[babeltrace.git] / src / plugins / ctf / fs-sink / translate-trace-ir-to-ctf-ir.cpp

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright 2019 Philippe Proulx <pproulx@efficios.com>
 */

#define BT_COMP_LOG_SELF_COMP (ctx->self_comp)
#define BT_LOG_OUTPUT_LEVEL   (ctx->log_level)
#define BT_LOG_TAG            "PLUGIN/SINK.CTF.FS/TRANSLATE-TRACE-IR-TO-CTF-IR"
#include "logging/comp-logging.h"

#include "translate-trace-ir-to-ctf-ir.hpp"

#include <babeltrace2/babeltrace.h>
#include "common/macros.h"
#include "common/common.h"
#include "common/assert.h"
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include <glib.h>

#include "fs-sink.hpp"
#include "fs-sink-ctf-meta.hpp"

struct field_path_elem
{
    uint64_t index_in_parent;
    GString *name;

    /* Weak */
    const bt_field_class *ir_fc;

    /* Weak */
    struct fs_sink_ctf_field_class *parent_fc;
};

struct ctx
{
    bt_logging_level log_level;
    bt_self_component *self_comp;

    /* Weak */
    struct fs_sink_ctf_stream_class *cur_sc;

    /* Weak */
    struct fs_sink_ctf_event_class *cur_ec;

    bt_field_path_scope cur_scope;

    /*
     * Array of `struct field_path_elem` */
    GArray *cur_path;
};

static inline struct field_path_elem *cur_path_stack_at(struct ctx *ctx, uint64_t i)
{
    BT_ASSERT(i < ctx->cur_path->len);
    return &g_array_index(ctx->cur_path, struct field_path_elem, i);
}

static inline struct field_path_elem *cur_path_stack_top(struct ctx *ctx)
{
    BT_ASSERT(ctx->cur_path->len > 0);
    return cur_path_stack_at(ctx, ctx->cur_path->len - 1);
}

static inline bool is_reserved_member_name(const char *name, const char *reserved_name)
{
    bool is_reserved = false;

    if (strcmp(name, reserved_name) == 0) {
        is_reserved = true;
        goto end;
    }

    if (name[0] == '_' && strcmp(&name[1], reserved_name) == 0) {
        is_reserved = true;
        goto end;
    }

end:
    return is_reserved;
}

static const char *reserved_tsdl_keywords[] = {
    "align",   "callsite", "const",          "char",   "clock",   "double",   "enum",
    "env",     "event",    "floating_point", "float",  "integer", "int",      "long",
    "short",   "signed",   "stream",         "string", "struct",  "trace",    "typealias",
    "typedef", "unsigned", "variant",        "void",   "_Bool",   "_Complex", "_Imaginary",
};

static inline bool ist_valid_identifier(const char *name)
{
    const char *at;
    uint64_t i;
    bool ist_valid = true;

    /* Make sure the name is not a reserved keyword */
    for (i = 0; i < sizeof(reserved_tsdl_keywords) / sizeof(*reserved_tsdl_keywords); i++) {
        if (strcmp(name, reserved_tsdl_keywords[i]) == 0) {
            ist_valid = false;
            goto end;
        }
    }

    /* Make sure the name is not an empty string */
    if (strlen(name) == 0) {
        ist_valid = false;
        goto end;
    }

    /* Make sure the name starts with a letter or `_` */
    if (!isalpha((unsigned char) name[0]) && name[0] != '_') {
        ist_valid = false;
        goto end;
    }

    /* Make sure the name only contains letters, digits, and `_` */
    for (at = name; *at != '\0'; at++) {
        if (!isalnum((unsigned char) *at) && *at != '_') {
            ist_valid = false;
            goto end;
        }
    }

end:
    return ist_valid;
}

static inline bool must_protect_identifier(const char *name)
{
    uint64_t i;
    bool must_protect = false;

    /* Protect a reserved keyword */
    for (i = 0; i < sizeof(reserved_tsdl_keywords) / sizeof(*reserved_tsdl_keywords); i++) {
        if (strcmp(name, reserved_tsdl_keywords[i]) == 0) {
            must_protect = true;
            goto end;
        }
    }

    /* Protect an identifier which already starts with `_` */
    if (name[0] == '_') {
        must_protect = true;
        goto end;
    }

end:
    return must_protect;
}

static inline int cur_path_stack_push(struct ctx *ctx, uint64_t index_in_parent, const char *name,
                                      bool force_protect_name, const bt_field_class *ir_fc,
                                      struct fs_sink_ctf_field_class *parent_fc)
{
    int ret = 0;
    struct field_path_elem *field_path_elem;

    g_array_set_size(ctx->cur_path, ctx->cur_path->len + 1);
    field_path_elem = cur_path_stack_top(ctx);
    field_path_elem->index_in_parent = index_in_parent;
    field_path_elem->name = g_string_new(NULL);

    if (name) {
        if (force_protect_name) {
            g_string_assign(field_path_elem->name, "_");
        }

        g_string_append(field_path_elem->name, name);

        if (ctx->cur_scope == BT_FIELD_PATH_SCOPE_PACKET_CONTEXT) {
            if (is_reserved_member_name(name, "packet_size") ||
                is_reserved_member_name(name, "content_size") ||
                is_reserved_member_name(name, "timestamp_begin") ||
                is_reserved_member_name(name, "timestamp_end") ||
                is_reserved_member_name(name, "events_discarded") ||
                is_reserved_member_name(name, "packet_seq_num")) {
                BT_COMP_LOGE("Unsupported reserved TSDL structure field class member "
                             "or variant field class option name: name=\"%s\"",
                             name);
                ret = -1;
                goto end;
            }
        }

        if (!ist_valid_identifier(field_path_elem->name->str)) {
            ret = -1;
            BT_COMP_LOGE("Unsupported non-TSDL structure field class member "
                         "or variant field class option name: name=\"%s\"",
                         field_path_elem->name->str);
            goto end;
        }
    }

    field_path_elem->ir_fc = ir_fc;
    field_path_elem->parent_fc = parent_fc;

end:
    return ret;
}

static inline void cur_path_stack_pop(struct ctx *ctx)
{
    struct field_path_elem *field_path_elem;

    BT_ASSERT(ctx->cur_path->len > 0);
    field_path_elem = cur_path_stack_top(ctx);

    if (field_path_elem->name) {
        g_string_free(field_path_elem->name, TRUE);
        field_path_elem->name = NULL;
    }

    g_array_set_size(ctx->cur_path, ctx->cur_path->len - 1);
}

/*
 * Creates a relative field ref (a single name) from IR field path
 * `tgt_ir_field_path`.
 *
 * This function tries to locate the target field class recursively from
 * the top to the bottom of the context's current path using only the
 * target field class's own name. This is because many CTF reading tools
 * do not support a relative field ref with more than one element, for
 * example `prev_struct.len`.
 *
 * Returns a negative value if this resolving operation failed.
 */
static int create_relative_field_ref(struct ctx *ctx, const bt_field_path *tgt_ir_field_path,
                                     GString *tgt_field_ref,
                                     struct fs_sink_ctf_field_class **user_tgt_fc)
{
    int ret = 0;
    struct fs_sink_ctf_field_class *tgt_fc = NULL;
    uint64_t i;
    int64_t si;
    const char *tgt_fc_name = NULL;
    struct field_path_elem *field_path_elem;

