libusb/os/events_windows.c - third_party/libusb - Git at Google

 /*
  * libusb event abstraction on Microsoft Windows
  *
  * Copyright © 2020 Chris Dickens <christopher.a.dickens@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */

 #include <config.h>

 #include "libusbi.h"
 #include "windows_common.h"

 int usbi_create_event(usbi_event_t *event)
 {
 	event->hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
 	if (event->hEvent == NULL) {
 		usbi_err(NULL, "CreateEvent failed: %s", windows_error_str(0));
 		return LIBUSB_ERROR_OTHER;
 	}

 	return 0;
 }

 void usbi_destroy_event(usbi_event_t *event)
 {
 	if (!CloseHandle(event->hEvent))
 		usbi_warn(NULL, "CloseHandle failed: %s", windows_error_str(0));
 }

 void usbi_signal_event(usbi_event_t *event)
 {
 	if (!SetEvent(event->hEvent))
 		usbi_warn(NULL, "SetEvent failed: %s", windows_error_str(0));
 }

 void usbi_clear_event(usbi_event_t *event)
 {
 	if (!ResetEvent(event->hEvent))
 		usbi_warn(NULL, "ResetEvent failed: %s", windows_error_str(0));
 }

 #ifdef HAVE_OS_TIMER
 int usbi_create_timer(usbi_timer_t *timer)
 {
 	timer->hTimer = CreateWaitableTimer(NULL, TRUE, NULL);
 	if (timer->hTimer == NULL) {
 		usbi_warn(NULL, "CreateWaitableTimer failed: %s", windows_error_str(0));
 		return LIBUSB_ERROR_OTHER;
 	}

 	return 0;
 }

 void usbi_destroy_timer(usbi_timer_t *timer)
 {
 	if (!CloseHandle(timer->hTimer))
 		usbi_warn(NULL, "CloseHandle failed: %s", windows_error_str(0));
 }

 int usbi_arm_timer(usbi_timer_t *timer, const struct timespec *timeout)
 {
 	struct timespec systime, remaining;
 	FILETIME filetime;
 	LARGE_INTEGER dueTime;

 	/* Transfer timeouts are based on the monotonic clock and the waitable
 	 * timers on the system clock. This requires a conversion between the
 	 * two, so we calculate the remaining time relative to the monotonic
 	 * clock and calculate an absolute system time for the timer expiration.
 	 * Note that if the timeout has already passed, the remaining time will
 	 * be negative and thus an absolute system time in the past will be set.
 	 * This works just as intended because the timer becomes signalled
 	 * immediately. */
 	usbi_get_monotonic_time(&systime);

 	TIMESPEC_SUB(timeout, &systime, &remaining);

 	GetSystemTimeAsFileTime(&filetime);
 	dueTime.LowPart = filetime.dwLowDateTime;
 	dueTime.HighPart = filetime.dwHighDateTime;
 	dueTime.QuadPart += (remaining.tv_sec * 10000000LL) + (remaining.tv_nsec / 100LL);

 	if (!SetWaitableTimer(timer->hTimer, &dueTime, 0, NULL, NULL, FALSE)) {
 		usbi_warn(NULL, "SetWaitableTimer failed: %s", windows_error_str(0));
 		return LIBUSB_ERROR_OTHER;
 	}

 	return 0;
 }

 int usbi_disarm_timer(usbi_timer_t *timer)
 {
 	LARGE_INTEGER dueTime;

 	/* A manual-reset waitable timer will stay in the signalled state until
 	 * another call to SetWaitableTimer() is made. It is possible that the
 	 * timer has already expired by the time we come in to disarm it, so to
 	 * be entirely sure the timer is disarmed and not in the signalled state,
 	 * we will set it with an impossibly large expiration and immediately
 	 * cancel. */
 	dueTime.QuadPart = LLONG_MAX;
 	if (!SetWaitableTimer(timer->hTimer, &dueTime, 0, NULL, NULL, FALSE)) {
 		usbi_warn(NULL, "SetWaitableTimer failed: %s", windows_error_str(0));
 		return LIBUSB_ERROR_OTHER;
 	}

 	if (!CancelWaitableTimer(timer->hTimer)) {
 		usbi_warn(NULL, "SetWaitableTimer failed: %s", windows_error_str(0));
 		return LIBUSB_ERROR_OTHER;
 	}

 	return 0;
 }
 #endif

 int usbi_alloc_event_data(struct libusb_context *ctx)
 {
 	struct usbi_event_source *ievent_source;
 	HANDLE *handles;
 	size_t i = 0;

 	/* Event sources are only added during usbi_io_init(). We should not
 	 * be running this function again if the event data has already been
 	 * allocated. */
 	if (ctx->event_data) {
 		usbi_warn(ctx, "program assertion failed - event data already allocated");
 		return LIBUSB_ERROR_OTHER;
 	}

 	ctx->event_data_cnt = 0;
 	for_each_event_source(ctx, ievent_source)
 		ctx->event_data_cnt++;

