Imported Upstream version 0.8.0~pre1upstream/0.8.0_pre1

1 files changed, 200 insertions, 0 deletions

diff --git a/src/common/evqueue.h b/src/common/evqueue.h
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+/*  Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/*!
+ * \file evqueue.h
+ *
+ * \author Marek Vavrusa <marek.vavrusa@nic.cz>
+ *
+ * \brief Event queue.
+ *
+ * \addtogroup common_lib
+ * @{
+ */
+
+#ifndef _KNOTD_COMMON_EVQUEUE_H_
+#define _KNOTD_COMMON_EVQUEUE_H_
+
+#include <pthread.h>
+#include <signal.h> // sigset_t
+#include <time.h>
+#include <sys/time.h>
+
+//#include "knot/common.h"
+#include "common/lists.h"
+
+struct event_t;
+
+/*!
+ * \brief Event callback.
+ *
+ * Pointer to whole event structure is passed to the callback.
+ * Callback should return 0 on success and negative integer on error.
+ *
+ * Example callback:
+ * \code
+ * int print_callback(event_t *t) {
+ *    return printf("Callback: %s\n", t->data);
+ * }
+ * \endcode
+ */
+typedef int (*event_cb_t)(struct event_t *);
+
+/*!
+ * \brief Event structure.
+ */
+typedef struct event_t {
+	node n;            /*!< Node for event queue. */
+	int type;          /*!< Event type. */
+	struct timeval tv; /*!< Event scheduled time. */
+	void *data;        /*!< Usable data ptr. */
+	event_cb_t cb;     /*!< Event callback. */
+	void *parent;      /*!< Pointer to parent (evqueue, scheduler...) */
+} event_t;
+
+/*!
+ * \brief Event queue constants.
+ */
+enum {
+	EVQUEUE_READFD  = 0,
+	EVQUEUE_WRITEFD = 1
+};
+
+/*!
+ * \brief Event queue structure.
+ */
+typedef struct {
+	int fds[2]; /*!< Read and Write fds. */
+} evqueue_t;
+
+/*!
+ * \brief Create new event queue.
+ *
+ * Event queue is thread-safe and POSIX signal-safe.
+ * It uses piped fds for queueing and pselect(2) to
+ * wait for events.
+ *
+ * \retval New instance on success.
+ * \retval NULL on error.
+ */
+evqueue_t *evqueue_new();
+
+/*!
+ * \brief Deinitialize and free event queue.
+ *
+ * \param q Pointer to queue instance.
+ * \note *q is set to 0.
+ */
+void evqueue_free(evqueue_t **q);
+
+/*!
+ * \brief Poll for new events.
+ *
+ * Unblocked signals during polling are specified
+ * in a sigmask.
+ *
+ * \param q Event queue.
+ * \param ts Timeout (or NULL for infinite).
+ * \param sigmask Bitmask of signals to receive (or NULL).
+ *
+ * \retval Number of polled events on success.
+ * \retval -1 On error or signal interrupt.
+ */
+int evqueue_poll(evqueue_t *q, const struct timespec *ts, const sigset_t *sigmask);
+
+/*!
+ * \brief Return evqueue pollable fd.
+ *
+ * \param q Event queue.
+ *
+ * \retval File descriptor available for polling.
+ * \retval -1 On error.
+ */
+static inline int evqueue_pollfd(evqueue_t *q) {
+	return q->fds[EVQUEUE_READFD];
+}
+
+/*!
+ * \brief Read data from event queue.
+ *
+ * This function is useful for sending custom
+ * events or other data types through the event queue.
+ *
+ * \param q Event queue.
+ * \param dst Destination buffer.
+ * \param len Number of bytes to read.
+ *
+ * \retval Number of read bytes on success.
+ * \retval -1 on error, \see read(2).
+ */
+int evqueue_read(evqueue_t *q, void *dst, size_t len);
+
+/*!
+ * \brief Write data to event queue.
+ *
+ * This function is useful for sending custom
+ * events or other data types through the event queue.
+ *
+ * \param q Event queue.
+ * \param src Source buffer.
+ * \param len Number of bytes to write.
+ *
+ * \retval Number of written bytes on success.
+ * \retval -1 on error, \see write(2).
+ */
+int evqueue_write(evqueue_t *q, const void *src, size_t len);
+
+/*!
+ * \brief Read event from event queue.
+ *
+ * \param q Event queue.
+ * \param ev Event structure for writing.
+ *
+ * \retval 0 on success.
+ * \retval -1 on error.
+ */
+int evqueue_get(evqueue_t *q, event_t *ev);
+
+/*!
+ * \brief Add event to queue.
+ *
+ * \param q Event queue.
+ * \param ev Event structure to read.
+ *
+ * \retval 0 on success.
+ * \retval -1 on error.
+ */
+int evqueue_add(evqueue_t *q, const event_t *ev);
+
+/* Singleton event queue pointer. */
+extern evqueue_t *s_evqueue;
+
+/*!
+ * \brief Event queue singleton.
+ */
+static inline evqueue_t *evqueue() {
+	return s_evqueue;
+}
+
+/*!
+ * \brief Set event queue singleton.
+ */
+static inline void evqueue_set(evqueue_t *q) {
+	s_evqueue = q;
+}
+
+#endif /* _KNOTD_COMMON_EVQUEUE_H_ */
+
+/*! @} */