Implement extension registration from an extension.json file

[mediawiki.git] / includes / api / ApiResult.php

<?php
/**
 *
 *
 * Created on Sep 4, 2006
 *
 * Copyright © 2006 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
 *
 * 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
 */

/**
 * This class represents the result of the API operations.
 * It simply wraps a nested array() structure, adding some functions to simplify
 * array's modifications. As various modules execute, they add different pieces
 * of information to this result, structuring it as it will be given to the client.
 *
 * Each subarray may either be a dictionary - key-value pairs with unique keys,
 * or lists, where the items are added using $data[] = $value notation.
 *
 * There are three special key values that change how XML output is generated:
 *   '_element'     This key sets the tag name for the rest of the elements in the current array.
 *                  It is only inserted if the formatter returned true for getNeedsRawData()
 *   '_subelements' This key causes the specified elements to be returned as subelements rather than attributes.
 *                  It is only inserted if the formatter returned true for getNeedsRawData()
 *   '*'            This key has special meaning only to the XML formatter, and is outputted as is
 *                  for all others. In XML it becomes the content of the current element.
 *
 * @ingroup API
 */
class ApiResult extends ApiBase {

        /**
         * override existing value in addValue() and setElement()
         * @since 1.21
         */
        const OVERRIDE = 1;

        /**
         * For addValue() and setElement(), if the value does not exist, add it as the first element.
         * In case the new value has no name (numerical index), all indexes will be renumbered.
         * @since 1.21
         */
        const ADD_ON_TOP = 2;

        /**
         * For addValue() and setElement(), do not check size while adding a value
         * Don't use this unless you REALLY know what you're doing.
         * Values added while the size checking was disabled will never be counted
         * @since 1.24
         */
        const NO_SIZE_CHECK = 4;

        private $mData, $mIsRawMode, $mSize, $mCheckingSize;

        private $continueAllModules = array();
        private $continueGeneratedModules = array();
        private $continuationData = array();
        private $generatorContinuationData = array();
        private $generatorParams = array();
        private $generatorDone = false;

        /**
         * @param ApiMain $main
         */
        public function __construct( ApiMain $main ) {
                parent::__construct( $main, 'result' );
                $this->mIsRawMode = false;
                $this->mCheckingSize = true;
                $this->reset();
        }

        /**
         * Clear the current result data.
         */
        public function reset() {
                $this->mData = array();
                $this->mSize = 0;
        }

        /**
         * Call this function when special elements such as '_element'
         * are needed by the formatter, for example in XML printing.
         * @since 1.23 $flag parameter added
         * @param bool $flag Set the raw mode flag to this state
         */
        public function setRawMode( $flag = true ) {
                $this->mIsRawMode = $flag;
        }

        /**
         * Returns true whether the formatter requested raw data.
         * @return bool
         */
        public function getIsRawMode() {
                return $this->mIsRawMode;
        }

        /**
         * Get the result's internal data array (read-only)
         * @return array
         */
        public function getData() {
                return $this->mData;
        }

        /**
         * Get the 'real' size of a result item. This means the strlen() of the item,
         * or the sum of the strlen()s of the elements if the item is an array.
         * @param mixed $value
         * @return int
         */
        public static function size( $value ) {
                $s = 0;
                if ( is_array( $value ) ) {
                        foreach ( $value as $v ) {
                                $s += self::size( $v );
                        }
                } elseif ( !is_object( $value ) ) {
                        // Objects can't always be cast to string
                        $s = strlen( $value );
                }

                return $s;
        }

        /**
         * Get the size of the result, i.e. the amount of bytes in it
         * @return int
         */
        public function getSize() {
                return $this->mSize;
        }

        /**
         * Disable size checking in addValue(). Don't use this unless you
         * REALLY know what you're doing. Values added while size checking
         * was disabled will not be counted (ever)
         * @deprecated since 1.24, use ApiResult::NO_SIZE_CHECK
         */
        public function disableSizeCheck() {
                $this->mCheckingSize = false;
        }

