src.ctf.fs: make ctf_msg_iter_create return a unique_ptr

[babeltrace.git] / src / plugins / ctf / fs-src / fs.cpp

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright 2015-2017 Philippe Proulx <pproulx@efficios.com>
 * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * Babeltrace CTF file system Reader Component
 */

#include <glib.h>
#include <inttypes.h>

#include <babeltrace2/babeltrace.h>

#include "common/assert.h"
#include "common/common.h"
#include "common/uuid.h"
#include "cpp-common/bt2s/make-unique.hpp"

#include "plugins/common/param-validation/param-validation.h"

#include "../common/src/metadata/tsdl/ctf-meta-configure-ir-trace.hpp"
#include "../common/src/msg-iter/msg-iter.hpp"
#include "data-stream-file.hpp"
#include "file.hpp"
#include "fs.hpp"
#include "metadata.hpp"
#include "query.hpp"

struct tracer_info
{
    const char *name;
    int64_t major;
    int64_t minor;
    int64_t patch;
};

static void ctf_fs_msg_iter_data_destroy(struct ctf_fs_msg_iter_data *msg_iter_data)
{
    if (!msg_iter_data) {
        return;
    }

    if (msg_iter_data->msg_iter) {
        ctf_msg_iter_destroy(msg_iter_data->msg_iter);
    }

    delete msg_iter_data;
}

static bt_message_iterator_class_next_method_status
ctf_fs_iterator_next_one(struct ctf_fs_msg_iter_data *msg_iter_data, const bt_message **out_msg)
{
    bt_message_iterator_class_next_method_status status;
    enum ctf_msg_iter_status msg_iter_status;

    msg_iter_status = ctf_msg_iter_get_next_message(msg_iter_data->msg_iter, out_msg);

    switch (msg_iter_status) {
    case CTF_MSG_ITER_STATUS_OK:
        /* Cool, message has been written to *out_msg. */
        status = BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_OK;
        break;

    case CTF_MSG_ITER_STATUS_EOF:
        status = BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_END;
        break;

    case CTF_MSG_ITER_STATUS_AGAIN:
        /*
         * Should not make it this far as this is
         * medium-specific; there is nothing for the user to do
         * and it should have been handled upstream.
         */
        bt_common_abort();

    case CTF_MSG_ITER_STATUS_ERROR:
        BT_CPPLOGE_APPEND_CAUSE_SPEC(msg_iter_data->logger,
                                     "Failed to get next message from CTF message iterator.");
        status = BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_ERROR;
        break;

    case CTF_MSG_ITER_STATUS_MEMORY_ERROR:
        BT_CPPLOGE_APPEND_CAUSE_SPEC(msg_iter_data->logger,
                                     "Failed to get next message from CTF message iterator.");
        status = BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_MEMORY_ERROR;
        break;

    default:
        bt_common_abort();
    }

    return status;
}

bt_message_iterator_class_next_method_status
ctf_fs_iterator_next(bt_self_message_iterator *iterator, bt_message_array_const msgs,
                     uint64_t capacity, uint64_t *count)
{
    try {
        bt_message_iterator_class_next_method_status status;
        struct ctf_fs_msg_iter_data *msg_iter_data =
            (struct ctf_fs_msg_iter_data *) bt_self_message_iterator_get_data(iterator);
        uint64_t i = 0;

        if (G_UNLIKELY(msg_iter_data->next_saved_error)) {
            /*
         * Last time we were called, we hit an error but had some
         * messages to deliver, so we stashed the error here.  Return
         * it now.
         */
            BT_CURRENT_THREAD_MOVE_ERROR_AND_RESET(msg_iter_data->next_saved_error);
            status = msg_iter_data->next_saved_status;
            goto end;
        }

        do {
            status = ctf_fs_iterator_next_one(msg_iter_data, &msgs[i]);
            if (status == BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_OK) {
                i++;
            }
        } while (i < capacity && status == BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_OK);

        if (i > 0) {
            /*
         * Even if ctf_fs_iterator_next_one() returned something
         * else than BT_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_OK, we
         * accumulated message objects in the output
         * message array, so we need to return
         * BT_MESSAGE_ITERATOR_NEXT_METHOD_STATUS_OK so that they are
         * transferred to downstream. This other status occurs
         * again the next time muxer_msg_iter_do_next() is
         * called, possibly without any accumulated
         * message, in which case we'll return it.
         */
            if (status < 0) {
                /*
             * Save this error for the next _next call.  Assume that
             * this component always appends error causes when
             * returning an error status code, which will cause the
             * current thread error to be non-NULL.
             */
                msg_iter_data->next_saved_error = bt_current_thread_take_error();
                BT_ASSERT(msg_iter_data->next_saved_error);
                msg_iter_data->next_saved_status = status;
            }

            *count = i;
            status = BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_OK;
        }

end:
        return status;
        return status;
    } catch (const std::bad_alloc&) {
        return BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_MEMORY_ERROR;
    } catch (const bt2::Error&) {
        return BT_MESSAGE_ITERATOR_CLASS_NEXT_METHOD_STATUS_ERROR;
    }
}

bt_message_iterator_class_seek_beginning_method_status
ctf_fs_iterator_seek_beginning(bt_self_message_iterator *it)
{
    try {
        struct ctf_fs_msg_iter_data *msg_iter_data =
            (struct ctf_fs_msg_iter_data *) bt_self_message_iterator_get_data(it);

        BT_ASSERT(msg_iter_data);

        ctf_msg_iter_reset(msg_iter_data->msg_iter);
        ctf_fs_ds_group_medops_data_reset(msg_iter_data->msg_iter_medops_data.get());

        return BT_MESSAGE_ITERATOR_CLASS_SEEK_BEGINNING_METHOD_STATUS_OK;
    } catch (const std::bad_alloc&) {
        return BT_MESSAGE_ITERATOR_CLASS_SEEK_BEGINNING_METHOD_STATUS_MEMORY_ERROR;
    } catch (const bt2::Error&) {
        return BT_MESSAGE_ITERATOR_CLASS_SEEK_BEGINNING_METHOD_STATUS_ERROR;
    }
}

void ctf_fs_iterator_finalize(bt_self_message_iterator *it)
{
    ctf_fs_msg_iter_data_destroy(
        (struct ctf_fs_msg_iter_data *) bt_self_message_iterator_get_data(it));
}

static bt_message_iterator_class_initialize_method_status
ctf_msg_iter_medium_status_to_msg_iter_initialize_status(enum ctf_msg_iter_medium_status status)
{
    switch (status) {
    case CTF_MSG_ITER_MEDIUM_STATUS_EOF:
    case CTF_MSG_ITER_MEDIUM_STATUS_AGAIN:
    case CTF_MSG_ITER_MEDIUM_STATUS_ERROR:
        return BT_MESSAGE_ITERATOR_CLASS_INITIALIZE_METHOD_STATUS_ERROR;
    case CTF_MSG_ITER_MEDIUM_STATUS_MEMORY_ERROR:
        return BT_MESSAGE_ITERATOR_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
    case CTF_MSG_ITER_MEDIUM_STATUS_OK:
        return BT_MESSAGE_ITERATOR_CLASS_INITIALIZE_METHOD_STATUS_OK;
    }

    bt_common_abort();
}

bt_message_iterator_class_initialize_method_status
ctf_fs_iterator_init(bt_self_message_iterator *self_msg_iter,
                     bt_self_message_iterator_configuration *config,
                     bt_self_component_port_output *self_port)
{
    try {
        struct ctf_fs_port_data *port_data;
        bt_message_iterator_class_initialize_method_status status;
        enum ctf_msg_iter_medium_status medium_status;

        port_data = (struct ctf_fs_port_data *) bt_self_component_port_get_data(
            bt_self_component_port_output_as_self_component_port(self_port));
        BT_ASSERT(port_data);

        ctf_fs_msg_iter_data *msg_iter_data = new ctf_fs_msg_iter_data {self_msg_iter};
        msg_iter_data->ds_file_group = port_data->ds_file_group;

        medium_status = ctf_fs_ds_group_medops_data_create(msg_iter_data->ds_file_group,
                                                           self_msg_iter, msg_iter_data->logger,
                                                           msg_iter_data->msg_iter_medops_data);
        BT_ASSERT(medium_status == CTF_MSG_ITER_MEDIUM_STATUS_OK ||
                  medium_status == CTF_MSG_ITER_MEDIUM_STATUS_ERROR ||
                  medium_status == CTF_MSG_ITER_MEDIUM_STATUS_MEMORY_ERROR);
        if (medium_status != CTF_MSG_ITER_MEDIUM_STATUS_OK) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(msg_iter_data->logger,
                                         "Failed to create ctf_fs_ds_group_medops");
            status = ctf_msg_iter_medium_status_to_msg_iter_initialize_status(medium_status);
            goto error;
        }

        msg_iter_data->msg_iter =
            ctf_msg_iter_create(
                msg_iter_data->ds_file_group->ctf_fs_trace->metadata->tc,
                bt_common_get_page_size(static_cast<int>(msg_iter_data->logger.level())) * 8,
                ctf_fs_ds_group_medops, msg_iter_data->msg_iter_medops_data.get(), self_msg_iter,
                msg_iter_data->logger)
                .release();
        if (!msg_iter_data->msg_iter) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(msg_iter_data->logger,
                                         "Cannot create a CTF message iterator.");
            status = BT_MESSAGE_ITERATOR_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
            goto error;
        }

