From 9285d183d714b33b9d7fb3a2e9f1c4896c351620 Mon Sep 17 00:00:00 2001
From: Jack Andersen <jackoalan@gmail.com>
Date: Sun, 11 Sep 2016 11:14:48 -1000
Subject: [PATCH] Recursive mutex for avoidng deadlocks during logging

---
 include/logvisor/logvisor.hpp |  5 +++--
 lib/logvisor.cpp              | 12 +-----------
 2 files changed, 4 insertions(+), 13 deletions(-)

diff --git a/include/logvisor/logvisor.hpp b/include/logvisor/logvisor.hpp
index d8fed01..c4236f3 100644
--- a/include/logvisor/logvisor.hpp
+++ b/include/logvisor/logvisor.hpp
@@ -87,13 +87,14 @@ extern std::atomic_uint_fast64_t FrameIndex;
  *
  * Ensures logging streams aren't written concurrently
  */
-extern std::mutex LogMutex;
+extern std::recursive_mutex LogMutex;
 
 /**
  * @brief Take a centralized lock for the logging output stream(s)
  * @return RAII mutex lock
  */
-static inline std::unique_lock<std::mutex> LockLog() {return std::unique_lock<std::mutex>{LogMutex};}
+static inline std::unique_lock<std::recursive_mutex> LockLog()
+{return std::unique_lock<std::recursive_mutex>{LogMutex};}
 
 /**
  * @brief Restore centralized logger vector to default state (silent operation)
diff --git a/lib/logvisor.cpp b/lib/logvisor.cpp
index f11e20d..2af1203 100644
--- a/lib/logvisor.cpp
+++ b/lib/logvisor.cpp
@@ -157,7 +157,7 @@ static std::chrono::steady_clock::time_point GlobalStart = MonoClock.now();
 static inline std::chrono::steady_clock::duration CurrentUptime()
 {return MonoClock.now() - GlobalStart;}
 std::atomic_uint_fast64_t FrameIndex(0);
-std::mutex LogMutex;
+std::recursive_mutex LogMutex;
 
 static inline int ConsoleWidth()
 {
@@ -184,7 +184,6 @@ static const char* Term = nullptr;
 bool XtermColor = false;
 struct ConsoleLogger : public ILogger
 {
-    std::mutex m;
     ConsoleLogger()
     {
 #if _WIN32
@@ -333,7 +332,6 @@ struct ConsoleLogger : public ILogger
     void report(const char* modName, Level severity,
                 const char* format, va_list ap)
     {
-        std::unique_lock<std::mutex> lk(m);
         _reportHead(modName, nullptr, severity);
         vfprintf(stderr, format, ap);
         fprintf(stderr, "\n");
@@ -342,7 +340,6 @@ struct ConsoleLogger : public ILogger
     void report(const char* modName, Level severity,
                 const wchar_t* format, va_list ap)
     {
-        std::unique_lock<std::mutex> lk(m);
         _reportHead(modName, nullptr, severity);
         vfwprintf(stderr, format, ap);
         fprintf(stderr, "\n");
@@ -352,7 +349,6 @@ struct ConsoleLogger : public ILogger
                       const char* file, unsigned linenum,
                       const char* format, va_list ap)
     {
-        std::unique_lock<std::mutex> lk(m);
         char sourceInfo[128];
         snprintf(sourceInfo, 128, "%s:%u", file, linenum);
         _reportHead(modName, sourceInfo, severity);
@@ -364,7 +360,6 @@ struct ConsoleLogger : public ILogger
                       const char* file, unsigned linenum,
                       const wchar_t* format, va_list ap)
     {
-        std::unique_lock<std::mutex> lk(m);
         char sourceInfo[128];
         snprintf(sourceInfo, 128, "%s:%u", file, linenum);
         _reportHead(modName, sourceInfo, severity);
@@ -408,7 +403,6 @@ void RegisterStandardExceptions()
 struct FileLogger : public ILogger
 {
     FILE* fp;
-    std::mutex m;
     virtual void openFile()=0;
     virtual void closeFile() {fclose(fp);}
 
@@ -456,7 +450,6 @@ struct FileLogger : public ILogger
     void report(const char* modName, Level severity,
                 const char* format, va_list ap)
     {
-        std::unique_lock<std::mutex> lk(m);
         openFile();
         _reportHead(modName, nullptr, severity);
         vfprintf(fp, format, ap);
@@ -467,7 +460,6 @@ struct FileLogger : public ILogger
     void report(const char* modName, Level severity,
                 const wchar_t* format, va_list ap)
     {
-        std::unique_lock<std::mutex> lk(m);
         openFile();
         _reportHead(modName, nullptr, severity);
         vfwprintf(fp, format, ap);
@@ -479,7 +471,6 @@ struct FileLogger : public ILogger
                       const char* file, unsigned linenum,
                       const char* format, va_list ap)
     {
-        std::unique_lock<std::mutex> lk(m);
         openFile();
         char sourceInfo[128];
         snprintf(sourceInfo, 128, "%s:%u", file, linenum);
@@ -493,7 +484,6 @@ struct FileLogger : public ILogger
                       const char* file, unsigned linenum,
                       const wchar_t* format, va_list ap)
     {
-        std::unique_lock<std::mutex> lk(m);
         openFile();
         char sourceInfo[128];
         snprintf(sourceInfo, 128, "%s:%u", file, linenum);