        /**
         * Re-enable size checking in addValue()
         * @deprecated since 1.24, use ApiResult::NO_SIZE_CHECK
         */
        public function enableSizeCheck() {
                $this->mCheckingSize = true;
        }

        /**
         * Add an output value to the array by name.
         * Verifies that value with the same name has not been added before.
         * @param array $arr To add $value to
         * @param string $name Index of $arr to add $value at
         * @param mixed $value
         * @param int $flags Zero or more OR-ed flags like OVERRIDE | ADD_ON_TOP.
         *    This parameter used to be boolean, and the value of OVERRIDE=1 was
         *    specifically chosen so that it would be backwards compatible with the
         *    new method signature.
         *
         * @since 1.21 int $flags replaced boolean $override
         */
        public static function setElement( &$arr, $name, $value, $flags = 0 ) {
                if ( $arr === null || $name === null || $value === null
                        || !is_array( $arr ) || is_array( $name )
                ) {
                        ApiBase::dieDebug( __METHOD__, 'Bad parameter' );
                }

                $exists = isset( $arr[$name] );
                if ( !$exists || ( $flags & ApiResult::OVERRIDE ) ) {
                        if ( !$exists && ( $flags & ApiResult::ADD_ON_TOP ) ) {
                                $arr = array( $name => $value ) + $arr;
                        } else {
                                $arr[$name] = $value;
                        }
                } elseif ( is_array( $arr[$name] ) && is_array( $value ) ) {
                        $merged = array_intersect_key( $arr[$name], $value );
                        if ( !count( $merged ) ) {
                                $arr[$name] += $value;
                        } else {
                                ApiBase::dieDebug( __METHOD__, "Attempting to merge element $name" );
                        }
                } else {
                        ApiBase::dieDebug(
                                __METHOD__,
                                "Attempting to add element $name=$value, existing value is {$arr[$name]}"
                        );
                }
        }

        /**
         * Adds a content element to an array.
         * Use this function instead of hardcoding the '*' element.
         * @param array $arr To add the content element to
         * @param mixed $value
         * @param string $subElemName When present, content element is created
         *  as a sub item of $arr. Use this parameter to create elements in
         *  format "<elem>text</elem>" without attributes.
         */
        public static function setContent( &$arr, $value, $subElemName = null ) {
                if ( is_array( $value ) ) {
                        ApiBase::dieDebug( __METHOD__, 'Bad parameter' );
                }
                if ( is_null( $subElemName ) ) {
                        ApiResult::setElement( $arr, '*', $value );
                } else {
                        if ( !isset( $arr[$subElemName] ) ) {
                                $arr[$subElemName] = array();
                        }
                        ApiResult::setElement( $arr[$subElemName], '*', $value );
                }
        }

        /**
         * Causes the elements with the specified names to be output as
         * subelements rather than attributes.
         * @param array $arr
         * @param array|string $names The element name(s) to be output as subelements
         */
        public function setSubelements( &$arr, $names ) {
                // In raw mode, add the '_subelements', otherwise just ignore
                if ( !$this->getIsRawMode() ) {
                        return;
                }
                if ( $arr === null || $names === null || !is_array( $arr ) ) {
                        ApiBase::dieDebug( __METHOD__, 'Bad parameter' );
                }
                if ( !is_array( $names ) ) {
                        $names = array( $names );
                }
                if ( !isset( $arr['_subelements'] ) ) {
                        $arr['_subelements'] = $names;
                } else {
                        $arr['_subelements'] = array_merge( $arr['_subelements'], $names );
                }
        }

        /**
         * In case the array contains indexed values (in addition to named),
         * give all indexed values the given tag name. This function MUST be
         * called on every array that has numerical indexes.
         * @param array $arr
         * @param string $tag Tag name
         */
        public function setIndexedTagName( &$arr, $tag ) {
                // In raw mode, add the '_element', otherwise just ignore
                if ( !$this->getIsRawMode() ) {
                        return;
                }
                if ( $arr === null || $tag === null || !is_array( $arr ) || is_array( $tag ) ) {
                        ApiBase::dieDebug( __METHOD__, 'Bad parameter' );
                }
                // Do not use setElement() as it is ok to call this more than once
                $arr['_element'] = $tag;
        }

