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<?php

/*
 *      module_image.inc.php
 *      Module for displaying images uploaded by the user
 *
 *      Copyright Gottfried Haider, Danja Vasiliev 2010.
 *      This source code is licensed under the GNU General Public License.
 *      See the file COPYING for more details.
 */

@require_once('config.inc.php');
require_once('html.inc.php');
require_once('modules.inc.php');
// module glue gets loaded on demand
require_once('util.inc.php');


/**
 *      return if GD image functions are available
 *
 *      @return bool
 */
function _gd_available()
{
        return function_exists('gd_info');
}


/**
 *      return the width and height of an image file
 *
 *      @param string $f filename
 *
 *      @return array with width and height in pixels
 */
function _gd_get_imagesize($f)
{
        $ret = @getimagesize($f);
        if ($ret === false) {
                return array(0, 0);
        } else {
                return array($ret[0], $ret[1]);
        }
}


/**
 *      implements alter_render_early
 *
 *      see image_render_object()
 */
function image_alter_render_early($args)
{
        $elem = &$args['elem'];
        $obj = $args['obj'];
        if (!elem_has_class($elem, 'image')) {
                return false;
        }
        
        // try to calculate original-{width,height} if not already set
        if (!empty($obj['image-file']) && (empty($obj['image-file-width']) || intval($obj['image-file-width']) == 0)) {
                if (_gd_available()) {
                        $a = expl('.', $obj['name']);
                        $fn = CONTENT_DIR.'/'.$a[0].'/shared/'.$obj['image-file'];
                        // resolve symlinks
                        if (@is_link($fn)) {
                                $target = @readlink($fn);
                                if (substr($target, 0, 1) == '/') {
                                        $fn = $target;
                                } else {
                                        $fn = dirname($fn).'/'.$target;
                                }
                        }
                        $size = _gd_get_imagesize($fn);
                        $obj['image-file-width'] = $size[0];
                        // update regular with as well if not set
                        if (empty($obj['object-width']) || intval($obj['object-width']) == 0) {
                                $obj['object-width'] = $size[0].'px';
                        }
                        $obj['image-file-height'] = $size[1];
                        if (empty($obj['object-height']) || intval($obj['object-height']) == 0) {
                                $obj['object-height'] = $size[1].'px';
                        }
                }
                save_object($obj);
        }
        
        // setup url
        // note: the url points to the object name, not the 
        // filename in the shared directory (the file eventually gets served 
        // in image_serve_resource())
        // TODO (later): support URLs as well
        if (SHORT_URLS) {
                $url = base_url().urlencode($obj['name']);
        } else {
                $url = base_url().'?'.urlencode($obj['name']);
        }
        
        // render a div with background if we have original-{width,height}
        // otherwise a div with an img inside
        if (empty($obj['image-file-width']) || intval($obj['image-file-width']) == 0) {
                // render a div with an img inside
                $i = elem('img');
                elem_attr($i, 'src', $url);
                if (!empty($obj['image-title'])) {
                        elem_attr($i, 'alt', $obj['image-title']);
                } else {
                        elem_attr($i, 'alt', '');
                }
                // make sure you only append to the element in alter_render_early 
                // handlers, don't assume that nothing is in there yet
                elem_append($elem, $i);
        } else {
                if (!$args['edit'] && IE8_COMPAT && (empty($obj['image-background-repeat']) || $obj['image-background-repeat'] == 'no-repeat')) {
                        // background-size is not supported by IE8, so render a div with an img inside instead
                        $i = elem('img');
                        elem_attr($i, 'src', $url);
                        if (!empty($obj['image-title'])) {
                                elem_attr($i, 'alt', $obj['image-title']);
                        } else {
                                elem_attr($i, 'alt', '');
                        }
                        elem_css($i, 'width', '100%');
                        elem_css($i, 'height', '100%');
                        elem_css($i, 'padding', '0px');
                        elem_css($i, 'border', '0px');
                        if (!empty($obj['image-background-position']) && $obj['image-background-position'] != '0px 0px' && $obj['image-background-position'] != '0% 0%') {
                                elem_css($elem, 'max-width', $obj['object-width']);
                                elem_css($elem, 'max-height', $obj['object-height']);
                                elem_css($elem, 'overflow', 'hidden');
                                // assume px
                                $a = expl(' ', $obj['image-background-position']);
                                elem_css($i, 'margin-left', @intval($a[0]).'px');
                                elem_css($i, 'margin-top', @intval($a[1]).'px');
                                elem_css($i, 'margin-right', '0px');
                                elem_css($i, 'margin-bottom', '0px');
                        } else {
                                elem_css($i, 'margin', '0px');
                        }
                        elem_append($elem, $i);
                } else {
                        // this is the regular case
                        // render a div with background
                        elem_css($elem, 'background-image', 'url('.$url.')');
                        // default to no tiling
                        if (empty($obj['image-background-repeat']) || $obj['image-background-repeat'] == 'no-repeat') {
                                elem_css($elem, 'background-repeat', 'no-repeat');
                                // set hardcoded background-size as well
                                elem_css($elem, 'background-size', '100% 100%');
                                // this is for Firefox 3.6
                                elem_css($elem, '-moz-background-size', '100% 100%');
                        } else {
                                elem_css($elem, 'background-repeat', $obj['image-background-repeat']);
                        }
                        if (!empty($obj['image-background-position'])) {
                                elem_css($elem, 'background-position', $obj['image-background-position']);
                        }
                }
        }
        