    /* Get target field class's name */
    switch (bt_field_path_get_root_scope(tgt_ir_field_path)) {
    case BT_FIELD_PATH_SCOPE_PACKET_CONTEXT:
        BT_ASSERT(ctx->cur_sc);
        tgt_fc = ctx->cur_sc->packet_context_fc;
        break;
    case BT_FIELD_PATH_SCOPE_EVENT_COMMON_CONTEXT:
        BT_ASSERT(ctx->cur_sc);
        tgt_fc = ctx->cur_sc->event_common_context_fc;
        break;
    case BT_FIELD_PATH_SCOPE_EVENT_SPECIFIC_CONTEXT:
        BT_ASSERT(ctx->cur_ec);
        tgt_fc = ctx->cur_ec->spec_context_fc;
        break;
    case BT_FIELD_PATH_SCOPE_EVENT_PAYLOAD:
        BT_ASSERT(ctx->cur_ec);
        tgt_fc = ctx->cur_ec->payload_fc;
        break;
    default:
        bt_common_abort();
    }

    i = 0;

    while (i < bt_field_path_get_item_count(tgt_ir_field_path)) {
        const bt_field_path_item *fp_item =
            bt_field_path_borrow_item_by_index_const(tgt_ir_field_path, i);
        struct fs_sink_ctf_named_field_class *named_fc = NULL;

        BT_ASSERT(tgt_fc);
        BT_ASSERT(fp_item);

        if (bt_field_path_item_get_type(fp_item) ==
            BT_FIELD_PATH_ITEM_TYPE_CURRENT_OPTION_CONTENT) {
            /* Not supported by CTF 1.8 */
            ret = -1;
            goto end;
        }

        switch (tgt_fc->type) {
        case FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT:
            BT_ASSERT(bt_field_path_item_get_type(fp_item) == BT_FIELD_PATH_ITEM_TYPE_INDEX);
            named_fc = fs_sink_ctf_field_class_struct_borrow_member_by_index(
                fs_sink_ctf_field_class_as_struct(tgt_fc),
                bt_field_path_item_index_get_index(fp_item));
            break;
        case FS_SINK_CTF_FIELD_CLASS_TYPE_VARIANT:
            BT_ASSERT(bt_field_path_item_get_type(fp_item) == BT_FIELD_PATH_ITEM_TYPE_INDEX);
            named_fc = fs_sink_ctf_field_class_variant_borrow_option_by_index(
                fs_sink_ctf_field_class_as_variant(tgt_fc),
                bt_field_path_item_index_get_index(fp_item));
            break;
        case FS_SINK_CTF_FIELD_CLASS_TYPE_ARRAY:
        case FS_SINK_CTF_FIELD_CLASS_TYPE_SEQUENCE:
        {
            struct fs_sink_ctf_field_class_array_base *array_base_fc =
                fs_sink_ctf_field_class_as_array_base(tgt_fc);

            BT_ASSERT(bt_field_path_item_get_type(fp_item) ==
                      BT_FIELD_PATH_ITEM_TYPE_CURRENT_ARRAY_ELEMENT);
            tgt_fc = array_base_fc->elem_fc;
            break;
        }
        default:
            bt_common_abort();
        }

        if (named_fc) {
            tgt_fc = named_fc->fc;
            tgt_fc_name = named_fc->name->str;
            i++;
        }
    }

    BT_ASSERT(tgt_fc);
    BT_ASSERT(tgt_fc->type == FS_SINK_CTF_FIELD_CLASS_TYPE_INT);
    BT_ASSERT(tgt_fc_name);

    /* Find target field class having this name in current context */
    for (si = ctx->cur_path->len - 1; si >= 0; si--) {
        struct fs_sink_ctf_field_class *fc;
        struct fs_sink_ctf_field_class_struct *struct_fc = NULL;
        struct fs_sink_ctf_field_class_variant *var_fc = NULL;
        struct fs_sink_ctf_named_field_class *named_fc;
        uint64_t len;

        field_path_elem = cur_path_stack_at(ctx, (uint64_t) si);
        fc = field_path_elem->parent_fc;
        if (!fc) {
            /* Reached stack's bottom */
            ret = -1;
            goto end;
        }

        switch (fc->type) {
        case FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT:
        case FS_SINK_CTF_FIELD_CLASS_TYPE_VARIANT:
            break;
        case FS_SINK_CTF_FIELD_CLASS_TYPE_ARRAY:
        case FS_SINK_CTF_FIELD_CLASS_TYPE_SEQUENCE:
            continue;
        default:
            /* Not supported by TSDL 1.8 */
            ret = -1;
            goto end;
        }

        if (fc->type == FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT) {
            struct_fc = fs_sink_ctf_field_class_as_struct(fc);
            len = struct_fc->members->len;
        } else {
            var_fc = fs_sink_ctf_field_class_as_variant(fc);
            len = var_fc->options->len;
        }

        for (i = 0; i < len; i++) {
            if (fc->type == FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT) {
                named_fc = fs_sink_ctf_field_class_struct_borrow_member_by_index(struct_fc, i);
            } else {
                named_fc = fs_sink_ctf_field_class_variant_borrow_option_by_index(var_fc, i);
            }

            if (strcmp(named_fc->name->str, tgt_fc_name) == 0) {
                if (named_fc->fc == tgt_fc) {
                    g_string_assign(tgt_field_ref, tgt_fc_name);

                    if (user_tgt_fc) {
                        *user_tgt_fc = tgt_fc;
                    }
                } else {
                    /*
                     * Using only the target field
                     * class's name, we're not
                     * reaching the target field
                     * class. This is not supported
                     * by TSDL 1.8.
                     */
                    ret = -1;
                }

                goto end;
            }
        }
    }

end:
    return ret;
}

/*
 * Creates an absolute field ref from IR field path `tgt_ir_field_path`.
 *
 * Returns a negative value if this resolving operation failed.
 */
static int create_absolute_field_ref(struct ctx *ctx, const bt_field_path *tgt_ir_field_path,
                                     GString *tgt_field_ref,
                                     struct fs_sink_ctf_field_class **user_tgt_fc)
{
    int ret = 0;
    struct fs_sink_ctf_field_class *fc = NULL;
    uint64_t i;

    switch (bt_field_path_get_root_scope(tgt_ir_field_path)) {
    case BT_FIELD_PATH_SCOPE_PACKET_CONTEXT:
        BT_ASSERT(ctx->cur_sc);
        fc = ctx->cur_sc->packet_context_fc;
        g_string_assign(tgt_field_ref, "stream.packet.context");
        break;
    case BT_FIELD_PATH_SCOPE_EVENT_COMMON_CONTEXT:
        BT_ASSERT(ctx->cur_sc);
        fc = ctx->cur_sc->event_common_context_fc;
        g_string_assign(tgt_field_ref, "stream.event.context");
        break;
    case BT_FIELD_PATH_SCOPE_EVENT_SPECIFIC_CONTEXT:
        BT_ASSERT(ctx->cur_ec);
        fc = ctx->cur_ec->spec_context_fc;
        g_string_assign(tgt_field_ref, "event.context");
        break;
    case BT_FIELD_PATH_SCOPE_EVENT_PAYLOAD:
        BT_ASSERT(ctx->cur_ec);
        fc = ctx->cur_ec->payload_fc;
        g_string_assign(tgt_field_ref, "event.fields");
        break;
    default:
        bt_common_abort();
    }

