Improve support for high-resolution stats

NOTE: Users of this library may need to make changes. I've also submitted a sister patch for
moonlight-qt that supports these changes and implements a few new features like an audio overlay.

* This patch adds a new microsecond-resolution function call, LiGetMicroseconds(), to complement
the existing LiGetMillis(). Many variables used by stats have been updated to work at this
higher resolution and now provide better results when displaying e.g. sub-millisecond frametime stats.
To try and avoid confusion, variables that now contain microseconds have been renamed with a suffix
of 'Us', and those ending in 'Ms' contain milliseconds. I originally experimented with nanoseconds but it
felt like overkill for our needs.

* Since this library is designed to be mostly standalone, I reorganized Platform.c a bit to make it compatible with
SDL's GetTicks64(), which starts its ticker at program start. A lot of the stats here are used with those in
moonlight-qt so I tried to simplify the functions as much as possible. Each platform now has its own few smaller
functions, instead of trying to fit a complex set of ifdef's inside the same function.

* I added a simple gtest suite for the Platform.c changes, and this test suite should be easy to extend to
other areas of the code.

Internal API:
void Plt_TicksInit(void);          // store initial timestamp
uint64_t Plt_GetTicks64_us(void);  // The most precision, in microseconds
uint64_t Plt_GetTicks64_ms(void);  // Plt_GetTicks64_ms returns the value in milliseconds
uint64_t Plt_GetTicks64(void);     // Alias to _ms() and compatible with SDL_GetTicks64 (ms since program start)
uint64_t PltGetMillis(void);       // replaced by Plt_GetTicks64_ms()

Public API in Limelight.h:
uint64_t LiGetMicroseconds(void);
uint64_t LiGetMillis(void);
PRTP_AUDIO_STATS LiGetRTPAudioStats(void);	// provides access to RTP data for the overlay stats
PRTP_VIDEO_STATS LiGetRTPVideoStats(void);

.gitignore

@@ -1,3 +1,4 @@
+.vscode/
 limelight-common/ARM/
 limelight-common/Debug/
 Build/

CMakeLists.txt

@@ -2,6 +2,7 @@
 cmake_minimum_required(VERSION 3.1)
 project(moonlight-common-c LANGUAGES C)
 
+string(TOUPPER "x${CMAKE_BUILD_TYPE}" BUILD_TYPE)
 set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
 
 option(USE_MBEDTLS "Use MbedTLS instead of OpenSSL" OFF)
@@ -24,7 +25,13 @@ if (NOT DEFINED BUILD_SHARED_LIBS)
   set(BUILD_SHARED_LIBS_OVERRIDE ON)
 endif()
 
-add_library(moonlight-common-c ${SRC_LIST})
+# XXX There is probably a better way to do this, but build a static library in debug mode on
+# Windows, so the tests can link to it. Release gets a DLL.
+if((MSVC OR MINGW) AND "${BUILD_TYPE}" STREQUAL "XDEBUG")
+  add_library(moonlight-common-c STATIC ${SRC_LIST})
+else()
+  add_library(moonlight-common-c ${SRC_LIST})
+endif()
 
 if (BUILD_SHARED_LIBS_OVERRIDE)
   unset(BUILD_SHARED_LIBS)
@@ -61,7 +68,6 @@ else()
   target_include_directories(moonlight-common-c SYSTEM PRIVATE ${OPENSSL_INCLUDE_DIR})
 endif()
 
-string(TOUPPER "x${CMAKE_BUILD_TYPE}" BUILD_TYPE)
 if("${BUILD_TYPE}" STREQUAL "XDEBUG")
   target_compile_definitions(moonlight-common-c PRIVATE LC_DEBUG)
 else()
@@ -74,10 +80,43 @@ else()
   endif()
 endif()
 
