Exception.php

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<?php
class MWException extends Exception {
        var $logId;

        function useOutputPage() {
                return $this->useMessageCache() &&
                        !empty( $GLOBALS['wgFullyInitialised'] ) &&
                        !empty( $GLOBALS['wgOut'] ) &&
                        !empty( $GLOBALS['wgTitle'] );
        }

        function useMessageCache() {
                global $wgLang;

                foreach ( $this->getTrace() as $frame ) {
                        if ( isset( $frame['class'] ) && $frame['class'] === 'LocalisationCache' ) {
                                return false;
                        }
                }

                return $wgLang instanceof Language;
        }

        function runHooks( $name, $args = array() ) {
                global $wgExceptionHooks;

                if ( !isset( $wgExceptionHooks ) || !is_array( $wgExceptionHooks ) ) {
                        return null; // Just silently ignore
                }

                if ( !array_key_exists( $name, $wgExceptionHooks ) || !is_array( $wgExceptionHooks[ $name ] ) ) {
                        return null;
                }

                $hooks = $wgExceptionHooks[ $name ];
                $callargs = array_merge( array( $this ), $args );

                foreach ( $hooks as $hook ) {
                        if ( is_string( $hook ) || ( is_array( $hook ) && count( $hook ) >= 2 && is_string( $hook[0] ) ) ) {    // 'function' or array( 'class', hook' )
                                $result = call_user_func_array( $hook, $callargs );
                        } else {
                                $result = null;
                        }

                        if ( is_string( $result ) ) {
                                return $result;
                        }
                }
                return null;
        }

        function msg( $key, $fallback /*[, params...] */ ) {
                $args = array_slice( func_get_args(), 2 );

                if ( $this->useMessageCache() ) {
                        return wfMessage( $key, $args )->plain();
                } else {
                        return wfMsgReplaceArgs( $fallback, $args );
                }
        }

        function getHTML() {
                global $wgShowExceptionDetails;

                if ( $wgShowExceptionDetails ) {
                        return '<p>' . nl2br( htmlspecialchars( $this->getMessage() ) ) .
                                '</p><p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
                                "</p>\n";
                } else {
                        return
                                "<div class=\"errorbox\">" .
                                '[' . $this->getLogId() . '] ' .
                                gmdate( 'Y-m-d H:i:s' ) .
                                ": Fatal exception of type " . get_class( $this ) . "</div>\n" .
                                "<!-- Set \$wgShowExceptionDetails = true; " .
                                "at the bottom of LocalSettings.php to show detailed " .
                                "debugging information. -->";
                }
        }

        function getText() {
                global $wgShowExceptionDetails;

                if ( $wgShowExceptionDetails ) {
                        return $this->getMessage() .
                                "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
                } else {
                        return "Set \$wgShowExceptionDetails = true; " .
                                "in LocalSettings.php to show detailed debugging information.\n";
                }
        }

        function getPageTitle() {
                return $this->msg( 'internalerror', "Internal error" );
        }

        function getLogId() {
                if ( $this->logId === null ) {
                        $this->logId = wfRandomString( 8 );
                }
                return $this->logId;
        }

        function getLogMessage() {
                global $wgRequest;

                $id = $this->getLogId();
                $file = $this->getFile();
                $line = $this->getLine();
                $message = $this->getMessage();

                if ( isset( $wgRequest ) && !$wgRequest instanceof FauxRequest ) {
                        $url = $wgRequest->getRequestURL();
                        if ( !$url ) {
                                $url = '[no URL]';
                        }
                } else {
                        $url = '[no req]';
                }

                return "[$id] $url   Exception from line $line of $file: $message";
        }

        function reportHTML() {
                global $wgOut;
                if ( $this->useOutputPage() ) {
                        $wgOut->prepareErrorPage( $this->getPageTitle() );

                        $hookResult = $this->runHooks( get_class( $this ) );
                        if ( $hookResult ) {
                                $wgOut->addHTML( $hookResult );
                        } else {
                                $wgOut->addHTML( $this->getHTML() );
                        }

