From 2622004af456bdd2dd15e2462fc285ff19904983 Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Fri, 17 Jul 2020 11:54:50 +0100
Subject: [PATCH] Logging: add log overload which copies filename

This is needed to fix a Valgrind error in the test-cases, due to logging
Nasal filenames which are GCed.
---
 simgear/debug/logstream.cxx | 20 +++++++++++++++++---
 simgear/debug/logstream.hxx |  8 ++++++++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/simgear/debug/logstream.cxx b/simgear/debug/logstream.cxx
index e459a569..e843a659 100644
--- a/simgear/debug/logstream.cxx
+++ b/simgear/debug/logstream.cxx
@@ -262,6 +262,7 @@ private:
         const char* file;
         const int line;
         const std::string message;
+        bool freeFilename = false;
     };
 
     /**
@@ -473,6 +474,10 @@ public:
                 (*cb)(entry.debugClass, entry.debugPriority,
                     entry.file, entry.line, entry.message);
             }
+            
+            if (entry.freeFilename) {
+                free(const_cast<char*>(entry.file));
+            }
         } // of main thread loop
     }
 
@@ -486,7 +491,7 @@ public:
 
             // log a special marker value, which will cause the thread to wakeup,
             // and then exit
-            log(SG_NONE, SG_ALERT, "done", -1, "");
+            log(SG_NONE, SG_ALERT, "done", -1, "", false);
         }
         join();
 
@@ -551,7 +556,8 @@ public:
     }
 
     void log( sgDebugClass c, sgDebugPriority p,
-            const char* fileName, int line, const std::string& msg)
+            const char* fileName, int line, const std::string& msg,
+             bool freeFilename)
     {
         p = translatePriority(p);
         if (!m_fileLine) {
@@ -559,6 +565,7 @@ public:
             line = -line;
         }
         LogEntry entry(c, p, fileName, line, msg);
+        entry.freeFilename = freeFilename;
         m_entries.push(entry);
     }
 
@@ -625,7 +632,14 @@ void
 logstream::log( sgDebugClass c, sgDebugPriority p,
         const char* fileName, int line, const std::string& msg)
 {
-    d->log(c, p, fileName, line, msg);
+    d->log(c, p, fileName, line, msg, false);
+}
+
+void
+logstream::logCopyingFilename( sgDebugClass c, sgDebugPriority p,
+         const char* fileName, int line, const std::string& msg)
+{
+    d->log(c, p, strdup(fileName), line, msg, true);
 }
 
 
diff --git a/simgear/debug/logstream.hxx b/simgear/debug/logstream.hxx
index fef41d05..3c2ef1ad 100644
--- a/simgear/debug/logstream.hxx
+++ b/simgear/debug/logstream.hxx
@@ -129,6 +129,14 @@ public:
     void log( sgDebugClass c, sgDebugPriority p,
             const char* fileName, int line, const std::string& msg);
 
+    // overload of above, which can transfer ownership of the file-name.
+    // this is unecesary overhead when logging from C++, since __FILE__ points
+    // to constant data, but it's needed when the filename is Nasal data (for
+    // example) since during shutdown the filename is freed by Nasal GC
+    // asynchronously with the logging thread.
+    void logCopyingFilename( sgDebugClass c, sgDebugPriority p,
+             const char* fileName, int line, const std::string& msg);
+    
     /**
     * output formatted hex dump of memory block
     */