Hi Sergey,
For the second approach I have created webrev for review.
Please review updated webrev :
http://cr.openjdk.java.net/~jdv/8044289/webrev.02/
Thanks,
Jay
-----Original Message-----
From: Jayathirth D V
Sent: Friday, March 18, 2016 2:23 PM
To: Sergey Bylokhov
Cc: 2d-dev@openjdk.java.net; Philip Race
Subject: RE: [OpenJDK 2D-Dev] Review Request for JDK-8044289 : In
ImageIO.read() and write() NPE is not handled properly for stream
Hi Sergey,
Thanks for your inputs.
Indeed all the null values returned by createImageInputStream() and
createImageInputStream() are valid only.
I went through the code more and found that there is no need for fix in
ImageIO.read() methods as null stream is handled in read(ImageInputStream
stream) which is called by all the remaining read() API's through IAE. So i can
remove the changes made in ImageIO.read() functions. Also istream is closed in
finally block of read(url).
For ImageIO.write(File) & ImageIO.write(OutputStream) NPE we have two
approaches for fix:
1) Keep the present changes of throwing IOException when stream is null and
change the throw clause of write() spec mentioning:
"IOException - if an error occurs during writing or not able to create
required ImageOutputStream"
2) Remove the present changes and handle null in doWrite() method by returning
false when stream is null & add code in finally block to close the stream
only when stream is not null. Along with this we can also change Returns clause of
spec to mention that write() might return false when we are not able to create
ImageOutputStream.
private static boolean doWrite(RenderedImage im, ImageWriter writer,
ImageOutputStream output) throws IOException {
if (writer == null) {
return false;
}
+ if (output == null) {
+ return false;
+ }
try {
return doWrite(im, writer, stream);
} finally {
+ if (stream != null)
stream.close();
}
Returns :
false if no appropriate writer is found or not able to create
required ImageOutputStream.
Please let me know your inputs.
Thanks,
Jay
-----Original Message-----
From: Sergey Bylokhov
Sent: Friday, March 18, 2016 12:24 AM
To: Jayathirth D V
Cc: 2d-dev@openjdk.java.net; Philip Race
Subject: Re: [OpenJDK 2D-Dev] Review Request for JDK-8044289 : In
ImageIO.read() and write() NPE is not handled properly for stream
On 17.03.16 21:14, Jayathirth D V wrote:
There are many places in createImageInputStream() and createImageOutputStream()
where it will return null for stream.
But when why you change the write/read methods? They should take null into
account and work according to specification. If some bogus null returns from
createImageInputStream/createImageOutputStream then it should be fixed in these
methods.
So for NPE described in bug to occur there can be multiple paths:
1) One of the path described in bug is when theRegistry.getServiceProviders()
throws IAE and we return null.
This is the case when we have no installed spi and should return null/false.
2) When we pass non-existent file path to ImageIO (as described in
http://stackoverflow.com/questions/11153200/with-imageio-write-api-call-i-get-nullpointerexception
). Here we catch FileNotFoundException but still we return stream as null at
the end which will cause NPE further.
This is same thing described in the bug(about stream.close()). The write method
call createImageOutputStream() and got FileNotFoundException.
This exception should be propagated to the user, but it is replaced in the
finally block, because we try to close the stream=null. So the fix for this
particular case is to check the stream to null in finally, No?
3) When we don't support the provider and theRegistry.getServiceProviders()
return iterator with size zero.
This means that our providers do not support this case, and we should return
null/false.
For us to follow first scenario we need access to categoryMap of IIORegistry
and delete the ImageInputStreamSpi/ ImageOutputStreamSpi but I was not able to
find a way to tamper it from test case. If we follow second case
FileNotFoundException will be thrown by default eventhough we handle NPE.
But you change the code and we now contradicts the specification, in your case
the test should expect false/null from write()/read().
In the test case we are trying to following third scenario to get stream as
null to verify the code changes.
To catch the bogus null we should try to use another approach, or change the
spec. But it seems all null values above are correct, we should be ready for
them.
As part of collective fix we are throwing IOException which will indicate that
we are not able to create required stream.
Thanks,
Jay
-----Original Message-----
From: Sergey Bylokhov
Sent: Thursday, March 17, 2016 7:27 PM
To: Phil Race
Cc: Jayathirth D V; 2d-dev@openjdk.java.net
Subject: Re: [OpenJDK 2D-Dev] Review Request for JDK-8044289 : In
ImageIO.read() and write() NPE is not handled properly for stream
On 17.03.16 0:36, Phil Race wrote:
I don't think that is the actual reason here
But the test doing exactly this thing -> deregister all spi => in this
case according to specification all related
methods(read/write/creatImageInputStream/creatImageOutputStream) should return
null or false.
- it seems likely that there
was some kind of internal error or bad SPI causing this.
So throwing an exception seems more appropriate.
the problem was in some of our methods which do not expect null in some
places(like stream.close() from the bug description).
And also the bug was originally solely about write(..).
-phil.
On 03/16/2016 01:35 PM, Sergey Bylokhov wrote:
As far as I understand the createImageInputStream() returns null is
this stream is unsupported by current plugins via spi. Probably the
read() method should return null too?
/**
* Returns a {@code BufferedImage} as the result of decoding
* a supplied {@code InputStream} with an {@code ImageReader}
* chosen automatically from among those currently registered.
* The {@code InputStream} is wrapped in an
* {@code ImageInputStream}. If no registered
* {@code ImageReader} claims to be able to read the
* resulting stream, {@code null} is returned.
*
.......
* @return a {@code BufferedImage} containing the decoded
* contents of the input, or {@code null}.
*/
public static BufferedImage read(InputStream input) throws
IOException
On 16.03.16 20:29, Philip Race wrote:
The test writes out into "test.src".
I believe that you should treat that as a "read-only" location.
Write to a tempfile (File.createTempFile()) or TESTCLASSES.
-phil.
On 3/15/16, 10:50 PM, Jayathirth D V wrote:
Hi Phil,All
_Please review the following fix in JDK9:_
__
Bug : https://bugs.openjdk.java.net/browse/JDK-8044289
Webrev : http://cr.openjdk.java.net/~jdv/8044289/webrev.00/
<http://cr.openjdk.java.net/%7Ejdv/8044289/webrev.00/>
Issue : When createImageInputStream() or createImageOutputStream
returns null in ImageIO.read() or ImageIO.write() we are seeing
NPE as it stream is used further without null check.
Root cause : "stream" is used without checking whether it is null
or not.
Solution : Handle null pointer of stream and throw IIOException.
Test case contains all possible scenarios where
createImageInputStream() or createImageOutputStream can return null.
Thanks,
Jay
--
Best regards, Sergey.
--
Best regards, Sergey.
