Remove KafkaConsumer::poll(std::chrono::milliseconds timeout, std::vector<consumer::ConsumerRecord>& output)

Author: kenneth-jia

.clang-tidy

@@ -25,6 +25,8 @@ Checks: "*,\
          -cppcoreguidelines-macro-usage,\
          -cppcoreguidelines-avoid-magic-numbers,\
          -cppcoreguidelines-avoid-non-const-global-variables,\
+         -cppcoreguidelines-avoid-const-or-ref-data-members,\
+         -cppcoreguidelines-avoid-do-while,\
          -cppcoreguidelines-pro-type-vararg,\
          -cppcoreguidelines-pro-bounds-array-to-pointer-decay,\
          -cppcoreguidelines-pro-bounds-pointer-arithmetic,\

include/kafka/KafkaConsumer.h

@@ -213,16 +213,6 @@ class KafkaConsumer: public KafkaClient
      */
     std::vector<consumer::ConsumerRecord> poll(std::chrono::milliseconds timeout);
 
-    /**
-     * Fetch data for the topics or partitions specified using one of the subscribe/assign APIs.
-     * Returns the number of polled records (which have been saved into parameter `output`).
-     * Note: 1) The result could be fetched through ConsumerRecord (with member function `error`).
-     *       2) Make sure the `ConsumerRecord` be destructed before the `KafkaConsumer.close()`.
-     * Throws KafkaException with errors:
-     *   - RD_KAFKA_RESP_ERR__UNKNOWN_PARTITION: Unknow partition
-     */
-    std::size_t poll(std::chrono::milliseconds timeout, std::vector<consumer::ConsumerRecord>& output);
-
     /**
      * Suspend fetching from the requested partitions. Future calls to poll() will not return any records from these partitions until they have been resumed using resume().
      * Note: 1) After pausing, the application still need to call `poll()` at regular intervals.
@@ -320,8 +310,6 @@ class KafkaConsumer: public KafkaClient
     // Register Callbacks for rd_kafka_conf_t
     static void registerConfigCallbacks(rd_kafka_conf_t* conf);
 
-    void pollMessages(int timeoutMs, std::vector<consumer::ConsumerRecord>& output);
-
     enum class PauseOrResumeOperation { Pause, Resume };
     void pauseOrResumePartitions(const TopicPartitions& topicPartitions, PauseOrResumeOperation op);
 
@@ -820,45 +808,28 @@ KafkaConsumer::storeOffsetsIfNecessary(const std::vector<consumer::ConsumerRecor
     }
 }
 
-// Fetch messages (internally used)
-inline void
-KafkaConsumer::pollMessages(int timeoutMs, std::vector<consumer::ConsumerRecord>& output)
+// Fetch messages
+inline std::vector<consumer::ConsumerRecord>
+KafkaConsumer::poll(std::chrono::milliseconds timeout)
 {
     // Commit the offsets for these messages which had been polled last time (for "enable.auto.commit=true" case)
     commitStoredOffsetsIfNecessary(CommitType::Async);
 
     // Poll messages with librdkafka's API
     std::vector<rd_kafka_message_t*> msgPtrArray(_maxPollRecords);
-    auto msgReceived = rd_kafka_consume_batch_queue(_rk_queue.get(), timeoutMs, msgPtrArray.data(), _maxPollRecords);
+    auto msgReceived = rd_kafka_consume_batch_queue(_rk_queue.get(), convertMsDurationToInt(timeout), msgPtrArray.data(), _maxPollRecords);
     if (msgReceived < 0)
     {
         KAFKA_THROW_ERROR(Error(rd_kafka_last_error()));
     }
 
     // Wrap messages with ConsumerRecord
-    output.clear();
-    output.reserve(static_cast<std::size_t>(msgReceived));
-    std::for_each(msgPtrArray.begin(), msgPtrArray.begin() + msgReceived, [&output](rd_kafka_message_t* rkMsg) { output.emplace_back(rkMsg); });
+    std::vector<consumer::ConsumerRecord> records(msgPtrArray.begin(), msgPtrArray.begin() + msgReceived);
 
     // Store the offsets for all these polled messages (for "enable.auto.commit=true" case)
-    storeOffsetsIfNecessary(output);
-}
-
-// Fetch messages (return via return value)
-inline std::vector<consumer::ConsumerRecord>
-KafkaConsumer::poll(std::chrono::milliseconds timeout)
-{
-    std::vector<consumer::ConsumerRecord> result;
-    poll(timeout, result);
-    return result;
-}
+    storeOffsetsIfNecessary(records);
 
-// Fetch messages (return via input parameter)
-inline std::size_t
-KafkaConsumer::poll(std::chrono::milliseconds timeout, std::vector<consumer::ConsumerRecord>& output)
-{
-    pollMessages(convertMsDurationToInt(timeout), output);
-    return output.size();
+    return records;
 }
 
 inline void