From 2954e48e5e3dff58b0096747d37ab869c7df7bd6 Mon Sep 17 00:00:00 2001
From: Ryan Curtin <ryan@ratml.org>
Date: Tue, 11 Oct 2016 09:31:24 -0400
Subject: [PATCH 1/2] Refactor singletons into one .cpp file.

This causes these singletons to only appear once in libmlpack.so and not in
every executable.
---
 src/mlpack/core/util/CMakeLists.txt  |  2 ++
 src/mlpack/core/util/cli.cpp         |  2 --
 src/mlpack/core/util/cli_deleter.hpp |  5 +--
 src/mlpack/core/util/log.cpp         | 32 -------------------
 src/mlpack/core/util/singletons.cpp  | 48 ++++++++++++++++++++++++++++
 src/mlpack/core/util/singletons.hpp  | 21 ++++++++++++
 6 files changed, 72 insertions(+), 38 deletions(-)
 create mode 100644 src/mlpack/core/util/singletons.cpp
 create mode 100644 src/mlpack/core/util/singletons.hpp

diff --git a/src/mlpack/core/util/CMakeLists.txt b/src/mlpack/core/util/CMakeLists.txt
index b7830b1a93f..84b1a9c6e78 100644
--- a/src/mlpack/core/util/CMakeLists.txt
+++ b/src/mlpack/core/util/CMakeLists.txt
@@ -21,6 +21,8 @@ set(SOURCES
   prefixedoutstream.cpp
   prefixedoutstream_impl.hpp
   sfinae_utility.hpp
+  singletons.hpp
+  singletons.cpp
   timers.hpp
   timers.cpp
   version.hpp
diff --git a/src/mlpack/core/util/cli.cpp b/src/mlpack/core/util/cli.cpp
index aa8716769a2..a90e93d293e 100644
--- a/src/mlpack/core/util/cli.cpp
+++ b/src/mlpack/core/util/cli.cpp
@@ -15,8 +15,6 @@
 using namespace mlpack;
 using namespace mlpack::util;
 
-CLI* CLI::singleton = NULL;
-
 /* For clarity, we will alias boost's namespace. */
 namespace po = boost::program_options;
 
diff --git a/src/mlpack/core/util/cli_deleter.hpp b/src/mlpack/core/util/cli_deleter.hpp
index 168db8e8254..f1c0193bde0 100644
--- a/src/mlpack/core/util/cli_deleter.hpp
+++ b/src/mlpack/core/util/cli_deleter.hpp
@@ -24,10 +24,7 @@ class CLIDeleter
   ~CLIDeleter();
 };
 
-//! Declare the deleter.
-static CLIDeleter cliDeleter;
-
-} // namespace io
+} // namespace util
 } // namespace mlpack
 
 #endif
diff --git a/src/mlpack/core/util/log.cpp b/src/mlpack/core/util/log.cpp
index 17a8e48b227..6189f17bf4b 100644
--- a/src/mlpack/core/util/log.cpp
+++ b/src/mlpack/core/util/log.cpp
@@ -10,41 +10,9 @@
   #include "backtrace.hpp"
 #endif
 
-// Color code escape sequences -- but not on Windows.
-#ifndef _WIN32
-  #define BASH_RED "\033[0;31m"
-  #define BASH_GREEN "\033[0;32m"
-  #define BASH_YELLOW "\033[0;33m"
-  #define BASH_CYAN "\033[0;36m"
-  #define BASH_CLEAR "\033[0m"
-#else
-  #define BASH_RED ""
-  #define BASH_GREEN ""
-  #define BASH_YELLOW ""
-  #define BASH_CYAN ""
-  #define BASH_CLEAR ""
-#endif
-
 using namespace mlpack;
 using namespace mlpack::util;
 
