mysql_statement.c

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/*
  +----------------------------------------------------------------------+
  | Copyright (c) The PHP Group                                          |
  +----------------------------------------------------------------------+
  | This source file is subject to version 3.01 of the PHP license,      |
  | that is bundled with this package in the file LICENSE, and is        |
  | available through the world-wide-web at the following url:           |
  | https://www.php.net/license/3_01.txt                                 |
  | If you did not receive a copy of the PHP license and are unable to   |
  | obtain it through the world-wide-web, please send a note to          |
  | license@php.net so we can mail you a copy immediately.               |
  +----------------------------------------------------------------------+
  | Author: George Schlossnagle <george@omniti.com>                      |
  |         Wez Furlong <wez@php.net>                                    |
  |         Johannes Schlueter <johannes@mysql.com>                      |
  +----------------------------------------------------------------------+
*/
 
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
 
#include "php.h"
#include "php_ini.h"
#include "ext/standard/info.h"
#include "ext/pdo/php_pdo.h"
#include "ext/pdo/php_pdo_driver.h"
#include "php_pdo_mysql.h"
#include "php_pdo_mysql_int.h"
 
#ifdef PDO_USE_MYSQLND
#   define pdo_mysql_stmt_execute_prepared(stmt) pdo_mysql_stmt_execute_prepared_mysqlnd(stmt)
#else
#   define pdo_mysql_stmt_execute_prepared(stmt) pdo_mysql_stmt_execute_prepared_libmysql(stmt)
#endif
 
static void pdo_mysql_free_result(pdo_mysql_stmt *S)
{
    if (S->result) {
#ifndef PDO_USE_MYSQLND
        if (S->bound_result) {
            /* We can't use stmt->column_count here, because it gets reset before the
             * next_rowset handler is called. */
            unsigned column_count = mysql_num_fields(S->result);
            for (unsigned i = 0; i < column_count; i++) {
                efree(S->bound_result[i].buffer);
            }
 
            efree(S->bound_result);
            efree(S->out_null);
            efree(S->out_length);
            S->bound_result = NULL;
        }
#else
        if (S->current_row) {
            unsigned column_count = mysql_num_fields(S->result);
            for (unsigned i = 0; i < column_count; i++) {
                zval_ptr_dtor_nogc(&S->current_row[i]);
            }
            efree(S->current_row);
            S->current_row = NULL;
        }
#endif
        mysql_free_result(S->result);
        S->result = NULL;
    }
}
 
static int pdo_mysql_stmt_dtor(pdo_stmt_t *stmt) /* {{{ */
{
    pdo_mysql_stmt *S = (pdo_mysql_stmt*)stmt->driver_data;
 
    PDO_DBG_ENTER("pdo_mysql_stmt_dtor");
    PDO_DBG_INF_FMT("stmt=%p", S->stmt);
 
    pdo_mysql_free_result(S);
    if (S->einfo.errmsg) {
        pefree(S->einfo.errmsg, stmt->dbh->is_persistent);
        S->einfo.errmsg = NULL;
    }
    if (S->stmt) {
        mysql_stmt_close(S->stmt);
        S->stmt = NULL;
    }
 
#ifndef PDO_USE_MYSQLND
    if (S->params) {
        efree(S->params);
    }
    if (S->in_null) {
        efree(S->in_null);
    }
    if (S->in_length) {
        efree(S->in_length);
    }
#endif
 
    if (!S->done && !Z_ISUNDEF(stmt->database_object_handle)
        && IS_OBJ_VALID(EG(objects_store).object_buckets[Z_OBJ_HANDLE(stmt->database_object_handle)])
        && (!(OBJ_FLAGS(Z_OBJ(stmt->database_object_handle)) & IS_OBJ_FREE_CALLED))) {
        while (mysql_more_results(S->H->server)) {
            MYSQL_RES *res;
            if (mysql_next_result(S->H->server) != 0) {
                break;
            }
 
            res = mysql_store_result(S->H->server);
            if (res) {
                mysql_free_result(res);
            }
        }
    }
 
    efree(S);
    PDO_DBG_RETURN(1);
}
/* }}} */
 
static void pdo_mysql_stmt_set_row_count(pdo_stmt_t *stmt) /* {{{ */
{
    pdo_mysql_stmt *S = stmt->driver_data;
    zend_long row_count = (zend_long) mysql_stmt_affected_rows(S->stmt);
    if (row_count != (zend_long)-1) {
        stmt->row_count = row_count;
    }
}
/* }}} */
 
