GenericTable: prevent passing NULL to strtotime

Thumbnails are normally created on demand, e.g. when processing the format codes in a post's body text.
Normally, the temporary URL is only used once to generate thumbnails ad-hoc. However, when cache is
enabled, a reference to the asset may be used in a cached version of a formatted body text, skipping
the normal thumbnail generation routine.

When an asset is replaced, currently, all thumbnails are removed and references to them are removed
from the database. In case the asset is still referenced in a cached formatted body text, this could lead
to an error when requesting the thumbnail, as the thumbnail request is no longer present in the system.

As we do not know what posts use particular assets at this point in the code, it is best to work around this
issue by unsetting the thumbnail filenames rather than deleting the entries outright. This effectively
generates them again on the next request.

In the future, we should aim to keep track of what posts make use of assets, so cache may be invalidated
in a more targeted way.

models/Database.php

@@ -488,7 +488,7 @@ class Database
 	/**
 	 * This function can be used to insert data into the database in a secure way.
 	 */
-	public function insert($method = 'replace', $table, $columns, $data)
+	public function insert($method, $table, $columns, $data)
 	{
 		// With nothing to insert, simply return.
 		if (empty($data))

models/GenericTable.php

@@ -43,7 +43,7 @@ class GenericTable
 		$this->start = empty($options['start']) || !is_numeric($options['start']) || $options['start'] < 0 || $options['start'] > $this->recordCount ? 0 : $options['start'];
 
 		// Figure out where we are on the whole, too.
-		$numPages = ceil($this->recordCount / $this->items_per_page);
+		$numPages = max(1, ceil($this->recordCount / $this->items_per_page));
 		$this->currentPage = min(ceil($this->start / $this->items_per_page) + 1, $numPages);
 
 		// Let's bear a few things in mind...
@@ -234,7 +234,9 @@ class GenericTable
 				else
 					$pattern = $options['data']['pattern'];
 
-				if (!is_numeric($rowData[$options['data']['timestamp']]))
+				if (!isset($rowData[$options['data']['timestamp']]))
+					$timestamp = 0;
+				elseif (!is_numeric($rowData[$options['data']['timestamp']]))
 					$timestamp = strtotime($rowData[$options['data']['timestamp']]);
 				else
 					$timestamp = (int) $rowData[$options['data']['timestamp']];

models/Image.php

@@ -67,14 +67,33 @@ class Image extends Asset
 		return EXIF::fromFile($this->getPath());
 	}
 
-	public function getPath()
+	public function getImageUrls($width = null, $height = null)
 	{
-		return ASSETSDIR . '/' . $this->subdir . '/' . $this->filename;
+		$image_urls = [];
+		if (isset($width) || isset($height))
+		{
+			$thumbnail = new Thumbnail($this);
+			$image_urls[1] = $this->getThumbnailUrl($width, $height, false);
+
+			// Can we afford to generate double-density thumbnails as well?
+			if ((!isset($width) || $this->image_width >= $width * 2) &&
+				(!isset($height) || $this->image_height >= $height * 2))
+				$image_urls[2] = $this->getThumbnailUrl($width * 2, $height * 2, false);
+			else
+				$image_urls[2] = $this->getThumbnailUrl($this->image_width, $this->image_height, true);
+		}
+		else
+			$image_urls[1] = $this->getUrl();
+
+		return $image_urls;
 	}
 
-	public function getUrl()
+	public function getInlineImage($width = null, $height = null, $className = 'inline-image')
 	{
-		return ASSETSURL . '/' . $this->subdir . '/' . $this->filename;
+		$image_urls = $this->getImageUrls($width, $height);
+
+		return '<img class="' . $className . '" src="' . $image_urls[1] . '" alt=""' .
+			(isset($image_urls[2]) ? ' srcset="' . $image_urls[2] . ' 2x"' : '') . '>';
 	}
 
 	/**
@@ -141,7 +160,8 @@ class Image extends Asset
 		}
 
 		return Registry::get('db')->query('
-			DELETE FROM assets_thumbs
+			UPDATE assets_thumbs
+			SET filename = NULL
 			WHERE id_asset = {int:id_asset}',
 			['id_asset' => $this->id_asset]);
 	}

models/PageIndex.php

@@ -63,9 +63,9 @@ class PageIndex
 			   lower     current/cont. pgs.       center            upper
 		*/
 
