/*

 * Copyright (c) 2009-2016 Petri Lehtinen <petri@digip.org>

 * Copyright (c) 2011-2012 Graeme Smecher <graeme.smecher@mail.mcgill.ca>

 *

 * Jansson is free software; you can redistribute it and/or modify

 * it under the terms of the MIT license. See LICENSE for details.

 */

#include "jansson.h"

#include "jansson_private.h"

#include "utf.h"

#include <string.h>

typedef struct {

    int line;

    int column;

    size_t pos;

    char token;

} token_t;

typedef struct {

    const char *start;

    const char *fmt;

    token_t prev_token;

    token_t token;

    token_t next_token;

    json_error_t *error;

    size_t flags;

    int line;

    int column;

    size_t pos;

    int has_error;

} scanner_t;

#define token(scanner) ((scanner)->token.token)

static const char *const type_names[] = {"object", "array", "string", "integer",

                                         "real",   "true",  "false",  "null"};

#define type_name(x) type_names[json_typeof(x)]

static const char unpack_value_starters[] = "{[siIbfFOon";

static void scanner_init(scanner_t *s, json_error_t *error, size_t flags,

                         const char *fmt) {

    s->error = error;

    s->flags = flags;

    s->fmt = s->start = fmt;

    memset(&s->prev_token, 0, sizeof(token_t));

    memset(&s->token, 0, sizeof(token_t));

    memset(&s->next_token, 0, sizeof(token_t));

    s->line = 1;

    s->column = 0;

    s->pos = 0;

    s->has_error = 0;

}

static void next_token(scanner_t *s) {

    const char *t;

    s->prev_token = s->token;

    if (s->next_token.line) {

        s->token = s->next_token;

        s->next_token.line = 0;

        return;

    }

    if (!token(s) && !*s->fmt)

        return;

    t = s->fmt;

    s->column++;

    s->pos++;

    /* skip space and ignored chars */

    while (*t == ' ' || *t == '\t' || *t == '\n' || *t == ',' || *t == ':') {

        if (*t == '\n') {

            s->line++;

            s->column = 1;

        } else

            s->column++;

        s->pos++;

        t++;

    }

    s->token.token = *t;

    s->token.line = s->line;

    s->token.column = s->column;

    s->token.pos = s->pos;

    if (*t)

        t++;

    s->fmt = t;

}

static void prev_token(scanner_t *s) {

    s->next_token = s->token;

    s->token = s->prev_token;

}

static void set_error(scanner_t *s, const char *source, enum json_error_code code,

                      const char *fmt, ...) {

    va_list ap;

    va_start(ap, fmt);

    jsonp_error_vset(s->error, s->token.line, s->token.column, s->token.pos, code, fmt,

                     ap);

    jsonp_error_set_source(s->error, source);

    va_end(ap);

}

static json_t *pack(scanner_t *s, va_list *ap);

/* ours will be set to 1 if jsonp_free() must be called for the result

   afterwards */

static char *read_string(scanner_t *s, va_list *ap, const char *purpose, size_t *out_len,

                         int *ours, int optional) {

    char t;

    strbuffer_t strbuff;

    const char *str;

    size_t length;

    next_token(s);

    t = token(s);

    prev_token(s);

    *ours = 0;

    if (t != '#' && t != '%' && t != '+') {

        /* Optimize the simple case */

        str = va_arg(*ap, const char *);

        if (!str) {

            if (!optional) {

                set_error(s, "<args>", json_error_null_value, "NULL %s", purpose);

                s->has_error = 1;

            }

            return NULL;

        }

        length = strlen(str);

        if (!utf8_check_string(str, length)) {

            set_error(s, "<args>", json_error_invalid_utf8, "Invalid UTF-8 %s", purpose);

            s->has_error = 1;

            return NULL;

        }

        *out_len = length;

        return (char *)str;

    } else if (optional) {

        set_error(s, "<format>", json_error_invalid_format,

                  "Cannot use '%c' on optional strings", t);

        s->has_error = 1;

        return NULL;

    }

    if (strbuffer_init(&strbuff)) {

        set_error(s, "<internal>", json_error_out_of_memory, "Out of memory");

        s->has_error = 1;

    }

    while (1) {

        str = va_arg(*ap, const char *);

        if (!str) {

            set_error(s, "<args>", json_error_null_value, "NULL %s", purpose);

            s->has_error = 1;

