bool Completion::complete() {
  auto guard = m_Waiters.acquire();
  if (m_Completed) {
    return false;
  }
 
  m_Completed = true;
  guard.wakeOne();
  return true;
}
 
bool Completion::isComplete() {
  auto guard = m_Waiters.acquire();
  return m_Completed;
}