Generalize socket-based event loop

src/controller/CHIPDeviceController.cpp

@@ -1,6 +1,6 @@
 /*
  *
- *    Copyright (c) 2020 Project CHIP Authors
+ *    Copyright (c) 2020-2021 Project CHIP Authors
  *    Copyright (c) 2013-2017 Nest Labs, Inc.
  *    All rights reserved.
  *
@@ -501,11 +501,11 @@ CHIP_ERROR DeviceController::ServiceEventSignal()
 {
     VerifyOrReturnError(mState == State::Initialized, CHIP_ERROR_INCORRECT_STATE);
 
-#if CONFIG_DEVICE_LAYER && (CHIP_SYSTEM_CONFIG_USE_SOCKETS || CHIP_SYSTEM_CONFIG_USE_NETWORK_FRAMEWORK)
-    DeviceLayer::SystemLayer.WakeSelect();
+#if CONFIG_DEVICE_LAYER && CHIP_SYSTEM_CONFIG_USE_IO_THREAD
+    DeviceLayer::SystemLayer.WakeIOThread();
 #else
     ReturnErrorOnFailure(CHIP_ERROR_UNSUPPORTED_CHIP_FEATURE);
-#endif // CONFIG_DEVICE_LAYER && (CHIP_SYSTEM_CONFIG_USE_SOCKETS || CHIP_SYSTEM_CONFIG_USE_NETWORK_FRAMEWORK)
+#endif // CONFIG_DEVICE_LAYER && CHIP_SYSTEM_CONFIG_USE_IO_THREAD
 
     return CHIP_NO_ERROR;
 }

src/controller/java/CHIPDeviceController-JNI.cpp

@@ -219,7 +219,7 @@ void JNI_OnUnload(JavaVM * jvm, void * reserved)
     if (sIOThread != PTHREAD_NULL)
     {
         sShutdown = true;
-        sSystemLayer.WakeSelect();
+        sSystemLayer.WakeIOThread();
 
         AndroidDeviceControllerWrapper::StackUnlockGuard unlockGuard(&sStackLock);
         pthread_join(sIOThread, NULL);
@@ -1013,9 +1013,6 @@ void * IOThreadMain(void * arg)
 {
     JNIEnv * env;
     JavaVMAttachArgs attachArgs;
-    struct timeval sleepTime;
-    fd_set readFDs, writeFDs, exceptFDs;
-    int numFDs = 0;
 
     // Attach the IO thread to the JVM as a daemon thread.
     // This allows the JVM to shutdown without waiting for this thread to exit.
@@ -1036,26 +1033,19 @@ void * IOThreadMain(void * arg)
     // Lock the stack to prevent collisions with Java threads.
     pthread_mutex_lock(&sStackLock);
 
+    System::WatchableEventManager & watchState = sSystemLayer.WatchableEvents();
+    watchState.EventLoopBegins();
+
     // Loop until we are told to exit.
     while (!quit.load(std::memory_order_relaxed))
     {
-        numFDs = 0;
-        FD_ZERO(&readFDs);
-        FD_ZERO(&writeFDs);
-        FD_ZERO(&exceptFDs);
-
-        sleepTime.tv_sec  = 10;
-        sleepTime.tv_usec = 0;
-
-        // Collect the currently active file descriptors.
-        sSystemLayer.PrepareSelect(numFDs, &readFDs, &writeFDs, &exceptFDs, sleepTime);
-        sInetLayer.PrepareSelect(numFDs, &readFDs, &writeFDs, &exceptFDs, sleepTime);
+        // TODO(#5556): add a timer for `sleepTime.tv_sec  = 10; sleepTime.tv_usec = 0;`
+        watchState.PrepareEvents();
 
         // Unlock the stack so that Java threads can make API calls.
         pthread_mutex_unlock(&sStackLock);
 
-        // Wait for for I/O or for the next timer to expire.
-        int selectRes = select(numFDs, &readFDs, &writeFDs, &exceptFDs, &sleepTime);
+        watchState.WaitForEvents();
 
         // Break the loop if requested to shutdown.
         // if (sShutdown)
@@ -1064,10 +1054,9 @@ void * IOThreadMain(void * arg)
         // Re-lock the stack.
         pthread_mutex_lock(&sStackLock);
 
-        // Perform I/O and/or dispatch timers.
-        sSystemLayer.HandleSelectResult(selectRes, &readFDs, &writeFDs, &exceptFDs);
-        sInetLayer.HandleSelectResult(selectRes, &readFDs, &writeFDs, &exceptFDs);
+        watchState.HandleEvents();
     }
+    watchState.EventLoopEnds();
 