static int pdo_mysql_fill_stmt_from_result(pdo_stmt_t *stmt) /* {{{ */
{
    pdo_mysql_stmt *S = (pdo_mysql_stmt*)stmt->driver_data;
    pdo_mysql_db_handle *H = S->H;
    my_ulonglong row_count;
    PDO_DBG_ENTER("pdo_mysql_fill_stmt_from_result");
 
    row_count = mysql_affected_rows(H->server);
    if (row_count == (my_ulonglong)-1) {
        /* we either have a query that returned a result set or an error occurred
           lets see if we have access to a result set */
        if (!H->buffered) {
            S->result = mysql_use_result(H->server);
        } else {
            S->result = mysql_store_result(H->server);
        }
        if (NULL == S->result) {
            pdo_mysql_error_stmt(stmt);
            PDO_DBG_RETURN(0);
        }
 
        stmt->row_count = (zend_long) mysql_num_rows(S->result);
        php_pdo_stmt_set_column_count(stmt, (int) mysql_num_fields(S->result));
        S->fields = mysql_fetch_fields(S->result);
    } else {
        /* this was a DML or DDL query (INSERT, UPDATE, DELETE, ... */
        stmt->row_count = (zend_long) row_count;
    }
 
    PDO_DBG_RETURN(1);
}
/* }}} */
 
static bool pdo_mysql_stmt_after_execute_prepared(pdo_stmt_t *stmt) {
    pdo_mysql_stmt *S = stmt->driver_data;
    pdo_mysql_db_handle *H = S->H;
 
#ifdef PDO_USE_MYSQLND
    /* For SHOW/DESCRIBE and others the column/field count is not available before execute. */
    php_pdo_stmt_set_column_count(stmt, mysql_stmt_field_count(S->stmt));
    for (int i = 0; i < stmt->column_count; i++) {
        mysqlnd_stmt_bind_one_result(S->stmt, i);
    }
 
    S->result = mysqlnd_stmt_result_metadata(S->stmt);
    if (S->result) {
        S->fields = mysql_fetch_fields(S->result);
        /* If buffered, pre-fetch all the data */
        if (H->buffered) {
            if (mysql_stmt_store_result(S->stmt)) {
                pdo_mysql_error_stmt(stmt);
                return false;
            }
        }
    }
#else
    /* figure out the result set format, if any */
    S->result = mysql_stmt_result_metadata(S->stmt);
    if (S->result) {
        int calc_max_length = H->buffered && S->max_length == 1;
        S->fields = mysql_fetch_fields(S->result);
 
        php_pdo_stmt_set_column_count(stmt, (int)mysql_num_fields(S->result));
        S->bound_result = ecalloc(stmt->column_count, sizeof(MYSQL_BIND));
        S->out_null = ecalloc(stmt->column_count, sizeof(my_bool));
        S->out_length = ecalloc(stmt->column_count, sizeof(zend_ulong));
 
        /* summon memory to hold the row */
        for (int i = 0; i < stmt->column_count; i++) {
            if (calc_max_length && S->fields[i].type == FIELD_TYPE_BLOB) {
                my_bool on = 1;
                mysql_stmt_attr_set(S->stmt, STMT_ATTR_UPDATE_MAX_LENGTH, &on);
                calc_max_length = 0;
            }
            switch (S->fields[i].type) {
                case FIELD_TYPE_INT24:
                    S->bound_result[i].buffer_length = MAX_MEDIUMINT_WIDTH + 1;
                    break;
                case FIELD_TYPE_LONG:
                    S->bound_result[i].buffer_length = MAX_INT_WIDTH + 1;
                    break;
                case FIELD_TYPE_LONGLONG:
                    S->bound_result[i].buffer_length = MAX_BIGINT_WIDTH + 1;
                    break;
                case FIELD_TYPE_TINY:
                    S->bound_result[i].buffer_length = MAX_TINYINT_WIDTH + 1;
                    break;
                case FIELD_TYPE_SHORT:
                    S->bound_result[i].buffer_length = MAX_SMALLINT_WIDTH + 1;
                    break;
                default:
                    S->bound_result[i].buffer_length =
                        S->fields[i].max_length? S->fields[i].max_length:
                        S->fields[i].length;
                    /* work-around for longtext and alike */
                    if (S->bound_result[i].buffer_length > H->max_buffer_size) {
                        S->bound_result[i].buffer_length = H->max_buffer_size;
                    }
            }
 