        // additional properties for both
        if (!empty($obj['image-title'])) {
                elem_attr($elem, 'title', $obj['image-title']);
        }
        
        return true;
}


/**
 *      implements alter_save
 *
 *      see image_save_state()
 */
function image_alter_save($args)
{
        $elem = $args['elem'];
        // make sure that obj is a reference to the other object here
        $obj = &$args['obj'];
        // only handle the element when we are one of its classes
        // notice the difference to image_save_state()?
        if (!elem_has_class($elem, 'image')) {
                return false;
        }
        
        // update the object based on the element's properties
        // by convention all properties are prefixed with the module name, in order 
        // to prevent any naming collisions
        if (elem_css($elem, 'background-repeat') !== NULL) {
                $val = elem_css($elem, 'background-repeat');
                // normalize
                if ($val == 'no-repeat no-repeat') {
                        $val = 'no-repeat';
                }
                $obj['image-background-repeat'] = $val;
        } else {
                unset($obj['image-background-repeat']);
        }
        if (elem_css($elem, 'background-position') !== NULL) {
                $obj['image-background-position'] = elem_css($elem, 'background-position');
        } else {
                unset($obj['image-background-position']);
        }
        
        // this is more out of courtesy than anything else
        return true;
}


/**
 *      implements delete_object
 */
function image_delete_object($args)
{
        $obj = $args['obj'];
        if (!isset($obj['type']) || $obj['type'] != 'image') {
                return false;
        }
        // we don't have to care about symlinks here as this hook is not called 
        // for those
        
        load_modules('glue');
        // delete original file
        if (!empty($obj['image-file'])) {
                $a = expl('.', $obj['name']);
                delete_upload(array('pagename'=>$a[0], 'file'=>$obj['image-file'], 'max_cnt'=>1));
        }
        // and resized one
        if (!empty($obj['image-resized-file'])) {
                $a = expl('.', $obj['name']);
                delete_upload(array('pagename'=>$a[0], 'file'=>$obj['image-resized-file'], 'max_cnt'=>1));
        }
}


/**
 *      implements has_reference
 */
function image_has_reference($args)
{
        $obj = $args['obj'];
        if (!isset($obj['type']) || $obj['type'] != 'image') {
                return false;
        }
        // symlinks have their referenced files in a different page that's why 
        // they are not relevant here
        if (@is_link(CONTENT_DIR.'/'.str_replace('.', '/', $obj['name']))) {
                return false;
        }
        
        if (!empty($obj['image-file']) && $obj['image-file'] == $args['file']) {
                return true;
        }
        if (!empty($obj['image-resized-file']) && $obj['image-resized-file'] == $args['file']) {
                return true;
        }
        
        return false;
}


/**
 *      implements render_object
 */
function image_render_object($args)
{
        $obj = $args['obj'];
        if (!isset($obj['type']) || $obj['type'] != 'image') {
                return false;
        }
        