     // Detach the thread from the JVM.
     sJVM->DetachCurrentThread();

src/include/platform/internal/GenericPlatformManagerImpl_POSIX.cpp

@@ -1,6 +1,6 @@
 /*
  *
- *    Copyright (c) 2020 Project CHIP Authors
+ *    Copyright (c) 2020-2021 Project CHIP Authors
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -24,7 +24,6 @@
 #ifndef GENERIC_PLATFORM_MANAGER_IMPL_POSIX_CPP
 #define GENERIC_PLATFORM_MANAGER_IMPL_POSIX_CPP
 
-#include "system/SystemError.h"
 #include <platform/PlatformManager.h>
 #include <platform/internal/CHIPDeviceLayerInternal.h>
 #include <platform/internal/GenericPlatformManagerImpl_POSIX.h>
@@ -36,28 +35,18 @@
 #endif
 #include <platform/internal/GenericPlatformManagerImpl.cpp>
 
+#include <system/SystemError.h>
 #include <system/SystemLayer.h>
 
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <poll.h>
 #include <sched.h>
-#include <sys/select.h>
 #include <unistd.h>
 
-#define DEFAULT_MIN_SLEEP_PERIOD (60 * 60 * 24 * 30) // Month [sec]
-
-#if CHIP_DEVICE_CONFIG_ENABLE_MDNS
 namespace chip {
-namespace Mdns {
-void UpdateMdnsDataset(fd_set & readFdSet, fd_set & writeFdSet, fd_set & errorFdSet, int & maxFd, timeval & timeout);
-void ProcessMdns(fd_set & readFdSet, fd_set & writeFdSet, fd_set & errorFdSet);
-} // namespace Mdns
-} // namespace chip
-#endif
 
-namespace chip {
 namespace DeviceLayer {
 namespace Internal {
 
@@ -140,6 +129,8 @@ bool GenericPlatformManagerImpl_POSIX<ImplClass>::_IsChipStackLockedByCurrentThr
 template <class ImplClass>
 CHIP_ERROR GenericPlatformManagerImpl_POSIX<ImplClass>::_StartChipTimer(int64_t aMilliseconds)
 {
+    // TODO(#5556): Integrate timer platform details with WatchableEventManager.
+
     // Let SystemLayer.PrepareSelect() handle timers.
     return CHIP_NO_ERROR;
 }
@@ -148,7 +139,10 @@ template <class ImplClass>
 void GenericPlatformManagerImpl_POSIX<ImplClass>::_PostEvent(const ChipDeviceEvent * event)
 {
     mChipEventQueue.Push(*event);
-    SysOnEventSignal(this); // Trigger wake select on CHIP thread
+
+#if CHIP_SYSTEM_CONFIG_USE_IO_THREAD
+    SystemLayer.WakeIOThread(); // Trigger wake select on CHIP thread
+#endif                          // CHIP_SYSTEM_CONFIG_USE_IO_THREAD
 }
 
 template <class ImplClass>
@@ -161,77 +155,6 @@ void GenericPlatformManagerImpl_POSIX<ImplClass>::ProcessDeviceEvents()
     }
 }
 