            /* there are cases where the length reported by mysql is too short.
             * eg: when describing a table that contains an enum column. Since
             * we have no way of knowing the true length either, we'll bump up
             * our buffer size to a reasonable size, just in case */
            if (S->fields[i].max_length == 0 && S->bound_result[i].buffer_length < 128 && MYSQL_TYPE_VAR_STRING) {
                S->bound_result[i].buffer_length = 128;
            }
 
            S->out_length[i] = 0;
 
            S->bound_result[i].buffer = emalloc(S->bound_result[i].buffer_length);
            S->bound_result[i].is_null = &S->out_null[i];
            S->bound_result[i].length = &S->out_length[i];
            S->bound_result[i].buffer_type = MYSQL_TYPE_STRING;
        }
 
        if (mysql_stmt_bind_result(S->stmt, S->bound_result)) {
            pdo_mysql_error_stmt(stmt);
            PDO_DBG_RETURN(0);
        }
 
        /* if buffered, pre-fetch all the data */
        if (H->buffered) {
            if (mysql_stmt_store_result(S->stmt)) {
                pdo_mysql_error_stmt(stmt);
                PDO_DBG_RETURN(0);
            }
        }
    }
#endif
 
    pdo_mysql_stmt_set_row_count(stmt);
    return true;
}
 
#ifndef PDO_USE_MYSQLND
static int pdo_mysql_stmt_execute_prepared_libmysql(pdo_stmt_t *stmt) /* {{{ */
{
    pdo_mysql_stmt *S = stmt->driver_data;
 
    PDO_DBG_ENTER("pdo_mysql_stmt_execute_prepared_libmysql");
 
    /* (re)bind the parameters */
    if (mysql_stmt_bind_param(S->stmt, S->params) || mysql_stmt_execute(S->stmt)) {
        if (S->params) {
            memset(S->params, 0, S->num_params * sizeof(MYSQL_BIND));
        }
        pdo_mysql_error_stmt(stmt);
        if (mysql_stmt_errno(S->stmt) == 2057) {
            /* CR_NEW_STMT_METADATA makes the statement unusable */
            S->stmt = NULL;
        }
        PDO_DBG_RETURN(0);
    }
 
    PDO_DBG_RETURN(pdo_mysql_stmt_after_execute_prepared(stmt));
}
/* }}} */
#endif
 
#ifdef PDO_USE_MYSQLND
static int pdo_mysql_stmt_execute_prepared_mysqlnd(pdo_stmt_t *stmt) /* {{{ */
{
    pdo_mysql_stmt *S = stmt->driver_data;
 
    PDO_DBG_ENTER("pdo_mysql_stmt_execute_prepared_mysqlnd");
 
    if (mysql_stmt_execute(S->stmt)) {
        pdo_mysql_error_stmt(stmt);
        PDO_DBG_RETURN(0);
    }
 
    PDO_DBG_RETURN(pdo_mysql_stmt_after_execute_prepared(stmt));
}
/* }}} */
#endif
 
static int pdo_mysql_stmt_execute(pdo_stmt_t *stmt) /* {{{ */
{
    pdo_mysql_stmt *S = (pdo_mysql_stmt*)stmt->driver_data;
    pdo_mysql_db_handle *H = S->H;
    PDO_DBG_ENTER("pdo_mysql_stmt_execute");
    PDO_DBG_INF_FMT("stmt=%p", S->stmt);
 
    /* ensure that we free any previous unfetched results */
    pdo_mysql_free_result(S);
    S->done = 0;
 
    if (S->stmt) {
        uint32_t num_bound_params =
            stmt->bound_params ? zend_hash_num_elements(stmt->bound_params) : 0;
        if (num_bound_params < (uint32_t) S->num_params) {
            /* too few parameter bound */
            PDO_DBG_ERR("too few parameters bound");
            strcpy(stmt->error_code, "HY093");
            PDO_DBG_RETURN(0);
        }
 
        PDO_DBG_RETURN(pdo_mysql_stmt_execute_prepared(stmt));
    }
 
    if (mysql_real_query(H->server, ZSTR_VAL(stmt->active_query_string), ZSTR_LEN(stmt->active_query_string)) != 0) {
        pdo_mysql_error_stmt(stmt);
        PDO_DBG_RETURN(0);
    }
 