        }

        next_token(s);

        if (token(s) == '#') {

            int len = va_arg(*ap, int);

            if (len < 0) {

                set_error(s, "<args>", json_error_invalid_argument,

                          "Invalid length for %s: %d", purpose, len);

                s->has_error = 1;

                length = 0;

            } else {

                length = (size_t)len;

            }

        } else if (token(s) == '%') {

            length = va_arg(*ap, size_t);

        } else {

            prev_token(s);

            length = s->has_error ? 0 : strlen(str);

        }

        if (!s->has_error && strbuffer_append_bytes(&strbuff, str, length) == -1) {

            set_error(s, "<internal>", json_error_out_of_memory, "Out of memory");

            s->has_error = 1;

        }

        next_token(s);

        if (token(s) != '+') {

            prev_token(s);

            break;

        }

    }

    if (s->has_error) {

        strbuffer_close(&strbuff);

        return NULL;

    }

    if (!utf8_check_string(strbuff.value, strbuff.length)) {

        set_error(s, "<args>", json_error_invalid_utf8, "Invalid UTF-8 %s", purpose);

        strbuffer_close(&strbuff);

        s->has_error = 1;

        return NULL;

    }

    *out_len = strbuff.length;

    *ours = 1;

    return strbuffer_steal_value(&strbuff);

}

static json_t *pack_object(scanner_t *s, va_list *ap) {

    json_t *object = json_object();

    next_token(s);

    while (token(s) != '}') {

        char *key;

        size_t len;

        int ours;

        json_t *value;

        char valueOptional;

        if (!token(s)) {

            set_error(s, "<format>", json_error_invalid_format,

                      "Unexpected end of format string");

            goto error;

        }

        if (token(s) != 's') {

            set_error(s, "<format>", json_error_invalid_format,

                      "Expected format 's', got '%c'", token(s));

            goto error;

        }

        key = read_string(s, ap, "object key", &len, &ours, 0);

        next_token(s);

        next_token(s);

        valueOptional = token(s);

        prev_token(s);

        value = pack(s, ap);

        if (!value) {

            if (ours)

                jsonp_free(key);

            if (valueOptional != '*') {

                set_error(s, "<args>", json_error_null_value, "NULL object value");

                s->has_error = 1;

            }

            next_token(s);

            continue;

        }

        if (s->has_error)

            json_decref(value);

        if (!s->has_error && json_object_setn_new_nocheck(object, key, len, value)) {

            set_error(s, "<internal>", json_error_out_of_memory,

                      "Unable to add key \"%s\"", key);

            s->has_error = 1;

        }

        if (ours)

            jsonp_free(key);

        next_token(s);

    }

    if (!s->has_error)

        return object;

error:

    json_decref(object);

    return NULL;

}

static json_t *pack_array(scanner_t *s, va_list *ap) {

    json_t *array = json_array();

    next_token(s);

    while (token(s) != ']') {

        json_t *value;

        char valueOptional;

        if (!token(s)) {

            set_error(s, "<format>", json_error_invalid_format,

                      "Unexpected end of format string");

            /* Format string errors are unrecoverable. */

            goto error;

        }

        next_token(s);

        valueOptional = token(s);

        prev_token(s);

        value = pack(s, ap);

        if (!value) {

            if (valueOptional != '*') {

                s->has_error = 1;

            }

            next_token(s);

            continue;

        }

        if (s->has_error)

            json_decref(value);

        if (!s->has_error && json_array_append_new(array, value)) {

            set_error(s, "<internal>", json_error_out_of_memory,

                      "Unable to append to array");

            s->has_error = 1;

        }

        next_token(s);

    }

    if (!s->has_error)

        return array;

error:

    json_decref(array);

    return NULL;

}

static json_t *pack_string(scanner_t *s, va_list *ap) {

    char *str;

    char t;

    size_t len;

    int ours;

    int optional;

    next_token(s);

    t = token(s);

    optional = t == '?' || t == '*';

    if (!optional)

        prev_token(s);

    str = read_string(s, ap, "string", &len, &ours, optional);

    if (!str)

        return t == '?' && !s->has_error ? json_null() : NULL;

    if (s->has_error) {

        /* It's impossible to reach this point if ours != 0, do not free str. */

        return NULL;

    }

    if (ours)

        return jsonp_stringn_nocheck_own(str, len);

    return json_stringn_nocheck(str, len);