    BT_ASSERT(fc);

    for (i = 0; i < bt_field_path_get_item_count(tgt_ir_field_path); i++) {
        const bt_field_path_item *fp_item =
            bt_field_path_borrow_item_by_index_const(tgt_ir_field_path, i);
        struct fs_sink_ctf_named_field_class *named_fc = NULL;

        if (bt_field_path_item_get_type(fp_item) != BT_FIELD_PATH_ITEM_TYPE_INDEX) {
            /* Not supported by TSDL 1.8 */
            ret = -1;
            goto end;
        }

        switch (fc->type) {
        case FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT:
            BT_ASSERT(bt_field_path_item_get_type(fp_item) == BT_FIELD_PATH_ITEM_TYPE_INDEX);
            named_fc = fs_sink_ctf_field_class_struct_borrow_member_by_index(
                fs_sink_ctf_field_class_as_struct(fc), bt_field_path_item_index_get_index(fp_item));
            break;
        case FS_SINK_CTF_FIELD_CLASS_TYPE_VARIANT:
            BT_ASSERT(bt_field_path_item_get_type(fp_item) == BT_FIELD_PATH_ITEM_TYPE_INDEX);
            named_fc = fs_sink_ctf_field_class_variant_borrow_option_by_index(
                fs_sink_ctf_field_class_as_variant(fc),
                bt_field_path_item_index_get_index(fp_item));
            break;
        default:
            bt_common_abort();
        }

        BT_ASSERT(named_fc);
        g_string_append_c(tgt_field_ref, '.');
        g_string_append(tgt_field_ref, named_fc->name->str);
        fc = named_fc->fc;
    }

    if (user_tgt_fc) {
        *user_tgt_fc = fc;
    }

end:
    return ret;
}

/*
 * Resolves a target field class located at `tgt_ir_field_path`, writing
 * the resolved field ref to `tgt_field_ref` and setting
 * `*create_before` according to whether or not the target field must be
 * created immediately before (in which case `tgt_field_ref` is
 * irrelevant).
 */
static void resolve_field_class(struct ctx *ctx, const bt_field_path *tgt_ir_field_path,
                                GString *tgt_field_ref, bool *create_before,
                                struct fs_sink_ctf_field_class **user_tgt_fc)
{
    int ret;
    bt_field_path_scope tgt_scope;

    *create_before = false;

    if (!tgt_ir_field_path) {
        *create_before = true;
        goto end;
    }

    tgt_scope = bt_field_path_get_root_scope(tgt_ir_field_path);

    if (tgt_scope == ctx->cur_scope) {
        /*
         * Try, in this order:
         *
         * 1. Use a relative path, using only the target field
         *    class's name. This is what is the most commonly
         *    supported by popular CTF reading tools.
         *
         * 2. Use an absolute path. This could fail if there's
         *    an array field class from the current root's field
         *    class to the target field class.
         *
         * 3. Create the target field class before the
         *    requesting field class (fallback).
         */
        ret = create_relative_field_ref(ctx, tgt_ir_field_path, tgt_field_ref, user_tgt_fc);
        if (ret) {
            ret = create_absolute_field_ref(ctx, tgt_ir_field_path, tgt_field_ref, user_tgt_fc);
            if (ret) {
                *create_before = true;
                goto end;
            }
        }
    } else {
        ret = create_absolute_field_ref(ctx, tgt_ir_field_path, tgt_field_ref, user_tgt_fc);

        /* It must always work in previous scopes */
        BT_ASSERT(ret == 0);
    }

end:
    return;
}

static int translate_field_class(struct ctx *ctx);

static inline void append_to_parent_field_class(struct ctx *ctx, struct fs_sink_ctf_field_class *fc)
{
    struct fs_sink_ctf_field_class *parent_fc = cur_path_stack_top(ctx)->parent_fc;

    switch (parent_fc->type) {
    case FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT:
        fs_sink_ctf_field_class_struct_append_member(fs_sink_ctf_field_class_as_struct(parent_fc),
                                                     cur_path_stack_top(ctx)->name->str, fc);
        break;
    case FS_SINK_CTF_FIELD_CLASS_TYPE_OPTION:
    {
        struct fs_sink_ctf_field_class_option *opt_fc =
            fs_sink_ctf_field_class_as_option(parent_fc);

        BT_ASSERT(!opt_fc->content_fc);
        opt_fc->content_fc = fc;
        opt_fc->base.alignment = fc->alignment;
        break;
    }
    case FS_SINK_CTF_FIELD_CLASS_TYPE_VARIANT:
        fs_sink_ctf_field_class_variant_append_option(fs_sink_ctf_field_class_as_variant(parent_fc),
                                                      cur_path_stack_top(ctx)->name->str, fc);
        break;
    case FS_SINK_CTF_FIELD_CLASS_TYPE_ARRAY:
    case FS_SINK_CTF_FIELD_CLASS_TYPE_SEQUENCE:
    {
        struct fs_sink_ctf_field_class_array_base *array_base_fc =
            fs_sink_ctf_field_class_as_array_base(parent_fc);

        BT_ASSERT(!array_base_fc->elem_fc);
        array_base_fc->elem_fc = fc;
        array_base_fc->base.alignment = fc->alignment;
        break;
    }
    default:
        bt_common_abort();
    }
}

static inline void update_parent_field_class_alignment(struct ctx *ctx, unsigned int alignment)
{
    struct fs_sink_ctf_field_class *parent_fc = cur_path_stack_top(ctx)->parent_fc;

    switch (parent_fc->type) {
    case FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT:
        fs_sink_ctf_field_class_struct_align_at_least(fs_sink_ctf_field_class_as_struct(parent_fc),
                                                      alignment);
        break;
    case FS_SINK_CTF_FIELD_CLASS_TYPE_ARRAY:
    case FS_SINK_CTF_FIELD_CLASS_TYPE_SEQUENCE:
    {
        struct fs_sink_ctf_field_class_array_base *array_base_fc =
            fs_sink_ctf_field_class_as_array_base(parent_fc);

        array_base_fc->base.alignment = alignment;
        break;
    }
    default:
        break;
    }
}

static inline int translate_structure_field_class_members(
    struct ctx *ctx, struct fs_sink_ctf_field_class_struct *struct_fc, const bt_field_class *ir_fc)
{
    int ret = 0;
    uint64_t i;

    for (i = 0; i < bt_field_class_structure_get_member_count(ir_fc); i++) {
        const bt_field_class_structure_member *member;
        const char *name;
        const bt_field_class *memb_ir_fc;

        member = bt_field_class_structure_borrow_member_by_index_const(ir_fc, i);
        name = bt_field_class_structure_member_get_name(member);
        memb_ir_fc = bt_field_class_structure_member_borrow_field_class_const(member);
        ret = cur_path_stack_push(ctx, i, name, true, memb_ir_fc, &struct_fc->base);
        if (ret) {
            BT_COMP_LOGE("Cannot translate structure field class member: "
                         "name=\"%s\"",
                         name);
            goto end;
        }

        ret = translate_field_class(ctx);
        if (ret) {
            BT_COMP_LOGE("Cannot translate structure field class member: "
                         "name=\"%s\"",
                         name);
            goto end;
        }

        cur_path_stack_pop(ctx);
    }

end:
    return ret;
}

static inline int translate_structure_field_class(struct ctx *ctx)
{
    int ret;
    struct fs_sink_ctf_field_class_struct *fc = fs_sink_ctf_field_class_struct_create_empty(
        cur_path_stack_top(ctx)->ir_fc, cur_path_stack_top(ctx)->index_in_parent);

