src/printer_xml.c

/**
 * @file printer_xml.c
 * @author Michal Vasko <mvasko@cesnet.cz>
 * @author Radek Krejci <rkrejci@cesnet.cz>
 * @brief XML printer for libyang data structure
 *
 * Copyright (c) 2015 - 2019 CESNET, z.s.p.o.
 *
 * This source code is licensed under BSD 3-Clause License (the "License").
 * You may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://opensource.org/licenses/BSD-3-Clause
 */

#include "common.h"

#include <stdlib.h>
#include <string.h>

#include "log.h"
#include "plugins_types.h"
#include "printer_data.h"
#include "printer_internal.h"
#include "tree.h"
#include "tree_data.h"
#include "tree_schema.h"
#include "xml.h"

/**
 * @brief XML printer context.
 */
struct xmlpr_ctx {
    struct lyout *out;  /**< output specification */
    unsigned int level; /**< current indentation level: 0 - no formatting, >= 1 indentation levels */
    int options;        /**< [Data printer flags](@ref dataprinterflags) */
    int toplevel;       /**< top-level flag */
};

#define LEVEL ctx->level                     /**< current level */
#define INDENT ((LEVEL) ? (LEVEL)*2 : 0),""  /**< indentation parameters for printer functions */
#define LEVEL_INC if (LEVEL) {LEVEL++;}      /**< increase indentation level */
#define LEVEL_DEC if (LEVEL) {LEVEL--;}      /**< decrease indentation level */

/**
 * TODO
 */
struct mlist {
    struct mlist *next;
    struct lys_module *module;
} *mlist = NULL, *mlist_new;

static LY_ERR
modlist_add(struct mlist **mlist, const struct lys_module *mod)
{
    struct mlist *iter;

    for (iter = *mlist; iter; iter = iter->next) {
        if (mod == iter->module) {
            break;
        }
    }

    if (!iter) {
        iter = malloc(sizeof *iter);
        LY_CHECK_ERR_RET(!iter, LOGMEM(mod->ctx), LY_EMEM);
        iter->next = *mlist;
        iter->module = (struct lys_module *)mod;
        *mlist = iter;
    }

    return LY_SUCCESS;
}

/**
 * TODO
 */
static void
xml_print_ns(struct xmlpr_ctx *ctx, const struct lyd_node *node)
{
    struct lyd_node *next, *cur, *child;
    struct lyd_attr *attr;

    struct mlist *mlist = NULL, *miter;
#if 0
    const struct lys_module *wdmod = NULL;
#endif
    /* add node attribute modules */
    for (attr = node->attr; attr; attr = attr->next) {
        if (!strcmp(node->schema->name, "filter") &&
                (!strcmp(node->schema->module->name, "ietf-netconf") ||
                 !strcmp(node->schema->module->name, "notifications"))) {
            /* exception for NETCONF's filter attributes */
            continue;
        } else if (modlist_add(&mlist, attr->annotation->module)) {
            goto print;
        }
    }

    /* add node children nodes and attribute modules */
    switch (node->schema->nodetype) {
    case LYS_LEAFLIST:
    case LYS_LEAF:
        /* TODO ietf-netconf-with-defaults namespace */
#if 0
        if (node->dflt && (options & (LYP_WD_ALL_TAG | LYP_WD_IMPL_TAG))) {
            /* get with-defaults module and print its namespace */
            wdmod = ly_ctx_get_module(node->schema->module->ctx, "ietf-netconf-with-defaults", NULL, 1);
            if (wdmod && modlist_add(&mlist, wdmod)) {
                goto print;
            }
        }
#endif
        break;
    case LYS_CONTAINER:
    case LYS_LIST:
    case LYS_ACTION:
    case LYS_NOTIF:
#if 0
        if (options & (LYP_WD_ALL_TAG | LYP_WD_IMPL_TAG)) {
            /* get with-defaults module and print its namespace */
            wdmod = ly_ctx_get_module(node->schema->module->ctx, "ietf-netconf-with-defaults", NULL, 1);
            if (wdmod && modlist_add(&mlist, wdmod)) {
                goto print;
            }
        }
#endif
        LY_LIST_FOR(((struct lyd_node_inner*)node)->child, child) {
            LYD_TREE_DFS_BEGIN(child, next, cur) {
                for (attr = cur->attr; attr; attr = attr->next) {
                    if (!strcmp(cur->schema->name, "filter") &&
                            (!strcmp(cur->schema->module->name, "ietf-netconf") ||
                             !strcmp(cur->schema->module->name, "notifications"))) {
                        /* exception for NETCONF's filter attributes */
                        continue;
                    } else {
                        /* TODO annotations r = modlist_add(&mlist, lys_main_module(attr->annotation->module)); */
                    }
                }
            LYD_TREE_DFS_END(child, next, cur)}
        }
        break;
    default:
        break;
    }

