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[mediawiki.git] / includes / media / XMPValidate.php

<?php
/**
 * Methods for validating XMP properties.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Media
 */

/**
 * This contains some static methods for
 * validating XMP properties. See XMPInfo and XMPReader classes.
 *
 * Each of these functions take the same parameters
 * * an info array which is a subset of the XMPInfo::items array
 * * A value (passed as reference) to validate. This can be either a
 *    simple value or an array
 * * A boolean to determine if this is validating a simple or complex values
 *
 * It should be noted that when an array is being validated, typically the validation
 * function is called once for each value, and then once at the end for the entire array.
 *
 * These validation functions can also be used to modify the data. See the gps and flash one's
 * for example.
 *
 * @see http://www.adobe.com/devnet/xmp/pdfs/XMPSpecificationPart1.pdf starting at pg 28
 * @see http://www.adobe.com/devnet/xmp/pdfs/XMPSpecificationPart2.pdf starting at pg 11
 */
class XMPValidate {
        /**
         * Function to validate boolean properties ( True or False )
         *
         * @param array $info Information about current property
         * @param mixed &$val Current value to validate
         * @param bool $standalone If this is a simple property or array
         */
        public static function validateBoolean( $info, &$val, $standalone ) {
                if ( !$standalone ) {
                        // this only validates standalone properties, not arrays, etc
                        return;
                }
                if ( $val !== 'True' && $val !== 'False' ) {
                        wfDebugLog( 'XMP', __METHOD__ . " Expected True or False but got $val" );
                        $val = null;
                }
        }

        /**
         * function to validate rational properties ( 12/10 )
         *
         * @param array $info Information about current property
         * @param mixed &$val Current value to validate
         * @param bool $standalone If this is a simple property or array
         */
        public static function validateRational( $info, &$val, $standalone ) {
                if ( !$standalone ) {
                        // this only validates standalone properties, not arrays, etc
                        return;
                }
                if ( !preg_match( '/^(?:-?\d+)\/(?:\d+[1-9]|[1-9]\d*)$/D', $val ) ) {
                        wfDebugLog( 'XMP', __METHOD__ . " Expected rational but got $val" );
                        $val = null;
                }
        }

        /**
         * function to validate rating properties -1, 0-5
         *
         * if its outside of range put it into range.
         *
         * @see MWG spec
         * @param array $info Information about current property
         * @param mixed &$val Current value to validate
         * @param bool $standalone If this is a simple property or array
         */
        public static function validateRating( $info, &$val, $standalone ) {
                if ( !$standalone ) {
                        // this only validates standalone properties, not arrays, etc
                        return;
                }
                if ( !preg_match( '/^[-+]?\d*(?:\.?\d*)$/D', $val )
                        || !is_numeric( $val )
                ) {
                        wfDebugLog( 'XMP', __METHOD__ . " Expected rating but got $val" );
                        $val = null;

                        return;
                } else {
                        $nVal = (float)$val;
                        if ( $nVal < 0 ) {
                                // We do < 0 here instead of < -1 here, since
                                // the values between 0 and -1 are also illegal
                                // as -1 is meant as a special reject rating.
                                wfDebugLog( 'XMP', __METHOD__ . " Rating too low, setting to -1 (Rejected)" );
                                $val = '-1';

                                return;
                        }
                        if ( $nVal > 5 ) {
                                wfDebugLog( 'XMP', __METHOD__ . " Rating too high, setting to 5" );
                                $val = '5';

                                return;
                        }
                }
        }

        /**
         * function to validate integers
         *
         * @param array $info Information about current property
         * @param mixed &$val Current value to validate
         * @param bool $standalone If this is a simple property or array
         */
        public static function validateInteger( $info, &$val, $standalone ) {
                if ( !$standalone ) {
                        // this only validates standalone properties, not arrays, etc
                        return;
                }
                if ( !preg_match( '/^[-+]?\d+$/D', $val ) ) {
                        wfDebugLog( 'XMP', __METHOD__ . " Expected integer but got $val" );
                        $val = null;
                }
        }

        /**
         * function to validate properties with a fixed number of allowed
         * choices. (closed choice)
         *
         * @param array $info Information about current property
         * @param mixed &$val Current value to validate
         * @param bool $standalone If this is a simple property or array
         */
        public static function validateClosed( $info, &$val, $standalone ) {
                if ( !$standalone ) {
                        // this only validates standalone properties, not arrays, etc
                        return;
                }

