/*
 * mono-threads-windows.c: Low-level threading, windows version
 *
 * Author:
 *	Rodrigo Kumpera (kumpera@gmail.com)
 *
 * (C) 2011 Novell, Inc
 */

#include <mono/utils/mono-threads.h>

#if defined(USE_WINDOWS_BACKEND)

#include <mono/utils/mono-compiler.h>
#include <mono/utils/mono-threads-debug.h>
#include <limits.h>


void
mono_threads_suspend_init (void)
{
}

static void CALLBACK
interrupt_apc (ULONG_PTR param)
{
}

gboolean
mono_threads_suspend_begin_async_suspend (MonoThreadInfo *info, gboolean interrupt_kernel)
{
	DWORD id = mono_thread_info_get_tid (info);
	HANDLE handle;
	DWORD result;

	handle = OpenThread (THREAD_ALL_ACCESS, FALSE, id);
	g_assert (handle);

	result = SuspendThread (handle);
	THREADS_SUSPEND_DEBUG ("SUSPEND %p -> %d\n", (void*)id, ret);
	if (result == (DWORD)-1) {
		CloseHandle (handle);
		return FALSE;
	}

	/* We're in the middle of a self-suspend, resume and register */
	if (!mono_threads_transition_finish_async_suspend (info)) {
		mono_threads_add_to_pending_operation_set (info);
		result = ResumeThread (handle);
		g_assert (result == 1);
		CloseHandle (handle);
		THREADS_SUSPEND_DEBUG ("FAILSAFE RESUME/1 %p -> %d\n", (void*)id, 0);
		//XXX interrupt_kernel doesn't make sense in this case as the target is not in a syscall
		return TRUE;
	}
	info->suspend_can_continue = mono_threads_get_runtime_callbacks ()->thread_state_init_from_handle (&info->thread_saved_state [ASYNC_SUSPEND_STATE_INDEX], info);
	THREADS_SUSPEND_DEBUG ("thread state %p -> %d\n", (void*)id, res);
	if (info->suspend_can_continue) {
		//FIXME do we need to QueueUserAPC on this case?
		if (interrupt_kernel)
			QueueUserAPC ((PAPCFUNC)interrupt_apc, handle, (ULONG_PTR)NULL);
	} else {
		THREADS_SUSPEND_DEBUG ("FAILSAFE RESUME/2 %p -> %d\n", (void*)info->native_handle, 0);
	}

	CloseHandle (handle);
	return TRUE;
}

gboolean
mono_threads_suspend_check_suspend_result (MonoThreadInfo *info)
{
	return info->suspend_can_continue;
}

static void CALLBACK
abort_apc (ULONG_PTR param)
{
	THREADS_INTERRUPT_DEBUG ("%06d - abort_apc () called", GetCurrentThreadId ());
}

void
mono_threads_suspend_abort_syscall (MonoThreadInfo *info)
{
	DWORD id = mono_thread_info_get_tid (info);
	HANDLE handle;

	handle = OpenThread (THREAD_ALL_ACCESS, FALSE, id);
	g_assert (handle);

	THREADS_INTERRUPT_DEBUG ("%06d - Aborting syscall in thread %06d", GetCurrentThreadId (), id);
	QueueUserAPC ((PAPCFUNC)abort_apc, handle, (ULONG_PTR)NULL);

	CloseHandle (handle);
}

gboolean
mono_threads_suspend_needs_abort_syscall (void)
{
	return TRUE;
}

gboolean
mono_threads_suspend_begin_async_resume (MonoThreadInfo *info)
{
	DWORD id = mono_thread_info_get_tid (info);
	HANDLE handle;
	DWORD result;

	handle = OpenThread (THREAD_ALL_ACCESS, FALSE, id);
	g_assert (handle);

	if (info->async_target) {
		MonoContext ctx;
		CONTEXT context;
		gboolean res;

		ctx = info->thread_saved_state [ASYNC_SUSPEND_STATE_INDEX].ctx;
		mono_threads_get_runtime_callbacks ()->setup_async_callback (&ctx, info->async_target, info->user_data);
		info->async_target = info->user_data = NULL;

		context.ContextFlags = CONTEXT_INTEGER | CONTEXT_CONTROL;

		if (!GetThreadContext (handle, &context)) {
			CloseHandle (handle);
			return FALSE;
		}