        /*
     * This iterator can seek forward if its stream class has a default
     * clock class.
     */
        if (msg_iter_data->ds_file_group->sc->default_clock_class) {
            bt_self_message_iterator_configuration_set_can_seek_forward(config, true);
        }

        bt_self_message_iterator_set_data(self_msg_iter, msg_iter_data);
        msg_iter_data = NULL;

        status = BT_MESSAGE_ITERATOR_CLASS_INITIALIZE_METHOD_STATUS_OK;
        goto end;

error:
        bt_self_message_iterator_set_data(self_msg_iter, NULL);

end:
        ctf_fs_msg_iter_data_destroy(msg_iter_data);
        return status;
    } catch (const std::bad_alloc&) {
        return BT_MESSAGE_ITERATOR_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
    } catch (const bt2::Error&) {
        return BT_MESSAGE_ITERATOR_CLASS_INITIALIZE_METHOD_STATUS_ERROR;
    }
}

static void ctf_fs_trace_destroy(struct ctf_fs_trace *ctf_fs_trace)
{
    if (!ctf_fs_trace) {
        return;
    }

    BT_TRACE_PUT_REF_AND_RESET(ctf_fs_trace->trace);

    if (ctf_fs_trace->path) {
        g_string_free(ctf_fs_trace->path, TRUE);
    }

    if (ctf_fs_trace->metadata) {
        ctf_fs_metadata_fini(ctf_fs_trace->metadata);
        delete ctf_fs_trace->metadata;
    }

    delete ctf_fs_trace;
}

void ctf_fs_trace_deleter::operator()(ctf_fs_trace * const trace) noexcept
{
    ctf_fs_trace_destroy(trace);
}

ctf_fs_component::UP ctf_fs_component_create(const bt2c::Logger& parentLogger)
{
    return bt2s::make_unique<ctf_fs_component>(parentLogger);
}

void ctf_fs_finalize(bt_self_component_source *component)
{
    ctf_fs_component::UP {static_cast<ctf_fs_component *>(
        bt_self_component_get_data(bt_self_component_source_as_self_component(component)))};
}

bt2c::GCharUP ctf_fs_make_port_name(struct ctf_fs_ds_file_group *ds_file_group)
{
    GString *name = g_string_new(NULL);

    /*
     * The unique port name is generated by concatenating unique identifiers
     * for:
     *
     *   - the trace
     *   - the stream class
     *   - the stream
     */

    /* For the trace, use the uuid if present, else the path. */
    if (ds_file_group->ctf_fs_trace->metadata->tc->is_uuid_set) {
        char uuid_str[BT_UUID_STR_LEN + 1];

        bt_uuid_to_str(ds_file_group->ctf_fs_trace->metadata->tc->uuid, uuid_str);
        g_string_assign(name, uuid_str);
    } else {
        g_string_assign(name, ds_file_group->ctf_fs_trace->path->str);
    }

    /*
     * For the stream class, use the id if present.  We can omit this field
     * otherwise, as there will only be a single stream class.
     */
    if (ds_file_group->sc->id != UINT64_C(-1)) {
        g_string_append_printf(name, " | %" PRIu64, ds_file_group->sc->id);
    }

    /* For the stream, use the id if present, else, use the path. */
    if (ds_file_group->stream_id != UINT64_C(-1)) {
        g_string_append_printf(name, " | %" PRIu64, ds_file_group->stream_id);
    } else {
        BT_ASSERT(ds_file_group->ds_file_infos.size() == 1);
        const auto& ds_file_info = *ds_file_group->ds_file_infos[0];
        g_string_append_printf(name, " | %s", ds_file_info.path.c_str());
    }

    return bt2c::GCharUP {g_string_free(name, FALSE)};
}

static int create_one_port_for_trace(struct ctf_fs_component *ctf_fs,
                                     struct ctf_fs_ds_file_group *ds_file_group,
                                     bt_self_component_source *self_comp_src)
{
    int ret = 0;
    ctf_fs_port_data::UP port_data;

    bt2c::GCharUP port_name = ctf_fs_make_port_name(ds_file_group);
    if (!port_name) {
        goto error;
    }

    BT_CPPLOGI_SPEC(ctf_fs->logger, "Creating one port named `{}`", port_name.get());

    /* Create output port for this file */
    port_data = bt2s::make_unique<ctf_fs_port_data>();
    port_data->ctf_fs = ctf_fs;
    port_data->ds_file_group = ds_file_group;
    ret = bt_self_component_source_add_output_port(self_comp_src, port_name.get(), port_data.get(),
                                                   NULL);
    if (ret) {
        goto error;
    }

    ctf_fs->port_data.emplace_back(std::move(port_data));
    goto end;

error:
    ret = -1;

end:
    return ret;
}

static int create_ports_for_trace(struct ctf_fs_component *ctf_fs,
                                  struct ctf_fs_trace *ctf_fs_trace,
                                  bt_self_component_source *self_comp_src)
{
    int ret = 0;

    /* Create one output port for each stream file group */
    for (const auto& ds_file_group : ctf_fs_trace->ds_file_groups) {
        ret = create_one_port_for_trace(ctf_fs, ds_file_group.get(), self_comp_src);
        if (ret) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs->logger, "Cannot create output port.");
            goto end;
        }
    }

end:
    return ret;
}

/*
 * Insert ds_file_info in ds_file_group's list of ds_file_infos at the right
 * place to keep it sorted.
 */

static void ds_file_group_insert_ds_file_info_sorted(struct ctf_fs_ds_file_group *ds_file_group,
                                                     ctf_fs_ds_file_info::UP ds_file_info)
{
    /* Find the spot where to insert this ds_file_info. */
    auto it = ds_file_group->ds_file_infos.begin();

    for (; it != ds_file_group->ds_file_infos.end(); ++it) {
        const ctf_fs_ds_file_info& other_ds_file_info = **it;

        if (ds_file_info->begin_ns < other_ds_file_info.begin_ns) {
            break;
        }
    }

    ds_file_group->ds_file_infos.insert(it, std::move(ds_file_info));
}

static bool ds_index_entries_equal(const struct ctf_fs_ds_index_entry *left,
                                   const struct ctf_fs_ds_index_entry *right)
{
    if (left->packetSize != right->packetSize) {
        return false;
    }

    if (left->timestamp_begin != right->timestamp_begin) {
        return false;
    }

    if (left->timestamp_end != right->timestamp_end) {
        return false;
    }

    if (left->packet_seq_num != right->packet_seq_num) {
        return false;
    }

    return true;
}

/*
 * Insert `entry` into `index`, without duplication.
 *
 * The entry is inserted only if there isn't an identical entry already.
 *
 * In any case, the ownership of `entry` is transferred to this function.  So if
 * the entry is not inserted, it is freed.
 */

static void ds_index_insert_ds_index_entry_sorted(struct ctf_fs_ds_index *index,
                                                  ctf_fs_ds_index_entry::UP entry)
{
    /* Find the spot where to insert this index entry. */
    auto otherEntry = index->entries.begin();
    for (; otherEntry != index->entries.end(); ++otherEntry) {
        if (entry->timestamp_begin_ns <= (*otherEntry)->timestamp_begin_ns) {
            break;
        }
    }

