hhvm/hphp/runtime/ext/asio/external_thread_event_wait_handle.cpp

/*
   +----------------------------------------------------------------------+
   | HipHop for PHP                                                       |
   +----------------------------------------------------------------------+
   | Copyright (c) 2010-2013 Facebook, Inc. (http://www.facebook.com)     |
   | Copyright (c) 1997-2010 The PHP Group                                |
   +----------------------------------------------------------------------+
   | This source file is subject to version 3.01 of the PHP license,      |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | http://www.php.net/license/3_01.txt                                  |
   | If you did not receive a copy of the PHP license and are unable to   |
   | obtain it through the world-wide-web, please send a note to          |
   | license@php.net so we can mail you a copy immediately.               |
   +----------------------------------------------------------------------+
*/

#include "hphp/runtime/ext/ext_asio.h"
#include "hphp/runtime/ext/asio/asio_external_thread_event.h"
#include "hphp/runtime/ext/asio/asio_external_thread_event_queue.h"
#include "hphp/runtime/ext/asio/asio_session.h"
#include "hphp/system/systemlib.h"

namespace HPHP {
///////////////////////////////////////////////////////////////////////////////

namespace {
  StaticString s_externalThreadEvent("<external-thread-event>");
}

c_ExternalThreadEventWaitHandle::c_ExternalThreadEventWaitHandle(Class *cb)
    : c_WaitableWaitHandle(cb) {
}

c_ExternalThreadEventWaitHandle::~c_ExternalThreadEventWaitHandle() {
}

void c_ExternalThreadEventWaitHandle::sweep() {
  assert(getState() == STATE_WAITING);

  if (m_event->cancel()) {
    // canceled; the processing thread will take care of cleanup
    return;
  }

  // event has finished, but process() was not called yet
  auto queue = AsioSession::Get()->getExternalThreadEventQueue();
  bool done = false;
  do {
    auto ete_wh = queue->consumeMulti();
    while (ete_wh) {
      done |= ete_wh == this;
      auto next_wh = ete_wh->getNextToProcess();
      ete_wh->abandon(true);
      ete_wh = next_wh;
    }
  } while (!done);
}

void c_ExternalThreadEventWaitHandle::t___construct() {
  Object e(SystemLib::AllocInvalidOperationExceptionObject(
        "ExternalThreadEventWaitHandle can be constructed only from extension"));
  throw e;
}

c_ExternalThreadEventWaitHandle* c_ExternalThreadEventWaitHandle::Create(AsioExternalThreadEvent* event, ObjectData* priv_data) {
  c_ExternalThreadEventWaitHandle* wh = NEWOBJ(c_ExternalThreadEventWaitHandle);
  wh->initialize(event, priv_data);
  return wh;
}

void c_ExternalThreadEventWaitHandle::initialize(AsioExternalThreadEvent* event, ObjectData* priv_data) {
  // this wait handle is owned by existence of unprocessed event
  incRefCount();
  m_event = event;
  m_privData = priv_data;

  setState(STATE_WAITING);
  if (isInContext()) {
    m_index = getContext()->registerExternalThreadEvent(this);
  }
}

void c_ExternalThreadEventWaitHandle::destroyEvent() {
  // destroy event and its private data
  m_event->release();
  m_event = nullptr;
  m_privData = nullptr;

  // unregister from sweep()
  unregister();

  // drop ownership by pending event (see initialize())
  decRefObj(this);
}

void c_ExternalThreadEventWaitHandle::abandon(bool sweeping) {
  assert(getState() == STATE_WAITING);
  assert(getCount() == 1 || sweeping);

  if (isInContext()) {
    getContext()->unregisterExternalThreadEvent(m_index);
  }

  // clean up
  destroyEvent();
}

void c_ExternalThreadEventWaitHandle::process() {
  assert(getState() == STATE_WAITING);

  if (isInContext()) {
    getContext()->unregisterExternalThreadEvent(m_index);
  }

  // clean up once event is processed
  auto exit_guard = folly::makeGuard([&] { destroyEvent(); });

  TypedValue result;
  try {
    m_event->unserialize(&result);
  } catch (const Object& exception) {
    setException(exception.get());
    return;
  } catch (...) {
    setException(AsioSession::Get()->getAbruptInterruptException().get());
    throw;
  }

  assert(tvIsPlausible(&result));
  setResult(&result);
  tvRefcountedDecRefCell(&result);
}

String c_ExternalThreadEventWaitHandle::getName() {
  return s_externalThreadEvent;
}

void c_ExternalThreadEventWaitHandle::enterContext(context_idx_t ctx_idx) {
  assert(AsioSession::Get()->getContext(ctx_idx));

  // stop before corrupting unioned data
  if (isFinished()) {
    return;
  }

  // already in the more specific context?
  if (LIKELY(getContextIdx() >= ctx_idx)) {
    return;
  }

  assert(getState() == STATE_WAITING);

  if (isInContext()) {
    getContext()->unregisterExternalThreadEvent(m_index);
  }

  setContextIdx(ctx_idx);
  m_index = getContext()->registerExternalThreadEvent(this);
}

void c_ExternalThreadEventWaitHandle::exitContext(context_idx_t ctx_idx) {
  assert(AsioSession::Get()->getContext(ctx_idx));
  assert(getContextIdx() == ctx_idx);
  assert(getState() == STATE_WAITING);

  // move us to the parent context
  setContextIdx(getContextIdx() - 1);

  // re-register if still in a context
  if (isInContext()) {
    getContext()->registerExternalThreadEvent(this);
  }

  // recursively move all wait handles blocked by us
  for (auto pwh = getFirstParent(); pwh; pwh = pwh->getNextParent()) {
    pwh->exitContextBlocked(ctx_idx);
  }
}

///////////////////////////////////////////////////////////////////////////////
}