1 files changed, 134 insertions, 0 deletions
diff --git a/src/global.c b/src/global.c
new file mode 100644
index 000000000..8ef286ef0
--- /dev/null
+++ b/src/global.c
@@ -0,0 +1,134 @@
+/*
+ * 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.
+ */
+#include "common.h"
+#include "global.h"
+#include "git2/threads.h" 
+#include "thread-utils.h"
+
+/**
+ * Handle the global state with TLS
+ *
+ * If libgit2 is built with GIT_THREADS enabled,
+ * the `git_threads_init()` function must be called
+ * before calling any other function of the library.
+ *
+ * This function allocates a TLS index (using pthreads
+ * or the native Win32 API) to store the global state
+ * on a per-thread basis.
+ *
+ * Any internal method that requires global state will
+ * then call `git__global_state()` which returns a pointer
+ * to the global state structure; this pointer is lazily
+ * allocated on each thread.
+ *
+ * Before shutting down the library, the
+ * `git_threads_shutdown` method must be called to free
+ * the previously reserved TLS index.
+ *
+ * If libgit2 is built without threading support, the
+ * `git__global_statestate()` call returns a pointer to a single,
+ * statically allocated global state. The `git_thread_`
+ * functions are not available in that case.
+ */
+
+#if defined(GIT_THREADS) && defined(GIT_WIN32)
+
+static DWORD _tls_index;
+static int _tls_init = 0;
+
+void git_threads_init(void)
+{
+	if (_tls_init)
+		return;
+
+	_tls_index = TlsAlloc();
+	_tls_init = 1;
+}
+
+void git_threads_shutdown(void)
+{
+	TlsFree(_tls_index);
+	_tls_init = 0;
+}
+
+git_global_st *git__global_state(void)
+{
+	void *ptr;
+
+	if ((ptr = TlsGetValue(_tls_index)) != NULL)
+		return ptr;
+
+	ptr = malloc(sizeof(git_global_st));
+	if (!ptr)
+		return NULL;
+
+	memset(ptr, 0x0, sizeof(git_global_st));
+	TlsSetValue(_tls_index, ptr);
+	return ptr;
+}
+
+#elif defined(GIT_THREADS) && defined(_POSIX_THREADS)
+
+static pthread_key_t _tls_key;
+static int _tls_init = 0;
+
+static void cb__free_status(void *st)
+{
+	free(st);
+}
+
+void git_threads_init(void)
+{
+	if (_tls_init)
+		return;
+
+	pthread_key_create(&_tls_key, &cb__free_status);
+	_tls_init = 1;
+}
+
+void git_threads_shutdown(void)
+{
+	pthread_key_delete(_tls_key);
+	_tls_init = 0;
+}
+
+git_global_st *git__global_state(void)
+{
+	void *ptr;
+
+	if ((ptr = pthread_getspecific(_tls_key)) != NULL)
+		return ptr;
+
+	ptr = malloc(sizeof(git_global_st));
+	if (!ptr)
+		return NULL;
+
+	memset(ptr, 0x0, sizeof(git_global_st));
+	pthread_setspecific(_tls_key, ptr);
+	return ptr;
+}
+
+#else
+
+static git_global_st __state;
+
+void git_threads_init(void)
+{
+	/* noop */ 
+}
+
+void git_threads_shutdown(void)
+{
+	/* noop */
+}
+
+git_global_st *git__global_state(void)
+{
+	return &__state;
+}
+
+#endif /* GIT_THREADS */