    /*
     * Insert the entry only if a duplicate doesn't already exist.
     *
     * There can be duplicate packets if reading multiple overlapping
     * snapshots of the same trace.  We then want the index to contain
     * a reference to only one copy of that packet.
     */
    if (otherEntry == index->entries.end() ||
        !ds_index_entries_equal(entry.get(), otherEntry->get())) {
        index->entries.insert(otherEntry, std::move(entry));
    }
}

static void merge_ctf_fs_ds_indexes(struct ctf_fs_ds_index *dest, ctf_fs_ds_index::UP src)
{
    for (auto& entry : src->entries) {
        ds_index_insert_ds_index_entry_sorted(dest, std::move(entry));
    }
}

static int add_ds_file_to_ds_file_group(struct ctf_fs_trace *ctf_fs_trace, const char *path)
{
    int64_t stream_instance_id = -1;
    int64_t begin_ns = -1;
    struct ctf_fs_ds_file_group *ds_file_group = NULL;
    ctf_fs_ds_file_group::UP new_ds_file_group;
    int ret;
    ctf_fs_ds_file_info::UP ds_file_info;
    ctf_fs_ds_index::UP index;
    struct ctf_msg_iter *msg_iter = NULL;
    struct ctf_stream_class *sc = NULL;
    struct ctf_msg_iter_packet_properties props;

    /*
     * Create a temporary ds_file to read some properties about the data
     * stream file.
     */
    const auto ds_file =
        ctf_fs_ds_file_create(ctf_fs_trace, bt2::Stream::Shared {}, path, ctf_fs_trace->logger);
    if (!ds_file) {
        goto error;
    }

    /* Create a temporary iterator to read the ds_file. */
    msg_iter = ctf_msg_iter_create(
                   ctf_fs_trace->metadata->tc,
                   bt_common_get_page_size(static_cast<int>(ctf_fs_trace->logger.level())) * 8,
                   ctf_fs_ds_file_medops, ds_file.get(), nullptr, ctf_fs_trace->logger)
                   .release();
    if (!msg_iter) {
        BT_CPPLOGE_STR_SPEC(ctf_fs_trace->logger, "Cannot create a CTF message iterator.");
        goto error;
    }

    ctf_msg_iter_set_dry_run(msg_iter, true);

    ret = ctf_msg_iter_get_packet_properties(msg_iter, &props);
    if (ret) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(
            ctf_fs_trace->logger,
            "Cannot get stream file's first packet's header and context fields (`{}`).", path);
        goto error;
    }

    sc = ctf_trace_class_borrow_stream_class_by_id(ds_file->metadata->tc, props.stream_class_id);
    BT_ASSERT(sc);
    stream_instance_id = props.data_stream_id;

    if (props.snapshots.beginning_clock != UINT64_C(-1)) {
        BT_ASSERT(sc->default_clock_class);
        ret = bt_util_clock_cycles_to_ns_from_origin(
            props.snapshots.beginning_clock, sc->default_clock_class->frequency,
            sc->default_clock_class->offset_seconds, sc->default_clock_class->offset_cycles,
            &begin_ns);
        if (ret) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(
                ctf_fs_trace->logger,
                "Cannot convert clock cycles to nanoseconds from origin (`{}`).", path);
            goto error;
        }
    }

    ds_file_info = ctf_fs_ds_file_info_create(path, begin_ns);
    if (!ds_file_info) {
        goto error;
    }

    index = ctf_fs_ds_file_build_index(ds_file.get(), ds_file_info.get(), msg_iter);
    if (!index) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs_trace->logger, "Failed to index CTF stream file \'{}\'",
                                     ds_file->file->path);
        goto error;
    }

    if (begin_ns == -1) {
        /*
         * No beginning timestamp to sort the stream files
         * within a stream file group, so consider that this
         * file must be the only one within its group.
         */
        stream_instance_id = -1;
    }

    if (stream_instance_id == -1) {
        /*
         * No stream instance ID or no beginning timestamp:
         * create a unique stream file group for this stream
         * file because, even if there's a stream instance ID,
         * there's no timestamp to order the file within its
         * group.
         */
        new_ds_file_group =
            ctf_fs_ds_file_group_create(ctf_fs_trace, sc, UINT64_C(-1), std::move(index));

        if (!new_ds_file_group) {
            goto error;
        }

        ds_file_group_insert_ds_file_info_sorted(new_ds_file_group.get(), std::move(ds_file_info));
        ctf_fs_trace->ds_file_groups.emplace_back(std::move(new_ds_file_group));
        goto end;
    }

    BT_ASSERT(stream_instance_id != -1);
    BT_ASSERT(begin_ns != -1);

    /* Find an existing stream file group with this ID */
    for (const auto& candidate : ctf_fs_trace->ds_file_groups) {
        if (candidate->sc == sc && candidate->stream_id == stream_instance_id) {
            ds_file_group = candidate.get();
            break;
        }
    }

    if (!ds_file_group) {
        new_ds_file_group =
            ctf_fs_ds_file_group_create(ctf_fs_trace, sc, stream_instance_id, std::move(index));
        if (!new_ds_file_group) {
            goto error;
        }

        ds_file_group = new_ds_file_group.get();
        ctf_fs_trace->ds_file_groups.emplace_back(std::move(new_ds_file_group));
    } else {
        merge_ctf_fs_ds_indexes(ds_file_group->index.get(), std::move(index));
    }

    ds_file_group_insert_ds_file_info_sorted(ds_file_group, std::move(ds_file_info));

    goto end;

error:
    ret = -1;

end:
    if (msg_iter) {
        ctf_msg_iter_destroy(msg_iter);
    }

    return ret;
}

static int create_ds_file_groups(struct ctf_fs_trace *ctf_fs_trace)
{
    int ret = 0;
    const char *basename;
    GError *error = NULL;
    GDir *dir = NULL;

    /* Check each file in the path directory, except specific ones */
    dir = g_dir_open(ctf_fs_trace->path->str, 0, &error);
    if (!dir) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs_trace->logger,
                                     "Cannot open directory `{}`: {} (code {})",
                                     ctf_fs_trace->path->str, error->message, error->code);
        goto error;
    }

    while ((basename = g_dir_read_name(dir))) {
        if (strcmp(basename, CTF_FS_METADATA_FILENAME) == 0) {
            /* Ignore the metadata stream. */
            BT_CPPLOGI_SPEC(ctf_fs_trace->logger,
                            "Ignoring metadata file `{}" G_DIR_SEPARATOR_S "{}`",
                            ctf_fs_trace->path->str, basename);
            continue;
        }

        if (basename[0] == '.') {
            BT_CPPLOGI_SPEC(ctf_fs_trace->logger,
                            "Ignoring hidden file `{}" G_DIR_SEPARATOR_S "{}`",
                            ctf_fs_trace->path->str, basename);
            continue;
        }

        /* Create the file. */
        const auto file = ctf_fs_file_create(ctf_fs_trace->logger);
        if (!file) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(
                ctf_fs_trace->logger,
                "Cannot create stream file object for file `{}" G_DIR_SEPARATOR_S "{}`",
                ctf_fs_trace->path->str, basename);
            goto error;
        }

        /* Create full path string. */
        file->path = fmt::format("{}" G_DIR_SEPARATOR_S "{}", ctf_fs_trace->path->str, basename);

        if (!g_file_test(file->path.c_str(), G_FILE_TEST_IS_REGULAR)) {
            BT_CPPLOGI_SPEC(ctf_fs_trace->logger, "Ignoring non-regular file `{}`", file->path);
            continue;
        }

        ret = ctf_fs_file_open(file.get(), "rb");
        if (ret) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs_trace->logger, "Cannot open stream file `{}`",
                                         file->path);
            goto error;
        }

        if (file->size == 0) {
            /* Skip empty stream. */
            BT_CPPLOGI_SPEC(ctf_fs_trace->logger, "Ignoring empty file `{}`", file->path);
            continue;
        }

        ret = add_ds_file_to_ds_file_group(ctf_fs_trace, file->path.c_str());
        if (ret) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs_trace->logger,
                                         "Cannot add stream file `{}` to stream file group",
                                         file->path);
            goto error;
        }
    }

    goto end;

error:
    ret = -1;

end:
    if (dir) {
        g_dir_close(dir);
        dir = NULL;
    }

    if (error) {
        g_error_free(error);
    }

    return ret;
}

static int set_trace_name(bt_trace *trace, const char *name_suffix, const bt2c::Logger& logger)
{
    int ret = 0;
    const bt_value *val;
    GString *name;

    name = g_string_new(NULL);
    if (!name) {
        BT_CPPLOGE_STR_SPEC(logger, "Failed to allocate a GString.");
        ret = -1;
        goto end;
    }

