[wpiutil] Add DataLog Stop()

ntcoreffi/src/main/native/symbols.txt

@@ -245,6 +245,7 @@ WPI_DataLog_Resume
 WPI_DataLog_SetFilename
 WPI_DataLog_SetMetadata
 WPI_DataLog_Start
+WPI_DataLog_Stop
 WPI_DestroyEvent
 WPI_DestroySemaphore
 WPI_DestroySignalObject

wpiutil/src/main/native/cpp/DataLog.cpp

@@ -229,12 +229,16 @@ void DataLog::AddSchema(std::string_view name, std::string_view type,
   if (entryInfo.id != 0) {
     return;  // don't add duplicates
   }
+  entryInfo.schemaData.assign(schema.begin(), schema.end());
   int entry = StartImpl(fullName, type, {}, timestamp);
 
   // inline AppendRaw() without releasing lock
   if (entry <= 0) {
     [[unlikely]] return;  // should never happen, but check anyway
   }
+  if (m_stopped) {
+    [[unlikely]] return;
+  }
   StartRecord(entry, timestamp, schema.size(), 0);
   AppendImpl(schema);
 }
@@ -521,9 +525,9 @@ int DataLog::StartImpl(std::string_view name, std::string_view type,
   if (entryInfo.id == 0) {
     entryInfo.id = ++m_lastId;
   }
-  auto& savedCount = m_entryCounts[entryInfo.id];
-  ++savedCount;
-  if (savedCount > 1) {
+  auto& entryInfo2 = m_entryIds[entryInfo.id];
+  ++entryInfo2.count;
+  if (entryInfo2.count > 1) {
     if (entryInfo.type != type) {
       WPI_ERROR(m_msglog,
                 "type mismatch for '{}': was '{}', requested '{}'; ignoring",
@@ -533,6 +537,12 @@ int DataLog::StartImpl(std::string_view name, std::string_view type,
     return entryInfo.id;
   }
   entryInfo.type = type;
+  entryInfo2.metadata = metadata;
+
+  if (m_stopped) {
+    [[unlikely]] return entryInfo.id;
+  }
+
   size_t strsize = name.size() + type.size() + metadata.size();
   uint8_t* buf = StartRecord(0, timestamp, 5 + 12 + strsize, 5);
   *buf++ = impl::kControlStart;
@@ -549,15 +559,18 @@ void DataLog::Finish(int entry, int64_t timestamp) {
     return;
   }
   std::scoped_lock lock{m_mutex};
-  auto& savedCount = m_entryCounts[entry];
-  if (savedCount == 0) {
+  auto& entryInfo2 = m_entryIds[entry];
+  if (entryInfo2.count == 0) {
     return;
   }
-  --savedCount;
-  if (savedCount != 0) {
+  --entryInfo2.count;
+  if (entryInfo2.count != 0) {
     return;
   }
-  m_entryCounts.erase(entry);
+  m_entryIds.erase(entry);
+  if (m_stopped) {
+    [[unlikely]] return;
+  }
   uint8_t* buf = StartRecord(0, timestamp, 5, 5);
   *buf++ = impl::kControlFinish;
   wpi::support::endian::write32le(buf, entry);
@@ -569,6 +582,10 @@ void DataLog::SetMetadata(int entry, std::string_view metadata,
     return;
   }
   std::scoped_lock lock{m_mutex};
+  m_entryIds[entry].metadata = metadata;
+  if (m_stopped) {
+    [[unlikely]] return;
+  }
   uint8_t* buf = StartRecord(0, timestamp, 5 + 4 + metadata.size(), 5);
   *buf++ = impl::kControlSetMetadata;
   wpi::support::endian::write32le(buf, entry);

wpiutil/src/main/native/include/wpi/DataLog.h

@@ -174,10 +174,18 @@ class DataLog final {
   void Pause();
 
   /**
-   * Resumes appending of data records to the log.
+   * Resumes appending of data records to the log.  If called after Stop(),
+   * opens a new file (with random name if SetFilename was not called after
+   * Stop()) and appends Start records and schema data values for all previously
+   * started entries and schemas.
    */
   void Resume();
 
+  /**
+   * Stops appending all records to the log, and closes the log file.
+   */
+  void Stop();
+
   /**
    * Returns whether there is a data schema already registered with the given
    * name.
@@ -475,6 +483,7 @@ class DataLog final {
   bool m_active{true};
   bool m_doFlush{false};
   bool m_paused{false};
+  bool m_stopped{false};
   double m_period;
   std::string m_extraHeader;
   std::string m_newFilename;
@@ -483,10 +492,15 @@ class DataLog final {
   std::vector<Buffer> m_outgoing;
   struct EntryInfo {
     std::string type;
+    std::vector<uint8_t> schemaData;  // only set for schema entries
     int id{0};
   };
   wpi::StringMap<EntryInfo> m_entries;
-  wpi::DenseMap<int, unsigned int> m_entryCounts;
+  struct EntryInfo2 {
+    std::string metadata;
+    unsigned int count;
+  };
+  wpi::DenseMap<int, EntryInfo2> m_entryIds;
   int m_lastId = 0;
   std::thread m_thread;
 };
@@ -1113,12 +1127,22 @@ void WPI_DataLog_Flush(struct WPI_DataLog* datalog);
 void WPI_DataLog_Pause(struct WPI_DataLog* datalog);
 
 /**
- * Resumes appending of data records to the log.
+ * Resumes appending of data records to the log.  If called after Stop(),
+ * opens a new file (with random name if SetFilename was not called after
+ * Stop()) and appends Start records and schema data values for all previously
+ * started entries and schemas.
  *
  * @param datalog data log
  */
 void WPI_DataLog_Resume(struct WPI_DataLog* datalog);
 
+/**
+ * Stops appending all records to the log, and closes the log file.
+ *
+ * @param datalog data log
+ */
+void WPI_DataLog_Stop(struct WPI_DataLog* datalog);
+
 /**
  * Start an entry.  Duplicate names are allowed (with the same type), and
  * result in the same index being returned (Start/Finish are reference