        /**
         * Calls setIndexedTagName() on each sub-array of $arr
         * @param array $arr
         * @param string $tag Tag name
         */
        public function setIndexedTagName_recursive( &$arr, $tag ) {
                if ( !is_array( $arr ) ) {
                        return;
                }
                foreach ( $arr as &$a ) {
                        if ( !is_array( $a ) ) {
                                continue;
                        }
                        $this->setIndexedTagName( $a, $tag );
                        $this->setIndexedTagName_recursive( $a, $tag );
                }
        }

        /**
         * Calls setIndexedTagName() on an array already in the result.
         * Don't specify a path to a value that's not in the result, or
         * you'll get nasty errors.
         * @param array $path Path to the array, like addValue()'s $path
         * @param string $tag
         */
        public function setIndexedTagName_internal( $path, $tag ) {
                $data = &$this->mData;
                foreach ( (array)$path as $p ) {
                        if ( !isset( $data[$p] ) ) {
                                $data[$p] = array();
                        }
                        $data = &$data[$p];
                }
                if ( is_null( $data ) ) {
                        return;
                }
                $this->setIndexedTagName( $data, $tag );
        }

        /**
         * Add value to the output data at the given path.
         * Path can be an indexed array, each element specifying the branch at which to add the new
         * value. Setting $path to array('a','b','c') is equivalent to data['a']['b']['c'] = $value.
         * If $path is null, the value will be inserted at the data root.
         * If $name is empty, the $value is added as a next list element data[] = $value.
         *
         * @param array|string|null $path
         * @param string $name
         * @param mixed $value
         * @param int $flags Zero or more OR-ed flags like OVERRIDE | ADD_ON_TOP.
         *   This parameter used to be boolean, and the value of OVERRIDE=1 was specifically
         *   chosen so that it would be backwards compatible with the new method signature.
         * @return bool True if $value fits in the result, false if not
         *
         * @since 1.21 int $flags replaced boolean $override
         */
        public function addValue( $path, $name, $value, $flags = 0 ) {
                $data = &$this->mData;
                if ( $this->mCheckingSize && !( $flags & ApiResult::NO_SIZE_CHECK ) ) {
                        $newsize = $this->mSize + self::size( $value );
                        $maxResultSize = $this->getConfig()->get( 'APIMaxResultSize' );
                        if ( $newsize > $maxResultSize ) {
                                $this->setWarning(
                                        "This result was truncated because it would otherwise be larger than the " .
                                                "limit of {$maxResultSize} bytes" );

                                return false;
                        }
                        $this->mSize = $newsize;
                }

                $addOnTop = $flags & ApiResult::ADD_ON_TOP;
                if ( $path !== null ) {
                        foreach ( (array)$path as $p ) {
                                if ( !isset( $data[$p] ) ) {
                                        if ( $addOnTop ) {
                                                $data = array( $p => array() ) + $data;
                                                $addOnTop = false;
                                        } else {
                                                $data[$p] = array();
                                        }
                                }
                                $data = &$data[$p];
                        }
                }

                if ( !$name ) {
                        // Add list element
                        if ( $addOnTop ) {
                                // This element needs to be inserted in the beginning
                                // Numerical indexes will be renumbered
                                array_unshift( $data, $value );
                        } else {
                                // Add new value at the end
                                $data[] = $value;
                        }
                } else {
                        // Add named element
                        self::setElement( $data, $name, $value, $flags );
                }

                return true;
        }

        /**
         * Add a parsed limit=max to the result.
         *
         * @param string $moduleName
         * @param int $limit
         */
        public function setParsedLimit( $moduleName, $limit ) {
                // Add value, allowing overwriting
                $this->addValue( 'limits', $moduleName, $limit, ApiResult::OVERRIDE );
        }