 	/* We only expect up to two HANDLEs to wait on, one for the internal
 	 * signalling event and the other for the timer. */
 	if (ctx->event_data_cnt != 1 && ctx->event_data_cnt != 2) {
 		usbi_err(ctx, "program assertion failed - expected exactly 1 or 2 HANDLEs");
 		return LIBUSB_ERROR_OTHER;
 	}

 	handles = calloc(ctx->event_data_cnt, sizeof(HANDLE));
 	if (!handles)
 		return LIBUSB_ERROR_NO_MEM;

 	for_each_event_source(ctx, ievent_source) {
 		handles[i] = ievent_source->data.os_handle;
 		i++;
 	}

 	ctx->event_data = handles;
 	return 0;
 }

 int usbi_wait_for_events(struct libusb_context *ctx,
 	struct usbi_reported_events *reported_events, int timeout_ms)
 {
 	HANDLE *handles = ctx->event_data;
 	DWORD num_handles = (DWORD)ctx->event_data_cnt;
 	DWORD result;

 	usbi_dbg(ctx, "WaitForMultipleObjects() for %lu HANDLEs with timeout in %dms", ULONG_CAST(num_handles), timeout_ms);
 	result = WaitForMultipleObjects(num_handles, handles, FALSE, (DWORD)timeout_ms);
 	usbi_dbg(ctx, "WaitForMultipleObjects() returned %lu", ULONG_CAST(result));
 	if (result == WAIT_TIMEOUT) {
 		if (usbi_using_timer(ctx))
 			goto done;
 		return LIBUSB_ERROR_TIMEOUT;
 	} else if (result == WAIT_FAILED) {
 		usbi_err(ctx, "WaitForMultipleObjects() failed: %s", windows_error_str(0));
 		return LIBUSB_ERROR_IO;
 	}

 	result -= WAIT_OBJECT_0;

 	/* handles[0] is always the internal signalling event */
 	if (result == 0)
 		reported_events->event_triggered = 1;
 	else
 		reported_events->event_triggered = 0;

 #ifdef HAVE_OS_TIMER
 	/* on timer configurations, handles[1] is the timer */
 	if (usbi_using_timer(ctx)) {
 		/* The WaitForMultipleObjects() function reports the index of
 		 * the first object that became signalled. If the internal
 		 * signalling event was reported, we need to also check and
 		 * report whether the timer is in the signalled state. */
 		if (result == 1 || WaitForSingleObject(handles[1], 0) == WAIT_OBJECT_0)
 			reported_events->timer_triggered = 1;
 		else
 			reported_events->timer_triggered = 0;
 	} else {
 		reported_events->timer_triggered = 0;
 	}
 #endif

 done:
 	/* no events are ever reported to the backend */
 	reported_events->num_ready = 0;
 	return LIBUSB_SUCCESS;
 }
	/*
	* libusb event abstraction on Microsoft Windows
	*
	* Copyright © 2020 Chris Dickens <christopher.a.dickens@gmail.com>
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this library; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	#include <config.h>

	#include "libusbi.h"
	#include "windows_common.h"

	int usbi_create_event(usbi_event_t *event)
	{
	event->hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
	if (event->hEvent == NULL) {
	usbi_err(NULL, "CreateEvent failed: %s", windows_error_str(0));
	return LIBUSB_ERROR_OTHER;
	}

	return 0;
	}

	void usbi_destroy_event(usbi_event_t *event)
	{
	if (!CloseHandle(event->hEvent))
	usbi_warn(NULL, "CloseHandle failed: %s", windows_error_str(0));
	}

	void usbi_signal_event(usbi_event_t *event)
	{
	if (!SetEvent(event->hEvent))
	usbi_warn(NULL, "SetEvent failed: %s", windows_error_str(0));
	}

	void usbi_clear_event(usbi_event_t *event)
	{
	if (!ResetEvent(event->hEvent))
	usbi_warn(NULL, "ResetEvent failed: %s", windows_error_str(0));
	}

	#ifdef HAVE_OS_TIMER
	int usbi_create_timer(usbi_timer_t *timer)
	{
	timer->hTimer = CreateWaitableTimer(NULL, TRUE, NULL);
	if (timer->hTimer == NULL) {
	usbi_warn(NULL, "CreateWaitableTimer failed: %s", windows_error_str(0));
	return LIBUSB_ERROR_OTHER;
	}

	return 0;
	}

	void usbi_destroy_timer(usbi_timer_t *timer)
	{
	if (!CloseHandle(timer->hTimer))
	usbi_warn(NULL, "CloseHandle failed: %s", windows_error_str(0));
	}

	int usbi_arm_timer(usbi_timer_t timer, const struct timespec timeout)
	{
	struct timespec systime, remaining;
	FILETIME filetime;
	LARGE_INTEGER dueTime;

	/* Transfer timeouts are based on the monotonic clock and the waitable
	* timers on the system clock. This requires a conversion between the
	* two, so we calculate the remaining time relative to the monotonic
	* clock and calculate an absolute system time for the timer expiration.
	* Note that if the timeout has already passed, the remaining time will
	* be negative and thus an absolute system time in the past will be set.
	* This works just as intended because the timer becomes signalled
	* immediately. */
	usbi_get_monotonic_time(&systime);