print:
    /* print used namespaces */
    while (mlist) {
        miter = mlist;
        mlist = mlist->next;

        ly_print(ctx->out, " xmlns:%s=\"%s\"", miter->module->prefix, miter->module->ns);
        free(miter);
    }
}

/**
 * @brief XML mapping of YANG modules to prefixes in values.
 *
 * Implementation of ly_clb_get_prefix
 */
static const char *
xml_print_get_prefix(const struct lys_module *mod, void *private)
{
    struct ly_set *ns_list = (struct ly_set*)private;

    ly_set_add(ns_list, (void*)mod, 0);
    return mod->prefix;
}

/**
 * TODO
 */
static LY_ERR
xml_print_attrs(struct xmlpr_ctx *ctx, const struct lyd_node *node)
{
    struct lyd_attr *attr;
#if 0
    const char **prefs, **nss;
    const char *xml_expr = NULL, *mod_name;
    uint32_t ns_count, i;
    int rpc_filter = 0;
    const struct lys_module *wdmod = NULL;
    char *p;
    size_t len;
#endif
    struct ly_set ns_list = {0};
    int dynamic;
    unsigned int u;

#if 0
    /* with-defaults */
    if (node->schema->nodetype & (LYS_LEAF | LYS_LEAFLIST)) {
        if ((node->dflt && (options & (LYP_WD_ALL_TAG | LYP_WD_IMPL_TAG))) ||
                (!node->dflt && (options & LYP_WD_ALL_TAG) && lyd_wd_default((struct lyd_node_leaf_list *)node))) {
            /* we have implicit OR explicit default node */
            /* get with-defaults module */
            wdmod = ly_ctx_get_module(node->schema->module->ctx, "ietf-netconf-with-defaults", NULL, 1);
            if (wdmod) {
                /* print attribute only if context include with-defaults schema */
                ly_print(out, " %s:default=\"true\"", wdmod->prefix);
            }
        }
    }
    /* technically, check for the extension get-filter-element-attributes from ietf-netconf */
    if (!strcmp(node->schema->name, "filter")
            && (!strcmp(node->schema->module->name, "ietf-netconf") || !strcmp(node->schema->module->name, "notifications"))) {
        rpc_filter = 1;
    }
#endif
    for (attr = node->attr; attr; attr = attr->next) {
        const char *value = attr->value.realtype->plugin->print(&attr->value, LYD_XML, xml_print_get_prefix, &ns_list, &dynamic);

        /* print namespaces connected with the values's prefixes */
        for (u = 0; u < ns_list.count; ++u) {
            const struct lys_module *mod = (const struct lys_module*)ns_list.objs[u];
            ly_print(ctx->out, " xmlns:%s=\"%s\"", mod->prefix, mod->ns);
        }
        ly_set_erase(&ns_list, NULL);

#if 0
        if (rpc_filter) {
            /* exception for NETCONF's filter's attributes */
            if (!strcmp(attr->name, "select")) {
                /* xpath content, we have to convert the JSON format into XML first */
                xml_expr = transform_json2xml(node->schema->module, attr->value_str, 0, &prefs, &nss, &ns_count);
                if (!xml_expr) {
                    /* error */
                    return EXIT_FAILURE;
                }

                for (i = 0; i < ns_count; ++i) {
                    ly_print(out, " xmlns:%s=\"%s\"", prefs[i], nss[i]);
                }
                free(prefs);
                free(nss);
            }
            ly_print(out, " %s=\"", attr->name);
        } else {
#endif
            ly_print(ctx->out, " %s:%s=\"", attr->annotation->module->prefix, attr->name);
#if 0
        }
#endif