        // the outer element must be a div or something else that can contain 
        // other elements
        // we only set up the most basic element here - all the other work is 
        // done inside the alter_render_early hook
        // this way also object that "derive" from this (which don't have their 
        // $obj['type'] set to image) can use this code
        $e = elem('div');
        elem_attr($e, 'id', $obj['name']);
        elem_add_class($e, 'image');
        elem_add_class($e, 'resizable');
        elem_add_class($e, 'object');
        
        // hook
        // elem is passed as reference here
        // it is suggested that we first call our own function before any others 
        // that might want to modify the element that is being set up
        invoke_hook_first('alter_render_early', 'image', array('obj'=>$obj, 'elem'=>&$e, 'edit'=>$args['edit']));
        $html = elem_finalize($e);
        // html is passed as reference here
        // it is suggested that we call our own function after all others
        invoke_hook_last('alter_render_late', 'image', array('obj'=>$obj, 'html'=>&$html, 'elem'=>$e, 'edit'=>$args['edit']));
        
        return $html;
}

register_hook('alter_render_early', 'invoked early in the object rendering process (possible to change array representation)');
register_hook('alter_render_late', 'invoked late in the object rendering process (possible to change html string)');


/**
 *      implements render_page_early
 */
function image_render_page_early($args)
{
        if ($args['edit']) {
                if (USE_MIN_FILES) {
                        html_add_js(base_url().'modules/image/image-edit.min.js');
                } else {
                        html_add_js(base_url().'modules/image/image-edit.js');
                }
                if (!_gd_available()) {
                        html_add_js_var('$.glue.conf.image.resizing', false);
                        log_msg('debug', 'image: disabling image resizing as gd is not available');
                } else {
                        html_add_js_var('$.glue.conf.image.resizing', IMAGE_RESIZING);          
                }
                html_add_js_var('$.glue.conf.image.upload_resize_larger', IMAGE_UPLOAD_RESIZE_LARGER);
                html_add_js_var('$.glue.conf.image.upload_resize_to', IMAGE_UPLOAD_RESIZE_TO);
        }
}

/**
 *      determine if file is animated gif
 *      
 *      function takes filename and returns 'true' if the file header contains
 *      multiple frames:
 *      * a static 4-byte sequence (\x00\x21\xF9\x04)
 *      * 4 variable bytes
 *      * a static 2-byte sequence (\x00\x2C) (some variants may use \x00\x21 ?)
 *      
 *      based on: http://www.php.net/manual/en/function.imagecreatefromgif.php#104473
 */
function is_ani($filename) {
        if(!($fh = @fopen($filename, 'rb')))
                return false;
        $count = 0;
        while(!feof($fh) && $count < 2) {
                $chunk = fread($fh, 1024 * 100); //read 100kb at a time
                $count += preg_match_all('#\x00\x21\xF9\x04.{4}\x00(\x2C|\x21)#s', $chunk, $matches);
        }
        fclose($fh);
        return $count > 1;
}

/**
 *      resize an image object
 *
 *      this function drops the reference to any currently resized version, 
 *      saves the resized image together with the original image in the page's 
 *      shared folder and updates the object file to use the resized version.
 *      @param array $args arguments
 *              key 'name' name of the objects
 *              key 'width' width in px
 *              key 'height' height in px
 *      @return array response
 *              true if the client is advised to reload the image, false if not
 */
function image_resize($args)
{
        // check for gd
        if (!_gd_available()) {
                return response('Host does not have gd', 500);
        }
        // set requested width & height
        if (($width = @intval($args['width'])) == 0) {
                return response('Required argument "width" is zero or does not exist', 400);
        }
        if (($height = @intval($args['height'])) == 0) {
                return response('Required argument "height" is zero or does not exist', 400);
        }
        load_modules('glue');
        // resolve symlinks
        $ret = object_get_symlink($args);
        if ($ret['#error']) {
                return $ret;
        } elseif ($ret['#data'] !== false) {
                log_msg('debug', 'image_resize: resolved object '.quot($args['name']).' into '.quot($ret['#data']));
                $args['name'] = $ret['#data'];
        }       
        // load object
        $obj = load_object($args);
        if ($obj['#error']) {
                return $obj;
        } else {
                $obj = $obj['#data'];
        }
        if (@intval($obj['image-file-width']) == 0 || @intval($obj['image-file-height']) == 0) {
                return response('Original dimensions are not available', 500);
        }
        // set pagename
        $pn = array_shift(expl('.', $obj['name']));
        