        /**
         * Unset a value previously added to the result set.
         * Fails silently if the value isn't found.
         * For parameters, see addValue()
         * @param array|null $path
         * @param string $name
         */
        public function unsetValue( $path, $name ) {
                $data = &$this->mData;
                if ( $path !== null ) {
                        foreach ( (array)$path as $p ) {
                                if ( !isset( $data[$p] ) ) {
                                        return;
                                }
                                $data = &$data[$p];
                        }
                }
                $this->mSize -= self::size( $data[$name] );
                unset( $data[$name] );
        }

        /**
         * Ensure all values in this result are valid UTF-8.
         */
        public function cleanUpUTF8() {
                array_walk_recursive( $this->mData, array( 'ApiResult', 'cleanUp_helper' ) );
        }

        /**
         * Callback function for cleanUpUTF8()
         *
         * @param string $s
         */
        private static function cleanUp_helper( &$s ) {
                if ( !is_string( $s ) ) {
                        return;
                }
                global $wgContLang;
                $s = $wgContLang->normalize( $s );
        }

        /**
         * Converts a Status object to an array suitable for addValue
         * @param Status $status
         * @param string $errorType
         * @return array
         */
        public function convertStatusToArray( $status, $errorType = 'error' ) {
                if ( $status->isGood() ) {
                        return array();
                }

                $result = array();
                foreach ( $status->getErrorsByType( $errorType ) as $error ) {
                        $this->setIndexedTagName( $error['params'], 'param' );
                        $result[] = $error;
                }
                $this->setIndexedTagName( $result, $errorType );

                return $result;
        }

        public function execute() {
                ApiBase::dieDebug( __METHOD__, 'execute() is not supported on Result object' );
        }

        /**
         * Parse a 'continue' parameter and return status information.
         *
         * This must be balanced by a call to endContinuation().
         *
         * @since 1.24
         * @param string|null $continue The "continue" parameter, if any
         * @param ApiBase[] $allModules Contains ApiBase instances that will be executed
         * @param array $generatedModules Names of modules that depend on the generator
         * @return array Two elements: a boolean indicating if the generator is done,
         *   and an array of modules to actually execute.
         */
        public function beginContinuation(
                $continue, array $allModules = array(), array $generatedModules = array()
        ) {
                $this->continueGeneratedModules = $generatedModules
                        ? array_combine( $generatedModules, $generatedModules )
                        : array();
                $this->continuationData = array();
                $this->generatorContinuationData = array();
                $this->generatorParams = array();

                $skip = array();
                if ( is_string( $continue ) && $continue !== '' ) {
                        $continue = explode( '||', $continue );
                        $this->dieContinueUsageIf( count( $continue ) !== 2 );
                        $this->generatorDone = ( $continue[0] === '-' );
                        $skip = explode( '|', $continue[1] );
                        if ( !$this->generatorDone ) {
                                $this->generatorParams = explode( '|', $continue[0] );
                        } else {
                                // When the generator is complete, don't run any modules that
                                // depend on it.
                                $skip += $this->continueGeneratedModules;
                        }
                }

                $this->continueAllModules = array();
                $runModules = array();
                foreach ( $allModules as $module ) {
                        $name = $module->getModuleName();
                        if ( in_array( $name, $skip ) ) {
                                $this->continueAllModules[$name] = false;
                                // Prevent spurious "unused parameter" warnings
                                $module->extractRequestParams();
                        } else {
                                $this->continueAllModules[$name] = true;
                                $runModules[] = $module;
                        }
                }

                return array(
                        $this->generatorDone,
                        $runModules,
                );
        }