-template <class ImplClass>
-void GenericPlatformManagerImpl_POSIX<ImplClass>::SysOnEventSignal(void * arg)
-{
-    SystemLayer.WakeSelect();
-}
-
-template <class ImplClass>
-void GenericPlatformManagerImpl_POSIX<ImplClass>::SysUpdate()
-{
-    FD_ZERO(&mReadSet);
-    FD_ZERO(&mWriteSet);
-    FD_ZERO(&mErrorSet);
-    mMaxFd = 0;
-
-    // Max out this duration and let CHIP set it appropriately.
-    mNextTimeout.tv_sec  = DEFAULT_MIN_SLEEP_PERIOD;
-    mNextTimeout.tv_usec = 0;
-
-    if (SystemLayer.State() == System::kLayerState_Initialized)
-    {
-        SystemLayer.PrepareSelect(mMaxFd, &mReadSet, &mWriteSet, &mErrorSet, mNextTimeout);
-    }
-
-#if !(CHIP_SYSTEM_CONFIG_USE_NETWORK_FRAMEWORK)
-    if (InetLayer.State == InetLayer::kState_Initialized)
-    {
-        InetLayer.PrepareSelect(mMaxFd, &mReadSet, &mWriteSet, &mErrorSet, mNextTimeout);
-    }
-#endif // !(CHIP_SYSTEM_CONFIG_USE_NETWORK_FRAMEWORK)
-#if CHIP_DEVICE_CONFIG_ENABLE_MDNS
-    chip::Mdns::UpdateMdnsDataset(mReadSet, mWriteSet, mErrorSet, mMaxFd, mNextTimeout);
-#endif
-}
-
-template <class ImplClass>
-void GenericPlatformManagerImpl_POSIX<ImplClass>::SysProcess()
-{
-    int selectRes;
-    int64_t nextTimeoutMs;
-
-    nextTimeoutMs = mNextTimeout.tv_sec * 1000 + mNextTimeout.tv_usec / 1000;
-    _StartChipTimer(nextTimeoutMs);
-
-    Impl()->UnlockChipStack();
-    selectRes = select(mMaxFd + 1, &mReadSet, &mWriteSet, &mErrorSet, &mNextTimeout);
-    Impl()->LockChipStack();
-
-    if (selectRes < 0)
-    {
-        ChipLogError(DeviceLayer, "select failed: %s\n", ErrorStr(System::MapErrorPOSIX(errno)));
-        return;
-    }
-
-    if (SystemLayer.State() == System::kLayerState_Initialized)
-    {
-        SystemLayer.HandleSelectResult(mMaxFd, &mReadSet, &mWriteSet, &mErrorSet);
-    }
-
-#if !(CHIP_SYSTEM_CONFIG_USE_NETWORK_FRAMEWORK)
-    if (InetLayer.State == InetLayer::kState_Initialized)
-    {
-        InetLayer.HandleSelectResult(mMaxFd, &mReadSet, &mWriteSet, &mErrorSet);
-    }
-#endif // !(CHIP_SYSTEM_CONFIG_USE_NETWORK_FRAMEWORK)
-
-    ProcessDeviceEvents();
-#if CHIP_DEVICE_CONFIG_ENABLE_MDNS
-    chip::Mdns::ProcessMdns(mReadSet, mWriteSet, mErrorSet);
-#endif
-}
-
 template <class ImplClass>
 void GenericPlatformManagerImpl_POSIX<ImplClass>::_RunEventLoop()
 {
@@ -254,11 +177,21 @@ void GenericPlatformManagerImpl_POSIX<ImplClass>::_RunEventLoop()
 
     Impl()->LockChipStack();
 
+    System::WatchableEventManager & watchState = SystemLayer.WatchableEvents();
+    watchState.EventLoopBegins();
     do
     {
-        SysUpdate();
-        SysProcess();
+        watchState.PrepareEvents();
+
+        Impl()->UnlockChipStack();
+        watchState.WaitForEvents();
+        Impl()->LockChipStack();
+
+        watchState.HandleEvents();
+
+        ProcessDeviceEvents();
     } while (mShouldRunEventLoop.load(std::memory_order_relaxed));
+    watchState.EventLoopEnds();
 
     Impl()->UnlockChipStack();
 
@@ -340,7 +273,7 @@ CHIP_ERROR GenericPlatformManagerImpl_POSIX<ImplClass>::_StopEventLoopTask()
         // SystemLayer.
         //
         Impl()->LockChipStack();
-        SystemLayer.WakeSelect();
+        SystemLayer.WakeIOThread();
         Impl()->UnlockChipStack();
 
         pthread_mutex_lock(&mStateLock);

src/include/platform/internal/GenericPlatformManagerImpl_POSIX.h

@@ -1,6 +1,6 @@
 /*
  *
- *    Copyright (c) 2020 Project CHIP Authors
+ *    Copyright (c) 2020-2021 Project CHIP Authors
  *    Copyright (c) 2018 Nest Labs, Inc.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
@@ -29,7 +29,6 @@
 
 #include <fcntl.h>
 #include <sched.h>
-#include <sys/select.h>
 #include <sys/time.h>
 #include <unistd.h>
 
@@ -53,13 +52,6 @@ template <class ImplClass>
 class GenericPlatformManagerImpl_POSIX : public GenericPlatformManagerImpl<ImplClass>
 {
 protected:
-    // Members for select loop
-    int mMaxFd;
-    fd_set mReadSet;
-    fd_set mWriteSet;
-    fd_set mErrorSet;
-    struct timeval mNextTimeout;
-
     // OS-specific members (pthread)
     pthread_mutex_t mChipStackLock;
 
@@ -115,10 +107,6 @@ class GenericPlatformManagerImpl_POSIX : public GenericPlatformManagerImpl<ImplC
 
     inline ImplClass * Impl() { return static_cast<ImplClass *>(this); }
 
-    void SysUpdate();
-    void SysProcess();
-    static void SysOnEventSignal(void * arg);
-
     void ProcessDeviceEvents();
 
     DeviceSafeQueue mChipEventQueue;