}

static json_t *pack_object_inter(scanner_t *s, va_list *ap, int need_incref) {

    json_t *json;

    char ntoken;

    next_token(s);

    ntoken = token(s);

    if (ntoken != '?' && ntoken != '*')

        prev_token(s);

    json = va_arg(*ap, json_t *);

    if (json)

        return need_incref ? json_incref(json) : json;

    switch (ntoken) {

        case '?':

            return json_null();

        case '*':

            return NULL;

        default:

            break;

    }

    set_error(s, "<args>", json_error_null_value, "NULL object");

    s->has_error = 1;

    return NULL;

}

static json_t *pack_integer(scanner_t *s, json_int_t value) {

    json_t *json = json_integer(value);

    if (!json) {

        set_error(s, "<internal>", json_error_out_of_memory, "Out of memory");

        s->has_error = 1;

    }

    return json;

}

static json_t *pack_real(scanner_t *s, double value) {

    /* Allocate without setting value so we can identify OOM error. */

    json_t *json = json_real(0.0);

    if (!json) {

        set_error(s, "<internal>", json_error_out_of_memory, "Out of memory");

        s->has_error = 1;

        return NULL;

    }

    if (json_real_set(json, value)) {

        json_decref(json);

        set_error(s, "<args>", json_error_numeric_overflow,

                  "Invalid floating point value");

        s->has_error = 1;

        return NULL;

    }

    return json;

}

static json_t *pack(scanner_t *s, va_list *ap) {

    switch (token(s)) {

        case '{':

            return pack_object(s, ap);

        case '[':

            return pack_array(s, ap);

        case 's': /* string */

            return pack_string(s, ap);

        case 'n': /* null */

            return json_null();

        case 'b': /* boolean */

            return va_arg(*ap, int) ? json_true() : json_false();

        case 'i': /* integer from int */

            return pack_integer(s, va_arg(*ap, int));

        case 'I': /* integer from json_int_t */

            return pack_integer(s, va_arg(*ap, json_int_t));

        case 'f': /* real */

            return pack_real(s, va_arg(*ap, double));

        case 'O': /* a json_t object; increments refcount */

            return pack_object_inter(s, ap, 1);

        case 'o': /* a json_t object; doesn't increment refcount */

            return pack_object_inter(s, ap, 0);

        default:

            set_error(s, "<format>", json_error_invalid_format,

                      "Unexpected format character '%c'", token(s));

            s->has_error = 1;

            return NULL;

    }

}

static int unpack(scanner_t *s, json_t *root, va_list *ap, const char *key);

static int unpack_object(scanner_t *s, json_t *root, va_list *ap,

                         const char *parent_key) {

    int ret = -1;

    int strict = 0;

    int gotopt = 0;

    /* Use a set (emulated by a hashtable) to check that all object

       keys are accessed. Checking that the correct number of keys

       were accessed is not enough, as the same key can be unpacked

       multiple times.

    */

    hashtable_t key_set;

    if (hashtable_init(&key_set)) {

        set_error(s, "<internal>", json_error_out_of_memory, "Out of memory");

        return -1;

    }

    if (root && !json_is_object(root)) {

        set_error(s, "<validation>", json_error_wrong_type, "Expected object, got %s%s%s",

                  type_name(root), parent_key ? " for key " : "",

                  parent_key ? parent_key : "");

        goto out;

    }

    next_token(s);

    while (token(s) != '}') {

        const char *key;

        size_t key_len;

        json_t *value;

        int opt = 0;

        if (strict != 0) {

            set_error(s, "<format>", json_error_invalid_format,

                      "Expected '}' after '%c', got '%c'", (strict == 1 ? '!' : '*'),

                      token(s));

            goto out;

        }

        if (!token(s)) {

            set_error(s, "<format>", json_error_invalid_format,

                      "Unexpected end of format string");

            goto out;

        }

        if (token(s) == '!' || token(s) == '*') {

            strict = (token(s) == '!' ? 1 : -1);

            next_token(s);

            continue;

        }

        if (token(s) != 's') {

            set_error(s, "<format>", json_error_invalid_format,

                      "Expected format 's', got '%c'", token(s));

            goto out;

        }

        key = va_arg(*ap, const char *);

        if (!key) {

            set_error(s, "<args>", json_error_null_value, "NULL object key");

            goto out;

        }

        key_len = strlen(key);

        next_token(s);

        if (token(s) == '?') {

            opt = gotopt = 1;

            next_token(s);

        }

        if (!root) {

            /* skipping */

            value = NULL;

        } else {

            value = json_object_getn(root, key, key_len);

            if (!value && !opt) {

                set_error(s, "<validation>", json_error_item_not_found,

                          "Object item not found: %s", key);

                goto out;