    PDO_DBG_RETURN(pdo_mysql_fill_stmt_from_result(stmt));
}
/* }}} */
 
static int pdo_mysql_stmt_next_rowset(pdo_stmt_t *stmt) /* {{{ */
{
    pdo_mysql_stmt *S = (pdo_mysql_stmt*)stmt->driver_data;
    pdo_mysql_db_handle *H = S->H;
    PDO_DBG_ENTER("pdo_mysql_stmt_next_rowset");
    PDO_DBG_INF_FMT("stmt=%p", S->stmt);
 
    /* ensure that we free any previous unfetched results */
    pdo_mysql_free_result(S);
 
    if (S->stmt) {
        mysql_stmt_free_result(S->stmt);
        if (mysql_stmt_next_result(S->stmt)) {
            pdo_mysql_error_stmt(stmt);
            S->done = 1;
            PDO_DBG_RETURN(0);
        }
        PDO_DBG_RETURN(pdo_mysql_stmt_after_execute_prepared(stmt));
    } else {
        if (mysql_next_result(H->server)) {
            pdo_mysql_error_stmt(stmt);
            S->done = 1;
            PDO_DBG_RETURN(0);
        }
        PDO_DBG_RETURN(pdo_mysql_fill_stmt_from_result(stmt));
    }
}
/* }}} */
 
 
static const char * const pdo_param_event_names[] =
{
    "PDO_PARAM_EVT_ALLOC",
    "PDO_PARAM_EVT_FREE",
    "PDO_PARAM_EVT_EXEC_PRE",
    "PDO_PARAM_EVT_EXEC_POST",
    "PDO_PARAM_EVT_FETCH_PRE",
    "PDO_PARAM_EVT_FETCH_POST",
    "PDO_PARAM_EVT_NORMALIZE",
};
 
#ifndef PDO_USE_MYSQLND
static unsigned char libmysql_false_buffer = 0;
static unsigned char libmysql_true_buffer = 1;
#endif
 
static int pdo_mysql_stmt_param_hook(pdo_stmt_t *stmt, struct pdo_bound_param_data *param, enum pdo_param_event event_type) /* {{{ */
{
    zval *parameter;
#ifndef PDO_USE_MYSQLND
    PDO_MYSQL_PARAM_BIND *b;
#endif
    pdo_mysql_stmt *S = (pdo_mysql_stmt*)stmt->driver_data;
 
    PDO_DBG_ENTER("pdo_mysql_stmt_param_hook");
    PDO_DBG_INF_FMT("stmt=%p", S->stmt);
    PDO_DBG_INF_FMT("event = %s", pdo_param_event_names[event_type]);
    if (S->stmt && param->is_param) {
        switch (event_type) {
            case PDO_PARAM_EVT_ALLOC:
                /* sanity check parameter number range */
                if (param->paramno < 0 || param->paramno >= S->num_params) {
                    strcpy(stmt->error_code, "HY093");
                    PDO_DBG_RETURN(0);
                }
 
#ifndef PDO_USE_MYSQLND
                b = &S->params[param->paramno];
                param->driver_data = b;
                b->is_null = &S->in_null[param->paramno];
                b->length = &S->in_length[param->paramno];
                /* recall how many parameters have been provided */
#endif
                PDO_DBG_RETURN(1);
 
            case PDO_PARAM_EVT_EXEC_PRE:
                if (!Z_ISREF(param->parameter)) {
                    parameter = &param->parameter;
                } else {
                    parameter = Z_REFVAL(param->parameter);
                }
 
#ifdef PDO_USE_MYSQLND
                if (PDO_PARAM_TYPE(param->param_type) == PDO_PARAM_NULL || (Z_TYPE_P(parameter) == IS_NULL)) {
                    mysqlnd_stmt_bind_one_param(S->stmt, param->paramno, parameter, MYSQL_TYPE_NULL);
                    PDO_DBG_RETURN(1);
                }
#else
                b = (PDO_MYSQL_PARAM_BIND*)param->driver_data;
                *b->is_null = 0;
                if (PDO_PARAM_TYPE(param->param_type) == PDO_PARAM_NULL || Z_TYPE_P(parameter) == IS_NULL) {
                    *b->is_null = 1;
                    b->buffer_type = MYSQL_TYPE_STRING;
                    b->buffer = NULL;
                    b->buffer_length = 0;
                    *b->length = 0;
                    PDO_DBG_RETURN(1);
                }
#endif /* PDO_USE_MYSQLND */
 
