transaction_provider.h

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#ifndef MYSQL_CSA_CORE_TRANSACTION_PROVIDER_H
#define MYSQL_CSA_CORE_TRANSACTION_PROVIDER_H
 
#include <memory>
#include "sql/changestreams/apply/jobs/job.h"
#include "sql/changestreams/apply/storage/relay_log/relay_log_adaptive_reader.h"
 
namespace mysql::csa {
 
class Transaction_provider;
using Transaction_provider_sptr = std::shared_ptr<Transaction_provider>;
 
/// Interface for all transaction providers.
/// Transaction provider shall implement the following methods:
/// - start - start provider in case this provider is asynchronous
/// - stop - stops provider and wakes blocking reads
/// - finish - completes provider shutdown from the provider owner thread
/// - is_stopped - checks if stop has been requested internally or externally
/// - next - blocks until next transaction is fetched or provider reaches
///          stop conditions (is_stopped will return true) or temporarily
///          wakes up thread requesting the next transaction
class Transaction_provider {
 public:
  // using Common_reader_type = Reader_relaylog;
  using Common_reader_type = Relay_log_adaptive_reader;
  /// Get the next job
  /// @return Job smart pointer
  virtual Job_ptr next() = 0;
  /// Checks whether provider has been stopped externally or internally
  /// @brief True if stopped, false otherwise
  virtual bool is_stopped() const = 0;
  /// Start provider (if asynchronous)
  virtual void start() = 0;
  /// Stop provider and wake blocked reader calls.
  virtual void stop() = 0;
  /// Complete provider shutdown from the owner thread (transaction receiver).
  /// Requires stop to have been called first; otherwise it is a no-op.
  virtual void finish() = 0;
  /// @brief Check if provider has an error
  /// @return True in case an error occurred, false otherwise
  virtual bool is_error() const = 0;
  /// Destructor
  virtual ~Transaction_provider() = default;
};
 
}  // namespace mysql::csa
 
#endif  // MYSQL_CSA_CORE_TRANSACTION_PROVIDER_H