        // resizing might not be necessary at all
        if (!empty($obj['image-resized-file']) && @intval($obj['image-resized-width']) == $width && @intval($obj['image-resized-height'] == $height)) {
                log_msg('debug', 'image_resize: width and height match the current resized file, no resize necessary');
                return response(false);
        }
        
        // else remove any currently resized file
        if (!empty($obj['image-resized-file'])) {
                log_msg('info', 'image_resize: dropping reference to previous resized file '.quot($obj['image-resized-file']));
                delete_upload(array('pagename'=>$pn, 'file'=>$obj['image-resized-file'], 'max_cnt'=>1));
                unset($obj['image-resized-file']);
                unset($obj['image-resized-width']);
                unset($obj['image-resized-height']);
                // update object file as well
                $ret = object_remove_attr(array('name'=>$obj['name'], 'attr'=>array('image-resized-file', 'image-resized-width', 'image-resized-height')));
                if ($ret['#error']) {
                        return $ret;
                }
                $was_resized = true;
        } else {
                $was_resized = false;
        }
        
        // check if width or height are larger than the original
        if (@intval($obj['image-file-width']) <= $width || @intval($obj['image-file-height']) <= $height) {
                log_msg('debug', 'image_resize: dimensions requested are larger or equal than the original file is, no resize necessary');
                // the client need not reload the the image if we were using the 
                // original before
                if (!$was_resized) {
                        return response(false);
                } else {
                        return response(true);
                }
        }
        
        // check if we really have a source image
        if (empty($obj['image-file-mime']) && empty($obj['image-file'])) {
                return response(false);
        }
        
        // TODO (later): make this a generic function
        // load source file
        $ext = filext($obj['image-file']);
        $fn = CONTENT_DIR.'/'.$pn.'/shared/'.$obj['image-file'];
        if ($obj['image-file-mime'] == 'image/jpeg' || in_array($ext, array('jpg', 'jpeg'))) {
                $orig = @imagecreatefromjpeg($fn);
                $dest_ext = 'jpg';
        } elseif ($obj['image-file-mime'] == 'image/png' || $ext == 'png') {
                $orig = @imagecreatefrompng($fn);
                $dest_ext = 'png';
        } elseif (is_ani($fn)) {
                // animated images shall not be resized
                log_msg('debug', 'image_resize: animated image, not resizing');
                return response(true);
        } elseif ($obj['image-file-mime'] == 'image/gif' || $ext == 'gif') {
                $orig = @imagecreatefromgif($fn);
                // save gifs as png
                // TODO (later): check for animated gif (see php.net/manual/en/function.imagecreatefromgif.php)
                $dest_ext = 'png';
        } else {
                return response('Unsupported source file format '.quot($obj['image-file']), 500);
        }
        if ($orig === false) {
                return response('Error loading source file '.quot($obj['image-file']), 500);
        }
        // get source file dimensions
        $orig_size = @getimagesize($fn);
        // create resized image
        if (($resized = @imagecreatetruecolor($width, $height)) === false) {
                @imagedestroy($orig);
                return response('Error creating the resized image', 500);
        }
        // preserve any alpha channel
        @imagealphablending($resized, false);
        @imagesavealpha($resized, true);
        // try to resize
        if (!@imagecopyresampled($resized, $orig, 0, 0, 0, 0, $width, $height, $orig_size[0], $orig_size[1])) {
                @imagedestroy($resized);
                @imagedestroy($orig);
                return response('Error resizing the source image', 500);
        }
        // setup destination filename
        $a = expl('.', $obj['image-file']);
        if (1 < count($a)) {
                // throw the previous extension away
                $fn = CONTENT_DIR.'/'.$pn.'/shared/'.implode('.', array_slice($a, 0, -1)).'-'.$width.'x'.$height.'.'.$dest_ext;
        } else {
                $fn = CONTENT_DIR.'/'.$pn.'/shared/'.$a[0].'-'.$width.'x'.$height.'.'.$dest_ext;
        }
        $m = umask(0111);
        if ($dest_ext == 'jpg') {
                $ret = @imagejpeg($resized, $fn, IMAGE_JPEG_QUAL);
        } else if ($dest_ext == 'png') {
                // preserve any alpha channel
                @imagealphablending($resized, false);
                @imagesavealpha($resized, true);
                $ret = @imagepng($resized, $fn, IMAGE_PNG_QUAL);
        }
        umask($m);
        // destroy images again
        @imagedestroy($resized);
        @imagedestroy($orig);
        if (!$ret) {
                return response('Error saving the resized image', 500);
        } else {
                log_msg('info', 'image_resize: created a resized image of '.quot($obj['name']).' -> '.quot(basename($fn)));
        }
        