                switch (PDO_PARAM_TYPE(param->param_type)) {
                    case PDO_PARAM_STMT:
                        PDO_DBG_RETURN(0);
                    case PDO_PARAM_LOB:
                        PDO_DBG_INF("PDO_PARAM_LOB");
                        if (!Z_ISREF(param->parameter)) {
                            parameter = &param->parameter;
                        } else {
                            parameter = Z_REFVAL(param->parameter);
                        }
                        if (Z_TYPE_P(parameter) == IS_RESOURCE) {
                            php_stream *stm = NULL;
                            php_stream_from_zval_no_verify(stm, parameter);
                            if (stm) {
                                zend_string *mem = php_stream_copy_to_mem(stm, PHP_STREAM_COPY_ALL, 0);
                                zval_ptr_dtor(parameter);
                                ZVAL_STR(parameter, mem ? mem : ZSTR_EMPTY_ALLOC());
                            } else {
                                pdo_raise_impl_error(stmt->dbh, stmt, "HY105", "Expected a stream resource");
                                return 0;
                            }
                        }
                        /* fall through */
 
                    default:
                        ;
                }
 
#ifdef PDO_USE_MYSQLND
                /* Is it really correct to check the zval's type? - But well, that's what the old code below does, too */
                PDO_DBG_INF_FMT("param->parameter->type=%d", Z_TYPE(param->parameter));
                if (!Z_ISREF(param->parameter)) {
                    parameter = &param->parameter;
                } else {
                    parameter = Z_REFVAL(param->parameter);
                }
                switch (Z_TYPE_P(parameter)) {
                    case IS_STRING:
                        mysqlnd_stmt_bind_one_param(S->stmt, param->paramno, parameter, MYSQL_TYPE_VAR_STRING);
                        break;
                    case IS_LONG:
#if SIZEOF_ZEND_LONG==8
                        mysqlnd_stmt_bind_one_param(S->stmt, param->paramno, parameter, MYSQL_TYPE_LONGLONG);
#elif SIZEOF_ZEND_LONG==4
                        mysqlnd_stmt_bind_one_param(S->stmt, param->paramno, parameter, MYSQL_TYPE_LONG);
#endif /* SIZEOF_LONG */
                        break;
                    case IS_TRUE:
                    case IS_FALSE:
                        mysqlnd_stmt_bind_one_param(S->stmt, param->paramno, parameter, MYSQL_TYPE_TINY);
                        break;
                    case IS_DOUBLE:
                        mysqlnd_stmt_bind_one_param(S->stmt, param->paramno, parameter, MYSQL_TYPE_DOUBLE);
                        break;
                    default:
                        PDO_DBG_RETURN(0);
                }
 
                PDO_DBG_RETURN(1);
#else
                PDO_DBG_INF_FMT("param->parameter->type=%d", Z_TYPE(param->parameter));
                if (!Z_ISREF(param->parameter)) {
                    parameter = &param->parameter;
                } else {
                    parameter = Z_REFVAL(param->parameter);
                }
                switch (Z_TYPE_P(parameter)) {
                    case IS_STRING:
                        b->buffer_type = MYSQL_TYPE_STRING;
                        b->buffer = Z_STRVAL_P(parameter);
                        b->buffer_length = Z_STRLEN_P(parameter);
                        *b->length = Z_STRLEN_P(parameter);
                        PDO_DBG_RETURN(1);
 
                    case IS_FALSE:
                        b->buffer_type = MYSQL_TYPE_TINY;
                        b->buffer = &libmysql_false_buffer;
                        PDO_DBG_RETURN(1);
 
                    case IS_TRUE:
                        b->buffer_type = MYSQL_TYPE_TINY;
                        b->buffer = &libmysql_true_buffer;
                        PDO_DBG_RETURN(1);
 
                    case IS_LONG:
                        b->buffer_type = MYSQL_TYPE_LONG;
                        b->buffer = &Z_LVAL_P(parameter);
                        PDO_DBG_RETURN(1);
 
                    case IS_DOUBLE:
                        b->buffer_type = MYSQL_TYPE_DOUBLE;
                        b->buffer = &Z_DVAL_P(parameter);
                        PDO_DBG_RETURN(1);
 
                    default:
                        PDO_DBG_RETURN(0);
                }
#endif /* PDO_USE_MYSQLND */
        case PDO_PARAM_EVT_FREE:
        case PDO_PARAM_EVT_EXEC_POST:
        case PDO_PARAM_EVT_FETCH_PRE:
        case PDO_PARAM_EVT_FETCH_POST:
        case PDO_PARAM_EVT_NORMALIZE:
            /* do nothing */
            break;
        }
    }
 