-// Only output debugging output if in debug mode.
-#ifdef DEBUG
-PrefixedOutStream Log::Debug = PrefixedOutStream(std::cout,
-    BASH_CYAN "[DEBUG] " BASH_CLEAR);
-#else
-NullOutStream Log::Debug = NullOutStream();
-#endif
-
-PrefixedOutStream Log::Info = PrefixedOutStream(std::cout,
-    BASH_GREEN "[INFO ] " BASH_CLEAR, true /* unless --verbose */, false);
-PrefixedOutStream Log::Warn = PrefixedOutStream(std::cout,
-    BASH_YELLOW "[WARN ] " BASH_CLEAR, false, false);
-PrefixedOutStream Log::Fatal = PrefixedOutStream(std::cerr,
-    BASH_RED "[FATAL] " BASH_CLEAR, false, true /* fatal */);
-
-std::ostream& Log::cout = std::cout;
-
 // Only do anything for Assert() if in debugging mode.
 #ifdef DEBUG
 void Log::Assert(bool condition, const std::string& message)
diff --git a/src/mlpack/core/util/singletons.cpp b/src/mlpack/core/util/singletons.cpp
new file mode 100644
index 00000000000..e0fcd238dcd
--- /dev/null
+++ b/src/mlpack/core/util/singletons.cpp
@@ -0,0 +1,48 @@
+/**
+ * @file singletons.cpp
+ * @author Ryan Curtin
+ */
+#include "singletons.hpp"
+#include "log.hpp"
+#include "cli.hpp"
+
+using namespace mlpack;
+using namespace mlpack::util;
+
+// Color code escape sequences -- but not on Windows.
+#ifndef _WIN32
+  #define BASH_RED "\033[0;31m"
+  #define BASH_GREEN "\033[0;32m"
+  #define BASH_YELLOW "\033[0;33m"
+  #define BASH_CYAN "\033[0;36m"
+  #define BASH_CLEAR "\033[0m"
+#else
+  #define BASH_RED ""
+  #define BASH_GREEN ""
+  #define BASH_YELLOW ""
+  #define BASH_CYAN ""
+  #define BASH_CLEAR ""
+#endif
+
+CLI* CLI::singleton = NULL;
+
+// Only output debugging output if in debug mode.
+#ifdef DEBUG
+PrefixedOutStream Log::Debug = PrefixedOutStream(std::cout,
+    BASH_CYAN "[DEBUG] " BASH_CLEAR);
+#else
+NullOutStream Log::Debug = NullOutStream();
+#endif
+
+PrefixedOutStream Log::Info = PrefixedOutStream(std::cout,
+    BASH_GREEN "[INFO ] " BASH_CLEAR, true /* unless --verbose */, false);
+PrefixedOutStream Log::Warn = PrefixedOutStream(std::cout,
+    BASH_YELLOW "[WARN ] " BASH_CLEAR, false, false);
+PrefixedOutStream Log::Fatal = PrefixedOutStream(std::cerr,
+    BASH_RED "[FATAL] " BASH_CLEAR, false, true /* fatal */);
+
+/**
+ * This has to be last, so that the CLI object is destroyed before the Log
+ * output objects are destroyed.
+ */
+CLIDeleter cliDeleter;
diff --git a/src/mlpack/core/util/singletons.hpp b/src/mlpack/core/util/singletons.hpp
new file mode 100644
index 00000000000..ec43cc82ff1
--- /dev/null
+++ b/src/mlpack/core/util/singletons.hpp
@@ -0,0 +1,21 @@
+/**
+ * @file singletons.hpp
+ * @author Ryan Curtin
+ *
+ * Definitions of singletons used by libmlpack.so.
+ */
+#ifndef MLPACK_CORE_UTIL_SINGLETONS_HPP
+#define MLPACK_CORE_UTIL_SINGLETONS_HPP
+
+#include "cli_deleter.hpp"
+#include <mlpack/mlpack_export.hpp>
+
+namespace mlpack {
+namespace util {
+
+extern MLPACK_EXPORT CLIDeleter cliDeleter;
+
+} // namespace util
+} // namespace mlpack
+
+#endif

From b35088d0f860cb9b0ba499497dce4a4ddb85850a Mon Sep 17 00:00:00 2001
From: Ryan Curtin <ryan@ratml.org>
Date: Tue, 11 Oct 2016 14:15:22 -0400
Subject: [PATCH 2/2] Add clarifying comment.

---
 src/mlpack/core/util/singletons.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/mlpack/core/util/singletons.cpp b/src/mlpack/core/util/singletons.cpp
index e0fcd238dcd..e1401f9b174 100644
--- a/src/mlpack/core/util/singletons.cpp
+++ b/src/mlpack/core/util/singletons.cpp
@@ -1,6 +1,8 @@
 /**
  * @file singletons.cpp
  * @author Ryan Curtin
+ *
+ * Declaration of singletons in libmlpack.so.
  */
 #include "singletons.hpp"
 #include "log.hpp"