    BT_ASSERT(fc);
    append_to_parent_field_class(ctx, &fc->base);
    ret = translate_structure_field_class_members(ctx, fc, fc->base.ir_fc);
    if (ret) {
        goto end;
    }

    update_parent_field_class_alignment(ctx, fc->base.alignment);

end:
    return ret;
}

/*
 * This function protects a given variant FC option name (with the `_`
 * prefix) if required. On success, `name_buf->str` contains the variant
 * FC option name to use (original option name or protected if
 * required).
 *
 * One of the goals of `sink.ctf.fs` is to write a CTF trace which is as
 * close as possible to an original CTF trace as decoded by
 * `src.ctf.fs`.
 *
 * This scenario is valid in CTF 1.8:
 *
 *     enum {
 *         HELLO,
 *         MEOW
 *     } tag;
 *
 *     variant <tag> {
 *         int HELLO;
 *         string MEOW;
 *     };
 *
 * Once in trace IR, the enumeration FC mapping names and variant FC
 * option names are kept as is. For this reason, we don't want to
 * protect the variant FC option names here (by prepending `_`): this
 * would make the variant FC option name and the enumeration FC mapping
 * name not match.
 *
 * This scenario is also valid in CTF 1.8:
 *
 *     enum {
 *         _HELLO,
 *         MEOW
 *     } tag;
 *
 *     variant <tag> {
 *         int _HELLO;
 *         string MEOW;
 *     };
 *
 * Once in trace IR, the enumeration FC mapping names are kept as is,
 * but the `_HELLO` variant FC option name becomes `HELLO` (unprotected
 * for presentation, as recommended by CTF 1.8). When going back to
 * TSDL, we need to protect `HELLO` so that it becomes `_HELLO` to match
 * the corresponding enumeration FC mapping name.
 *
 * This scenario is also valid in CTF 1.8:
 *
 *     enum {
 *         __HELLO,
 *         MEOW
 *     } tag;
 *
 *     variant <tag> {
 *         int __HELLO;
 *         string MEOW;
 *     };
 *
 * Once in trace IR, the enumeration FC mapping names are kept as is,
 * but the `__HELLO` variant FC option name becomes `_HELLO`
 * (unprotected). When going back to TSDL, we need to protect `_HELLO`
 * so that it becomes `__HELLO` to match the corresponding enumeration
 * FC mapping name.
 *
 * `src.ctf.fs` always uses the _same_ integer range sets for a selector
 * FC mapping and a corresponding variant FC option. We can use that
 * fact to find the original variant FC option names by matching variant
 * FC options and enumeration FC mappings by range set.
 */
static int maybe_protect_variant_option_name(const bt_field_class *ir_var_fc,
                                             const bt_field_class *ir_tag_fc, uint64_t opt_i,
                                             GString *name_buf)
{
    int ret = 0;
    uint64_t i;
    bt_field_class_type ir_var_fc_type;
    const bt_integer_range_set_unsigned *opt_ranges_unsigned = NULL;
    const bt_integer_range_set_signed *opt_ranges_signed = NULL;
    const char *mapping_label = NULL;
    const char *ir_opt_name;
    const bt_field_class_variant_option *base_var_opt;
    bool force_protect = false;

    ir_var_fc_type = bt_field_class_get_type(ir_var_fc);
    base_var_opt = bt_field_class_variant_borrow_option_by_index_const(ir_var_fc, opt_i);
    BT_ASSERT(base_var_opt);
    ir_opt_name = bt_field_class_variant_option_get_name(base_var_opt);
    BT_ASSERT(ir_opt_name);

    /*
     * Check if the variant FC option name is required to be
     * protected (reserved TSDL keyword or starts with `_`). In that
     * case, the name of the selector FC mapping we find must match
     * exactly the protected name.
     */
    force_protect = must_protect_identifier(ir_opt_name);
    if (force_protect) {
        g_string_assign(name_buf, "_");
        g_string_append(name_buf, ir_opt_name);
    } else {
        g_string_assign(name_buf, ir_opt_name);
    }

    /* Borrow option's ranges */
    if (ir_var_fc_type == BT_FIELD_CLASS_TYPE_VARIANT_WITHOUT_SELECTOR_FIELD) {
        /* No ranges: we're done */
        goto end;
    }
    if (ir_var_fc_type == BT_FIELD_CLASS_TYPE_VARIANT_WITH_UNSIGNED_INTEGER_SELECTOR_FIELD) {
        const bt_field_class_variant_with_selector_field_integer_unsigned_option *var_opt =
            bt_field_class_variant_with_selector_field_integer_unsigned_borrow_option_by_index_const(
                ir_var_fc, opt_i);
        opt_ranges_unsigned =
            bt_field_class_variant_with_selector_field_integer_unsigned_option_borrow_ranges_const(
                var_opt);
    } else {
        const bt_field_class_variant_with_selector_field_integer_signed_option *var_opt =
            bt_field_class_variant_with_selector_field_integer_signed_borrow_option_by_index_const(
                ir_var_fc, opt_i);
        opt_ranges_signed =
            bt_field_class_variant_with_selector_field_integer_signed_option_borrow_ranges_const(
                var_opt);
    }

    /* Find corresponding mapping by range set in selector FC */
    for (i = 0; i < bt_field_class_enumeration_get_mapping_count(ir_tag_fc); i++) {
        if (ir_var_fc_type == BT_FIELD_CLASS_TYPE_VARIANT_WITH_UNSIGNED_INTEGER_SELECTOR_FIELD) {
            const bt_field_class_enumeration_mapping *mapping_base;
            const bt_field_class_enumeration_unsigned_mapping *mapping;
            const bt_integer_range_set_unsigned *mapping_ranges;

            mapping =
                bt_field_class_enumeration_unsigned_borrow_mapping_by_index_const(ir_tag_fc, i);
            mapping_ranges =
                bt_field_class_enumeration_unsigned_mapping_borrow_ranges_const(mapping);

            if (bt_integer_range_set_unsigned_is_equal(opt_ranges_unsigned, mapping_ranges)) {
                /* We have a winner */
                mapping_base =
                    bt_field_class_enumeration_unsigned_mapping_as_mapping_const(mapping);
                mapping_label = bt_field_class_enumeration_mapping_get_label(mapping_base);
                break;
            }
        } else {
            const bt_field_class_enumeration_mapping *mapping_base;
            const bt_field_class_enumeration_signed_mapping *mapping;
            const bt_integer_range_set_signed *mapping_ranges;

            mapping = bt_field_class_enumeration_signed_borrow_mapping_by_index_const(ir_tag_fc, i);
            mapping_ranges = bt_field_class_enumeration_signed_mapping_borrow_ranges_const(mapping);

            if (bt_integer_range_set_signed_is_equal(opt_ranges_signed, mapping_ranges)) {
                /* We have a winner */
                mapping_base = bt_field_class_enumeration_signed_mapping_as_mapping_const(mapping);
                mapping_label = bt_field_class_enumeration_mapping_get_label(mapping_base);
                break;
            }
        }
    }

    if (!mapping_label) {
        /* Range set not found: invalid selector for CTF 1.8 */
        ret = -1;
        goto end;
    }

    /*
     * If the enumeration FC mapping name is not the same as the
     * variant FC option name and we didn't protect already, try
     * protecting the option name and check again.
     */
    if (strcmp(mapping_label, name_buf->str) != 0) {
        if (force_protect) {
            ret = -1;
            goto end;
        }

        if (mapping_label[0] == '\0') {
            ret = -1;
            goto end;
        }

        g_string_assign(name_buf, "_");
        g_string_append(name_buf, ir_opt_name);

        if (strcmp(mapping_label, name_buf->str) != 0) {
            ret = -1;
            goto end;
        }
    }

end:
    return ret;
}

static inline int translate_option_field_class(struct ctx *ctx)
{
    struct fs_sink_ctf_field_class_option *fc = fs_sink_ctf_field_class_option_create_empty(
        cur_path_stack_top(ctx)->ir_fc, cur_path_stack_top(ctx)->index_in_parent);
    const bt_field_class *content_ir_fc =
        bt_field_class_option_borrow_field_class_const(fc->base.ir_fc);
    int ret;