    PDO_DBG_RETURN(1);
}
/* }}} */
 
static int pdo_mysql_stmt_fetch(pdo_stmt_t *stmt, enum pdo_fetch_orientation ori, zend_long offset) /* {{{ */
{
    pdo_mysql_stmt *S = (pdo_mysql_stmt*)stmt->driver_data;
 
    if (!S->result) {
        PDO_DBG_RETURN(0);
    }
 
#ifdef PDO_USE_MYSQLND
    bool fetched_anything;
 
    PDO_DBG_ENTER("pdo_mysql_stmt_fetch");
    PDO_DBG_INF_FMT("stmt=%p", S->stmt);
    if (S->stmt) {
        if (FAIL == mysqlnd_stmt_fetch(S->stmt, &fetched_anything) || !fetched_anything) {
            pdo_mysql_error_stmt(stmt);
            PDO_DBG_RETURN(0);
        }
 
        PDO_DBG_RETURN(1);
    }
 
    zval *row_data;
    if (mysqlnd_fetch_row_zval(S->result, &row_data, &fetched_anything) == FAIL) {
        pdo_mysql_error_stmt(stmt);
        PDO_DBG_RETURN(0);
    }
 
    if (!fetched_anything) {
        PDO_DBG_RETURN(0);
    }
 
    if (!S->current_row) {
        S->current_row = ecalloc(stmt->column_count, sizeof(zval));
    }
    for (unsigned i = 0; i < stmt->column_count; i++) {
        zval_ptr_dtor_nogc(&S->current_row[i]);
        ZVAL_COPY_VALUE(&S->current_row[i], &row_data[i]);
    }
    PDO_DBG_RETURN(1);
#else
    int ret;
 
    if (S->stmt) {
        ret = mysql_stmt_fetch(S->stmt);
 
#       ifdef MYSQL_DATA_TRUNCATED
        if (ret == MYSQL_DATA_TRUNCATED) {
            ret = 0;
        }
#       endif
 
        if (ret) {
            if (ret != MYSQL_NO_DATA) {
                pdo_mysql_error_stmt(stmt);
            }
            PDO_DBG_RETURN(0);
        }
 
        PDO_DBG_RETURN(1);
    }
 
    if ((S->current_data = mysql_fetch_row(S->result)) == NULL) {
        if (!S->H->buffered && mysql_errno(S->H->server)) {
            pdo_mysql_error_stmt(stmt);
        }
        PDO_DBG_RETURN(0);
    }
 
    S->current_lengths = mysql_fetch_lengths(S->result);
    PDO_DBG_RETURN(1);
#endif /* PDO_USE_MYSQLND */
}
/* }}} */
 
static int pdo_mysql_stmt_describe(pdo_stmt_t *stmt, int colno) /* {{{ */
{
    pdo_mysql_stmt *S = (pdo_mysql_stmt*)stmt->driver_data;
    struct pdo_column_data *cols = stmt->columns;
    int i;
 
    PDO_DBG_ENTER("pdo_mysql_stmt_describe");
    PDO_DBG_INF_FMT("stmt=%p", S->stmt);
    if (!S->result) {
        PDO_DBG_RETURN(0);
    }
 
    if (colno >= stmt->column_count) {
        /* error invalid column */
        PDO_DBG_RETURN(0);
    }
 
    /* fetch all on demand, this seems easiest
    ** if we've been here before bail out
    */
    if (cols[0].name) {
        PDO_DBG_RETURN(1);
    }
    for (i = 0; i < stmt->column_count; i++) {
 
        if (S->H->fetch_table_names) {
            cols[i].name = strpprintf(0, "%s.%s", S->fields[i].table, S->fields[i].name);
        } else {
#ifdef PDO_USE_MYSQLND
            cols[i].name = zend_string_copy(S->fields[i].sname);
#else
            cols[i].name = zend_string_init(S->fields[i].name, S->fields[i].name_length, 0);
#endif
        }
 
        cols[i].precision = S->fields[i].decimals;
        cols[i].maxlen = S->fields[i].length;
    }
    PDO_DBG_RETURN(1);
}
/* }}} */
 
static int pdo_mysql_stmt_get_col(
        pdo_stmt_t *stmt, int colno, zval *result, enum pdo_param_type *type) /* {{{ */
{
    pdo_mysql_stmt *S = (pdo_mysql_stmt*)stmt->driver_data;
 
