Add Event class

include/cppkafka/event.h

@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2018, Matias Fontanini
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following disclaimer
+ *   in the documentation and/or other materials provided with the
+ *   distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef CPPKAFKA_EVENT_H
+#define CPPKAFKA_EVENT_H
+
+#include <memory>
+#include <string>
+#include <vector>
+#include "error.h"
+#include "message.h"
+#include "topic_partition.h"
+#include "topic_partition_list.h"
+
+namespace cppkafka {
+
+class Event {
+public:
+    /**
+     * Construct an Event from a rdkafka event handle and take ownership of it
+     *
+     * /param handle The handle to construct this event from
+     */
+    Event(rd_kafka_event_t* handle);
+
+    /**
+     * Returns the name of this event
+     */
+    std::string get_name() const;
+
+    /**
+     * Returns the type of this event
+     */
+    rd_kafka_event_type_t get_type() const;
+
+    /**
+     * \brief Gets the next message contained in this event.
+     *
+     * This call is only valid if the event type is one of:
+     * * RD_KAFKA_EVENT_FETCH
+     * * RD_KAFKA_EVENT_DR
+     *
+     * \note The returned message's lifetime *is tied to this Event*. That is, if the event
+     * is free'd so will the contents of the message.
+     */
+    Message get_next_message() const;
+
+    /**
+     * \brief Gets all messages in this event (if any)
+     *
+     * This call is only valid if the event type is one of:
+     * * RD_KAFKA_EVENT_FETCH
+     * * RD_KAFKA_EVENT_DR
+     *
+     * \note The returned messages' lifetime *is tied to this Event*. That is, if the event
+     * is free'd so will the contents of the messages.
+     *
+     * \return A vector containing 0 or more messages
+     */
+    std::vector<Message> get_messages();
+
+    /**
+     * \brief Gets all messages in this event (if any)
+     *
+     * This call is only valid if the event type is one of:
+     * * RD_KAFKA_EVENT_FETCH
+     * * RD_KAFKA_EVENT_DR
+     *
+     * \param allocator The allocator to use on the output vector
+     *
+     * \note The returned messages' lifetime *is tied to this Event*. That is, if the event
+     * is free'd so will the contents of the messages.
+     *
+     * \return A vector containing 0 or more messages
+     */
+    template <typename Allocator>
+    std::vector<Message, Allocator> get_messages(const Allocator allocator);
+
+    /**
+     * \brief Gets the number of messages contained in this event
+     *
+     * This call is only valid if the event type is one of:
+     * * RD_KAFKA_EVENT_FETCH
+     * * RD_KAFKA_EVENT_DR
+     */
+    size_t get_message_count() const;
+
+    /**
+     * \brief Returns the error in this event
+     */
+    Error get_error() const;
+
+    /**
+     * Gets the opaque pointer in this event
+     */
+    void* get_opaque() const;
+
+    /**
+     * \brief Gets the stats in this event
+     *
+     * This call is only valid if the event type is RD_KAFKA_EVENT_STATS
+     */
+    std::string get_stats() const;
+
+    /**
+     * \brief Gets the topic/partition for this event
+     *
+     * This call is only valid if the event type is RD_KAFKA_EVENT_ERROR
+     */
+    TopicPartition get_topic_partition() const;
+
+    /**
+     * \brief Gets the list of topic/partitions in this event
+     *
+     * This call is only valid if the event type is one of:
+     * * RD_KAFKA_EVENT_REBALANCE
+     * * RD_KAFKA_EVENT_OFFSET_COMMIT
+     */
+    TopicPartitionList get_topic_partition_list() const;
+private:
+    using HandlePtr = std::unique_ptr<rd_kafka_event_t, decltype(&rd_kafka_event_destroy)>;
+
+    HandlePtr handle_;
+};
+
+template <typename Allocator>
+std::vector<Message, Allocator> Event::get_messages(const Allocator allocator) {
+    const size_t total_messages = get_message_count();
+    std::vector<const rd_kafka_message_t*> raw_messages(total_messages);
+    const auto messages_read = rd_kafka_event_message_array(handle_.get(),
+                                                            raw_messages.data(),
+                                                            total_messages);
+    std::vector<Message, Allocator> output(allocator);
+    output.reserve(messages_read);
+    for (auto message : raw_messages) {
+        output.emplace_back(Message::make_non_owning(const_cast<rd_kafka_message_t*>(message)));
+    }
+    return output;
+}
+
+} // cppkafka
+
+#endif // CPPKAFKA_EVENT_H