    /*
     * Check if we have a trace environment string value named `hostname`.
     * If so, use it as the trace name's prefix.
     */
    val = bt_trace_borrow_environment_entry_value_by_name_const(trace, "hostname");
    if (val && bt_value_is_string(val)) {
        g_string_append(name, bt_value_string_get(val));

        if (name_suffix) {
            g_string_append_c(name, G_DIR_SEPARATOR);
        }
    }

    if (name_suffix) {
        g_string_append(name, name_suffix);
    }

    ret = bt_trace_set_name(trace, name->str);
    if (ret) {
        goto end;
    }

    goto end;

end:
    if (name) {
        g_string_free(name, TRUE);
    }

    return ret;
}

static ctf_fs_trace::UP ctf_fs_trace_create(const char *path, const char *name,
                                            const ctf::src::ClkClsCfg& clkClsCfg,
                                            bt_self_component *selfComp,
                                            const bt2c::Logger& parentLogger)
{
    int ret;

    ctf_fs_trace::UP ctf_fs_trace {new struct ctf_fs_trace(parentLogger)};
    ctf_fs_trace->path = g_string_new(path);
    if (!ctf_fs_trace->path) {
        goto error;
    }

    ctf_fs_trace->metadata = new ctf_fs_metadata;
    ctf_fs_metadata_init(ctf_fs_trace->metadata);

    ret = ctf_fs_metadata_set_trace_class(selfComp, ctf_fs_trace.get(), clkClsCfg);
    if (ret) {
        goto error;
    }

    if (ctf_fs_trace->metadata->trace_class) {
        ctf_fs_trace->trace = bt_trace_create(ctf_fs_trace->metadata->trace_class);
        if (!ctf_fs_trace->trace) {
            goto error;
        }
    }

    if (ctf_fs_trace->trace) {
        ret = ctf_trace_class_configure_ir_trace(ctf_fs_trace->metadata->tc, ctf_fs_trace->trace);
        if (ret) {
            goto error;
        }

        ret = set_trace_name(ctf_fs_trace->trace, name, ctf_fs_trace->logger);
        if (ret) {
            goto error;
        }
    }

    ret = create_ds_file_groups(ctf_fs_trace.get());
    if (ret) {
        goto error;
    }

    goto end;

error:
    ctf_fs_trace.reset();

end:
    return ctf_fs_trace;
}

static int path_is_ctf_trace(const char *path)
{
    GString *metadata_path = g_string_new(NULL);
    int ret = 0;

    if (!metadata_path) {
        ret = -1;
        goto end;
    }

    g_string_printf(metadata_path, "%s" G_DIR_SEPARATOR_S "%s", path, CTF_FS_METADATA_FILENAME);

    if (g_file_test(metadata_path->str, G_FILE_TEST_IS_REGULAR)) {
        ret = 1;
        goto end;
    }

end:
    g_string_free(metadata_path, TRUE);
    return ret;
}

/* Helper for ctf_fs_component_create_ctf_fs_trace, to handle a single path. */

static int ctf_fs_component_create_ctf_fs_trace_one_path(struct ctf_fs_component *ctf_fs,
                                                         const char *path_param,
                                                         const char *trace_name,
                                                         std::vector<ctf_fs_trace::UP>& traces,
                                                         bt_self_component *selfComp)
{
    ctf_fs_trace::UP ctf_fs_trace;
    int ret;
    GString *norm_path;

    norm_path = bt_common_normalize_path(path_param, NULL);
    if (!norm_path) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs->logger, "Failed to normalize path: `{}`.", path_param);
        goto error;
    }

    ret = path_is_ctf_trace(norm_path->str);
    if (ret < 0) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(
            ctf_fs->logger, "Failed to check if path is a CTF trace: path={}", norm_path->str);
        goto error;
    } else if (ret == 0) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(
            ctf_fs->logger, "Path is not a CTF trace (does not contain a metadata file): `{}`.",
            norm_path->str);
        goto error;
    }

    // FIXME: Remove or ifdef for __MINGW32__
    if (strcmp(norm_path->str, "/") == 0) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs->logger, "Opening a trace in `/` is not supported.");
        ret = -1;
        goto end;
    }

    ctf_fs_trace = ctf_fs_trace_create(norm_path->str, trace_name, ctf_fs->clkClsCfg, selfComp,
                                       ctf_fs->logger);
    if (!ctf_fs_trace) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs->logger, "Cannot create trace for `{}`.",
                                     norm_path->str);
        goto error;
    }

    traces.emplace_back(std::move(ctf_fs_trace));

    ret = 0;
    goto end;

error:
    ret = -1;

end:
    if (norm_path) {
        g_string_free(norm_path, TRUE);
    }

    return ret;
}

/*
 * Count the number of stream and event classes defined by this trace's metadata.
 *
 * This is used to determine which metadata is the "latest", out of multiple
 * traces sharing the same UUID.  It is assumed that amongst all these metadatas,
 * a bigger metadata is a superset of a smaller metadata.  Therefore, it is
 * enough to just count the classes.
 */

static unsigned int metadata_count_stream_and_event_classes(struct ctf_fs_trace *trace)
{
    unsigned int num = trace->metadata->tc->stream_classes->len;
    guint i;

    for (i = 0; i < trace->metadata->tc->stream_classes->len; i++) {
        struct ctf_stream_class *sc =
            (struct ctf_stream_class *) trace->metadata->tc->stream_classes->pdata[i];
        num += sc->event_classes->len;
    }

    return num;
}

/*
 * Merge the src ds_file_group into dest.  This consists of merging their
 * ds_file_infos, making sure to keep the result sorted.
 */

static void merge_ctf_fs_ds_file_groups(struct ctf_fs_ds_file_group *dest,
                                        ctf_fs_ds_file_group::UP src)
{
    for (auto& ds_file_info : src->ds_file_infos) {
        ds_file_group_insert_ds_file_info_sorted(dest, std::move(ds_file_info));
    }

    /* Merge both indexes. */
    merge_ctf_fs_ds_indexes(dest->index.get(), std::move(src->index));
}

/* Merge src_trace's data stream file groups into dest_trace's. */

static int merge_matching_ctf_fs_ds_file_groups(struct ctf_fs_trace *dest_trace,
                                                ctf_fs_trace::UP src_trace)
{
    std::vector<ctf_fs_ds_file_group::UP>& dest = dest_trace->ds_file_groups;
    std::vector<ctf_fs_ds_file_group::UP>& src = src_trace->ds_file_groups;
    int ret = 0;

    /*
     * Save the initial length of dest: we only want to check against the
     * original elements in the inner loop.
     */
    size_t dest_len = dest.size();

    for (auto& src_group : src) {
        struct ctf_fs_ds_file_group *dest_group = NULL;

        /* A stream instance without ID can't match a stream in the other trace.  */
        if (src_group->stream_id != -1) {
            /* Let's search for a matching ds_file_group in the destination.  */
            for (size_t d_i = 0; d_i < dest_len; ++d_i) {
                ctf_fs_ds_file_group *candidate_dest = dest[d_i].get();

                /* Can't match a stream instance without ID.  */
                if (candidate_dest->stream_id == -1) {
                    continue;
                }

                /*
                 * If the two groups have the same stream instance id
                 * and belong to the same stream class (stream instance
                 * ids are per-stream class), they represent the same
                 * stream instance.
                 */
                if (candidate_dest->stream_id != src_group->stream_id ||
                    candidate_dest->sc->id != src_group->sc->id) {
                    continue;
                }

                dest_group = candidate_dest;
                break;
            }
        }

        /*
         * Didn't find a friend in dest to merge our src_group into?
         * Create a new empty one. This can happen if a stream was
         * active in the source trace chunk but not in the destination
         * trace chunk.
         */
        if (!dest_group) {
            struct ctf_stream_class *sc;

            sc = ctf_trace_class_borrow_stream_class_by_id(dest_trace->metadata->tc,
                                                           src_group->sc->id);
            BT_ASSERT(sc);

            auto index = ctf_fs_ds_index_create();
            if (!index) {
                ret = -1;
                goto end;
            }

            auto new_dest_group =
                ctf_fs_ds_file_group_create(dest_trace, sc, src_group->stream_id, std::move(index));

            if (!new_dest_group) {
                ret = -1;
                goto end;
            }

            dest_group = new_dest_group.get();
            dest_trace->ds_file_groups.emplace_back(std::move(new_dest_group));
        }