    PDO_DBG_ENTER("pdo_mysql_stmt_get_col");
    PDO_DBG_INF_FMT("stmt=%p", S->stmt);
    if (!S->result) {
        PDO_DBG_RETURN(0);
    }
 
    if (colno >= stmt->column_count) {
        /* error invalid column */
        PDO_DBG_RETURN(0);
    }
#ifdef PDO_USE_MYSQLND
    if (S->stmt) {
        ZVAL_COPY(result, &S->stmt->data->result_bind[colno].zv);
    } else {
        ZVAL_COPY(result, &S->current_row[colno]);
    }
    PDO_DBG_RETURN(1);
#else
    if (S->stmt) {
        if (S->out_null[colno]) {
            PDO_DBG_RETURN(1);
        }
 
        size_t length = S->out_length[colno];
        if (length > S->bound_result[colno].buffer_length) {
            /* mysql lied about the column width */
            strcpy(stmt->error_code, "01004"); /* truncated */
            length = S->out_length[colno] = S->bound_result[colno].buffer_length;
        }
        ZVAL_STRINGL_FAST(result, S->bound_result[colno].buffer, length);
        PDO_DBG_RETURN(1);
    }
 
    if (S->current_data == NULL) {
        PDO_DBG_RETURN(0);
    }
    if (S->current_data[colno]) {
        ZVAL_STRINGL_FAST(result, S->current_data[colno], S->current_lengths[colno]);
    }
    PDO_DBG_RETURN(1);
#endif
} /* }}} */
 
static char *type_to_name_native(int type) /* {{{ */
{
#define PDO_MYSQL_NATIVE_TYPE_NAME(x)   case FIELD_TYPE_##x: return #x;
 
    switch (type) {
        PDO_MYSQL_NATIVE_TYPE_NAME(STRING)
        PDO_MYSQL_NATIVE_TYPE_NAME(VAR_STRING)
#ifdef FIELD_TYPE_TINY
        PDO_MYSQL_NATIVE_TYPE_NAME(TINY)
#endif
#ifdef FIELD_TYPE_BIT
        PDO_MYSQL_NATIVE_TYPE_NAME(BIT)
#endif
        PDO_MYSQL_NATIVE_TYPE_NAME(SHORT)
        PDO_MYSQL_NATIVE_TYPE_NAME(LONG)
        PDO_MYSQL_NATIVE_TYPE_NAME(LONGLONG)
        PDO_MYSQL_NATIVE_TYPE_NAME(INT24)
        PDO_MYSQL_NATIVE_TYPE_NAME(FLOAT)
        PDO_MYSQL_NATIVE_TYPE_NAME(DOUBLE)
        PDO_MYSQL_NATIVE_TYPE_NAME(DECIMAL)
#ifdef FIELD_TYPE_NEWDECIMAL
        PDO_MYSQL_NATIVE_TYPE_NAME(NEWDECIMAL)
#endif
#ifdef FIELD_TYPE_GEOMETRY
        PDO_MYSQL_NATIVE_TYPE_NAME(GEOMETRY)
#endif
        PDO_MYSQL_NATIVE_TYPE_NAME(TIMESTAMP)
#ifdef FIELD_TYPE_YEAR
        PDO_MYSQL_NATIVE_TYPE_NAME(YEAR)
#endif
        PDO_MYSQL_NATIVE_TYPE_NAME(SET)
        PDO_MYSQL_NATIVE_TYPE_NAME(ENUM)
        PDO_MYSQL_NATIVE_TYPE_NAME(DATE)
#ifdef FIELD_TYPE_NEWDATE
        PDO_MYSQL_NATIVE_TYPE_NAME(NEWDATE)
#endif
        PDO_MYSQL_NATIVE_TYPE_NAME(TIME)
        PDO_MYSQL_NATIVE_TYPE_NAME(DATETIME)
        PDO_MYSQL_NATIVE_TYPE_NAME(TINY_BLOB)
        PDO_MYSQL_NATIVE_TYPE_NAME(MEDIUM_BLOB)
        PDO_MYSQL_NATIVE_TYPE_NAME(LONG_BLOB)
        PDO_MYSQL_NATIVE_TYPE_NAME(BLOB)
        PDO_MYSQL_NATIVE_TYPE_NAME(NULL)
        default:
            return NULL;
    }
#undef PDO_MYSQL_NATIVE_TYPE_NAME
} /* }}} */
 