        if (value && value[0]) {
            lyxml_dump_text(ctx->out, value, 1);
        }
        ly_print(ctx->out, "\"");
        if (dynamic) {
            free((void*)value);
        }
    }

    return LY_SUCCESS;
}

/**
 * @brief Print generic XML element despite of the data node type.
 *
 * Prints the element name, attributes and necessary namespaces.
 *
 * @param[in] ctx XML printer context.
 * @param[in] node Data node to be printed.
 * @return LY_ERR value.
 */
static LY_ERR
xml_print_node_open(struct xmlpr_ctx *ctx, const struct lyd_node *node)
{
    if (ctx->toplevel || !node->parent || node->schema->module != node->parent->schema->module) {
        /* print "namespace" */
        ly_print(ctx->out, "%*s<%s xmlns=\"%s\"", INDENT, node->schema->name, node->schema->module->ns);
    } else {
        ly_print(ctx->out, "%*s<%s", INDENT, node->schema->name);
    }

    if (ctx->toplevel) {
        xml_print_ns(ctx, node);
        ctx->toplevel = 0;
    }

    LY_CHECK_RET(xml_print_attrs(ctx, node));

    return LY_SUCCESS;
}

static LY_ERR xml_print_node(struct xmlpr_ctx *ctx, const struct lyd_node *node);

/**
 * @brief Print XML element representing lyd_node_term.
 *
 * @param[in] ctx XML printer context.
 * @param[in] node Data node to be printed.
 * @return LY_ERR value.
 */
static LY_ERR
xml_print_term(struct xmlpr_ctx *ctx, const struct lyd_node_term *node)
{
    struct ly_set ns_list = {0};
    unsigned int u;
    int dynamic;
    const char *value;

    LY_CHECK_RET(xml_print_node_open(ctx, (struct lyd_node *)node));
    value = node->value.realtype->plugin->print(&node->value, LYD_XML, xml_print_get_prefix, &ns_list, &dynamic);

    /* print namespaces connected with the values's prefixes */
    for (u = 0; u < ns_list.count; ++u) {
        const struct lys_module *mod = (const struct lys_module*)ns_list.objs[u];
        ly_print(ctx->out, "%sxmlns:%s=\"%s\"", u ? " " : "", mod->prefix, mod->ns);
    }
    ly_set_erase(&ns_list, NULL);

    if (!value || !value[0]) {
        ly_print(ctx->out, "/>%s", LEVEL ? "\n" : "");
    } else {
        ly_print(ctx->out, ">");
        lyxml_dump_text(ctx->out, value, 0);
        ly_print(ctx->out, "</%s>%s", node->schema->name, LEVEL ? "\n" : "");
    }
    if (dynamic) {
        free((void*)value);
    }

    return LY_SUCCESS;
}

/**
 * @brief Print XML element representing lyd_node_inner.
 *
 * @param[in] ctx XML printer context.
 * @param[in] node Data node to be printed.
 * @return LY_ERR value.
 */
static LY_ERR
xml_print_inner(struct xmlpr_ctx *ctx, const struct lyd_node_inner *node)
{
    LY_ERR ret;
    struct lyd_node *child;

    LY_CHECK_RET(xml_print_node_open(ctx, (struct lyd_node *)node));

    if (!node->child) {
        ly_print(ctx->out, "/>%s", ctx->level ? "\n" : "");
        return LY_SUCCESS;
    }

    /* children */
    ly_print(ctx->out, ">%s", ctx->level ? "\n" : "");

    LEVEL_INC;
    LY_LIST_FOR(node->child, child) {
        ret = xml_print_node(ctx, child);
        LY_CHECK_ERR_RET(ret, LEVEL_DEC, ret);
    }
    LEVEL_DEC;

    ly_print(ctx->out, "%*s</%s>%s", INDENT, node->schema->name, LEVEL ? "\n" : "");

    return LY_SUCCESS;
}

static LY_ERR
xml_print_anydata(struct xmlpr_ctx *ctx, const struct lyd_node_any *node)
{
    struct lyd_node_any *any = (struct lyd_node_any *)node;
    struct lyd_node *iter;
    int options_backup;