        BT_ASSERT(dest_group);
        merge_ctf_fs_ds_file_groups(dest_group, std::move(src_group));
    }

end:
    return ret;
}

/*
 * Collapse the given traces, which must all share the same UUID, in a single
 * one.
 *
 * The trace with the most expansive metadata is chosen and all other traces
 * are merged into that one.  On return, the elements of `traces` are nullptr
 * and the merged trace is placed in `out_trace`.
 */

static int merge_ctf_fs_traces(std::vector<ctf_fs_trace::UP> traces, ctf_fs_trace::UP& out_trace)
{
    unsigned int winner_count;
    struct ctf_fs_trace *winner;
    guint i, winner_i;
    int ret = 0;

    BT_ASSERT(traces.size() >= 2);

    winner_count = metadata_count_stream_and_event_classes(traces[0].get());
    winner = traces[0].get();
    winner_i = 0;

    /* Find the trace with the largest metadata. */
    for (i = 1; i < traces.size(); i++) {
        ctf_fs_trace *candidate = traces[i].get();
        unsigned int candidate_count;

        /* A bit of sanity check. */
        BT_ASSERT(bt_uuid_compare(winner->metadata->tc->uuid, candidate->metadata->tc->uuid) == 0);

        candidate_count = metadata_count_stream_and_event_classes(candidate);

        if (candidate_count > winner_count) {
            winner_count = candidate_count;
            winner = candidate;
            winner_i = i;
        }
    }

    /* Merge all the other traces in the winning trace. */
    for (ctf_fs_trace::UP& trace : traces) {
        /* Don't merge the winner into itself. */
        if (trace.get() == winner) {
            continue;
        }

        /* Merge trace's data stream file groups into winner's. */
        ret = merge_matching_ctf_fs_ds_file_groups(winner, std::move(trace));
        if (ret) {
            goto end;
        }
    }

    /*
     * Move the winner out of the array, into `*out_trace`.
     */
    out_trace = std::move(traces[winner_i]);

end:
    return ret;
}

enum target_event
{
    FIRST_EVENT,
    LAST_EVENT,
};

static int decode_clock_snapshot_after_event(struct ctf_fs_trace *ctf_fs_trace,
                                             struct ctf_clock_class *default_cc,
                                             struct ctf_fs_ds_index_entry *index_entry,
                                             enum target_event target_event, uint64_t *cs,
                                             int64_t *ts_ns)
{
    enum ctf_msg_iter_status iter_status = CTF_MSG_ITER_STATUS_OK;
    struct ctf_msg_iter *msg_iter = NULL;
    int ret = 0;

    BT_ASSERT(ctf_fs_trace);
    BT_ASSERT(index_entry);
    BT_ASSERT(index_entry->path);

    const auto ds_file = ctf_fs_ds_file_create(ctf_fs_trace, bt2::Stream::Shared {},
                                               index_entry->path, ctf_fs_trace->logger);
    if (!ds_file) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs_trace->logger, "Failed to create a ctf_fs_ds_file");
        ret = -1;
        goto end;
    }

    BT_ASSERT(ctf_fs_trace->metadata);
    BT_ASSERT(ctf_fs_trace->metadata->tc);

    msg_iter = ctf_msg_iter_create(
                   ctf_fs_trace->metadata->tc,
                   bt_common_get_page_size(static_cast<int>(ctf_fs_trace->logger.level())) * 8,
                   ctf_fs_ds_file_medops, ds_file.get(), NULL, ctf_fs_trace->logger)
                   .release();
    if (!msg_iter) {
        /* ctf_msg_iter_create() logs errors. */
        ret = -1;
        goto end;
    }

    /*
     * Turn on dry run mode to prevent the creation and usage of Babeltrace
     * library objects (bt_field, bt_message_*, etc.).
     */
    ctf_msg_iter_set_dry_run(msg_iter, true);

    /* Seek to the beginning of the target packet. */
    iter_status = ctf_msg_iter_seek(msg_iter, index_entry->offset.bytes());
    if (iter_status) {
        /* ctf_msg_iter_seek() logs errors. */
        ret = -1;
        goto end;
    }

    switch (target_event) {
    case FIRST_EVENT:
        /*
         * Start to decode the packet until we reach the end of
         * the first event. To extract the first event's clock
         * snapshot.
         */
        iter_status = ctf_msg_iter_curr_packet_first_event_clock_snapshot(msg_iter, cs);
        break;
    case LAST_EVENT:
        /* Decode the packet to extract the last event's clock snapshot. */
        iter_status = ctf_msg_iter_curr_packet_last_event_clock_snapshot(msg_iter, cs);
        break;
    default:
        bt_common_abort();
    }
    if (iter_status) {
        ret = -1;
        goto end;
    }

    /* Convert clock snapshot to timestamp. */
    ret = bt_util_clock_cycles_to_ns_from_origin(
        *cs, default_cc->frequency, default_cc->offset_seconds, default_cc->offset_cycles, ts_ns);
    if (ret) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs_trace->logger,
                                     "Failed to convert clock snapshot to timestamp");
        goto end;
    }

end:
    if (msg_iter) {
        ctf_msg_iter_destroy(msg_iter);
    }

    return ret;
}

static int decode_packet_first_event_timestamp(struct ctf_fs_trace *ctf_fs_trace,
                                               struct ctf_clock_class *default_cc,
                                               struct ctf_fs_ds_index_entry *index_entry,
                                               uint64_t *cs, int64_t *ts_ns)
{
    return decode_clock_snapshot_after_event(ctf_fs_trace, default_cc, index_entry, FIRST_EVENT, cs,
                                             ts_ns);
}

static int decode_packet_last_event_timestamp(struct ctf_fs_trace *ctf_fs_trace,
                                              struct ctf_clock_class *default_cc,
                                              struct ctf_fs_ds_index_entry *index_entry,
                                              uint64_t *cs, int64_t *ts_ns)
{
    return decode_clock_snapshot_after_event(ctf_fs_trace, default_cc, index_entry, LAST_EVENT, cs,
                                             ts_ns);
}

/*
 * Fix up packet index entries for lttng's "event-after-packet" bug.
 * Some buggy lttng tracer versions may emit events with a timestamp that is
 * larger (after) than the timestamp_end of the their packets.
 *
 * To fix up this erroneous data we do the following:
 *  1. If it's not the stream file's last packet: set the packet index entry's
 *	end time to the next packet's beginning time.
 *  2. If it's the stream file's last packet, set the packet index entry's end
 *	time to the packet's last event's time, if any, or to the packet's
 *  	beginning time otherwise.
 *
 * Known buggy tracer versions:
 *  - before lttng-ust 2.11.0
 *  - before lttng-module 2.11.0
 *  - before lttng-module 2.10.10
 *  - before lttng-module 2.9.13
 */
static int fix_index_lttng_event_after_packet_bug(struct ctf_fs_trace *trace)
{
    int ret = 0;

    for (const auto& ds_file_group : trace->ds_file_groups) {
        struct ctf_clock_class *default_cc;

        BT_ASSERT(ds_file_group);
        const auto index = ds_file_group->index.get();

        BT_ASSERT(index);
        BT_ASSERT(!index->entries.empty());

        /*
         * Iterate over all entries but the last one. The last one is
         * fixed differently after.
         */
        for (size_t entry_i = 0; entry_i < index->entries.size() - 1; ++entry_i) {
            ctf_fs_ds_index_entry *curr_entry = index->entries[entry_i].get();
            ctf_fs_ds_index_entry *next_entry = index->entries[entry_i + 1].get();

            /*
             * 1. Set the current index entry `end` timestamp to
             * the next index entry `begin` timestamp.
             */
            curr_entry->timestamp_end = next_entry->timestamp_begin;
            curr_entry->timestamp_end_ns = next_entry->timestamp_begin_ns;
        }

        /*
         * 2. Fix the last entry by decoding the last event of the last
         * packet.
         */
        const auto last_entry = index->entries.back().get();
        BT_ASSERT(last_entry);

        BT_ASSERT(ds_file_group->sc->default_clock_class);
        default_cc = ds_file_group->sc->default_clock_class;

        /*
         * Decode packet to read the timestamp of the last event of the
         * entry.
         */
        ret = decode_packet_last_event_timestamp(trace, default_cc, last_entry,
                                                 &last_entry->timestamp_end,
                                                 &last_entry->timestamp_end_ns);
        if (ret) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(
                trace->logger,
                "Failed to decode stream's last packet to get its last event's clock snapshot.");
            goto end;
        }
    }

end:
    return ret;
}

/*
 * Fix up packet index entries for barectf's "event-before-packet" bug.
 * Some buggy barectf tracer versions may emit events with a timestamp that is
 * less than the timestamp_begin of the their packets.
 *
 * To fix up this erroneous data we do the following:
 *  1. Starting at the second index entry, set the timestamp_begin of the
 *     current entry to the timestamp of the first event of the packet.
 *  2. Set the previous entry's timestamp_end to the timestamp_begin of the
 *     current packet.
 *
 * Known buggy tracer versions:
 *  - before barectf 2.3.1
 */
static int fix_index_barectf_event_before_packet_bug(struct ctf_fs_trace *trace)
{
    int ret = 0;

    for (const auto& ds_file_group : trace->ds_file_groups) {
        struct ctf_clock_class *default_cc;
        const auto index = ds_file_group->index.get();