        // the code above can take a while, so read in the object anew via 
        // update_object()
        $update = array();
        $update['name'] = $obj['name'];
        $update['image-resized-file'] = basename($fn);
        $update['image-resized-width'] = $width;
        $update['image-resized-height'] = $height;
        // we change width and height here as well since we are racing with the 
        // save_object from the frontend after resize
        $update['object-width'] = $width.'px';
        $update['object-height'] = $height.'px';
        
        return update_object($update);
}

register_service('image.resize', 'image_resize', array('auth'=>true));


/**
 *      implements save_state
 */
function image_save_state($args)
{
        $elem = $args['elem'];
        $obj = $args['obj'];
        // only take responsibility for the element when we are its main class
        if (array_shift(elem_classes($elem)) != 'image') {
                return false;
        }
        
        // make sure the type is set
        $obj['type'] = 'image';
        $obj['module'] = 'image';
        
        // by convention the main retrieving of the elements properties takes 
        // place in alter_state
        // this way other objects types may "derive" from this one
        // it also allows other modules to chime in
        // notice: obj is passed as reference here
        // obj might be (almost) empty for newly created objects, so rely only 
        // on $elem
        invoke_hook('alter_save', array('obj'=>&$obj, 'elem'=>$elem));
        // see image_alter_save() above
        
        // we could do some overriding here if we wanted to
        
        // finally save the object
        load_modules('glue');
        $ret = save_object($obj);
        if ($ret['#error']) {
                log_msg('error', 'image_save_state: save_object returned '.quot($ret['#data']));
                return false;
        } else {
                return true;
        }
}

register_hook('alter_save', 'invoked in the object saving process (possible to augment the object to be saved)');


/**
 *      implements serve_resource
 */
function image_serve_resource($args)
{
        $obj = $args['obj'];
        if (!isset($obj['type']) || $obj['type'] != 'image') {
                return false;
        }
        // we don't have to care about symlinks here as they are being resolved 
        // before this hook is called
        $pn = array_shift(expl('.', $obj['name']));
        
        if (!empty($obj['image-resized-file']) && !$args['dl']) {
                // we have a resized file and don't want to download the original
                $fn = CONTENT_DIR.'/'.$pn.'/shared/'.$obj['image-resized-file'];
                $ext = filext($fn);
                if ($ext == 'jpg' || $ext == 'jpeg') {
                        serve_file($fn, false, 'image/jpeg');
                } else if ($ext == 'png') {
                        serve_file($fn, false, 'image/png');
                } else {
                        log_msg('warn', 'image_serve_resource: unsupported image-resized-file '.quot($fn));
                }
                // if we're still alive it means that the resized file has not been 
                // found
                log_msg('warn', 'image_serve_resource: could not serve image-resized-file '.quot($fn).', falling back to original');
                $need_auth = false;
        } elseif (empty($obj['image-resized-file'])) {
                // we don't have a resized file
                $need_auth = false;
        } else {
                // we really want to download the original
                $need_auth = true;
        }
        
        if (!empty($obj['image-file'])) {
                // we have the original file
                if ($need_auth && !is_auth()) {
                        // require authentication
                        prompt_auth(true);
                }
                if (empty($obj['image-file-mime'])) {
                        $obj['image-file-mime'] = '';
                }
                serve_file(CONTENT_DIR.'/'.$pn.'/shared/'.$obj['image-file'], $args['dl'], $obj['image-file-mime']);
        }
        
