base/message_loop/message_pump_android.cc

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/message_loop/message_pump_android.h"

#include <android/looper.h>
#include <errno.h>
#include <fcntl.h>
#include <jni.h>
#include <sys/eventfd.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
#include <utility>

#include "base/android/jni_android.h"
#include "base/android/scoped_java_ref.h"
#include "base/callback_helpers.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/run_loop.h"
#include "build/build_config.h"

// Android stripped sys/timerfd.h out of their platform headers, so we have to
// use syscall to make use of timerfd. Once the min API level is 20, we can
// directly use timerfd.h.
#ifndef __NR_timerfd_create
#error "Unable to find syscall for __NR_timerfd_create"
#endif

#ifndef TFD_TIMER_ABSTIME
#define TFD_TIMER_ABSTIME (1 << 0)
#endif

using base::android::JavaParamRef;
using base::android::ScopedJavaLocalRef;

namespace base {

namespace {

// See sys/timerfd.h
int timerfd_create(int clockid, int flags) {
  return syscall(__NR_timerfd_create, clockid, flags);
}

// See sys/timerfd.h
int timerfd_settime(int ufc,
                    int flags,
                    const struct itimerspec* utmr,
                    struct itimerspec* otmr) {
  return syscall(__NR_timerfd_settime, ufc, flags, utmr, otmr);
}

// https://crbug.com/873588. The stack may not be aligned when the ALooper calls
// into our code due to the inconsistent ABI on older Android OS versions.
#if defined(ARCH_CPU_X86)
#define STACK_ALIGN __attribute__((force_align_arg_pointer))
#else
#define STACK_ALIGN
#endif

STACK_ALIGN int NonDelayedLooperCallback(int fd, int events, void* data) {
  if (events & ALOOPER_EVENT_HANGUP)
    return 0;

  DCHECK(events & ALOOPER_EVENT_INPUT);
  MessagePumpForUI* pump = reinterpret_cast<MessagePumpForUI*>(data);
  pump->OnNonDelayedLooperCallback();
  return 1;  // continue listening for events
}

STACK_ALIGN int DelayedLooperCallback(int fd, int events, void* data) {
  if (events & ALOOPER_EVENT_HANGUP)
    return 0;