static int pdo_mysql_stmt_col_meta(pdo_stmt_t *stmt, zend_long colno, zval *return_value) /* {{{ */
{
    pdo_mysql_stmt *S = (pdo_mysql_stmt*)stmt->driver_data;
    const MYSQL_FIELD *F;
    zval flags;
    char *str;
 
    PDO_DBG_ENTER("pdo_mysql_stmt_col_meta");
    PDO_DBG_INF_FMT("stmt=%p", S->stmt);
    if (!S->result) {
        PDO_DBG_RETURN(FAILURE);
    }
    if (colno >= stmt->column_count) {
        /* error invalid column */
        PDO_DBG_RETURN(FAILURE);
    }
 
    array_init(return_value);
    array_init(&flags);
 
    F = S->fields + colno;
 
    if (F->def) {
        add_assoc_string(return_value, "mysql:def", F->def);
    }
    if (IS_NOT_NULL(F->flags)) {
        add_next_index_string(&flags, "not_null");
    }
    if (IS_PRI_KEY(F->flags)) {
        add_next_index_string(&flags, "primary_key");
    }
    if (F->flags & MULTIPLE_KEY_FLAG) {
        add_next_index_string(&flags, "multiple_key");
    }
    if (F->flags & UNIQUE_KEY_FLAG) {
        add_next_index_string(&flags, "unique_key");
    }
    if (IS_BLOB(F->flags)) {
        add_next_index_string(&flags, "blob");
    }
    str = type_to_name_native(F->type);
    if (str) {
        add_assoc_string(return_value, "native_type", str);
    }
 
    enum pdo_param_type param_type;
    switch (F->type) {
        case MYSQL_TYPE_BIT:
        case MYSQL_TYPE_YEAR:
        case MYSQL_TYPE_TINY:
        case MYSQL_TYPE_SHORT:
        case MYSQL_TYPE_INT24:
        case MYSQL_TYPE_LONG:
#if SIZEOF_ZEND_LONG==8
        case MYSQL_TYPE_LONGLONG:
#endif
            param_type = PDO_PARAM_INT;
            break;
        default:
            param_type = PDO_PARAM_STR;
            break;
    }
    add_assoc_long(return_value, "pdo_type", param_type);
 
    add_assoc_zval(return_value, "flags", &flags);
    add_assoc_string(return_value, "table", (char *) (F->table?F->table : ""));
 
    PDO_DBG_RETURN(SUCCESS);
} /* }}} */
 
static int pdo_mysql_stmt_cursor_closer(pdo_stmt_t *stmt) /* {{{ */
{
    pdo_mysql_stmt *S = (pdo_mysql_stmt*)stmt->driver_data;
 
    PDO_DBG_ENTER("pdo_mysql_stmt_cursor_closer");
    PDO_DBG_INF_FMT("stmt=%p", S->stmt);
 
    S->done = 1;
    pdo_mysql_free_result(S);
    if (S->stmt) {
        mysql_stmt_free_result(S->stmt);
    }
 
    while (mysql_more_results(S->H->server)) {
        MYSQL_RES *res;
        if (mysql_next_result(S->H->server) != 0) {
            pdo_mysql_error_stmt(stmt);
            PDO_DBG_RETURN(0);
        }
        res = mysql_store_result(S->H->server);
        if (res) {
            mysql_free_result(res);
        }
    }
    PDO_DBG_RETURN(1);
}
/* }}} */
 
const struct pdo_stmt_methods mysql_stmt_methods = {
    pdo_mysql_stmt_dtor,
    pdo_mysql_stmt_execute,
    pdo_mysql_stmt_fetch,
    pdo_mysql_stmt_describe,
    pdo_mysql_stmt_get_col,
    pdo_mysql_stmt_param_hook,
    NULL, /* set_attr */
    NULL, /* get_attr */
    pdo_mysql_stmt_col_meta,
    pdo_mysql_stmt_next_rowset,
    pdo_mysql_stmt_cursor_closer
};