+if (NOT(MSVC OR APPLE))
+  include(CheckLibraryExists)
+  CHECK_LIBRARY_EXISTS(rt clock_gettime "" HAVE_CLOCK_GETTIME)
+
+  if (NOT HAVE_CLOCK_GETTIME)
+    set(CMAKE_EXTRA_INCLUDE_FILES time.h)
+    CHECK_FUNCTION_EXISTS(clock_gettime HAVE_CLOCK_GETTIME)
+    SET(CMAKE_EXTRA_INCLUDE_FILES)
+  endif()
+
+  foreach(clock CLOCK_MONOTONIC CLOCK_MONOTONIC_RAW)
+    message(STATUS "Testing whether ${clock} can be used")
+    CHECK_CXX_SOURCE_COMPILES(
+"#define _POSIX_C_SOURCE 200112L
+#include <time.h>
+int main ()
+{
+  struct timespec ts[1];
+  clock_gettime (${clock}, ts);
+  return 0;
+}" HAVE_${clock})
+    if(HAVE_${clock})
+    message(STATUS "Testing whether ${clock} can be used -- Success")
+    else()
+    message(STATUS "Testing whether ${clock} can be used -- Failed")
+    endif()
+  endforeach()
+
+endif()
+
 target_include_directories(moonlight-common-c SYSTEM PUBLIC src)
 
 target_include_directories(moonlight-common-c PRIVATE
   ${CMAKE_CURRENT_SOURCE_DIR}/reedsolomon
 )
 
-target_compile_definitions(moonlight-common-c PRIVATE HAS_SOCKLEN_T)
+target_compile_definitions(moonlight-common-c PRIVATE HAS_SOCKLEN_T)
+
+enable_testing()
+add_subdirectory(tests)

appveyor.yml

@@ -37,6 +37,8 @@ build_script:
   - cmd: 'cmake %CMAKE_ARGS% -DCMAKE_BUILD_TYPE=Debug ..'
   - sh: 'cmake --build .'
   - cmd: 'cmake --build . --config Debug'
+  - sh: 'ctest --output-on-failure --repeat until-pass:1000'
+  - cmd: 'ctest --output-on-failure --repeat until-pass:1000'
   - 'cd ..'
   - 'mkdir build_release'
   - 'cd build_release'

src/AudioStream.c

@@ -275,7 +275,7 @@ static void AudioReceiveThreadProc(void* context) {
         }
         else if (packet->header.size == 0) {
             // Receive timed out; try again
-            
+
             if (!receivedDataFromPeer) {
                 waitingForAudioMs += UDP_RECV_POLL_TIMEOUT_MS;
             }
@@ -299,7 +299,9 @@ static void AudioReceiveThreadProc(void* context) {
             Limelog("Received first audio packet after %d ms\n", waitingForAudioMs);
 
             if (firstReceiveTime != 0) {
-                packetsToDrop += (uint32_t)(PltGetMillis() - firstReceiveTime) / AudioPacketDuration;
+                // XXX firstReceiveTime is never set here...
+                // We're already dropping 500ms of audio so this probably doesn't matter
+                packetsToDrop += (uint32_t)(Plt_GetTicks64_ms() - firstReceiveTime) / AudioPacketDuration;
             }
 
             Limelog("Initial audio resync period: %d milliseconds\n", packetsToDrop * AudioPacketDuration);
@@ -366,15 +368,15 @@ static void AudioReceiveThreadProc(void* context) {
                         free(queuedPacket);
                     }
                 }
-                
+
                 // Break on exit
                 if (queuedPacket != NULL) {
                     break;
                 }
             }
         }
     }
-    
+
     if (packet != NULL) {
         free(packet);
     }
@@ -405,12 +407,12 @@ void stopAudioStream(void) {
     AudioCallbacks.stop();
 