    BT_ASSERT(fc);

    /*
     * CTF 1.8 does not support the option field class type. To
     * write something anyway, this component translates this type
     * to a variant field class where the options are:
     *
     * * An empty structure field class.
     * * The optional field class itself.
     *
     * The "tag" is always generated/before in that case (an 8-bit
     * unsigned enumeration field class).
     */
    append_to_parent_field_class(ctx, &fc->base);
    ret = cur_path_stack_push(ctx, UINT64_C(-1), NULL, false, content_ir_fc, &fc->base);
    if (ret) {
        BT_COMP_LOGE_STR("Cannot translate option field class content.");
        goto end;
    }

    ret = translate_field_class(ctx);
    if (ret) {
        BT_COMP_LOGE_STR("Cannot translate option field class content.");
        goto end;
    }

    cur_path_stack_pop(ctx);
    update_parent_field_class_alignment(ctx, fc->base.alignment);

end:
    return ret;
}

static inline int translate_variant_field_class(struct ctx *ctx)
{
    int ret = 0;
    uint64_t i;
    struct fs_sink_ctf_field_class_variant *fc = fs_sink_ctf_field_class_variant_create_empty(
        cur_path_stack_top(ctx)->ir_fc, cur_path_stack_top(ctx)->index_in_parent);
    bt_field_class_type ir_fc_type;
    const bt_field_path *ir_selector_field_path = NULL;
    struct fs_sink_ctf_field_class *tgt_fc = NULL;
    GString *name_buf = g_string_new(NULL);
    bt_value *prot_opt_names = bt_value_array_create();
    uint64_t opt_count;

    BT_ASSERT(fc);
    BT_ASSERT(name_buf);
    BT_ASSERT(prot_opt_names);
    ir_fc_type = bt_field_class_get_type(fc->base.ir_fc);
    opt_count = bt_field_class_variant_get_option_count(fc->base.ir_fc);

    if (bt_field_class_type_is(ir_fc_type, BT_FIELD_CLASS_TYPE_VARIANT_WITH_SELECTOR_FIELD)) {
        ir_selector_field_path =
            bt_field_class_variant_with_selector_field_borrow_selector_field_path_const(
                fc->base.ir_fc);
        BT_ASSERT(ir_selector_field_path);
    }

    /* Resolve tag field class before appending to parent */
    resolve_field_class(ctx, ir_selector_field_path, fc->tag_ref, &fc->tag_is_before, &tgt_fc);

    if (ir_selector_field_path && tgt_fc) {
        uint64_t mapping_count;
        uint64_t option_count;

        /* CTF 1.8: selector FC must be an enumeration FC */
        bt_field_class_type type = bt_field_class_get_type(tgt_fc->ir_fc);

        if (!bt_field_class_type_is(type, BT_FIELD_CLASS_TYPE_ENUMERATION)) {
            fc->tag_is_before = true;
            goto validate_opts;
        }

        /*
         * Call maybe_protect_variant_option_name() for each
         * option below. In that case we also want selector FC
         * to contain as many mappings as the variant FC has
         * options.
         */
        mapping_count = bt_field_class_enumeration_get_mapping_count(tgt_fc->ir_fc);
        option_count = bt_field_class_variant_get_option_count(fc->base.ir_fc);

        if (mapping_count != option_count) {
            fc->tag_is_before = true;
            goto validate_opts;
        }
    } else {
        /*
         * No compatible selector field class for CTF 1.8:
         * create the appropriate selector field class.
         */
        fc->tag_is_before = true;
        goto validate_opts;
    }

validate_opts:
    /*
     * First pass: detect any option name clash with option name
     * protection. In that case, we don't fail: just create the
     * selector field class before the variant field class.
     *
     * After this, `prot_opt_names` contains the final option names,
     * potentially protected if needed. They can still be invalid
     * TSDL identifiers however; this will be checked by
     * cur_path_stack_push().
     */
    for (i = 0; i < opt_count; i++) {
        if (!fc->tag_is_before) {
            BT_ASSERT(tgt_fc->ir_fc);
            ret = maybe_protect_variant_option_name(fc->base.ir_fc, tgt_fc->ir_fc, i, name_buf);
            if (ret) {
                fc->tag_is_before = true;
            }
        }

        ret = bt_value_array_append_string_element(prot_opt_names, name_buf->str);
        if (ret) {
            goto end;
        }
    }

    for (i = 0; i < opt_count; i++) {
        uint64_t j;
        const bt_value *opt_name_a =
            bt_value_array_borrow_element_by_index_const(prot_opt_names, i);

        for (j = 0; j < opt_count; j++) {
            const bt_value *opt_name_b;

            if (i == j) {
                continue;
            }

            opt_name_b = bt_value_array_borrow_element_by_index_const(prot_opt_names, j);
            if (bt_value_is_equal(opt_name_a, opt_name_b)) {
                /*
                 * Variant FC option names are not
                 * unique when protected.
                 */
                fc->tag_is_before = true;
                goto append_to_parent;
            }
        }
    }

append_to_parent:
    append_to_parent_field_class(ctx, &fc->base);

    for (i = 0; i < opt_count; i++) {
        const bt_field_class_variant_option *opt;
        const bt_field_class *opt_ir_fc;
        const bt_value *prot_opt_name_val =
            bt_value_array_borrow_element_by_index_const(prot_opt_names, i);
        const char *prot_opt_name = bt_value_string_get(prot_opt_name_val);

        BT_ASSERT(prot_opt_name);
        opt = bt_field_class_variant_borrow_option_by_index_const(fc->base.ir_fc, i);
        opt_ir_fc = bt_field_class_variant_option_borrow_field_class_const(opt);

        /*
         * We don't ask cur_path_stack_push() to protect the
         * option name because it's already protected at this
         * point.
         */
        ret = cur_path_stack_push(ctx, i, prot_opt_name, false, opt_ir_fc, &fc->base);
        if (ret) {
            BT_COMP_LOGE("Cannot translate variant field class option: "
                         "name=\"%s\"",
                         prot_opt_name);
            goto end;
        }

        ret = translate_field_class(ctx);
        if (ret) {
            BT_COMP_LOGE("Cannot translate variant field class option: "
                         "name=\"%s\"",
                         prot_opt_name);
            goto end;
        }

        cur_path_stack_pop(ctx);
    }

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

    bt_value_put_ref(prot_opt_names);
    return ret;
}

static inline int translate_static_array_field_class(struct ctx *ctx)
{
    struct fs_sink_ctf_field_class_array *fc = fs_sink_ctf_field_class_array_create_empty(
        cur_path_stack_top(ctx)->ir_fc, cur_path_stack_top(ctx)->index_in_parent);
    const bt_field_class *elem_ir_fc =
        bt_field_class_array_borrow_element_field_class_const(fc->base.base.ir_fc);
    int ret;