-		$this->num_pages = ceil($this->recordCount / $this->items_per_page);
+		$this->num_pages = max(1, ceil($this->recordCount / $this->items_per_page));
 		$this->current_page = min(ceil($this->start / $this->items_per_page) + 1, $this->num_pages);
-		if ($this->num_pages == 0)
+		if ($this->num_pages <= 1)
 		{
 			$this->needsPageIndex = false;
 			return;

models/Thumbnail.php

@@ -9,6 +9,7 @@
 class Thumbnail
 {
 	private $image;
+	private $image_meta;
 	private $thumbnails;
 
 	private $properly_initialised;
@@ -23,7 +24,7 @@ class Thumbnail
 	const CROP_MODE_SLICE_CENTRE = 4;
 	const CROP_MODE_SLICE_BOTTOM = 5;
 
-	public function __construct($image)
+	public function __construct(Image $image)
 	{
 		$this->image      = $image;
 		$this->image_meta = $image->getMeta();
@@ -45,51 +46,45 @@ class Thumbnail
 		$thumb_selector = $this->width . 'x' . $this->height . $this->filename_suffix;
 		if (!empty($this->thumbnails[$thumb_selector]))
 		{
-			$thumb_path = '/' . $this->image->getSubdir() . '/' . $this->thumbnails[$thumb_selector];
-			if (file_exists(THUMBSDIR . $thumb_path))
-				return THUMBSURL . $thumb_path;
+			$thumb_filename = $this->image->getSubdir() . '/' . $this->thumbnails[$thumb_selector];
+			if (file_exists(THUMBSDIR . '/' . $thumb_filename))
+				return THUMBSURL . '/' . $thumb_filename;
 		}
 
 		// Do we have a custom thumbnail on file?
 		$custom_selector = 'custom_' . $this->width . 'x' . $this->height;
 		if (isset($this->image_meta[$custom_selector]))
 		{
-			$custom_thumb_path = '/' . $this->image->getSubdir() . '/' . $this->image_meta[$custom_selector];
-			if (file_exists(ASSETSDIR . $custom_thumb_path))
+			$custom_filename = $this->image->getSubdir() . '/' . $this->image_meta[$custom_selector];
+			if (file_exists(ASSETSDIR . '/' . $custom_filename))
 			{
-				// Ensure destination thumbnail directory exists.
-				if (!file_exists($this->image->getSubdir()))
-					@mkdir(THUMBSDIR . '/' . $this->image->getSubdir(), 0755, true);
-
 				// Copy the custom thumbail to the general thumbnail directory.
-				copy(ASSETSDIR . $custom_thumb_path, THUMBSDIR . $custom_thumb_path);
+				copy(ASSETSDIR . '/' . $custom_filename, THUMBSDIR . '/' . $custom_filename);
 
 				// Let's remember this for future reference.
 				$this->markAsGenerated($this->image_meta[$custom_selector]);
 
-				return THUMBSURL . $custom_thumb_path;
+				return THUMBSURL . '/' . $custom_filename;
 			}
 			else
 				throw new UnexpectedValueException('Custom thumbnail expected, but missing in file system!');
 		}
 
 		// Is this the right moment to generate a thumbnail, then?
-		if ($generate && array_key_exists($thumb_selector, $this->thumbnails))
+		if ($generate)
 		{
-			return $this->generate();
+			if (array_key_exists($thumb_selector, $this->thumbnails))
+				return $this->generate();
+			else
+				throw new Exception("Trying to generate a thumbnail not previously queued by the system\n" .
+					print_r(func_get_args(), true));
 		}
 
 		// If not, queue it for generation at another time, and return a URL to generate it with.
-		elseif (!$generate)
-		{
-			$this->markAsQueued();
-			return BASEURL . '/thumbnail/' . $this->image->getId() . '/' . $this->width . 'x' . $this->height . $this->filename_suffix . '/';
-		}
-
-		// Still here..? What are you up to? ..Sneaking?
 		else
 		{
-			throw new Exception("Trying to generate a thumbnail for selector " . $thumb_selector . ", which does not appear to have been requested by the system.\n" . print_r(func_get_args(), true));
+			$this->markAsQueued();
+			return BASEURL . '/thumbnail/' . $this->image->getId() . '/' . $thumb_selector . '/';
 		}
 	}
 
