Replay.hpp

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#pragma once

#include <fstream>
#include <map>
#include <vector>
#include <set>
#include <string>

#include "definitions.hpp"

#include <px4_platform_common/module.h>
#include <uORB/uORBTopics.h>
#include <uORB/topics/ekf2_timestamps.h>

namespace px4
{

/**
 * @class Replay
 * Parses an ULog file and replays it in 'real-time'. The timestamp of each replayed message is offset
 * to match the starting time of replay. It keeps a stream for each subscription to find the next message
 * to replay. This is necessary because data messages from different subscriptions don't need to be in
 * monotonic increasing order.
 */
class Replay : public ModuleBase<Replay>
{
public:
    Replay() = default;

    virtual ~Replay();

    /** @see ModuleBase */
    static int task_spawn(int argc, char *argv[]);

    /** @see ModuleBase */
    static Replay *instantiate(int argc, char *argv[]);

    /** @see ModuleBase */
    static int custom_command(int argc, char *argv[]);

    /** @see ModuleBase */
    static int print_usage(const char *reason = nullptr);

    /** @see ModuleBase::run() */
    void run() override;

    /**
     * Apply the parameters from the log
     * @param quiet do not print an error if true and no log file given via ENV
     * @return 0 on success
     */
    static int applyParams(bool quiet);

    /**
     * Tell the replay module that we want to use replay mode.
     * After that, only 'replay start' must be executed (typically the last step after startup).
     * @param file_name file name of the used log replay file. Will be copied.
     */
    static void setupReplayFile(const char *file_name);

    static bool isSetup() { return _replay_file; }

protected:

    /**
     * @class Compatibility base class to convert topics to an updated format
     */
    class CompatBase
    {
    public:
        virtual ~CompatBase() = default;

        /**
         * apply compatibility to a topic
         * @param data input topic (can be modified in place)
         * @return new topic data
         */
        virtual void *apply(void *data) = 0;
    };

    class CompatSensorCombinedDtType : public CompatBase
    {
    public:
        CompatSensorCombinedDtType(int gyro_integral_dt_offset_log, int gyro_integral_dt_offset_intern,
                       int accelerometer_integral_dt_offset_log, int accelerometer_integral_dt_offset_intern);

        void *apply(void *data) override;
    private:
        int _gyro_integral_dt_offset_log;
        int _gyro_integral_dt_offset_intern;
        int _accelerometer_integral_dt_offset_log;
        int _accelerometer_integral_dt_offset_intern;
    };

    struct Subscription {

        const orb_metadata *orb_meta = nullptr; ///< if nullptr, this subscription is invalid
        orb_advert_t orb_advert = nullptr;
        uint8_t multi_id;
        int timestamp_offset; ///< marks the field of the timestamp

        bool ignored = false; ///< if true, it will not be considered for publication in the main loop

        std::streampos next_read_pos;
        uint64_t next_timestamp; ///< timestamp of the file

        CompatBase *compat = nullptr;

        // statistics
        int error_counter = 0;
        int publication_counter = 0;
    };

    /**
     * Find the offset & field size in bytes for a given field name
     * @param format format string, as specified by ULog
     * @param field_name search for this field
     * @param offset returned offset
     * @param field_size returned field size
     * @return true if found, false otherwise
     */
    static bool findFieldOffset(const std::string &format, const std::string &field_name, int &offset, int &field_size);

    /**
     * publish an orb topic
     * @param sub
     * @param data
     * @return true if published, false otherwise
     */
    bool publishTopic(Subscription &sub, void *data);

    /**
     * called when entering the main replay loop
     */
    virtual void onEnterMainLoop() {}

    /**
     * called when exiting the main replay loop
     */
    virtual void onExitMainLoop() {}

    /**
     * called when a new subscription is added
     */
    virtual void onSubscriptionAdded(Subscription &sub, uint16_t msg_id) {}

    /**
     * handle delay until topic can be published.
     * @param next_file_timestamp timestamp of next message to publish
     * @param timestamp_offset offset between file start time and replay start time
     * @return timestamp that the message to publish should have
     */
    virtual uint64_t handleTopicDelay(uint64_t next_file_time, uint64_t timestamp_offset);

    /**
     * handle the publication of a topic update
     * @return true if published, false otherwise
     */
    virtual bool handleTopicUpdate(Subscription &sub, void *data, std::ifstream &replay_file);

    /**
     * read a topic from the file (offset given by the subscription) into _read_buffer
     */
    void readTopicDataToBuffer(const Subscription &sub, std::ifstream &replay_file);

    /**
     * Find next data message for this subscription, starting with the stored file offset.
     * Skip the first message, and if found, read the timestamp and store the new file offset.
     * This also takes care of new subscriptions and parameter updates. When reaching EOF,
     * the subscription is set to invalid.
     * File seek position is arbitrary after this call.
     * @return false on file error
     */
    bool nextDataMessage(std::ifstream &file, Subscription &subscription, int msg_id);

    std::vector<Subscription *> _subscriptions;
    std::vector<uint8_t> _read_buffer;

private:
    std::set<std::string> _overridden_params;
    std::map<std::string, std::string> _file_formats; ///< all formats we read from the file

    uint64_t _file_start_time;
    uint64_t _replay_start_time;
    std::streampos _data_section_start; ///< first ADD_LOGGED_MSG message

    /** keep track of file position to avoid adding a subscription multiple times. */
    std::streampos _subscription_file_pos = 0;

    int64_t _read_until_file_position = 1ULL << 60; ///< read limit if log contains appended data

    bool readFileHeader(std::ifstream &file);

    /**
     * Read definitions section: check formats, apply parameters and store
     * the start of the data section.
     * @return true on success
     */
    bool readFileDefinitions(std::ifstream &file);

    ///file parsing methods. They return false, when further parsing should be aborted.
    bool readFormat(std::ifstream &file, uint16_t msg_size);
    bool readAndAddSubscription(std::ifstream &file, uint16_t msg_size);
    bool readFlagBits(std::ifstream &file, uint16_t msg_size);

    /**
     * Read the file header and definitions sections. Apply the parameters from this section
     * and apply user-defined overridden parameters.
     * @return true on success
     */
    bool readDefinitionsAndApplyParams(std::ifstream &file);

    /**
     * Read and handle additional messages starting at current file position, while position < end_position.
     * This handles dropout and parameter update messages.
     * We need to handle these separately, because they have no timestamp. We look at the file position instead.
     * @return false on file error
     */
    bool readAndHandleAdditionalMessages(std::ifstream &file, std::streampos end_position);
    bool readDropout(std::ifstream &file, uint16_t msg_size);
    bool readAndApplyParameter(std::ifstream &file, uint16_t msg_size);

    static const orb_metadata *findTopic(const std::string &name);

    /** get the array size from a type. eg. float[3] -> return float */
    static std::string extractArraySize(const std::string &type_name_full, int &array_size);

    /** get the size of a type that is not an array */
    static size_t sizeOfType(const std::string &type_name);

    /** get the size of a type that can be an array */
    static size_t sizeOfFullType(const std::string &type_name_full);

    void setUserParams(const char *filename);

    static char *_replay_file;
};

} //namespace px4