            }

        }

        if (unpack(s, value, ap, key))

            goto out;

        hashtable_set(&key_set, key, key_len, json_null());

        next_token(s);

    }

    if (strict == 0 && (s->flags & JSON_STRICT))

        strict = 1;

    if (root && strict == 1) {

        /* We need to check that all non optional items have been parsed */

        const char *key;

        size_t key_len;

        /* keys_res is 1 for uninitialized, 0 for success, -1 for error. */

        int keys_res = 1;

        strbuffer_t unrecognized_keys;

        json_t *value;

        long unpacked = 0;

        if (gotopt || json_object_size(root) != key_set.size) {

            json_object_keylen_foreach(root, key, key_len, value) {

                if (!hashtable_get(&key_set, key, key_len)) {

                    unpacked++;

                    /* Save unrecognized keys for the error message */

                    if (keys_res == 1) {

                        keys_res = strbuffer_init(&unrecognized_keys);

                    } else if (!keys_res) {

                        keys_res = strbuffer_append_bytes(&unrecognized_keys, ", ", 2);

                    }

                    if (!keys_res)

                        keys_res =

                            strbuffer_append_bytes(&unrecognized_keys, key, key_len);

                }

            }

        }

        if (unpacked) {

            set_error(s, "<validation>", json_error_end_of_input_expected,

                      "%li object item(s) left unpacked: %s", unpacked,

                      keys_res ? "<unknown>" : strbuffer_value(&unrecognized_keys));

            strbuffer_close(&unrecognized_keys);

            goto out;

        }

    }

    ret = 0;

out:

    hashtable_close(&key_set);

    return ret;

}

static int unpack_array(scanner_t *s, json_t *root, va_list *ap, const char *parent_key) {

    size_t i = 0;

    int strict = 0;

    if (root && !json_is_array(root)) {

        set_error(s, "<validation>", json_error_wrong_type, "Expected array, got %s%s%s",

                  type_name(root), parent_key ? " for key " : "",

                  parent_key ? parent_key : "");

        return -1;

    }

    next_token(s);

    while (token(s) != ']') {

        json_t *value;

        if (strict != 0) {

            set_error(s, "<format>", json_error_invalid_format,

                      "Expected ']' after '%c', got '%c'", (strict == 1 ? '!' : '*'),

                      token(s));

            return -1;

        }

        if (!token(s)) {

            set_error(s, "<format>", json_error_invalid_format,

                      "Unexpected end of format string");

            return -1;

        }

        if (token(s) == '!' || token(s) == '*') {

            strict = (token(s) == '!' ? 1 : -1);

            next_token(s);

            continue;

        }

        if (!strchr(unpack_value_starters, token(s))) {

            set_error(s, "<format>", json_error_invalid_format,

                      "Unexpected format character '%c'", token(s));

            return -1;

        }

        if (!root) {

            /* skipping */

            value = NULL;

        } else {

            value = json_array_get(root, i);

            if (!value) {

                set_error(s, "<validation>", json_error_index_out_of_range,

                          "Array index %lu out of range", (unsigned long)i);

                return -1;

            }

        }

        if (unpack(s, value, ap, NULL))

            return -1;

        next_token(s);

        i++;

    }

    if (strict == 0 && (s->flags & JSON_STRICT))

        strict = 1;

    if (root && strict == 1 && i != json_array_size(root)) {

        long diff = (long)json_array_size(root) - (long)i;

        set_error(s, "<validation>", json_error_end_of_input_expected,

                  "%li array item(s) left unpacked", diff);

        return -1;

    }

    return 0;

}

static int unpack(scanner_t *s, json_t *root, va_list *ap, const char *key) {

    switch (token(s)) {

        case '{':

            return unpack_object(s, root, ap, key);

        case '[':

            return unpack_array(s, root, ap, key);

        case 's':

            if (root && !json_is_string(root)) {

                set_error(s, "<validation>", json_error_wrong_type,

                          "Expected string, got %s%s%s", type_name(root),

                          key ? " for key " : "", key ? key : "");

                return -1;

            }

            if (!(s->flags & JSON_VALIDATE_ONLY)) {

                const char **str_target;

                size_t *len_target = NULL;

                str_target = va_arg(*ap, const char **);

                if (!str_target) {

                    set_error(s, "<args>", json_error_null_value, "NULL string argument");

                    return -1;