                        $wgOut->output();
                } else {
                        header( "Content-Type: text/html; charset=utf-8" );
                        echo "<!doctype html>\n" .
                                '<html><head>' .
                                '<title>' . htmlspecialchars( $this->getPageTitle() ) . '</title>' .
                                "</head><body>\n";

                        $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
                        if ( $hookResult ) {
                                echo $hookResult;
                        } else {
                                echo $this->getHTML();
                        }

                        echo "</body></html>\n";
                }
        }

        function report() {
                global $wgLogExceptionBacktrace;
                $log = $this->getLogMessage();

                if ( $log ) {
                        if ( $wgLogExceptionBacktrace ) {
                                wfDebugLog( 'exception', $log . "\n" . $this->getTraceAsString() . "\n" );
                        } else {
                                wfDebugLog( 'exception', $log );
                        }
                }

                if ( defined( 'MW_API' ) ) {
                        // Unhandled API exception, we can't be sure that format printer is alive
                        header( 'MediaWiki-API-Error: internal_api_error_' . get_class( $this ) );
                        wfHttpError(500, 'Internal Server Error', $this->getText() );
                } elseif ( self::isCommandLine() ) {
                        MWExceptionHandler::printError( $this->getText() );
                } else {
                        header( "HTTP/1.1 500 MediaWiki exception" );
                        header( "Status: 500 MediaWiki exception", true );

                        $this->reportHTML();
                }
        }

        static function isCommandLine() {
                return !empty( $GLOBALS['wgCommandLineMode'] );
        }
}

class FatalError extends MWException {

        function getHTML() {
                return $this->getMessage();
        }

        function getText() {
                return $this->getMessage();
        }
}

class ErrorPageError extends MWException {
        public $title, $msg, $params;

        function __construct( $title, $msg, $params = null ) {
                $this->title = $title;
                $this->msg = $msg;
                $this->params = $params;

                if( $msg instanceof Message ){
                        parent::__construct( $msg );
                } else {
                        parent::__construct( wfMessage( $msg )->text() );
                }
        }

        function report() {
                global $wgOut;

                $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
                $wgOut->output();
        }
}

class BadTitleError extends ErrorPageError {
        function __construct( $msg = 'badtitletext', $params = null ) {
                parent::__construct( 'badtitle', $msg, $params );
        }

        function report() {
                global $wgOut;

                // bug 33646: a badtitle error page need to return an error code
                // to let mobile browser now that it is not a normal page.
                $wgOut->setStatusCode( 400 );
                parent::report();
        }

}

class PermissionsError extends ErrorPageError {
        public $permission, $errors;

        function __construct( $permission, $errors = array() ) {
                global $wgLang;

                $this->permission = $permission;

                if ( !count( $errors ) ) {
                        $groups = array_map(
                                array( 'User', 'makeGroupLinkWiki' ),
                                User::getGroupsWithPermission( $this->permission )
                        );

                        if ( $groups ) {
                                $errors[] = array( 'badaccess-groups', $wgLang->commaList( $groups ), count( $groups ) );
                        } else {
                                $errors[] = array( 'badaccess-group0' );
                        }
                }

                $this->errors = $errors;
        }

        function report() {
                global $wgOut;

                $wgOut->showPermissionsErrorPage( $this->errors, $this->permission );
                $wgOut->output();
        }
}

class ReadOnlyError extends ErrorPageError {
        public function __construct(){
                parent::__construct(
                        'readonly',
                        'readonlytext',
                        wfReadOnlyReason()
                );
        }
}

class ThrottledError extends ErrorPageError {
        public function __construct(){
                parent::__construct(
                        'actionthrottled',
                        'actionthrottledtext'
                );
        }

        public function report(){
                global $wgOut;
                $wgOut->setStatusCode( 503 );
                parent::report();
        }
}

class UserBlockedError extends ErrorPageError {
        public function __construct( Block $block ){
                global $wgLang, $wgRequest;

                $blocker = $block->getBlocker();
                if ( $blocker instanceof User ) { // local user
                        $blockerUserpage = $block->getBlocker()->getUserPage();
                        $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
                } else { // foreign user
                        $link = $blocker;
                }