        BT_ASSERT(index);
        BT_ASSERT(!index->entries.empty());

        BT_ASSERT(ds_file_group->sc->default_clock_class);
        default_cc = ds_file_group->sc->default_clock_class;

        /*
         * 1. Iterate over the index, starting from the second entry
         * (index = 1).
         */
        for (size_t entry_i = 1; entry_i < index->entries.size(); ++entry_i) {
            ctf_fs_ds_index_entry *prev_entry = index->entries[entry_i - 1].get();
            ctf_fs_ds_index_entry *curr_entry = index->entries[entry_i].get();
            /*
             * 2. Set the current entry `begin` timestamp to the
             * timestamp of the first event of the current packet.
             */
            ret = decode_packet_first_event_timestamp(trace, default_cc, curr_entry,
                                                      &curr_entry->timestamp_begin,
                                                      &curr_entry->timestamp_begin_ns);
            if (ret) {
                BT_CPPLOGE_APPEND_CAUSE_SPEC(trace->logger,
                                             "Failed to decode first event's clock snapshot");
                goto end;
            }

            /*
             * 3. Set the previous entry `end` timestamp to the
             * timestamp of the first event of the current packet.
             */
            prev_entry->timestamp_end = curr_entry->timestamp_begin;
            prev_entry->timestamp_end_ns = curr_entry->timestamp_begin_ns;
        }
    }
end:
    return ret;
}

/*
 * When using the lttng-crash feature it's likely that the last packets of each
 * stream have their timestamp_end set to zero. This is caused by the fact that
 * the tracer crashed and was not able to properly close the packets.
 *
 * To fix up this erroneous data we do the following:
 * For each index entry, if the entry's timestamp_end is 0 and the
 * timestamp_begin is not 0:
 *  - If it's the stream file's last packet: set the packet index entry's end
 *    time to the packet's last event's time, if any, or to the packet's
 *    beginning time otherwise.
 *  - If it's not the stream file's last packet: set the packet index
 *    entry's end time to the next packet's beginning time.
 *
 * Affected versions:
 * - All current and future lttng-ust and lttng-modules versions.
 */
static int fix_index_lttng_crash_quirk(struct ctf_fs_trace *trace)
{
    int ret = 0;

    for (const auto& ds_file_group : trace->ds_file_groups) {
        struct ctf_clock_class *default_cc;

        BT_ASSERT(ds_file_group);
        const auto index = ds_file_group->index.get();

        BT_ASSERT(ds_file_group->sc->default_clock_class);
        default_cc = ds_file_group->sc->default_clock_class;

        BT_ASSERT(index);
        BT_ASSERT(!index->entries.empty());

        const auto last_entry = index->entries.back().get();
        BT_ASSERT(last_entry);

        /* 1. Fix the last entry first. */
        if (last_entry->timestamp_end == 0 && last_entry->timestamp_begin != 0) {
            /*
             * Decode packet to read the timestamp of the
             * last event of the stream file.
             */
            ret = decode_packet_last_event_timestamp(trace, default_cc, last_entry,
                                                     &last_entry->timestamp_end,
                                                     &last_entry->timestamp_end_ns);
            if (ret) {
                BT_CPPLOGE_APPEND_CAUSE_SPEC(trace->logger,
                                             "Failed to decode last event's clock snapshot");
                goto end;
            }
        }

        /* Iterate over all entries but the last one. */
        for (size_t entry_idx = 0; entry_idx < index->entries.size() - 1; ++entry_idx) {
            ctf_fs_ds_index_entry *curr_entry = index->entries[entry_idx].get();
            ctf_fs_ds_index_entry *next_entry = index->entries[entry_idx + 1].get();

            if (curr_entry->timestamp_end == 0 && curr_entry->timestamp_begin != 0) {
                /*
                 * 2. Set the current index entry `end` timestamp to
                 * the next index entry `begin` timestamp.
                 */
                curr_entry->timestamp_end = next_entry->timestamp_begin;
                curr_entry->timestamp_end_ns = next_entry->timestamp_begin_ns;
            }
        }
    }

end:
    return ret;
}

/*
 * Extract the tracer information necessary to compare versions.
 * Returns 0 on success, and -1 if the extraction is not successful because the
 * necessary fields are absents in the trace metadata.
 */
static int extract_tracer_info(struct ctf_fs_trace *trace, struct tracer_info *current_tracer_info)
{
    int ret = 0;
    struct ctf_trace_class_env_entry *entry;

    /* Clear the current_tracer_info struct */
    memset(current_tracer_info, 0, sizeof(*current_tracer_info));

    /*
     * To compare 2 tracer versions, at least the tracer name and it's
     * major version are needed. If one of these is missing, consider it an
     * extraction failure.
     */
    entry = ctf_trace_class_borrow_env_entry_by_name(trace->metadata->tc, "tracer_name");
    if (!entry || entry->type != CTF_TRACE_CLASS_ENV_ENTRY_TYPE_STR) {
        goto missing_bare_minimum;
    }

    /* Set tracer name. */
    current_tracer_info->name = entry->value.str->str;

    entry = ctf_trace_class_borrow_env_entry_by_name(trace->metadata->tc, "tracer_major");
    if (!entry || entry->type != CTF_TRACE_CLASS_ENV_ENTRY_TYPE_INT) {
        goto missing_bare_minimum;
    }

    /* Set major version number. */
    current_tracer_info->major = entry->value.i;

    entry = ctf_trace_class_borrow_env_entry_by_name(trace->metadata->tc, "tracer_minor");
    if (!entry || entry->type != CTF_TRACE_CLASS_ENV_ENTRY_TYPE_INT) {
        goto end;
    }

    /* Set minor version number. */
    current_tracer_info->minor = entry->value.i;

    entry = ctf_trace_class_borrow_env_entry_by_name(trace->metadata->tc, "tracer_patch");
    if (!entry) {
        /*
         * If `tracer_patch` doesn't exist `tracer_patchlevel` might.
         * For example, `lttng-modules` uses entry name
         * `tracer_patchlevel`.
         */
        entry = ctf_trace_class_borrow_env_entry_by_name(trace->metadata->tc, "tracer_patchlevel");
    }

    if (!entry || entry->type != CTF_TRACE_CLASS_ENV_ENTRY_TYPE_INT) {
        goto end;
    }

    /* Set patch version number. */
    current_tracer_info->patch = entry->value.i;

    goto end;

missing_bare_minimum:
    ret = -1;
end:
    return ret;
}

static bool is_tracer_affected_by_lttng_event_after_packet_bug(struct tracer_info *curr_tracer_info)
{
    bool is_affected = false;

    if (strcmp(curr_tracer_info->name, "lttng-ust") == 0) {
        if (curr_tracer_info->major < 2) {
            is_affected = true;
        } else if (curr_tracer_info->major == 2) {
            /* fixed in lttng-ust 2.11.0 */
            if (curr_tracer_info->minor < 11) {
                is_affected = true;
            }
        }
    } else if (strcmp(curr_tracer_info->name, "lttng-modules") == 0) {
        if (curr_tracer_info->major < 2) {
            is_affected = true;
        } else if (curr_tracer_info->major == 2) {
            /* fixed in lttng-modules 2.11.0 */
            if (curr_tracer_info->minor == 10) {
                /* fixed in lttng-modules 2.10.10 */
                if (curr_tracer_info->patch < 10) {
                    is_affected = true;
                }
            } else if (curr_tracer_info->minor == 9) {
                /* fixed in lttng-modules 2.9.13 */
                if (curr_tracer_info->patch < 13) {
                    is_affected = true;
                }
            } else if (curr_tracer_info->minor < 9) {
                is_affected = true;
            }
        }
    }

    return is_affected;
}

static bool
is_tracer_affected_by_barectf_event_before_packet_bug(struct tracer_info *curr_tracer_info)
{
    bool is_affected = false;

    if (strcmp(curr_tracer_info->name, "barectf") == 0) {
        if (curr_tracer_info->major < 2) {
            is_affected = true;
        } else if (curr_tracer_info->major == 2) {
            if (curr_tracer_info->minor < 3) {
                is_affected = true;
            } else if (curr_tracer_info->minor == 3) {
                /* fixed in barectf 2.3.1 */
                if (curr_tracer_info->patch < 1) {
                    is_affected = true;
                }
            }
        }
    }

    return is_affected;
}

static bool is_tracer_affected_by_lttng_crash_quirk(struct tracer_info *curr_tracer_info)
{
    bool is_affected = false;