@@ -260,14 +255,18 @@ class Thumbnail
 				'_' . $this->width . 'x' . $this->height . $this->filename_suffix . '.' . $ext;
 
 			// Ensure the thumbnail subdirectory exists.
-			if (!is_dir(THUMBSDIR . '/' . $this->image->getSubdir()))
-				mkdir(THUMBSDIR . '/' . $this->image->getSubdir(), 0755, true);
+			$target_dir = THUMBSDIR . '/' . $this->image->getSubdir();
+			if (!is_dir($target_dir))
+				mkdir($target_dir, 0755, true);
+
+			if (!is_writable($target_dir))
+				throw new Exception('Thumbnail directory is not writable!');
 
 			// No need to preserve every detail.
 			$thumb->setImageCompressionQuality(80);
 
 			// Save it in a public spot.
-			$thumb->writeImage(THUMBSDIR . '/' . $this->image->getSubdir() . '/' . $thumb_filename);
+			$thumb->writeImage($target_dir . '/' . $thumb_filename);
 
 			// Let's remember this for future reference...
 			$this->markAsGenerated($thumb_filename);
@@ -278,7 +277,6 @@ class Thumbnail
 			// Finally, return the URL for the generated thumbnail image.
 			return THUMBSURL . '/' . $this->image->getSubdir() . '/' . $thumb_filename;
 		}
-		// Blast! Curse your sudden but inevitable betrayal!
 		catch (ImagickException $e)
 		{
 			throw new Exception('ImageMagick error occurred while generating thumbnail. Output: ' . $e->getMessage());
@@ -336,10 +334,16 @@ class Thumbnail
 		if ($success)
 		{
 			$thumb_selector = $this->width . 'x' . $this->height . $this->filename_suffix;
-			$this->thumbnails[$thumb_selector] = $filename !== 'NULL' ? $filename : '';
-		}
+			$this->thumbnails[$thumb_selector] = $filename !== 'NULL' ? $filename : null;
 
-		return $success;
+			// For consistency, write new thumbnail filename to parent Image object.
+			// TODO: there could still be an inconsistency if multiple objects exists for the same image asset.
+			$this->image->getThumbnails()[$thumb_selector] = $this->thumbnails[$thumb_selector];
+
+			return $success;
+		}
+		else
+			throw new UnexpectedValueException('Thumbnail queuing query failed');
 	}
 
 	private function markAsQueued()

templates/PhotoPage.php

@@ -65,11 +65,9 @@ class PhotoPage extends SubTemplate
 					<a href="', $this->photo->getUrl(), '">';
 
 		if ($this->photo->isPortrait())
-			echo '
-						<img src="', $this->photo->getThumbnailUrl(null, 960), '" alt="">';
+			echo $this->photo->getInlineImage(null, 960);
 		else
-			echo '
-						<img src="', $this->photo->getThumbnailUrl(1280, null), '" alt="">';
+			echo $this->photo->getInlineImage(1280, null);
 
 		echo '
 					</a>

templates/PhotosIndex.php

@@ -90,8 +90,14 @@ class PhotosIndex extends SubTemplate
 					<a class="edit" href="', BASEURL, '/editasset/?id=', $image->getId(), '">Edit</a>';
 
 		echo '
-					<a href="', $image->getPageUrl(), $this->url_suffix, '">
-						<img src="', $image->getThumbnailUrl($width, $height, $crop, $fit), '" alt="" title="', $image->getTitle(), '">';
+					<a href="', $image->getPageUrl(), $this->url_suffix, '#photo_frame">
+						<img src="', $image->getThumbnailUrl($width, $height, $crop, $fit), '"';
+
+		// Can we offer double-density thumbs?
+		if ($image->width() >= $width * 2 && $image->height() >= $height * 2)
+			echo ' srcset="', $image->getThumbnailUrl($width * 2, $height * 2, $crop, $fit), ' 2x"';
+
+		echo ' alt="" title="', $image->getTitle(), '">';
 
 		if ($this->show_labels)
 			echo '