        // if everything fails
        return false;
}


/**
 *      implements snapshot_symlink
 *
 *      see snapshot() in module_glue.inc.php
 */
function image_snapshot_symlink($args)
{
        $obj = $args['obj'];
        if (!isset($obj['type']) || $obj['type'] != 'image') {
                return false;
        }
        
        // consider the following:
        // * an image object is on page a, which at some point got distributed to all 
        // other pages through symlinks
        // * we are now creating a snapshot of any page b, come across the symlink 
        // pointing to an object and page a
        // in this case we don't copy the symlink but the current content of the 
        // object, as we by all means want to preserve the current _state_ we copy 
        // the symlink's content (this happens in snapshot() in module_glue.inc.php) 
        // - thus turning it into a first-class object on the new snapshot-page
        // because of this we need to copy any referenced files as well from the 
        // shared directory in page a to the one on page b, this happens in this 
        // hook
        
        $dest_dir = CONTENT_DIR.'/'.array_shift(expl('.', $obj['name'])).'/shared';
        $src_dir = CONTENT_DIR.'/'.array_shift(expl('.', $args['origin'])).'/shared';
        
        // we do this for image-file and image-resized-file
        // .. to add a bit of complexity ;)
        foreach (array('image-file', 'image-resized-file') as $field) {
                if (empty($obj[$field])) {
                        continue;
                } else {
                        $src_file = $src_dir.'/'.$obj[$field];
                }
                if (($f = dir_has_same_file($dest_dir, $src_file)) !== false) {
                        $obj[$field] = $f;
                } else {
                        // copy file
                        $dest_file = $dest_dir.'/'.unique_filename($dest_dir, $src_file);
                        $m = umask(0111);
                        if (!(@copy($src_file, $dest_file))) {
                                umask($m);
                                log_msg('error', 'image_snapshot_symlink: error copying referenced file '.quot($src_file).' to '.quot($dest_file));
                                return false;
                        }
                        umask($m);
                        $obj[$field] = basename($dest_file);
                        log_msg('info', 'image_snapshot_symlink: copied referenced file to '.quot($dest_file));
                }
        }
        
        // save changes in the object
        $ret = save_object($obj);
        if ($ret['#error']) {
                log_msg('error', 'image_snapshot_symlink: error saving object '.quot($obj['name']));
                return false;
        } else {
                return true;
        }
}


/**
 *      implements upload
 */
function image_upload($args)
{
        // check if supported file
        if (!in_array($args['mime'], array('image/jpeg', 'image/png', 'image/gif')) || ($args['mime'] == '' && !in_array(filext($args['file']), array('jpg', 'jpeg', 'png', 'gif')))) {
                return false;
        }
        
        load_modules('glue');
        // create new object
        $obj = create_object($args);
        if ($obj['#error']) {
                return false;
        } else {
                $obj = $obj['#data'];
        }
        $obj['type'] = 'image';
        // this is for a potential future speedup
        $obj['module'] = 'image';
        $obj['image-file'] = $args['file'];
        $obj['image-file-mime'] = $args['mime'];
        // save original-{width,height} if we can calculate it
        if (_gd_available()) {
                $a = expl('.', $args['page']);
                $size = _gd_get_imagesize(CONTENT_DIR.'/'.$a[0].'/shared/'.$obj['image-file']);
                $obj['image-file-width'] = $size[0];
                $obj['object-width'] = $size[0].'px';
                $obj['image-file-height'] = $size[1];
                $obj['object-height'] = $size[1].'px';
        }
        save_object($obj);
        
        // render object and return html
        $ret = render_object(array('name'=>$obj['name'], 'edit'=>true));
        if ($ret['#error']) {
                return false;
        } else {
                return $ret['#data'];
        }
}

---