     PltInterruptThread(&receiveThread);
-    if ((AudioCallbacks.capabilities & CAPABILITY_DIRECT_SUBMIT) == 0) {        
+    if ((AudioCallbacks.capabilities & CAPABILITY_DIRECT_SUBMIT) == 0) {
         // Signal threads waiting on the LBQ
         LbqSignalQueueShutdown(&packetQueue);
         PltInterruptThread(&decoderThread);
     }
-    
+
     PltJoinThread(&receiveThread);
     if ((AudioCallbacks.capabilities & CAPABILITY_DIRECT_SUBMIT) == 0) {
         PltJoinThread(&decoderThread);
@@ -474,3 +476,7 @@ int LiGetPendingAudioFrames(void) {
 int LiGetPendingAudioDuration(void) {
     return LiGetPendingAudioFrames() * AudioPacketDuration;
 }
+
+PRTP_AUDIO_STATS LiGetRTPAudioStats(void) {
+    return &rtpAudioQueue.stats;
+}

src/ControlStream.c

@@ -425,7 +425,7 @@ void connectionSendFrameFecStatus(PSS_FRAME_FEC_STATUS fecStatus) {
 void connectionSawFrame(uint32_t frameIndex) {
     LC_ASSERT_VT(!isBefore16(frameIndex, lastSeenFrame));
 
-    uint64_t now = PltGetMillis();
+    uint64_t now = Plt_GetTicks64_ms();
 
     // Suppress connection status warnings for the first sampling period
     // to allow the network and host to settle.

src/InputStream.c

@@ -95,7 +95,7 @@ typedef struct _PACKET_HOLDER {
 // Initializes the input stream
 int initializeInputStream(void) {
     memcpy(currentAesIv, StreamConfig.remoteInputAesIv, sizeof(currentAesIv));
-    
+
     // Set a high maximum queue size limit to ensure input isn't dropped
     // while the input send thread is blocked for short periods.
     LbqInitializeLinkedBlockingQueue(&packetQueue, MAX_QUEUED_INPUT_PACKETS);
@@ -129,7 +129,7 @@ int initializeInputStream(void) {
 // Destroys and cleans up the input stream
 void destroyInputStream(void) {
     PLINKED_BLOCKING_QUEUE_ENTRY entry, nextEntry;
-    
+
     PltDestroyCryptoContext(cryptoContext);
 
     entry = LbqDestroyLinkedBlockingQueue(&packetQueue);
@@ -350,15 +350,15 @@ static void inputSendThreadProc(void* context) {
             PPACKET_HOLDER controllerBatchHolder;
             PNV_MULTI_CONTROLLER_PACKET origPkt;
             short controllerNumber = LE16(holder->packet.multiController.controllerNumber);
-            uint64_t now = PltGetMillis();
+            uint64_t now = Plt_GetTicks64_ms();
 
             LC_ASSERT(controllerNumber < MAX_GAMEPADS);
 
             // Delay for batching if required
             if (now < lastControllerPacketTime[controllerNumber] + CONTROLLER_BATCHING_INTERVAL_MS) {
                 flushInputOnControlStream();
                 PltSleepMs((int)(lastControllerPacketTime[controllerNumber] + CONTROLLER_BATCHING_INTERVAL_MS - now));
-                now = PltGetMillis();
+                now = Plt_GetTicks64_ms();
             }
 
             origPkt = &holder->packet.multiController;
@@ -410,13 +410,13 @@ static void inputSendThreadProc(void* context) {
         }
         // If it's a relative mouse move packet, we can also do batching
         else if (holder->packet.header.magic == relMouseMagicLE) {
-            uint64_t now = PltGetMillis();
+            uint64_t now = Plt_GetTicks64_ms();
 
             // Delay for batching if required
             if (now < lastMousePacketTime + MOUSE_BATCHING_INTERVAL_MS) {
                 flushInputOnControlStream();
                 PltSleepMs((int)(lastMousePacketTime + MOUSE_BATCHING_INTERVAL_MS - now));
-                now = PltGetMillis();
+                now = Plt_GetTicks64_ms();
             }
 
             PltLockMutex(&batchedInputMutex);
@@ -481,13 +481,13 @@ static void inputSendThreadProc(void* context) {
         }
         // If it's an absolute mouse move packet, we should only send the latest
         else if (holder->packet.header.magic == LE32(MOUSE_MOVE_ABS_MAGIC)) {
-            uint64_t now = PltGetMillis();
+            uint64_t now = Plt_GetTicks64_ms();
 