    BT_ASSERT(fc);
    append_to_parent_field_class(ctx, &fc->base.base);
    ret = cur_path_stack_push(ctx, UINT64_C(-1), NULL, false, elem_ir_fc, &fc->base.base);
    if (ret) {
        BT_COMP_LOGE_STR("Cannot translate static array field class element.");
        goto end;
    }

    ret = translate_field_class(ctx);
    if (ret) {
        BT_COMP_LOGE_STR("Cannot translate static array field class element.");
        goto end;
    }

    cur_path_stack_pop(ctx);
    update_parent_field_class_alignment(ctx, fc->base.base.alignment);

end:
    return ret;
}

static inline int translate_dynamic_array_field_class(struct ctx *ctx)
{
    struct fs_sink_ctf_field_class_sequence *fc = fs_sink_ctf_field_class_sequence_create_empty(
        cur_path_stack_top(ctx)->ir_fc, cur_path_stack_top(ctx)->index_in_parent);
    const bt_field_class *elem_ir_fc =
        bt_field_class_array_borrow_element_field_class_const(fc->base.base.ir_fc);
    int ret;

    BT_ASSERT(fc);

    /* Resolve length field class before appending to parent */
    if (bt_field_class_get_type(cur_path_stack_top(ctx)->ir_fc) ==
        BT_FIELD_CLASS_TYPE_DYNAMIC_ARRAY_WITH_LENGTH_FIELD) {
        resolve_field_class(
            ctx,
            bt_field_class_array_dynamic_with_length_field_borrow_length_field_path_const(
                fc->base.base.ir_fc),
            fc->length_ref, &fc->length_is_before, NULL);
    }

    append_to_parent_field_class(ctx, &fc->base.base);
    ret = cur_path_stack_push(ctx, UINT64_C(-1), NULL, false, elem_ir_fc, &fc->base.base);
    if (ret) {
        BT_COMP_LOGE_STR("Cannot translate dynamic array field class element.");
        goto end;
    }

    ret = translate_field_class(ctx);
    if (ret) {
        BT_COMP_LOGE_STR("Cannot translate dynamic array field class element.");
        goto end;
    }

    cur_path_stack_pop(ctx);
    update_parent_field_class_alignment(ctx, fc->base.base.alignment);

end:
    return ret;
}

static inline int translate_bool_field_class(struct ctx *ctx)
{
    struct fs_sink_ctf_field_class_bool *fc = fs_sink_ctf_field_class_bool_create(
        cur_path_stack_top(ctx)->ir_fc, cur_path_stack_top(ctx)->index_in_parent);

    BT_ASSERT(fc);
    append_to_parent_field_class(ctx, &fc->base.base);
    return 0;
}

static inline int translate_bit_array_field_class(struct ctx *ctx)
{
    struct fs_sink_ctf_field_class_bit_array *fc = fs_sink_ctf_field_class_bit_array_create(
        cur_path_stack_top(ctx)->ir_fc, cur_path_stack_top(ctx)->index_in_parent);

    BT_ASSERT(fc);
    append_to_parent_field_class(ctx, &fc->base);
    return 0;
}

static inline int translate_integer_field_class(struct ctx *ctx)
{
    struct fs_sink_ctf_field_class_int *fc = fs_sink_ctf_field_class_int_create(
        cur_path_stack_top(ctx)->ir_fc, cur_path_stack_top(ctx)->index_in_parent);

    BT_ASSERT(fc);
    append_to_parent_field_class(ctx, &fc->base.base);
    return 0;
}

static inline int translate_real_field_class(struct ctx *ctx)
{
    struct fs_sink_ctf_field_class_float *fc = fs_sink_ctf_field_class_float_create(
        cur_path_stack_top(ctx)->ir_fc, cur_path_stack_top(ctx)->index_in_parent);

    BT_ASSERT(fc);
    append_to_parent_field_class(ctx, &fc->base.base);
    return 0;
}

static inline int translate_string_field_class(struct ctx *ctx)
{
    struct fs_sink_ctf_field_class_string *fc = fs_sink_ctf_field_class_string_create(
        cur_path_stack_top(ctx)->ir_fc, cur_path_stack_top(ctx)->index_in_parent);

    BT_ASSERT(fc);
    append_to_parent_field_class(ctx, &fc->base);
    return 0;
}

/*
 * Translates a field class, recursively.
 *
 * The field class's IR field class, parent field class, and index
 * within its parent are in the context's current path's top element
 * (cur_path_stack_top()).
 */
static int translate_field_class(struct ctx *ctx)
{
    int ret;
    bt_field_class_type ir_fc_type = bt_field_class_get_type(cur_path_stack_top(ctx)->ir_fc);

    if (ir_fc_type == BT_FIELD_CLASS_TYPE_BOOL) {
        ret = translate_bool_field_class(ctx);
    } else if (ir_fc_type == BT_FIELD_CLASS_TYPE_BIT_ARRAY) {
        ret = translate_bit_array_field_class(ctx);
    } else if (bt_field_class_type_is(ir_fc_type, BT_FIELD_CLASS_TYPE_INTEGER)) {
        ret = translate_integer_field_class(ctx);
    } else if (bt_field_class_type_is(ir_fc_type, BT_FIELD_CLASS_TYPE_REAL)) {
        ret = translate_real_field_class(ctx);
    } else if (ir_fc_type == BT_FIELD_CLASS_TYPE_STRING) {
        ret = translate_string_field_class(ctx);
    } else if (ir_fc_type == BT_FIELD_CLASS_TYPE_STRUCTURE) {
        ret = translate_structure_field_class(ctx);
    } else if (ir_fc_type == BT_FIELD_CLASS_TYPE_STATIC_ARRAY) {
        ret = translate_static_array_field_class(ctx);
    } else if (bt_field_class_type_is(ir_fc_type, BT_FIELD_CLASS_TYPE_DYNAMIC_ARRAY)) {
        ret = translate_dynamic_array_field_class(ctx);
    } else if (bt_field_class_type_is(ir_fc_type, BT_FIELD_CLASS_TYPE_OPTION)) {
        ret = translate_option_field_class(ctx);
    } else if (bt_field_class_type_is(ir_fc_type, BT_FIELD_CLASS_TYPE_VARIANT)) {
        ret = translate_variant_field_class(ctx);
    } else {
        bt_common_abort();
    }

    return ret;
}

static int set_field_ref(struct fs_sink_ctf_field_class *fc, const char *fc_name,
                         struct fs_sink_ctf_field_class *parent_fc)
{
    int ret = 0;
    GString *field_ref = NULL;
    bool is_before;
    const char *tgt_type;
    struct fs_sink_ctf_field_class_struct *parent_struct_fc =
        fs_sink_ctf_field_class_as_struct(parent_fc);
    uint64_t i;
    unsigned int suffix = 0;

    if (!fc_name || !parent_fc || parent_fc->type != FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT) {
        /* Not supported */
        ret = -1;
        goto end;
    }

    switch (fc->type) {
    case FS_SINK_CTF_FIELD_CLASS_TYPE_OPTION:
    {
        /*
         * CTF 1.8 does not support the option field class type.
         * To write something anyway, this component translates
         * this type to a variant field class where the options
         * are:
         *
         * * An empty structure field class.
         * * The optional field class itself.
         *
         * Because the option field class becomes a CTF variant
         * field class, we use the term "tag" too here.
         *
         * The "tag" is always generated/before in that case (an
         * 8-bit unsigned enumeration field class).
         */
        struct fs_sink_ctf_field_class_option *opt_fc = fs_sink_ctf_field_class_as_option(fc);

        field_ref = opt_fc->tag_ref;
        is_before = true;
        tgt_type = "tag";
        break;
    }
    case FS_SINK_CTF_FIELD_CLASS_TYPE_SEQUENCE:
    {
        struct fs_sink_ctf_field_class_sequence *seq_fc = fs_sink_ctf_field_class_as_sequence(fc);

        field_ref = seq_fc->length_ref;
        is_before = seq_fc->length_is_before;
        tgt_type = "len";
        break;
    }
    case FS_SINK_CTF_FIELD_CLASS_TYPE_VARIANT:
    {
        struct fs_sink_ctf_field_class_variant *var_fc = fs_sink_ctf_field_class_as_variant(fc);

        field_ref = var_fc->tag_ref;
        is_before = var_fc->tag_is_before;
        tgt_type = "tag";
        break;
    }
    default:
        bt_common_abort();
    }

