From 3e5187ff328ba66d606781da7e4d384a277300ba Mon Sep 17 00:00:00 2001
From: Gold856 <117957790+Gold856@users.noreply.github.com>
Date: Sun, 21 Apr 2024 23:34:05 -0400
Subject: [PATCH] [wpilibj] DataLogManager: Fix behavior when low on space
 (#6486)

Uses getUsableSpace in Java, matching how C++ determines available space (C++ calls it available, but they mean the same thing.) This fixes a bug where logs wouldn't get deleted due to incorrect available space detection.

The DataLog thread now also checks if the state was marked as stopped after a call to StartLogFile.
---
 .../src/main/java/edu/wpi/first/wpilibj/DataLogManager.java   | 4 ++--
 wpiutil/src/main/native/cpp/DataLog.cpp                       | 3 +++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/wpilibj/src/main/java/edu/wpi/first/wpilibj/DataLogManager.java b/wpilibj/src/main/java/edu/wpi/first/wpilibj/DataLogManager.java
index d4ec796c88..770db82716 100644
--- a/wpilibj/src/main/java/edu/wpi/first/wpilibj/DataLogManager.java
+++ b/wpilibj/src/main/java/edu/wpi/first/wpilibj/DataLogManager.java
@@ -269,7 +269,7 @@ public final class DataLogManager {
     // based on free disk space, scan for "old" FRC_*.wpilog files and remove
     {
       File logDir = new File(m_logDir);
-      long freeSpace = logDir.getFreeSpace();
+      long freeSpace = logDir.getUsableSpace();
       if (freeSpace < kFreeSpaceThreshold) {
         // Delete oldest FRC_*.wpilog files (ignore FRC_TBD_*.wpilog as we just created one)
         File[] files =
@@ -304,7 +304,7 @@ public final class DataLogManager {
                 + freeSpace / 1000000
                 + " MB of free space remaining! Logs will get deleted below "
                 + kFreeSpaceThreshold / 1000000
-                + " MB of free space."
+                + " MB of free space. "
                 + "Consider deleting logs off the storage device.",
             false);
       }
diff --git a/wpiutil/src/main/native/cpp/DataLog.cpp b/wpiutil/src/main/native/cpp/DataLog.cpp
index 9f9981fe16..49f24a4315 100644
--- a/wpiutil/src/main/native/cpp/DataLog.cpp
+++ b/wpiutil/src/main/native/cpp/DataLog.cpp
@@ -463,6 +463,9 @@ void DataLog::WriterThreadMain(std::string_view dir) {
       lock.unlock();
       StartLogFile(state);
       lock.lock();
+      if (m_state == kStopped) {
+        continue;
+      }
       if (state.f != fs::kInvalidFile) {
         // Emit start and schema data records
         for (auto&& entryInfo : m_entries) {