                }

                next_token(s);

                if (token(s) == '%') {

                    len_target = va_arg(*ap, size_t *);

                    if (!len_target) {

                        set_error(s, "<args>", json_error_null_value,

                                  "NULL string length argument");

                        return -1;

                    }

                } else

                    prev_token(s);

                if (root) {

                    *str_target = json_string_value(root);

                    if (len_target)

                        *len_target = json_string_length(root);

                }

            }

            return 0;

        case 'i':

            if (root && !json_is_integer(root)) {

                set_error(s, "<validation>", json_error_wrong_type,

                          "Expected integer, got %s%s%s", type_name(root),

                          key ? " for key " : "", key ? key : "");

                return -1;

            }

            if (!(s->flags & JSON_VALIDATE_ONLY)) {

                int *target = va_arg(*ap, int *);

                if (root)

                    *target = (int)json_integer_value(root);

            }

            return 0;

        case 'I':

            if (root && !json_is_integer(root)) {

                set_error(s, "<validation>", json_error_wrong_type,

                          "Expected integer, got %s%s%s", type_name(root),

                          key ? " for key " : "", key ? key : "");

                return -1;

            }

            if (!(s->flags & JSON_VALIDATE_ONLY)) {

                json_int_t *target = va_arg(*ap, json_int_t *);

                if (root)

                    *target = json_integer_value(root);

            }

            return 0;

        case 'b':

            if (root && !json_is_boolean(root)) {

                set_error(s, "<validation>", json_error_wrong_type,

                          "Expected true or false, got %s%s%s", type_name(root),

                          key ? " for key " : "", key ? key : "");

                return -1;

            }

            if (!(s->flags & JSON_VALIDATE_ONLY)) {

                int *target = va_arg(*ap, int *);

                if (root)

                    *target = json_is_true(root);

            }

            return 0;

        case 'f':

            if (root && !json_is_real(root)) {

                set_error(s, "<validation>", json_error_wrong_type,

                          "Expected real, got %s%s%s", type_name(root),

                          key ? " for key " : "", key ? key : "");

                return -1;

            }

            if (!(s->flags & JSON_VALIDATE_ONLY)) {

                double *target = va_arg(*ap, double *);

                if (root)

                    *target = json_real_value(root);

            }

            return 0;

        case 'F':

            if (root && !json_is_number(root)) {

                set_error(s, "<validation>", json_error_wrong_type,

                          "Expected real or integer, got %s%s%s", type_name(root),

                          key ? " for key " : "", key ? key : "");

                return -1;

            }

            if (!(s->flags & JSON_VALIDATE_ONLY)) {

                double *target = va_arg(*ap, double *);

                if (root)

                    *target = json_number_value(root);

            }

            return 0;

        case 'O':

            if (root && !(s->flags & JSON_VALIDATE_ONLY))

                json_incref(root);

            /* Fall through */

        case 'o':

            if (!(s->flags & JSON_VALIDATE_ONLY)) {

                json_t **target = va_arg(*ap, json_t **);

                if (root)

                    *target = root;

            }

            return 0;

        case 'n':

            /* Never assign, just validate */

            if (root && !json_is_null(root)) {

                set_error(s, "<validation>", json_error_wrong_type,

                          "Expected null, got %s%s%s", type_name(root),

                          key ? " for key " : "", key ? key : "");

                return -1;

            }

            return 0;

        default:

            set_error(s, "<format>", json_error_invalid_format,

                      "Unexpected format character '%c'", token(s));

            return -1;

    }

}

json_t *json_vpack_ex(json_error_t *error, size_t flags, const char *fmt, va_list ap) {

    scanner_t s;

    va_list ap_copy;

    json_t *value;

    if (!fmt || !*fmt) {

        jsonp_error_init(error, "<format>");

        jsonp_error_set(error, -1, -1, 0, json_error_invalid_argument,

                        "NULL or empty format string");

        return NULL;

    }

    jsonp_error_init(error, NULL);

    scanner_init(&s, error, flags, fmt);

    next_token(&s);

    va_copy(ap_copy, ap);

    value = pack(&s, &ap_copy);

    va_end(ap_copy);

    /* This will cover all situations where s.has_error is true */

    if (!value)

        return NULL;

    next_token(&s);

    if (token(&s)) {

        json_decref(value);

        set_error(&s, "<format>", json_error_invalid_format,

                  "Garbage after format string");

        return NULL;

    }

    return value;

}

json_t *json_pack_ex(json_error_t *error, size_t flags, const char *fmt, ...) {