    BT_ASSERT(field_ref);

    if (!is_before) {
        goto end;
    }

    /* Initial field ref */
    g_string_printf(field_ref, "__%s_%s", fc_name, tgt_type);

    /*
     * Make sure field ref does not clash with an existing field
     * class name within the same parent structure field class.
     */
    while (true) {
        bool name_ok = true;

        for (i = 0; i < parent_struct_fc->members->len; i++) {
            struct fs_sink_ctf_named_field_class *named_fc =
                fs_sink_ctf_field_class_struct_borrow_member_by_index(parent_struct_fc, i);

            if (strcmp(field_ref->str, named_fc->name->str) == 0) {
                /* Name clash */
                name_ok = false;
                break;
            }
        }

        if (name_ok) {
            /* No clash: we're done */
            break;
        }

        /* Append suffix and try again */
        g_string_printf(field_ref, "__%s_%s_%u", fc_name, tgt_type, suffix);
        suffix++;
    }

end:
    return ret;
}

/*
 * This function recursively sets field refs of sequence and variant
 * field classes when they are immediately before, avoiding name clashes
 * with existing field class names.
 *
 * It can fail at this point if, for example, a sequence field class of
 * which to set the length's field ref has something else than a
 * structure field class as its parent: in this case, there's no
 * location to place the length field class immediately before the
 * sequence field class.
 */
static int set_field_refs(struct fs_sink_ctf_field_class * const fc, const char *fc_name,
                          struct fs_sink_ctf_field_class *parent_fc)
{
    int ret = 0;
    enum fs_sink_ctf_field_class_type fc_type;
    BT_ASSERT(fc);

    fc_type = fc->type;

    switch (fc_type) {
    case FS_SINK_CTF_FIELD_CLASS_TYPE_OPTION:
    {
        struct fs_sink_ctf_field_class_option *opt_fc = fs_sink_ctf_field_class_as_option(fc);

        ret = set_field_ref(fc, fc_name, parent_fc);
        if (ret) {
            goto end;
        }

        ret = set_field_refs(opt_fc->content_fc, NULL, fc);
        if (ret) {
            goto end;
        }

        break;
    }
    case FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT:
    case FS_SINK_CTF_FIELD_CLASS_TYPE_VARIANT:
    {
        uint64_t i;
        uint64_t len;
        struct fs_sink_ctf_field_class_struct *struct_fc = NULL;
        struct fs_sink_ctf_field_class_variant *var_fc = NULL;
        struct fs_sink_ctf_named_field_class *named_fc;

        if (fc_type == FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT) {
            struct_fc = fs_sink_ctf_field_class_as_struct(fc);
            len = struct_fc->members->len;
        } else {
            var_fc = fs_sink_ctf_field_class_as_variant(fc);
            len = var_fc->options->len;
            ret = set_field_ref(fc, fc_name, parent_fc);
            if (ret) {
                goto end;
            }
        }

        for (i = 0; i < len; i++) {
            if (fc_type == FS_SINK_CTF_FIELD_CLASS_TYPE_STRUCT) {
                named_fc = fs_sink_ctf_field_class_struct_borrow_member_by_index(struct_fc, i);
            } else {
                named_fc = fs_sink_ctf_field_class_variant_borrow_option_by_index(var_fc, i);
            }

            ret = set_field_refs(named_fc->fc, named_fc->name->str, fc);
            if (ret) {
                goto end;
            }
        }

        break;
    }
    case FS_SINK_CTF_FIELD_CLASS_TYPE_ARRAY:
    case FS_SINK_CTF_FIELD_CLASS_TYPE_SEQUENCE:
    {
        struct fs_sink_ctf_field_class_array_base *array_base_fc =
            fs_sink_ctf_field_class_as_array_base(fc);

        if (fc_type == FS_SINK_CTF_FIELD_CLASS_TYPE_SEQUENCE) {
            ret = set_field_ref(fc, fc_name, parent_fc);
            if (ret) {
                goto end;
            }
        }

        ret = set_field_refs(array_base_fc->elem_fc, NULL, fc);
        if (ret) {
            goto end;
        }

        break;
    }
    default:
        break;
    }

end:
    return ret;
}

/*
 * This function translates a root scope trace IR field class to
 * a CTF IR field class.
 *
 * The resulting CTF IR field class is written to `*fc` so that it
 * exists as the parent object's (stream class or event class) true root
 * field class during the recursive translation for resolving purposes.
 * This is also why this function creates the empty structure field
 * class and then calls translate_structure_field_class_members() to
 * fill it.
 */
static int translate_scope_field_class(struct ctx *ctx, bt_field_path_scope scope,
                                       struct fs_sink_ctf_field_class **fc,
                                       const bt_field_class *ir_fc)
{
    int ret = 0;

    if (!ir_fc) {
        goto end;
    }

    BT_ASSERT(bt_field_class_get_type(ir_fc) == BT_FIELD_CLASS_TYPE_STRUCTURE);
    BT_ASSERT(fc);
    *fc = &fs_sink_ctf_field_class_struct_create_empty(ir_fc, UINT64_C(-1))->base;
    BT_ASSERT(*fc);
    ctx->cur_scope = scope;
    BT_ASSERT(ctx->cur_path->len == 0);
    ret = cur_path_stack_push(ctx, UINT64_C(-1), NULL, false, ir_fc, NULL);
    if (ret) {
        BT_COMP_LOGE("Cannot translate scope structure field class: "
                     "scope=%d",
                     scope);
        goto end;
    }

    ret =
        translate_structure_field_class_members(ctx, fs_sink_ctf_field_class_as_struct(*fc), ir_fc);
    if (ret) {
        BT_COMP_LOGE("Cannot translate scope structure field class: "
                     "scope=%d",
                     scope);
        goto end;
    }

    cur_path_stack_pop(ctx);

    /* Set field refs for preceding targets */
    ret = set_field_refs(*fc, NULL, NULL);

end:
    return ret;
}

static inline void ctx_init(struct ctx *ctx, struct fs_sink_comp *fs_sink)
{
    memset(ctx, 0, sizeof(struct ctx));
    ctx->cur_path = g_array_new(FALSE, TRUE, sizeof(struct field_path_elem));
    BT_ASSERT(ctx->cur_path);
    ctx->log_level = fs_sink->log_level;
    ctx->self_comp = fs_sink->self_comp;
}

static inline void ctx_fini(struct ctx *ctx)
{
    if (ctx->cur_path) {
        g_array_free(ctx->cur_path, TRUE);
        ctx->cur_path = NULL;
    }
}

static int translate_event_class(struct fs_sink_comp *fs_sink, struct fs_sink_ctf_stream_class *sc,
                                 const bt_event_class *ir_ec,
                                 struct fs_sink_ctf_event_class **out_ec)
{
    int ret = 0;
    struct ctx ctx;
    struct fs_sink_ctf_event_class *ec;