    LY_CHECK_RET(xml_print_node_open(ctx, (struct lyd_node *)node));

    if (!any->value.tree) {
        /* no content */
no_content:
        ly_print(ctx->out, "/>%s", LEVEL ? "\n" : "");
        return LY_SUCCESS;
    } else {
        switch (any->value_type) {
        case LYD_ANYDATA_DATATREE:
            /* close opening tag and print data */
            options_backup = ctx->options;
            ctx->options &= ~(LYDP_WITHSIBLINGS | LYDP_NETCONF);
            LEVEL_INC;

            ly_print(ctx->out, ">%s", LEVEL ? "\n" : "");
            LY_LIST_FOR(any->value.tree, iter) {
                if (xml_print_node(ctx, iter)) {
                    return EXIT_FAILURE;
                }
            }

            LEVEL_DEC;
            ctx->options = options_backup;
            break;
        case LYD_ANYDATA_STRING:
            /* escape XML-sensitive characters */
            if (!any->value.str[0]) {
                goto no_content;
            }
            /* close opening tag and print data */
            ly_print(ctx->out, ">");
            lyxml_dump_text(ctx->out, any->value.str, 0);
            break;
        case LYD_ANYDATA_XML:
            /* print without escaping special characters */
            if (!any->value.str[0]) {
                goto no_content;
            }
            ly_print(ctx->out, ">%s", any->value.str);
            break;
        case LYD_ANYDATA_JSON:
#if 0 /* TODO LYB format */
        case LYD_ANYDATA_LYB:
#endif
            /* JSON and LYB format is not supported */
            LOGWRN(node->schema->module->ctx, "Unable to print anydata content (type %d) as XML.", any->value_type);
            goto no_content;
        }

        /* closing tag */
        if (any->value_type == LYD_ANYDATA_DATATREE) {
            ly_print(ctx->out, "%*s</%s>%s", INDENT, node->schema->name, LEVEL ? "\n" : "");
        } else {
            ly_print(ctx->out, "</%s>%s", node->schema->name, LEVEL ? "\n" : "");
        }
    }

    return LY_SUCCESS;
}

/**
 * @brief Print XML element representing lyd_node.
 *
 * @param[in] ctx XML printer context.
 * @param[in] node Data node to be printed.
 * @return LY_ERR value.
 */
static LY_ERR
xml_print_node(struct xmlpr_ctx *ctx, const struct lyd_node *node)
{
    LY_ERR ret = LY_SUCCESS;

    if (!ly_should_print(node, ctx->options)) {
        /* do not print at all */
        return EXIT_SUCCESS;
    }

    switch (node->schema->nodetype) {
    case LYS_CONTAINER:
    case LYS_LIST:
    case LYS_NOTIF:
    case LYS_ACTION:
        ret = xml_print_inner(ctx, (const struct lyd_node_inner*)node);
        break;
    case LYS_LEAF:
    case LYS_LEAFLIST:
        ret = xml_print_term(ctx, (const struct lyd_node_term*)node);
        break;
    case LYS_ANYXML:
    case LYS_ANYDATA:
        ret = xml_print_anydata(ctx, (const struct lyd_node_any*)node);
        break;
    default:
        LOGINT(node->schema->module->ctx);
        ret = LY_EINT;
        break;
    }

    return ret;
}

LY_ERR
xml_print_data(struct lyout *out, const struct lyd_node *root, int options)
{
    const struct lyd_node *node;
    struct xmlpr_ctx ctx_ = {.out = out, .level = (options & LYDP_FORMAT ? 1 : 0), .options = options, .toplevel = 1}, *ctx = &ctx_;

    if (!root) {
        if (out->type == LYOUT_MEMORY || out->type == LYOUT_CALLBACK) {
            ly_print(out, "");
        }
        goto finish;
    }

    /* content */
    LY_LIST_FOR(root, node) {
        if (xml_print_node(ctx, node)) {
            return EXIT_FAILURE;
        }
        if (!(options & LYDP_WITHSIBLINGS)) {
            break;
        }
    }

finish:
    ly_print_flush(out);
    return LY_SUCCESS;
}