threads: Fix the shared global state with TLS

See `global.c` for a description of what we're doing.

When libgit2 is built with GIT_THREADS support, the threading system
must be explicitly initialized with `git_threads_init()`.

3 files changed, 48 insertions, 73 deletions

diff --git a/include/git2/common.h b/include/git2/common.h
index ef279eac1..eee918a23 100644
--- a/include/git2/common.h
+++ b/include/git2/common.h
@@ -7,7 +7,6 @@
 #ifndef INCLUDE_git_common_h__
 #define INCLUDE_git_common_h__
 
-#include "thread-utils.h"
 #include <time.h>
 #include <stdlib.h>
 
@@ -38,18 +37,6 @@
 # define GIT_EXTERN(type) extern type
 #endif
 
-/** Declare a public TLS symbol exported for application use. */
-#if __GNUC__ >= 4
-# define GIT_EXTERN_TLS(type) extern \
-					__attribute__((visibility("default"))) \
-					GIT_TLS \
-					type
-#elif defined(_MSC_VER)
-# define GIT_EXTERN_TLS(type) __declspec(dllexport) GIT_TLS type
-#else
-# define GIT_EXTERN_TLS(type) extern GIT_TLS type
-#endif
-
 /** Declare a function as always inlined. */
 #if defined(_MSC_VER)
 # define GIT_INLINE(type) static __inline type
diff --git a/include/git2/thread-utils.h b/include/git2/thread-utils.h
deleted file mode 100644
index 81c62d135..000000000
--- a/include/git2/thread-utils.h
+++ /dev/null
@@ -1,60 +0,0 @@
-/*
- * Copyright (C) 2009-2011 the libgit2 contributors
- *
- * This file is part of libgit2, distributed under the GNU GPL v2 with
- * a Linking Exception. For full terms see the included COPYING file.
- */
-#ifndef INCLUDE_git_thread_utils_h__
-#define INCLUDE_git_thread_utils_h__
-
-/*
- * How TLS works is compiler+platform dependant
- * Sources: http://en.wikipedia.org/wiki/Thread-Specific_Storage
- *			http://predef.sourceforge.net/precomp.html
- */
-
-#ifdef GIT_THREADS
-#	define GIT_HAS_TLS 1
-
-/* No TLS in Cygwin */
-#	if defined(__CHECKER__) || defined(__CYGWIN__)
-#		undef GIT_HAS_TLS
-#		define GIT_TLS
-
-/* No TLS in Mach binaries for Mac OS X */
-#	elif defined(__APPLE__) && defined(__MACH__)
-#		undef GIT_TLS
-#		define GIT_TLS
-
-/* Normal TLS for GCC */
-#	elif defined(__GNUC__) || \
-		defined(__SUNPRO_C) || \
-		defined(__SUNPRO_CC) || \
-		defined(__xlc__) || \
-		defined(__xlC__)
-#		define GIT_TLS __thread
-
-/* ICC may run on Windows or Linux */
-#	elif defined(__INTEL_COMPILER)
-#		if defined(_WIN32) || defined(_WIN32_CE)
-#		define GIT_TLS __declspec(thread)
-#		else
-#		define GIT_TLS __thread
-#		endif
-
-/* Declspec for MSVC in Win32 */
-#	elif defined(_WIN32) || \
-		defined(_WIN32_CE) || \
-		defined(__BORLANDC__)
-#		define GIT_TLS __declspec(thread)
-
-/* Other platform; no TLS */
-#	else
-#		undef GIT_HAS_TLS
-#		define GIT_TLS /* nothing: tls vars are thread-global */
-#	endif
-#else /* Disable TLS if libgit2 is not threadsafe */
-#	define GIT_TLS
-#endif /* GIT_THREADS */
-
-#endif /* INCLUDE_git_thread_utils_h__ */
diff --git a/include/git2/threads.h b/include/git2/threads.h
new file mode 100644
index 000000000..85472a441
--- /dev/null
+++ b/include/git2/threads.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2009-2011 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_git_threads_h__
+#define INCLUDE_git_threads_h__
+
+#include "common.h"
+
+/**
+ * @file git2/threads.h
+ * @brief Library level thread functions
+ * @defgroup git_thread Threading functions
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * Init the threading system.
+ *
+ * If libgit2 has been built with GIT_THREADS
+ * on, this function must be called once before
+ * any other library functions.
+ *
+ * If libgit2 has been built without GIT_THREADS
+ * support, this function is a no-op.
+ */
+GIT_EXTERN(void) git_threads_init(void);
+
+/**
+ * Shutdown the threading system.
+ *
+ * If libgit2 has been built with GIT_THREADS
+ * on, this function must be called before shutting
+ * down the library.
+ *
+ * If libgit2 has been built without GIT_THREADS
+ * support, this function is a no-op.
+ */
+GIT_EXTERN(void) git_threads_shutdown(void);
+
+/** @} */
+GIT_END_DECL
+#endif
+