                //check if its in a numeric range
                $inRange = false;
                if ( isset( $info['rangeLow'] )
                        && isset( $info['rangeHigh'] )
                        && is_numeric( $val )
                        && ( intval( $val ) <= $info['rangeHigh'] )
                        && ( intval( $val ) >= $info['rangeLow'] )
                ) {
                        $inRange = true;
                }

                if ( !isset( $info['choices'][$val] ) && !$inRange ) {
                        wfDebugLog( 'XMP', __METHOD__ . " Expected closed choice, but got $val" );
                        $val = null;
                }
        }

        /**
         * function to validate and modify flash structure
         *
         * @param array $info Information about current property
         * @param mixed &$val Current value to validate
         * @param bool $standalone If this is a simple property or array
         */
        public static function validateFlash( $info, &$val, $standalone ) {
                if ( $standalone ) {
                        // this only validates flash structs, not individual properties
                        return;
                }
                if ( !( isset( $val['Fired'] )
                        && isset( $val['Function'] )
                        && isset( $val['Mode'] )
                        && isset( $val['RedEyeMode'] )
                        && isset( $val['Return'] )
                ) ) {
                        wfDebugLog( 'XMP', __METHOD__ . " Flash structure did not have all the required components" );
                        $val = null;
                } else {
                        $val = ( "\0" | ( $val['Fired'] === 'True' )
                                | ( intval( $val['Return'] ) << 1 )
                                | ( intval( $val['Mode'] ) << 3 )
                                | ( ( $val['Function'] === 'True' ) << 5 )
                                | ( ( $val['RedEyeMode'] === 'True' ) << 6 ) );
                }
        }

        /**
         * function to validate LangCode properties ( en-GB, etc )
         *
         * This is just a naive check to make sure it somewhat looks like a lang code.
         *
         * @see rfc 3066
         * @see http://www.adobe.com/devnet/xmp/pdfs/XMPSpecificationPart1.pdf page 30 (section 8.2.2.5)
         *
         * @param array $info Information about current property
         * @param mixed &$val Current value to validate
         * @param bool $standalone If this is a simple property or array
         */
        public static function validateLangCode( $info, &$val, $standalone ) {
                if ( !$standalone ) {
                        // this only validates standalone properties, not arrays, etc
                        return;
                }
                if ( !preg_match( '/^[-A-Za-z0-9]{2,}$/D', $val ) ) {
                        //this is a rather naive check.
                        wfDebugLog( 'XMP', __METHOD__ . " Expected Lang code but got $val" );
                        $val = null;
                }
        }

        /**
         * function to validate date properties, and convert to (partial) Exif format.
         *
         * Dates can be one of the following formats:
         * YYYY
         * YYYY-MM
         * YYYY-MM-DD
         * YYYY-MM-DDThh:mmTZD
         * YYYY-MM-DDThh:mm:ssTZD
         * YYYY-MM-DDThh:mm:ss.sTZD
         *
         * @param array $info Information about current property
         * @param mixed &$val Current value to validate. Converts to TS_EXIF as a side-effect.
         *    in cases where there's only a partial date, it will give things like
         *    2011:04.
         * @param bool $standalone If this is a simple property or array
         */
        public static function validateDate( $info, &$val, $standalone ) {
                if ( !$standalone ) {
                        // this only validates standalone properties, not arrays, etc
                        return;
                }
                $res = array();
                // @codingStandardsIgnoreStart Long line that cannot be broken
                if ( !preg_match(
                        /* ahh! scary regex... */
                        '/^([0-3]\d{3})(?:-([01]\d)(?:-([0-3]\d)(?:T([0-2]\d):([0-6]\d)(?::([0-6]\d)(?:\.\d+)?)?([-+]\d{2}:\d{2}|Z)?)?)?)?$/D',
                        $val, $res )
                ) {
                        // @codingStandardsIgnoreEnd