                $reason = $block->mReason;
                if( $reason == '' ) {
                        $reason = wfMessage( 'blockednoreason' )->text();
                }

                /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
                 * This could be a username, an IP range, or a single IP. */
                $intended = $block->getTarget();

                parent::__construct(
                        'blockedtitle',
                        $block->mAuto ? 'autoblockedtext' : 'blockedtext',
                        array(
                                $link,
                                $reason,
                                $wgRequest->getIP(),
                                $block->getByName(),
                                $block->getId(),
                                $wgLang->formatExpiry( $block->mExpiry ),
                                $intended,
                                $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
                        )
                );
        }
}

class UserNotLoggedIn extends ErrorPageError {

        public function __construct(
                $reasonMsg = 'exception-nologin-text',
                $titleMsg  = 'exception-nologin',
                $params = null
        ) {
                parent::__construct( $titleMsg, $reasonMsg, $params );
        }
}

class HttpError extends MWException {
        private $httpCode, $header, $content;

        public function __construct( $httpCode, $content, $header = null ){
                parent::__construct( $content );
                $this->httpCode = (int)$httpCode;
                $this->header = $header;
                $this->content = $content;
        }

        public function report() {
                $httpMessage = HttpStatus::getMessage( $this->httpCode );

                header( "Status: {$this->httpCode} {$httpMessage}" );
                header( 'Content-type: text/html; charset=utf-8' );

                if ( $this->header === null ) {
                        $header = $httpMessage;
                } elseif ( $this->header instanceof Message ) {
                        $header = $this->header->escaped();
                } else {
                        $header = htmlspecialchars( $this->header );
                }

                if ( $this->content instanceof Message ) {
                        $content = $this->content->escaped();
                } else {
                        $content = htmlspecialchars( $this->content );
                }

                print "<!DOCTYPE html>\n".
                        "<html><head><title>$header</title></head>\n" .
                        "<body><h1>$header</h1><p>$content</p></body></html>\n";
        }
}

class MWExceptionHandler {
        public static function installHandler() {
                set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
        }

        protected static function report( Exception $e ) {
                global $wgShowExceptionDetails;

                $cmdLine = MWException::isCommandLine();

                if ( $e instanceof MWException ) {
                        try {
                                // Try and show the exception prettily, with the normal skin infrastructure
                                $e->report();
                        } catch ( Exception $e2 ) {
                                // Exception occurred from within exception handler
                                // Show a simpler error message for the original exception,
                                // don't try to invoke report()
                                $message = "MediaWiki internal error.\n\n";

                                if ( $wgShowExceptionDetails ) {
                                        $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
                                                'Exception caught inside exception handler: ' . $e2->__toString();
                                } else {
                                        $message .= "Exception caught inside exception handler.\n\n" .
                                                "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
                                                "to show detailed debugging information.";
                                }

                                $message .= "\n";

                                if ( $cmdLine ) {
                                        self::printError( $message );
                                } else {
                                        echo nl2br( htmlspecialchars( $message ) ) . "\n";
                                }
                        }
                } else {
                        $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
                                $e->__toString() . "\n";

                        if ( $wgShowExceptionDetails ) {
                                $message .= "\n" . $e->getTraceAsString() . "\n";
                        }

                        if ( $cmdLine ) {
                                self::printError( $message );
                        } else {
                                echo nl2br( htmlspecialchars( $message ) ) . "\n";
                        }
                }
        }

        public static function printError( $message ) {
                # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
                #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
                if ( defined( 'STDERR' ) ) {
                        fwrite( STDERR, $message );
                } else {
                        echo( $message );
                }
        }

        public static function handle( $e ) {
                global $wgFullyInitialised;

                self::report( $e );

                // Final cleanup
                if ( $wgFullyInitialised ) {
                        try {
                                wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
                        } catch ( Exception $e ) {}
                }

                // Exit value should be nonzero for the benefit of shell jobs
                exit( 1 );
        }
}