    /* All LTTng tracer may be affected by this lttng crash quirk. */
    if (strcmp(curr_tracer_info->name, "lttng-ust") == 0) {
        is_affected = true;
    } else if (strcmp(curr_tracer_info->name, "lttng-modules") == 0) {
        is_affected = true;
    }

    return is_affected;
}

/*
 * Looks for trace produced by known buggy tracers and fix up the index
 * produced earlier.
 */
static int fix_packet_index_tracer_bugs(ctf_fs_trace *trace)
{
    int ret = 0;
    struct tracer_info current_tracer_info;

    ret = extract_tracer_info(trace, &current_tracer_info);
    if (ret) {
        /*
         * A trace may not have all the necessary environment
         * entries to do the tracer version comparison.
         * At least, the tracer name and major version number
         * are needed. Failing to extract these entries is not
         * an error.
         */
        ret = 0;
        BT_CPPLOGI_STR_SPEC(
            trace->logger,
            "Cannot extract tracer information necessary to compare with buggy versions.");
        goto end;
    }

    /* Check if the trace may be affected by old tracer bugs. */
    if (is_tracer_affected_by_lttng_event_after_packet_bug(&current_tracer_info)) {
        BT_CPPLOGI_STR_SPEC(
            trace->logger,
            "Trace may be affected by LTTng tracer packet timestamp bug. Fixing up.");
        ret = fix_index_lttng_event_after_packet_bug(trace);
        if (ret) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(trace->logger,
                                         "Failed to fix LTTng event-after-packet bug.");
            goto end;
        }
        trace->metadata->tc->quirks.lttng_event_after_packet = true;
    }

    if (is_tracer_affected_by_barectf_event_before_packet_bug(&current_tracer_info)) {
        BT_CPPLOGI_STR_SPEC(
            trace->logger,
            "Trace may be affected by barectf tracer packet timestamp bug. Fixing up.");
        ret = fix_index_barectf_event_before_packet_bug(trace);
        if (ret) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(trace->logger,
                                         "Failed to fix barectf event-before-packet bug.");
            goto end;
        }
        trace->metadata->tc->quirks.barectf_event_before_packet = true;
    }

    if (is_tracer_affected_by_lttng_crash_quirk(&current_tracer_info)) {
        ret = fix_index_lttng_crash_quirk(trace);
        if (ret) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(trace->logger,
                                         "Failed to fix lttng-crash timestamp quirks.");
            goto end;
        }
        trace->metadata->tc->quirks.lttng_crash = true;
    }

end:
    return ret;
}

static bool compare_ds_file_groups_by_first_path(const ctf_fs_ds_file_group::UP& ds_file_group_a,
                                                 const ctf_fs_ds_file_group::UP& ds_file_group_b)
{
    BT_ASSERT(!ds_file_group_a->ds_file_infos.empty());
    BT_ASSERT(!ds_file_group_b->ds_file_infos.empty());

    const auto& first_ds_file_info_a = *ds_file_group_a->ds_file_infos[0];
    const auto& first_ds_file_info_b = *ds_file_group_b->ds_file_infos[0];

    return first_ds_file_info_a.path < first_ds_file_info_b.path;
}

static gint compare_strings(gconstpointer p_a, gconstpointer p_b)
{
    const char *a = *((const char **) p_a);
    const char *b = *((const char **) p_b);

    return strcmp(a, b);
}

int ctf_fs_component_create_ctf_fs_trace(struct ctf_fs_component *ctf_fs,
                                         const bt_value *paths_value,
                                         const bt_value *trace_name_value,
                                         bt_self_component *selfComp)
{
    int ret = 0;
    uint64_t i;
    GPtrArray *paths = NULL;
    std::vector<ctf_fs_trace::UP> traces;
    const char *trace_name;

    BT_ASSERT(bt_value_get_type(paths_value) == BT_VALUE_TYPE_ARRAY);
    BT_ASSERT(!bt_value_array_is_empty(paths_value));

    paths = g_ptr_array_new_with_free_func(g_free);
    if (!paths) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs->logger, "Failed to allocate a GPtrArray.");
        goto error;
    }

    trace_name = trace_name_value ? bt_value_string_get(trace_name_value) : NULL;

    /*
     * Create a sorted array of the paths, to make the execution of this
     * component deterministic.
     */
    for (i = 0; i < bt_value_array_get_length(paths_value); i++) {
        const bt_value *path_value = bt_value_array_borrow_element_by_index_const(paths_value, i);
        const char *input = bt_value_string_get(path_value);
        gchar *input_copy;

        input_copy = g_strdup(input);
        if (!input_copy) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs->logger, "Failed to copy a string.");
            goto error;
        }

        g_ptr_array_add(paths, input_copy);
    }

    g_ptr_array_sort(paths, compare_strings);

    /* Create a separate ctf_fs_trace object for each path. */
    for (i = 0; i < paths->len; i++) {
        const char *path = (const char *) g_ptr_array_index(paths, i);

        ret = ctf_fs_component_create_ctf_fs_trace_one_path(ctf_fs, path, trace_name, traces,
                                                            selfComp);
        if (ret) {
            goto end;
        }
    }

    if (traces.size() > 1) {
        ctf_fs_trace *first_trace = traces[0].get();
        const uint8_t *first_trace_uuid = first_trace->metadata->tc->uuid;

        /*
         * We have more than one trace, they must all share the same
         * UUID, verify that.
         */
        for (i = 0; i < traces.size(); i++) {
            ctf_fs_trace *this_trace = traces[i].get();
            const uint8_t *this_trace_uuid = this_trace->metadata->tc->uuid;

            if (!this_trace->metadata->tc->is_uuid_set) {
                BT_CPPLOGE_APPEND_CAUSE_SPEC(
                    ctf_fs->logger,
                    "Multiple traces given, but a trace does not have a UUID: path={}",
                    this_trace->path->str);
                goto error;
            }

            if (bt_uuid_compare(first_trace_uuid, this_trace_uuid) != 0) {
                char first_trace_uuid_str[BT_UUID_STR_LEN + 1];
                char this_trace_uuid_str[BT_UUID_STR_LEN + 1];

                bt_uuid_to_str(first_trace_uuid, first_trace_uuid_str);
                bt_uuid_to_str(this_trace_uuid, this_trace_uuid_str);

                BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs->logger,
                                             "Multiple traces given, but UUIDs don't match: "
                                             "first-trace-uuid={}, first-trace-path={}, "
                                             "trace-uuid={}, trace-path={}",
                                             first_trace_uuid_str, first_trace->path->str,
                                             this_trace_uuid_str, this_trace->path->str);
                goto error;
            }
        }

        ret = merge_ctf_fs_traces(std::move(traces), ctf_fs->trace);
        if (ret) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs->logger,
                                         "Failed to merge traces with the same UUID.");
            goto error;
        }
    } else {
        /* Just one trace, it may or may not have a UUID, both are fine. */
        ctf_fs->trace = std::move(traces[0]);
    }

    ret = fix_packet_index_tracer_bugs(ctf_fs->trace.get());
    if (ret) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs->logger, "Failed to fix packet index tracer bugs.");
    }