             // Delay for batching if required
             if (now < lastMousePacketTime + MOUSE_BATCHING_INTERVAL_MS) {
                 flushInputOnControlStream();
                 PltSleepMs((int)(lastMousePacketTime + MOUSE_BATCHING_INTERVAL_MS - now));
-                now = PltGetMillis();
+                now = Plt_GetTicks64_ms();
             }
 
             PltLockMutex(&batchedInputMutex);
@@ -513,13 +513,13 @@ static void inputSendThreadProc(void* context) {
         }
         // If it's a pen packet, we should only send the latest move or hover events
         else if (holder->packet.header.magic == LE32(SS_PEN_MAGIC) && TOUCH_EVENT_IS_BATCHABLE(holder->packet.pen.eventType)) {
-            uint64_t now = PltGetMillis();
+            uint64_t now = Plt_GetTicks64_ms();
 
             // Delay for batching if required
             if (now < lastPenPacketTime + PEN_BATCHING_INTERVAL_MS) {
                 flushInputOnControlStream();
                 PltSleepMs((int)(lastPenPacketTime + PEN_BATCHING_INTERVAL_MS - now));
-                now = PltGetMillis();
+                now = Plt_GetTicks64_ms();
             }
 
             for (;;) {
@@ -740,7 +740,7 @@ int stopInputStream(void) {
     if (inputSock != INVALID_SOCKET) {
         shutdownTcpSocket(inputSock);
     }
-    
+
     if (inputSock != INVALID_SOCKET) {
         closeSocket(inputSock);
         inputSock = INVALID_SOCKET;

src/Limelight.h

@@ -69,7 +69,7 @@ typedef struct _STREAM_CONFIGURATION {
     // Specifies the channel configuration of the audio stream.
     // See AUDIO_CONFIGURATION constants and MAKE_AUDIO_CONFIGURATION() below.
     int audioConfiguration;
-    
+
     // Specifies the mask of supported video formats.
     // See VIDEO_FORMAT constants below.
     int supportedVideoFormats;
@@ -154,21 +154,20 @@ typedef struct _DECODE_UNIT {
     // (happens when the frame is repeated).
     uint16_t frameHostProcessingLatency;
 
-    // Receive time of first buffer. This value uses an implementation-defined epoch,
-    // but the same epoch as enqueueTimeMs and LiGetMillis().
-    uint64_t receiveTimeMs;
+    // Receive time of first buffer in microseconds.
+    uint64_t receiveTimeUs;
 
     // Time the frame was fully assembled and queued for the video decoder to process.
     // This is also approximately the same time as the final packet was received, so
-    // enqueueTimeMs - receiveTimeMs is the time taken to receive the frame. At the
+    // enqueueTimeUs - receiveTimeUs is the time taken to receive the frame. At the
     // time the decode unit is passed to submitDecodeUnit(), the total queue delay
-    // can be calculated by LiGetMillis() - enqueueTimeMs.
-    uint64_t enqueueTimeMs;
+    // can be calculated. This value is in microseconds.
+    uint64_t enqueueTimeUs;
 
     // Presentation time in milliseconds with the epoch at the first captured frame.
     // This can be used to aid frame pacing or to drop old frames that were queued too
     // long prior to display.
-    unsigned int presentationTimeMs;
+    uint64_t presentationTimeMs;
 
     // Length of the entire buffer chain in bytes
     int fullLength;
@@ -512,10 +511,10 @@ void LiInitializeConnectionCallbacks(PCONNECTION_LISTENER_CALLBACKS clCallbacks)
 typedef struct _SERVER_INFORMATION {
     // Server host name or IP address in text form
     const char* address;
-    
+
     // Text inside 'appversion' tag in /serverinfo
     const char* serverInfoAppVersion;
-    
+
     // Text inside 'GfeVersion' tag in /serverinfo (if present)
     const char* serverInfoGfeVersion;
 