    BT_ASSERT(sc);
    BT_ASSERT(ir_ec);

    ctx_init(&ctx, fs_sink);
    ec = fs_sink_ctf_event_class_create(sc, ir_ec);
    BT_ASSERT(ec);
    ctx.cur_sc = sc;
    ctx.cur_ec = ec;
    ret = translate_scope_field_class(
        &ctx, BT_FIELD_PATH_SCOPE_EVENT_SPECIFIC_CONTEXT, &ec->spec_context_fc,
        bt_event_class_borrow_specific_context_field_class_const(ir_ec));
    if (ret) {
        goto end;
    }

    ret = translate_scope_field_class(&ctx, BT_FIELD_PATH_SCOPE_EVENT_PAYLOAD, &ec->payload_fc,
                                      bt_event_class_borrow_payload_field_class_const(ir_ec));
    if (ret) {
        goto end;
    }

end:
    ctx_fini(&ctx);
    *out_ec = ec;
    return ret;
}

BT_HIDDEN
int try_translate_event_class_trace_ir_to_ctf_ir(struct fs_sink_comp *fs_sink,
                                                 struct fs_sink_ctf_stream_class *sc,
                                                 const bt_event_class *ir_ec,
                                                 struct fs_sink_ctf_event_class **out_ec)
{
    int ret = 0;

    BT_ASSERT(sc);
    BT_ASSERT(ir_ec);

    /* Check in hash table first */
    *out_ec = (fs_sink_ctf_event_class *) g_hash_table_lookup(sc->event_classes_from_ir, ir_ec);
    if (G_LIKELY(*out_ec)) {
        goto end;
    }

    ret = translate_event_class(fs_sink, sc, ir_ec, out_ec);

end:
    return ret;
}

static bool default_clock_class_name_exists(struct fs_sink_ctf_trace *trace, const char *name)
{
    bool exists = false;
    uint64_t i;

    for (i = 0; i < trace->stream_classes->len; i++) {
        struct fs_sink_ctf_stream_class *sc =
            (fs_sink_ctf_stream_class *) trace->stream_classes->pdata[i];

        if (sc->default_clock_class_name->len == 0) {
            /* No default clock class */
            continue;
        }

        if (strcmp(sc->default_clock_class_name->str, name) == 0) {
            exists = true;
            goto end;
        }
    }

end:
    return exists;
}

static void make_unique_default_clock_class_name(struct fs_sink_ctf_stream_class *sc)
{
    unsigned int suffix = 0;
    char buf[16];

    g_string_assign(sc->default_clock_class_name, "");
    sprintf(buf, "default");

    while (default_clock_class_name_exists(sc->trace, buf)) {
        sprintf(buf, "default%u", suffix);
        suffix++;
    }

    g_string_assign(sc->default_clock_class_name, buf);
}

static int translate_stream_class(struct fs_sink_comp *fs_sink, struct fs_sink_ctf_trace *trace,
                                  const bt_stream_class *ir_sc,
                                  struct fs_sink_ctf_stream_class **out_sc)
{
    int ret = 0;
    struct ctx ctx;

    BT_ASSERT(trace);
    BT_ASSERT(ir_sc);
    ctx_init(&ctx, fs_sink);
    *out_sc = fs_sink_ctf_stream_class_create(trace, ir_sc);
    BT_ASSERT(*out_sc);

    /* Set default clock class's protected name, if any */
    if ((*out_sc)->default_clock_class) {
        const char *name = bt_clock_class_get_name((*out_sc)->default_clock_class);

        if (name) {
            /* Try original name, protected */
            g_string_assign((*out_sc)->default_clock_class_name, "");

            if (must_protect_identifier(name)) {
                g_string_assign((*out_sc)->default_clock_class_name, "_");
            }

            g_string_assign((*out_sc)->default_clock_class_name, name);
            if (!ist_valid_identifier((*out_sc)->default_clock_class_name->str)) {
                /* Invalid: create a new name */
                make_unique_default_clock_class_name(*out_sc);
            }
        } else {
            /* No name: create a name */
            make_unique_default_clock_class_name(*out_sc);
        }
    }

    ctx.cur_sc = *out_sc;
    ret = translate_scope_field_class(
        &ctx, BT_FIELD_PATH_SCOPE_PACKET_CONTEXT, &(*out_sc)->packet_context_fc,
        bt_stream_class_borrow_packet_context_field_class_const(ir_sc));
    if (ret) {
        goto error;
    }

    if ((*out_sc)->packet_context_fc) {
        /*
         * Make sure the structure field class's alignment is
         * enough: 8 is what we use for our own special members
         * in the packet context.
         */
        fs_sink_ctf_field_class_struct_align_at_least(
            fs_sink_ctf_field_class_as_struct((*out_sc)->packet_context_fc), 8);
    }

    ret = translate_scope_field_class(
        &ctx, BT_FIELD_PATH_SCOPE_EVENT_COMMON_CONTEXT, &(*out_sc)->event_common_context_fc,
        bt_stream_class_borrow_event_common_context_field_class_const(ir_sc));
    if (ret) {
        goto error;
    }

    goto end;

error:
    fs_sink_ctf_stream_class_destroy(*out_sc);
    *out_sc = NULL;

end:
    ctx_fini(&ctx);
    return ret;
}

BT_HIDDEN
int try_translate_stream_class_trace_ir_to_ctf_ir(struct fs_sink_comp *fs_sink,
                                                  struct fs_sink_ctf_trace *trace,
                                                  const bt_stream_class *ir_sc,
                                                  struct fs_sink_ctf_stream_class **out_sc)
{
    int ret = 0;
    uint64_t i;

    BT_ASSERT(trace);
    BT_ASSERT(ir_sc);

    for (i = 0; i < trace->stream_classes->len; i++) {
        *out_sc = (fs_sink_ctf_stream_class *) trace->stream_classes->pdata[i];

        if ((*out_sc)->ir_sc == ir_sc) {
            goto end;
        }
    }

    ret = translate_stream_class(fs_sink, trace, ir_sc, out_sc);

end:
    return ret;
}

BT_HIDDEN
struct fs_sink_ctf_trace *translate_trace_trace_ir_to_ctf_ir(struct fs_sink_comp *fs_sink,
                                                             const bt_trace *ir_trace)
{
    uint64_t count;
    uint64_t i;
    struct fs_sink_ctf_trace *trace = NULL;

    /* Check that trace's environment is TSDL-compatible */
    count = bt_trace_get_environment_entry_count(ir_trace);
    for (i = 0; i < count; i++) {
        const char *name;
        const bt_value *val;

        bt_trace_borrow_environment_entry_by_index_const(ir_trace, i, &name, &val);

        if (!ist_valid_identifier(name)) {
            BT_COMP_LOG_CUR_LVL(BT_LOG_ERROR, fs_sink->log_level, fs_sink->self_comp,
                                "Unsupported trace class's environment entry name: "
                                "name=\"%s\"",
                                name);
            goto end;
        }

        switch (bt_value_get_type(val)) {
        case BT_VALUE_TYPE_SIGNED_INTEGER:
        case BT_VALUE_TYPE_STRING:
            break;
        default:
            BT_COMP_LOG_CUR_LVL(BT_LOG_ERROR, fs_sink->log_level, fs_sink->self_comp,
                                "Unsupported trace class's environment entry value type: "
                                "type=%s",
                                bt_common_value_type_string(bt_value_get_type(val)));
            goto end;
        }
    }

    trace = fs_sink_ctf_trace_create(ir_trace);
    BT_ASSERT(trace);

end:
    return trace;
}