    /*
     * Sort data stream file groups by first data stream file info
     * path to get a deterministic order. This order influences the
     * order of the output ports. It also influences the order of
     * the automatic stream IDs if the trace's packet headers do not
     * contain a `stream_instance_id` field, in which case the data
     * stream file to stream ID association is always the same,
     * whatever the build and the system.
     *
     * Having a deterministic order here can help debugging and
     * testing.
     */
    std::sort(ctf_fs->trace->ds_file_groups.begin(), ctf_fs->trace->ds_file_groups.end(),
              compare_ds_file_groups_by_first_path);
    goto end;
error:
    ret = -1;

end:
    if (paths) {
        g_ptr_array_free(paths, TRUE);
    }

    return ret;
}

static GString *get_stream_instance_unique_name(struct ctf_fs_ds_file_group *ds_file_group)
{
    GString *name;
    struct ctf_fs_ds_file_info *ds_file_info;

    name = g_string_new(NULL);
    if (!name) {
        goto end;
    }

    /*
     * If there's more than one stream file in the stream file
     * group, the first (earliest) stream file's path is used as
     * the stream's unique name.
     */
    BT_ASSERT(!ds_file_group->ds_file_infos.empty());
    ds_file_info = ds_file_group->ds_file_infos[0].get();
    g_string_assign(name, ds_file_info->path.c_str());

end:
    return name;
}

/* Create the IR stream objects for ctf_fs_trace. */

static int create_streams_for_trace(struct ctf_fs_trace *ctf_fs_trace)
{
    int ret;
    GString *name = NULL;

    for (const auto& ds_file_group : ctf_fs_trace->ds_file_groups) {
        name = get_stream_instance_unique_name(ds_file_group.get());

        if (!name) {
            goto error;
        }

        BT_ASSERT(ds_file_group->sc->ir_sc);
        BT_ASSERT(ctf_fs_trace->trace);

        bt_stream *stream;

        if (ds_file_group->stream_id == UINT64_C(-1)) {
            /* No stream ID: use 0 */
            stream = bt_stream_create_with_id(ds_file_group->sc->ir_sc, ctf_fs_trace->trace,
                                              ctf_fs_trace->next_stream_id);
            ctf_fs_trace->next_stream_id++;
        } else {
            /* Specific stream ID */
            stream = bt_stream_create_with_id(ds_file_group->sc->ir_sc, ctf_fs_trace->trace,
                                              (uint64_t) ds_file_group->stream_id);
        }

        if (!stream) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs_trace->logger,
                                         "Cannot create stream for DS file group: "
                                         "addr={}, stream-name=\"{}\"",
                                         fmt::ptr(ds_file_group), name->str);
            goto error;
        }

        ds_file_group->stream = bt2::Stream::Shared::createWithoutRef(stream);

        ret = bt_stream_set_name(ds_file_group->stream->libObjPtr(), name->str);
        if (ret) {
            BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs_trace->logger,
                                         "Cannot set stream's name: "
                                         "addr={}, stream-name=\"{}\"",
                                         fmt::ptr(ds_file_group->stream->libObjPtr()), name->str);
            goto error;
        }

        g_string_free(name, TRUE);
        name = NULL;
    }

    ret = 0;
    goto end;

error:
    ret = -1;

end:

    if (name) {
        g_string_free(name, TRUE);
    }
    return ret;
}

static const bt_param_validation_value_descr inputs_elem_descr =
    bt_param_validation_value_descr::makeString();

static bt_param_validation_map_value_entry_descr fs_params_entries_descr[] = {
    {"inputs", BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_MANDATORY,
     bt_param_validation_value_descr::makeArray(1, BT_PARAM_VALIDATION_INFINITE,
                                                inputs_elem_descr)},
    {"trace-name", BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_OPTIONAL,
     bt_param_validation_value_descr::makeString()},
    {"clock-class-offset-s", BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_OPTIONAL,
     bt_param_validation_value_descr::makeSignedInteger()},
    {"clock-class-offset-ns", BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_OPTIONAL,
     bt_param_validation_value_descr::makeSignedInteger()},
    {"force-clock-class-origin-unix-epoch", BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_OPTIONAL,
     bt_param_validation_value_descr::makeBool()},
    BT_PARAM_VALIDATION_MAP_VALUE_ENTRY_END};

bool read_src_fs_parameters(const bt_value *params, const bt_value **inputs,
                            const bt_value **trace_name, struct ctf_fs_component *ctf_fs)
{
    bool ret;
    const bt_value *value;
    enum bt_param_validation_status validate_value_status;
    gchar *error = NULL;

    validate_value_status = bt_param_validation_validate(params, fs_params_entries_descr, &error);
    if (validate_value_status != BT_PARAM_VALIDATION_STATUS_OK) {
        BT_CPPLOGE_APPEND_CAUSE_SPEC(ctf_fs->logger, "{}", error);
        ret = false;
        goto end;
    }

    /* inputs parameter */
    *inputs = bt_value_map_borrow_entry_value_const(params, "inputs");

    /* clock-class-offset-s parameter */
    value = bt_value_map_borrow_entry_value_const(params, "clock-class-offset-s");
    if (value) {
        ctf_fs->clkClsCfg.offsetSec = bt_value_integer_signed_get(value);
    }

    /* clock-class-offset-ns parameter */
    value = bt_value_map_borrow_entry_value_const(params, "clock-class-offset-ns");
    if (value) {
        ctf_fs->clkClsCfg.offsetNanoSec = bt_value_integer_signed_get(value);
    }

    /* force-clock-class-origin-unix-epoch parameter */
    value = bt_value_map_borrow_entry_value_const(params, "force-clock-class-origin-unix-epoch");
    if (value) {
        ctf_fs->clkClsCfg.forceOriginIsUnixEpoch = bt_value_bool_get(value);
    }

    /* trace-name parameter */
    *trace_name = bt_value_map_borrow_entry_value_const(params, "trace-name");

    ret = true;

end:
    g_free(error);
    return ret;
}

static ctf_fs_component::UP ctf_fs_create(const bt_value *params,
                                          bt_self_component_source *self_comp_src)
{
    const bt_value *inputs_value;
    const bt_value *trace_name_value;
    bt_self_component *self_comp = bt_self_component_source_as_self_component(self_comp_src);

    ctf_fs_component::UP ctf_fs = ctf_fs_component_create(
        bt2c::Logger {bt2::SelfSourceComponent {self_comp_src}, "PLUGIN/SRC.CTF.FS/COMP"});
    if (!ctf_fs) {
        return nullptr;
    }

    if (!read_src_fs_parameters(params, &inputs_value, &trace_name_value, ctf_fs.get())) {
        return nullptr;
    }

    if (ctf_fs_component_create_ctf_fs_trace(ctf_fs.get(), inputs_value, trace_name_value,
                                             self_comp)) {
        return nullptr;
    }

    if (create_streams_for_trace(ctf_fs->trace.get())) {
        return nullptr;
    }

    if (create_ports_for_trace(ctf_fs.get(), ctf_fs->trace.get(), self_comp_src)) {
        return nullptr;
    }

    return ctf_fs;
}

bt_component_class_initialize_method_status ctf_fs_init(bt_self_component_source *self_comp_src,
                                                        bt_self_component_source_configuration *,
                                                        const bt_value *params, void *)
{
    try {
        bt_component_class_initialize_method_status ret =
            BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_OK;

        ctf_fs_component::UP ctf_fs = ctf_fs_create(params, self_comp_src);
        if (!ctf_fs) {
            ret = BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_ERROR;
        }

        bt_self_component_set_data(bt_self_component_source_as_self_component(self_comp_src),
                                   ctf_fs.release());
        return ret;
    } catch (const std::bad_alloc&) {
        return BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_MEMORY_ERROR;
    } catch (const bt2::Error&) {
        return BT_COMPONENT_CLASS_INITIALIZE_METHOD_STATUS_ERROR;
    }
}

bt_component_class_query_method_status ctf_fs_query(bt_self_component_class_source *comp_class_src,
                                                    bt_private_query_executor *priv_query_exec,
                                                    const char *object, const bt_value *params,
                                                    __attribute__((unused)) void *method_data,
                                                    const bt_value **result)
{
    try {
        bt2c::Logger logger {bt2::SelfComponentClass {comp_class_src},
                             bt2::PrivateQueryExecutor {priv_query_exec},
                             "PLUGIN/SRC.CTF.FS/QUERY"};
        bt2::ConstMapValue paramsObj(params);
        bt2::Value::Shared resultObj;

        if (strcmp(object, "metadata-info") == 0) {
            resultObj = metadata_info_query(paramsObj, logger);
        } else if (strcmp(object, "babeltrace.trace-infos") == 0) {
            resultObj = trace_infos_query(paramsObj, logger);
        } else if (!strcmp(object, "babeltrace.support-info")) {
            resultObj = support_info_query(paramsObj, logger);
        } else {
            BT_CPPLOGE_SPEC(logger, "Unknown query object `{}`", object);
            return BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_UNKNOWN_OBJECT;
        }

        *result = resultObj.release().libObjPtr();

        return BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_OK;
    } catch (const std::bad_alloc&) {
        return BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_MEMORY_ERROR;
    } catch (const bt2::Error&) {
        return BT_COMPONENT_CLASS_QUERY_METHOD_STATUS_ERROR;
    }
}