From 84a0c49ec3d7395057e8a8babcd7eea3866471e3 Mon Sep 17 00:00:00 2001
From: Dane Springmeyer <dane@mapbox.com>
Date: Thu, 11 Jun 2015 14:02:34 -0700
Subject: [PATCH 1/2] Avoid crashing if we try to read a png as a jpeg - closes
 #2903

---
 src/jpeg_reader.cpp                 |  5 ++++-
 test/data                           |  2 +-
 test/unit/imaging/image_io_test.cpp | 15 +++++++++++++++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/jpeg_reader.cpp b/src/jpeg_reader.cpp
index 213469403..e6db1d527 100644
--- a/src/jpeg_reader.cpp
+++ b/src/jpeg_reader.cpp
@@ -206,8 +206,11 @@ void jpeg_reader<T>::attach_stream (j_decompress_ptr cinfo, input_stream* in)
 }
 
 template <typename T>
-void jpeg_reader<T>::on_error(j_common_ptr /*cinfo*/)
+void jpeg_reader<T>::on_error(j_common_ptr cinfo)
 {
+    char buffer[JMSG_LENGTH_MAX];
+    (*cinfo->err->format_message)(cinfo, buffer);
+    throw image_reader_exception(std::string("JPEG Reader: libjpeg could not read image: ") + buffer);
 }
 
 template <typename T>
diff --git a/test/data b/test/data
index bb25d5132..a6838f99a 160000
--- a/test/data
+++ b/test/data
@@ -1 +1 @@
-Subproject commit bb25d5132c0245aa6188d04b9e22d191fb5aca7c
+Subproject commit a6838f99a4c4be37989cea6718442cf4b53bd616
diff --git a/test/unit/imaging/image_io_test.cpp b/test/unit/imaging/image_io_test.cpp
index 8772ef3cd..eb38ae623 100644
--- a/test/unit/imaging/image_io_test.cpp
+++ b/test/unit/imaging/image_io_test.cpp
@@ -26,6 +26,21 @@ SECTION("readers") {
         type = mapnik::type_from_filename(should_throw);
         REQUIRE( type );
         REQUIRE_THROWS(std::unique_ptr<mapnik::image_reader> reader(mapnik::get_image_reader(should_throw,*type)));
+
+        // actually a png so jpeg reader should throw
+        should_throw = "./test/data/images/landusepattern.jpg";
+        REQUIRE( mapnik::util::exists( should_throw ) );
+        type = mapnik::type_from_filename(should_throw);
+        REQUIRE( type );
+        try
+        {
+            std::unique_ptr<mapnik::image_reader> reader(mapnik::get_image_reader(should_throw,*type));
+            REQUIRE(false);
+        }
+        catch (std::exception const& ex)
+        {
+            REQUIRE( std::string(ex.what()) == std::string("JPEG Reader: libjpeg could not read image: Not a JPEG file: starts with 0x89") );
+        }
 #endif
 
         REQUIRE_THROWS(mapnik::image_rgba8 im(-10,-10)); // should throw rather than overflow

From 5465adc2295cf91c8e122a7ec1a4f154001433b3 Mon Sep 17 00:00:00 2001
From: Dane Springmeyer <dane@mapbox.com>
Date: Thu, 11 Jun 2015 14:04:20 -0700
Subject: [PATCH 2/2] fix expected error message

---
 test/unit/imaging/image_io_test.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/unit/imaging/image_io_test.cpp b/test/unit/imaging/image_io_test.cpp
index eb38ae623..d0a984d7d 100644
--- a/test/unit/imaging/image_io_test.cpp
+++ b/test/unit/imaging/image_io_test.cpp
@@ -39,7 +39,7 @@ SECTION("readers") {
         }
         catch (std::exception const& ex)
         {
-            REQUIRE( std::string(ex.what()) == std::string("JPEG Reader: libjpeg could not read image: Not a JPEG file: starts with 0x89") );
+            REQUIRE( std::string(ex.what()) == std::string("JPEG Reader: libjpeg could not read image: Not a JPEG file: starts with 0x89 0x50") );
         }
 #endif