                        wfDebugLog( 'XMP', __METHOD__ . " Expected date but got $val" );
                        $val = null;
                } else {
                        /*
                         * $res is formatted as follows:
                         * 0 -> full date.
                         * 1 -> year, 2-> month, 3-> day, 4-> hour, 5-> minute, 6->second
                         * 7-> Timezone specifier (Z or something like +12:30 )
                         * many parts are optional, some aren't. For example if you specify
                         * minute, you must specify hour, day, month, and year but not second or TZ.
                         */

                        /*
                         * First of all, if year = 0000, Something is wrongish,
                         * so don't extract. This seems to happen when
                         * some programs convert between metadata formats.
                         */
                        if ( $res[1] === '0000' ) {
                                wfDebugLog( 'XMP', __METHOD__ . " Invalid date (year 0): $val" );
                                $val = null;

                                return;
                        }

                        if ( !isset( $res[4] ) ) { //hour
                                //just have the year month day (if that)
                                $val = $res[1];
                                if ( isset( $res[2] ) ) {
                                        $val .= ':' . $res[2];
                                }
                                if ( isset( $res[3] ) ) {
                                        $val .= ':' . $res[3];
                                }

                                return;
                        }

                        if ( !isset( $res[7] ) || $res[7] === 'Z' ) {
                                //if hour is set, then minute must also be or regex above will fail.
                                $val = $res[1] . ':' . $res[2] . ':' . $res[3]
                                        . ' ' . $res[4] . ':' . $res[5];
                                if ( isset( $res[6] ) && $res[6] !== '' ) {
                                        $val .= ':' . $res[6];
                                }

                                return;
                        }

                        // Extra check for empty string necessary due to TZ but no second case.
                        $stripSeconds = false;
                        if ( !isset( $res[6] ) || $res[6] === '' ) {
                                $res[6] = '00';
                                $stripSeconds = true;
                        }

                        // Do timezone processing. We've already done the case that tz = Z.

                        // We know that if we got to this step, year, month day hour and min must be set
                        // by virtue of regex not failing.

                        $unix = wfTimestamp( TS_UNIX, $res[1] . $res[2] . $res[3] . $res[4] . $res[5] . $res[6] );
                        $offset = intval( substr( $res[7], 1, 2 ) ) * 60 * 60;
                        $offset += intval( substr( $res[7], 4, 2 ) ) * 60;
                        if ( substr( $res[7], 0, 1 ) === '-' ) {
                                $offset = -$offset;
                        }
                        $val = wfTimestamp( TS_EXIF, $unix + $offset );

                        if ( $stripSeconds ) {
                                // If seconds weren't specified, remove the trailing ':00'.
                                $val = substr( $val, 0, -3 );
                        }
                }
        }

        /** function to validate, and more importantly
         * translate the XMP DMS form of gps coords to
         * the decimal form we use.
         *
         * @see http://www.adobe.com/devnet/xmp/pdfs/XMPSpecificationPart2.pdf
         *        section 1.2.7.4 on page 23
         *
         * @param array $info Unused (info about prop)
         * @param string &$val GPS string in either DDD,MM,SSk or
         *   or DDD,MM.mmk form
         * @param bool $standalone If its a simple prop (should always be true)
         */
        public static function validateGPS( $info, &$val, $standalone ) {
                if ( !$standalone ) {
                        return;
                }

                $m = array();
                if ( preg_match(
                        '/(\d{1,3}),(\d{1,2}),(\d{1,2})([NWSE])/D',
                        $val, $m )
                ) {
                        $coord = intval( $m[1] );
                        $coord += intval( $m[2] ) * ( 1 / 60 );
                        $coord += intval( $m[3] ) * ( 1 / 3600 );
                        if ( $m[4] === 'S' || $m[4] === 'W' ) {
                                $coord = -$coord;
                        }
                        $val = $coord;

                        return;
                } elseif ( preg_match(
                        '/(\d{1,3}),(\d{1,2}(?:.\d*)?)([NWSE])/D',
                        $val, $m )
                ) {
                        $coord = intval( $m[1] );
                        $coord += floatval( $m[2] ) * ( 1 / 60 );
                        if ( $m[3] === 'S' || $m[3] === 'W' ) {
                                $coord = -$coord;
                        }
                        $val = $coord;

                        return;
                } else {
                        wfDebugLog( 'XMP', __METHOD__
                                . " Expected GPSCoordinate, but got $val." );
                        $val = null;

                        return;
                }
        }
}