        /**
         * Set the continuation parameter for a module
         *
         * @since 1.24
         * @param ApiBase $module
         * @param string $paramName
         * @param string|array $paramValue
         * @throws MWException
         */
        public function setContinueParam( ApiBase $module, $paramName, $paramValue ) {
                $name = $module->getModuleName();
                if ( !isset( $this->continueAllModules[$name] ) ) {
                        throw new MWException(
                                "Module '$name' called ApiResult::setContinueParam but was not " .
                                'passed to ApiResult::beginContinuation'
                        );
                }
                if ( !$this->continueAllModules[$name] ) {
                        throw new MWException(
                                "Module '$name' was not supposed to have been executed, but " .
                                'it was executed anyway'
                        );
                }
                $paramName = $module->encodeParamName( $paramName );
                if ( is_array( $paramValue ) ) {
                        $paramValue = join( '|', $paramValue );
                }
                $this->continuationData[$name][$paramName] = $paramValue;
        }

        /**
         * Set the continuation parameter for the generator module
         *
         * @since 1.24
         * @param ApiBase $module
         * @param string $paramName
         * @param string|array $paramValue
         */
        public function setGeneratorContinueParam( ApiBase $module, $paramName, $paramValue ) {
                $name = $module->getModuleName();
                $paramName = $module->encodeParamName( $paramName );
                if ( is_array( $paramValue ) ) {
                        $paramValue = join( '|', $paramValue );
                }
                $this->generatorContinuationData[$name][$paramName] = $paramValue;
        }

        /**
         * Close continuation, writing the data into the result
         *
         * @since 1.24
         * @param string $style 'standard' for the new style since 1.21, 'raw' for
         *   the style used in 1.20 and earlier.
         */
        public function endContinuation( $style = 'standard' ) {
                if ( $style === 'raw' ) {
                        $key = 'query-continue';
                        $data = array_merge_recursive(
                                $this->continuationData, $this->generatorContinuationData
                        );
                } else {
                        $key = 'continue';
                        $data = array();
                        $batchcomplete = false;

                        $finishedModules = array_diff(
                                array_keys( $this->continueAllModules ),
                                array_keys( $this->continuationData )
                        );

                        // First, grab the non-generator-using continuation data
                        $continuationData = array_diff_key(
                                $this->continuationData, $this->continueGeneratedModules
                        );
                        foreach ( $continuationData as $module => $kvp ) {
                                $data += $kvp;
                        }

                        // Next, handle the generator-using continuation data
                        $continuationData = array_intersect_key(
                                $this->continuationData, $this->continueGeneratedModules
                        );
                        if ( $continuationData ) {
                                // Some modules are unfinished: include those params, and copy
                                // the generator params.
                                foreach ( $continuationData as $module => $kvp ) {
                                        $data += $kvp;
                                }
                                $data += array_intersect_key(
                                        $this->getMain()->getRequest()->getValues(),
                                        array_flip( $this->generatorParams )
                                );
                        } elseif ( $this->generatorContinuationData ) {
                                // All the generator-using modules are complete, but the
                                // generator isn't. Continue the generator and restart the
                                // generator-using modules
                                $this->generatorParams = array();
                                foreach ( $this->generatorContinuationData as $kvp ) {
                                        $this->generatorParams = array_merge(
                                                $this->generatorParams, array_keys( $kvp )
                                        );
                                        $data += $kvp;
                                }
                                $finishedModules = array_diff(
                                        $finishedModules, $this->continueGeneratedModules
                                );
                                $batchcomplete = true;
                        } else {
                                // Generator and prop modules are all done. Mark it so.
                                $this->generatorDone = true;
                                $batchcomplete = true;
                        }

                        // Set 'continue' if any continuation data is set or if the generator
                        // still needs to run
                        if ( $data || !$this->generatorDone ) {
                                $data['continue'] =
                                        ( $this->generatorDone ? '-' : join( '|', $this->generatorParams ) ) .
                                        '||' . join( '|', $finishedModules );
                        }

                        if ( $batchcomplete ) {
                                $this->addValue( null, 'batchcomplete', '', ApiResult::ADD_ON_TOP | ApiResult::NO_SIZE_CHECK );
                        }
                }
                if ( $data ) {
                        $this->addValue( null, $key, $data, ApiResult::ADD_ON_TOP | ApiResult::NO_SIZE_CHECK );
                }
        }
}