	TIMESPEC_SUB(timeout, &systime, &remaining);

	GetSystemTimeAsFileTime(&filetime);
	dueTime.LowPart = filetime.dwLowDateTime;
	dueTime.HighPart = filetime.dwHighDateTime;
	dueTime.QuadPart += (remaining.tv_sec * 10000000LL) + (remaining.tv_nsec / 100LL);

	if (!SetWaitableTimer(timer->hTimer, &dueTime, 0, NULL, NULL, FALSE)) {
	usbi_warn(NULL, "SetWaitableTimer failed: %s", windows_error_str(0));
	return LIBUSB_ERROR_OTHER;
	}

	return 0;
	}

	int usbi_disarm_timer(usbi_timer_t *timer)
	{
	LARGE_INTEGER dueTime;

	/* A manual-reset waitable timer will stay in the signalled state until
	* another call to SetWaitableTimer() is made. It is possible that the
	* timer has already expired by the time we come in to disarm it, so to
	* be entirely sure the timer is disarmed and not in the signalled state,
	* we will set it with an impossibly large expiration and immediately
	* cancel. */
	dueTime.QuadPart = LLONG_MAX;
	if (!SetWaitableTimer(timer->hTimer, &dueTime, 0, NULL, NULL, FALSE)) {
	usbi_warn(NULL, "SetWaitableTimer failed: %s", windows_error_str(0));
	return LIBUSB_ERROR_OTHER;
	}

	if (!CancelWaitableTimer(timer->hTimer)) {
	usbi_warn(NULL, "SetWaitableTimer failed: %s", windows_error_str(0));
	return LIBUSB_ERROR_OTHER;
	}

	return 0;
	}
	#endif

	int usbi_alloc_event_data(struct libusb_context *ctx)
	{
	struct usbi_event_source *ievent_source;
	HANDLE *handles;
	size_t i = 0;

	/* Event sources are only added during usbi_io_init(). We should not
	* be running this function again if the event data has already been
	* allocated. */
	if (ctx->event_data) {
	usbi_warn(ctx, "program assertion failed - event data already allocated");
	return LIBUSB_ERROR_OTHER;
	}

	ctx->event_data_cnt = 0;
	for_each_event_source(ctx, ievent_source)
	ctx->event_data_cnt++;

	/* We only expect up to two HANDLEs to wait on, one for the internal
	* signalling event and the other for the timer. */
	if (ctx->event_data_cnt != 1 && ctx->event_data_cnt != 2) {
	usbi_err(ctx, "program assertion failed - expected exactly 1 or 2 HANDLEs");
	return LIBUSB_ERROR_OTHER;
	}

	handles = calloc(ctx->event_data_cnt, sizeof(HANDLE));
	if (!handles)
	return LIBUSB_ERROR_NO_MEM;

	for_each_event_source(ctx, ievent_source) {
	handles[i] = ievent_source->data.os_handle;
	i++;
	}

	ctx->event_data = handles;
	return 0;
	}

	int usbi_wait_for_events(struct libusb_context *ctx,
	struct usbi_reported_events *reported_events, int timeout_ms)
	{
	HANDLE *handles = ctx->event_data;
	DWORD num_handles = (DWORD)ctx->event_data_cnt;
	DWORD result;

	usbi_dbg(ctx, "WaitForMultipleObjects() for %lu HANDLEs with timeout in %dms", ULONG_CAST(num_handles), timeout_ms);
	result = WaitForMultipleObjects(num_handles, handles, FALSE, (DWORD)timeout_ms);
	usbi_dbg(ctx, "WaitForMultipleObjects() returned %lu", ULONG_CAST(result));
	if (result == WAIT_TIMEOUT) {
	if (usbi_using_timer(ctx))
	goto done;
	return LIBUSB_ERROR_TIMEOUT;
	} else if (result == WAIT_FAILED) {
	usbi_err(ctx, "WaitForMultipleObjects() failed: %s", windows_error_str(0));
	return LIBUSB_ERROR_IO;
	}

	result -= WAIT_OBJECT_0;

	/* handles[0] is always the internal signalling event */
	if (result == 0)
	reported_events->event_triggered = 1;
	else
	reported_events->event_triggered = 0;

	#ifdef HAVE_OS_TIMER
	/* on timer configurations, handles[1] is the timer */
	if (usbi_using_timer(ctx)) {
	/* The WaitForMultipleObjects() function reports the index of
	* the first object that became signalled. If the internal
	* signalling event was reported, we need to also check and
	* report whether the timer is in the signalled state. */
	if (result == 1 \|\| WaitForSingleObject(handles[1], 0) == WAIT_OBJECT_0)
	reported_events->timer_triggered = 1;
	else
	reported_events->timer_triggered = 0;
	} else {
	reported_events->timer_triggered = 0;
	}
	#endif

	done:
	/* no events are ever reported to the backend */
	reported_events->num_ready = 0;
	return LIBUSB_SUCCESS;
	}