Improve handling oof corrupted PNG images (resolves openfl/openfl#1999)

project/src/graphics/format/PNG.cpp

@@ -21,9 +21,9 @@ namespace lime {
 
 		ReadBuffer (const unsigned char* data, int length) : data (data), length (length), position (0) {}
 
-		void Read (unsigned char* out, int count) {
+		bool Read (unsigned char* out, int count) {
 
-			if (position >= length) return;
+			if (position >= length) return false;
 
 			if (count > length - position) {
 
@@ -37,6 +37,8 @@ namespace lime {
 
 			}
 
+			return true;
+
 		}
 
 		char unused; // the first byte gets corrupted when passed to libpng?
@@ -57,7 +59,9 @@ namespace lime {
 	static void user_read_data_fn (png_structp png_ptr, png_bytep data, png_size_t length) {
 
 		ReadBuffer* buffer = (ReadBuffer*)png_get_io_ptr (png_ptr);
-		buffer->Read (data, length);
+		if (!buffer->Read (data, length)) {
+			png_error (png_ptr, "Read Error");
+		}
 
 	}
 

src/lime/graphics/Image.hx

@@ -724,8 +724,11 @@ class Image {
 
 		if (bytes == null) return null;
 		var image = new Image ();
-		image.__fromBytes (bytes);
-		return image;
+		if (image.__fromBytes (bytes)) {
+			return image;
+		} else {
+			return null;
+		}
 
 	}
 
@@ -768,8 +771,11 @@ class Image {
 
 		if (path == null) return null;
 		var image = new Image ();
-		image.__fromFile (path);
-		return image;
+		if (image.__fromFile (path)) {
+			return image;
+		} else {
+			return null;
+		}
 
 	}
 
@@ -1694,7 +1700,7 @@ class Image {
 	}
 
 
-	@:noCompletion private function __fromBytes (bytes:Bytes, onload:Image->Void = null):Void {
+	@:noCompletion private function __fromBytes (bytes:Bytes, onload:Image->Void = null):Bool {
 
 		#if (js && html5)
 
@@ -1720,6 +1726,7 @@ class Image {
 			}
 
 			__fromBase64 (__base64Encode (bytes), type, onload);
+			return true;
 
 		#elseif (lime_cffi && !macro)
 
@@ -1744,6 +1751,8 @@ class Image {
 
 				}
 
+				return true;
+
 			}
 
 		#else
@@ -1752,10 +1761,12 @@ class Image {
 
 		#end
 
+		return false;
+
 	}
 
 
-	@:noCompletion private function __fromFile (path:String, onload:Image->Void = null, onerror:Void->Void = null):Void {
+	@:noCompletion private function __fromFile (path:String, onload:Image->Void = null, onerror:Void->Void = null):Bool {
 
 		#if (kha && !macro)
 
@@ -1798,6 +1809,8 @@ class Image {
 
 					}
 
+					return true;
+
 				}
 
 			} catch (e:Dynamic) {}
@@ -1852,6 +1865,8 @@ class Image {
 			// (issue #1019768)
 			if (image.complete) { }
 
+			return true;
+
 		#elseif (lime_cffi || java)
 
 			var buffer:ImageBuffer = null;
@@ -1921,6 +1936,8 @@ class Image {
 
 				}
 
+				return true;
+
 			}
 
 		#else
@@ -1929,6 +1946,8 @@ class Image {
 
 		#end
 
+		return false;
+
 	}