		g_assert (context.ContextFlags & CONTEXT_INTEGER);
		g_assert (context.ContextFlags & CONTEXT_CONTROL);

		mono_monoctx_to_sigctx (&ctx, &context);

		context.ContextFlags = CONTEXT_INTEGER | CONTEXT_CONTROL;
		res = SetThreadContext (handle, &context);
		if (!res) {
			CloseHandle (handle);
			return FALSE;
		}
	}

	result = ResumeThread (handle);
	CloseHandle (handle);

	return result != (DWORD)-1;
}


void
mono_threads_suspend_register (MonoThreadInfo *info)
{
}

void
mono_threads_suspend_free (MonoThreadInfo *info)
{
}

void
mono_threads_suspend_init_signals (void)
{
}

gint
mono_threads_suspend_search_alternative_signal (void)
{
	g_assert_not_reached ();
}

gint
mono_threads_suspend_get_suspend_signal (void)
{
	return -1;
}

gint
mono_threads_suspend_get_restart_signal (void)
{
	return -1;
}

gint
mono_threads_suspend_get_abort_signal (void)
{
	return -1;
}

#endif

#if defined (HOST_WIN32)

int
mono_threads_platform_create_thread (MonoThreadStart thread_fn, gpointer thread_data, gsize* const stack_size, MonoNativeThreadId *out_tid)
{
	HANDLE result;
	DWORD thread_id;

	result = CreateThread (NULL, stack_size ? *stack_size : 0, (LPTHREAD_START_ROUTINE) thread_fn, thread_data, 0, &thread_id);
	if (!result)
		return -1;

	/* A new handle is open when attaching
	 * the thread, so we don't need this one */
	CloseHandle (result);

	if (out_tid)
		*out_tid = thread_id;

	if (stack_size) {
		// TOOD: Use VirtualQuery to get correct value 
		// http://stackoverflow.com/questions/2480095/thread-stack-size-on-windows-visual-c
		*stack_size = 2 * 1024 * 1024;
	}

	return 0;
}


MonoNativeThreadId
mono_native_thread_id_get (void)
{
	return GetCurrentThreadId ();
}

gboolean
mono_native_thread_id_equals (MonoNativeThreadId id1, MonoNativeThreadId id2)
{
	return id1 == id2;
}

gboolean
mono_native_thread_create (MonoNativeThreadId *tid, gpointer func, gpointer arg)
{
	return CreateThread (NULL, 0, (func), (arg), 0, (tid)) != NULL;
}

gboolean
mono_native_thread_join (MonoNativeThreadId tid)
{
	HANDLE handle;

	if (!(handle = OpenThread (THREAD_ALL_ACCESS, TRUE, tid)))
		return FALSE;

	DWORD res = WaitForSingleObject (handle, INFINITE);

	CloseHandle (handle);

	return res != WAIT_FAILED;
}

#if HAVE_DECL___READFSDWORD==0
static MONO_ALWAYS_INLINE unsigned long long
__readfsdword (unsigned long offset)
{
	unsigned long value;
	//	__asm__("movl %%fs:%a[offset], %k[value]" : [value] "=q" (value) : [offset] "irm" (offset));
   __asm__ volatile ("movl    %%fs:%1,%0"
     : "=r" (value) ,"=m" ((*(volatile long *) offset)));
	return value;
}
#endif

void
mono_threads_platform_get_stack_bounds (guint8 **staddr, size_t *stsize)
{
	MEMORY_BASIC_INFORMATION meminfo;
#ifdef _WIN64
	/* win7 apis */
	NT_TIB* tib = (NT_TIB*)NtCurrentTeb();
	guint8 *stackTop = (guint8*)tib->StackBase;
	guint8 *stackBottom = (guint8*)tib->StackLimit;
#else
	/* http://en.wikipedia.org/wiki/Win32_Thread_Information_Block */
	void* tib = (void*)__readfsdword(0x18);
	guint8 *stackTop = (guint8*)*(int*)((char*)tib + 4);
	guint8 *stackBottom = (guint8*)*(int*)((char*)tib + 8);
#endif
	/*
	Windows stacks are expanded on demand, one page at time. The TIB reports
	only the currently allocated amount.
	VirtualQuery will return the actual limit for the bottom, which is what we want.
	*/
	if (VirtualQuery (&meminfo, &meminfo, sizeof (meminfo)) == sizeof (meminfo))
		stackBottom = MIN (stackBottom, (guint8*)meminfo.AllocationBase);

