Improve error reporting of JPEG image encoder

Andrey Kamaev · Andrey Kamaev · commit 255cd61a8cd6 · 2013-01-28T16:55:00.000+04:00
OpenCV issue opencv#2604 After this patch applied an attempt to encode empty images produces exception saying "Raw image encoder error: Empty JPEG image (DNL not supported)"
diff --git a/modules/highgui/src/grfmt_base.cpp b/modules/highgui/src/grfmt_base.cpp
@@ -123,6 +123,15 @@ ImageEncoder BaseImageEncoder::newEncoder() const
     return ImageEncoder();
 }
 
+void BaseImageEncoder::throwOnEror() const
+{
+    if(!m_last_error.empty())
+    {
+        std::string msg = "Raw image encoder error: " + m_last_error;
+        CV_Error( CV_BadImageSize, msg.c_str() );
+    }
+}
+
 }
 
 /* End of file. */
diff --git a/modules/highgui/src/grfmt_base.hpp b/modules/highgui/src/grfmt_base.hpp
@@ -100,12 +100,16 @@ class BaseImageEncoder
     virtual string getDescription() const;
     virtual ImageEncoder newEncoder() const;
 
+    virtual void throwOnEror() const;
+
 protected:
     string m_description;
 
     string m_filename;
     vector<uchar>* m_buf;
     bool m_buf_supported;
+
+    string m_last_error;
 };
 
 }
diff --git a/modules/highgui/src/grfmt_jpeg.cpp b/modules/highgui/src/grfmt_jpeg.cpp
@@ -537,8 +537,10 @@ ImageEncoder JpegEncoder::newEncoder() const
     return new JpegEncoder;
 }
 
-bool  JpegEncoder::write( const Mat& img, const vector<int>& params )
+bool JpegEncoder::write( const Mat& img, const vector<int>& params )
 {
+    m_last_error.clear();
+
     struct fileWrapper
     {
         FILE* f;
@@ -633,6 +635,14 @@ bool  JpegEncoder::write( const Mat& img, const vector<int>& params )
     }
 
 _exit_:
+
+    if(!result)
+    {
+        char jmsg_buf[JMSG_LENGTH_MAX];
+        jerr.pub.format_message((j_common_ptr)&cinfo, jmsg_buf);
+        m_last_error = jmsg_buf;
+    }
+
     jpeg_destroy_compress( &cinfo );
 
     return result;
diff --git a/modules/highgui/src/loadsave.cpp b/modules/highgui/src/loadsave.cpp
@@ -426,15 +426,19 @@ bool imencode( const string& ext, InputArray _image,
     if( encoder->setDestination(buf) )
     {
         code = encoder->write(image, params);
+        encoder->throwOnEror();
         CV_Assert( code );
     }
     else
     {
         string filename = tempfile();
         code = encoder->setDestination(filename);
         CV_Assert( code );
+
         code = encoder->write(image, params);
+        encoder->throwOnEror();
         CV_Assert( code );
+
         FILE* f = fopen( filename.c_str(), "rb" );
         CV_Assert(f != 0);
         fseek( f, 0, SEEK_END );
diff --git a/modules/highgui/test/test_grfmt.cpp b/modules/highgui/test/test_grfmt.cpp
@@ -282,3 +282,12 @@ TEST(Highgui_ImreadVSCvtColor, regression)
 }
 #endif
 
+#ifdef HAVE_JPEG
+TEST(Highgui_Jpeg, encode_empty)
+{
+    cv::Mat img;
+    std::vector<uchar> jpegImg;
+
+    ASSERT_THROW(cv::imencode(".jpg", img, jpegImg), cv::Exception);
+}
+#endif

Original file line number	Diff line number	Diff line change
`@@ -123,6 +123,15 @@ ImageEncoder BaseImageEncoder::newEncoder() const`
`123`	`123`	`return ImageEncoder();`
`124`	`124`	`}`
`125`	`125`
	`126`	`+void BaseImageEncoder::throwOnEror() const`
	`127`	`+{`
	`128`	`+ if(!m_last_error.empty())`
	`129`	`+ {`
	`130`	`+ std::string msg = "Raw image encoder error: " + m_last_error;`
	`131`	`+ CV_Error( CV_BadImageSize, msg.c_str() );`
	`132`	`+ }`
	`133`	`+}`
	`134`	`+`
`126`	`135`	`}`
`127`	`136`
`128`	`137`	`/* End of file. */`
Original file line number	Diff line number	Diff line change
`@@ -537,8 +537,10 @@ ImageEncoder JpegEncoder::newEncoder() const`
`537`	`537`	`return new JpegEncoder;`
`538`	`538`	`}`
`539`	`539`
`540`		`-bool JpegEncoder::write( const Mat& img, const vector<int>& params )`
	`540`	`+bool JpegEncoder::write( const Mat& img, const vector<int>& params )`
`541`	`541`	`{`
	`542`	`+ m_last_error.clear();`
	`543`	`+`
`542`	`544`	`struct fileWrapper`
`543`	`545`	`{`
`544`	`546`	`FILE* f;`
`@@ -633,6 +635,14 @@ bool JpegEncoder::write( const Mat& img, const vector<int>& params )`
`633`	`635`	`}`
`634`	`636`
`635`	`637`	`_exit_:`
	`638`	`+`
	`639`	`+ if(!result)`
	`640`	`+ {`
	`641`	`+ char jmsg_buf[JMSG_LENGTH_MAX];`
	`642`	`+ jerr.pub.format_message((j_common_ptr)&cinfo, jmsg_buf);`
	`643`	`+ m_last_error = jmsg_buf;`
	`644`	`+ }`
	`645`	`+`
`636`	`646`	`jpeg_destroy_compress( &cinfo );`
`637`	`647`
`638`	`648`	`return result;`