From 1f6b3863253a9acb4599f69ed646f2d9d2e4d859 Mon Sep 17 00:00:00 2001
From: Peter Johnson <johnson.peter@gmail.com>
Date: Sat, 22 Oct 2016 22:09:47 -0700
Subject: [PATCH] Implement frame timestamps and use wpi::Now() for generation.

---
 src/Frame.h              |  3 +--
 src/MJPEGServerImpl.cpp  |  4 +---
 src/SourceImpl.cpp       | 10 ++++++++++
 src/SourceImpl.h         |  3 +++
 src/USBCameraImpl.cpp    |  3 ++-
 src/cameraserver_cpp.cpp |  7 ++++++-
 6 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/src/Frame.h b/src/Frame.h
index f0ae61de14..721c7b3f96 100644
--- a/src/Frame.h
+++ b/src/Frame.h
@@ -9,7 +9,6 @@
 #define CAMERASERVER_FRAME_H_
 
 #include <atomic>
-#include <chrono>
 #include <memory>
 
 #include "llvm/StringRef.h"
@@ -24,7 +23,7 @@ class Frame {
   friend class SourceImpl;
 
  public:
-  typedef std::chrono::system_clock::time_point Time;
+  typedef uint64_t Time;
 
  private:
   struct Data {
diff --git a/src/MJPEGServerImpl.cpp b/src/MJPEGServerImpl.cpp
index 435995ab6e..abbca3f4e6 100644
--- a/src/MJPEGServerImpl.cpp
+++ b/src/MJPEGServerImpl.cpp
@@ -401,9 +401,7 @@ void MJPEGServerImpl::SendStream(wpi::raw_socket_ostream& os) {
     // print the individual mimetype and the length
     // sending the content-length fixes random stream disruption observed
     // with firefox
-    double timestamp = std::chrono::duration_cast<std::chrono::seconds>(
-                           frame.time().time_since_epoch())
-                           .count();
+    double timestamp = frame.time() / 10000000.0;
     header.clear();
     oss << "Content-Type: image/jpeg\r\n"
         << "Content-Length: " << frame.size() << "\r\n"
diff --git a/src/SourceImpl.cpp b/src/SourceImpl.cpp
index ffea5e0b06..30e8041de3 100644
--- a/src/SourceImpl.cpp
+++ b/src/SourceImpl.cpp
@@ -32,6 +32,16 @@ SourceImpl::~SourceImpl() {
   // Everything else can clean up itself.
 }
 
+uint64_t SourceImpl::GetCurFrameTime() {
+  std::unique_lock<std::mutex> lock{m_frameMutex};
+  return m_frame.time();
+}
+
+Frame SourceImpl::GetCurFrame() {
+  std::unique_lock<std::mutex> lock{m_frameMutex};
+  return m_frame;
+}
+
 Frame SourceImpl::GetNextFrame() {
   std::unique_lock<std::mutex> lock{m_frameMutex};
   // TODO: handle spurious wakeup by comparing frame timestamps
diff --git a/src/SourceImpl.h b/src/SourceImpl.h
index 8f5e4c4d4f..0b710a7154 100644
--- a/src/SourceImpl.h
+++ b/src/SourceImpl.h
@@ -65,6 +65,9 @@ class SourceImpl {
     NumSinksEnabledChanged();
   }
 
+  // Gets the current frame time (without waiting for a new one).
+  uint64_t GetCurFrameTime();
+
   // Gets the current frame (without waiting for a new one).
   Frame GetCurFrame();
 
diff --git a/src/USBCameraImpl.cpp b/src/USBCameraImpl.cpp
index 25b000af6c..b65a42c272 100644
--- a/src/USBCameraImpl.cpp
+++ b/src/USBCameraImpl.cpp
@@ -31,6 +31,7 @@
 
 #include "llvm/raw_ostream.h"
 #include "llvm/SmallString.h"
+#include "support/timestamp.h"
 
 #include "cameraserver_cpp.h"
 #include "c_util.h"
@@ -561,7 +562,7 @@ void USBCameraImpl::CameraThreadMain() {
                  llvm::StringRef(
                      static_cast<const char*>(m_buffers[buf.index].m_data),
                      static_cast<std::size_t>(buf.bytesused)),
-                 Frame::Time{});  // TODO: time
+                 wpi::Now());  // TODO: time
       }
 
       // Requeue buffer
diff --git a/src/cameraserver_cpp.cpp b/src/cameraserver_cpp.cpp
index 7f733b2097..b73cf0519d 100644
--- a/src/cameraserver_cpp.cpp
+++ b/src/cameraserver_cpp.cpp
@@ -198,7 +198,12 @@ llvm::StringRef GetSourceDescription(CS_Source source,
 }
 
 uint64_t GetSourceLastFrameTime(CS_Source source, CS_Status* status) {
-  return 0;  // TODO
+  auto data = Sources::GetInstance().Get(source);
+  if (!data) {
+    *status = CS_INVALID_HANDLE;
+    return 0;
+  }
+  return data->source->GetCurFrameTime();
 }
 
 bool IsSourceConnected(CS_Source source, CS_Status* status) {