	*staddr = stackBottom;
	*stsize = stackTop - stackBottom;

}

#if SIZEOF_VOID_P == 4 && G_HAVE_API_SUPPORT(HAVE_CLASSIC_WINAPI_SUPPORT)
typedef BOOL (WINAPI *LPFN_ISWOW64PROCESS) (HANDLE, PBOOL);
static gboolean is_wow64 = FALSE;
#endif

/* We do this at init time to avoid potential races with module opening */
void
mono_threads_platform_init (void)
{
#if SIZEOF_VOID_P == 4 && G_HAVE_API_SUPPORT(HAVE_CLASSIC_WINAPI_SUPPORT)
	LPFN_ISWOW64PROCESS is_wow64_func = (LPFN_ISWOW64PROCESS) GetProcAddress (GetModuleHandle (TEXT ("kernel32")), "IsWow64Process");
	if (is_wow64_func)
		is_wow64_func (GetCurrentProcess (), &is_wow64);
#endif
}

/*
 * When running x86 process under x64 system syscalls are done through WoW64. This
 * needs to do a transition from x86 mode to x64 so it can syscall into the x64 system.
 * Apparently this transition invalidates the ESP that we would get from calling
 * GetThreadContext, so we would fail to scan parts of the thread stack. We attempt
 * to query whether the thread is in such a transition so we try to restart it later.
 * We check CONTEXT_EXCEPTION_ACTIVE for this, which is highly undocumented.
 */
gboolean
mono_threads_platform_in_critical_region (MonoNativeThreadId tid)
{
	gboolean ret = FALSE;
#if SIZEOF_VOID_P == 4 && G_HAVE_API_SUPPORT(HAVE_CLASSIC_WINAPI_SUPPORT)
/* FIXME On cygwin these are not defined */
#if defined(CONTEXT_EXCEPTION_REQUEST) && defined(CONTEXT_EXCEPTION_REPORTING) && defined(CONTEXT_EXCEPTION_ACTIVE)
	if (is_wow64) {
		HANDLE handle = OpenThread (THREAD_ALL_ACCESS, FALSE, tid);
		if (handle) {
			CONTEXT context;
			ZeroMemory (&context, sizeof (CONTEXT));
			context.ContextFlags = CONTEXT_EXCEPTION_REQUEST;
			if (GetThreadContext (handle, &context)) {
				if ((context.ContextFlags & CONTEXT_EXCEPTION_REPORTING) &&
						(context.ContextFlags & CONTEXT_EXCEPTION_ACTIVE))
					ret = TRUE;
			}
			CloseHandle (handle);
		}
	}
#endif
#endif
	return ret;
}

gboolean
mono_threads_platform_yield (void)
{
	return SwitchToThread ();
}

void
mono_threads_platform_exit (gsize exit_code)
{
	ExitThread (exit_code);
}

int
mono_threads_get_max_stack_size (void)
{
	//FIXME
	return INT_MAX;
}

#if defined(_MSC_VER)
const DWORD MS_VC_EXCEPTION=0x406D1388;
#pragma pack(push,8)
typedef struct tagTHREADNAME_INFO
{
   DWORD dwType; // Must be 0x1000.
   LPCSTR szName; // Pointer to name (in user addr space).
   DWORD dwThreadID; // Thread ID (-1=caller thread).
  DWORD dwFlags; // Reserved for future use, must be zero.
} THREADNAME_INFO;
#pragma pack(pop)
#endif

void
mono_native_thread_set_name (MonoNativeThreadId tid, const char *name)
{
#if defined(_MSC_VER)
	/* http://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx */
	THREADNAME_INFO info;
	info.dwType = 0x1000;
	info.szName = name;
	info.dwThreadID = tid;
	info.dwFlags = 0;

	__try {
		RaiseException( MS_VC_EXCEPTION, 0, sizeof(info)/sizeof(ULONG_PTR),       (ULONG_PTR*)&info );
	}
	__except(EXCEPTION_EXECUTE_HANDLER) {
	}
#endif
}

#endif