@@ -825,7 +824,11 @@ int LiSendHighResScrollEvent(short scrollAmount);
 int LiSendHScrollEvent(signed char scrollClicks);
 int LiSendHighResHScrollEvent(short scrollAmount);
 
-// This function returns a time in milliseconds with an implementation-defined epoch.
+// This function returns the time in microseconds since the program started running.
+uint64_t LiGetMicroseconds(void);
+
+// This function returns the time in milliseconds since the program started running.
+// This value will be the same as that returned by SDL_GetTicks64().
 uint64_t LiGetMillis(void);
 
 // This is a simplistic STUN function that can assist clients in getting the WAN address
@@ -848,6 +851,36 @@ int LiGetPendingAudioFrames(void);
 // negotiated audio frame duration.
 int LiGetPendingAudioDuration(void);
 
+// Returns a pointer to a struct containing various statistics about the RTP audio stream.
+// The data should be considered read-only and must not be modified.
+typedef struct _RTP_AUDIO_STATS {
+    uint32_t packetCountAudio;         // total audio packets
+    uint32_t packetCountFec;           // total packets of type FEC
+    uint32_t packetCountFecRecovered;  // a packet was saved
+    uint32_t packetCountFecFailed;     // tried to recover but too much was lost
+    uint32_t packetCountOOS;           // out-of-sequence packets
+    uint32_t packetCountInvalid;       // corrupted packets, etc
+    uint32_t packetCountFecInvalid;    // invalid FEC packet
+} RTP_AUDIO_STATS, *PRTP_AUDIO_STATS;
+
+PRTP_AUDIO_STATS LiGetRTPAudioStats(void);
+
+// Returns a pointer to a struct containing various statistics about the RTP video stream.
+// The data should be considered read-only and must not be modified.
+// Right now this is mainly used to track total video and FEC packets, as there are
+// many video stats already implemented at a higher level in moonlight-qt.
+typedef struct _RTP_VIDEO_STATS {
+    uint32_t packetCountVideo;         // total video packets
+    uint32_t packetCountFec;           // total packets of type FEC
+    uint32_t packetCountFecRecovered;  // a packet was saved
+    uint32_t packetCountFecFailed;     // tried to recover but too much was lost
+    uint32_t packetCountOOS;           // out-of-sequence packets
+    uint32_t packetCountInvalid;       // corrupted packets, etc
+    uint32_t packetCountFecInvalid;    // invalid FEC packet
+} RTP_VIDEO_STATS, *PRTP_VIDEO_STATS;
+
+PRTP_VIDEO_STATS LiGetRTPVideoStats(void);
+
 // Port index flags for use with LiGetPortFromPortFlagIndex() and LiGetProtocolFromPortFlagIndex()
 #define ML_PORT_INDEX_TCP_47984 0
 #define ML_PORT_INDEX_TCP_47989 1
@@ -875,7 +908,7 @@ int LiGetPendingAudioDuration(void);
 unsigned int LiGetPortFlagsFromStage(int stage);
 unsigned int LiGetPortFlagsFromTerminationErrorCode(int errorCode);
 
-// Returns the IPPROTO_* value for the specified port index 
+// Returns the IPPROTO_* value for the specified port index
 int LiGetProtocolFromPortFlagIndex(int portFlagIndex);
 
 // Returns the port number for the specified port index

src/Misc.c

@@ -99,7 +99,7 @@ int extractVersionQuadFromString(const char* string, int* quad) {
             nextNumber++;
         }
     }
-    
+
     return 0;
 }
 
@@ -145,7 +145,11 @@ void LiInitializeServerInformation(PSERVER_INFORMATION serverInfo) {
 }
 
 uint64_t LiGetMillis(void) {
-    return PltGetMillis();
+    return Plt_GetTicks64_ms();
+}
+
+uint64_t LiGetMicroseconds(void) {
+    return Plt_GetTicks64_us();
 }
 
 uint32_t LiGetHostFeatureFlags(void) {