Exiv2

Thomas

May I ask you to have a look at this please? This is a "gray one" in which the existing behaviour is neither right nor wrong. I don't remember the details here, however you can see my thoughts when I opened this issue in response to topic 1582.

If you would like a bigger challenge, it would be good to make the -g option respect regular expressions. However do not use boost. The build consequences of boost outweigh the benefits of -g regular-expression. If you know/find decent public domain code for regular-expressions, can you add it to utils.cpp and use it to support the -g option?

Robin

On Linux, the GNU regex.h library seems to be available. I created a patch that will add support for regular-expressions in -g (attached), but I'm not sure if that compiles on all platforms...

Patch attached for the following behavior:

o Return code is only an error (-3 i.e. 253) if none of the requested meta data type is present: when all types are requested (-pa), any type suffices. When a specific type (e.g. IPTC, -pi) is requested, some data of its type must be present.

o If tag filters are given, no error is returned when no key matches.

o Error "No (Exif|IPTC|XMP) data found in the file" is reported without giving -v argument, but only if no data of another requested type is present.

I'm going to mark this as 'Resolved" as it builds and passes the test suite on the build server. http://exiv2.dyndns.org:8080/job/Exiv2-trunk/1835/

I've also changed the Assignee to Thomas Schmidt to ensure he is credited with this fix when the v0.25 release notes are compiled. Thank You, Thomas for working on this.

I'm going to reopen this because I'm rather unhappy with a consequence of the fix. The most common report I request with exiv2 is -pa = print all. However, if there is no IPTC metadata, a message is written to stderr, however the return code is set to 0.

581 rmills@rmillsmbp:~/gnu/exiv2/trunk/test $ exiv2 -pa ~/R.jpg | wc
/Users/rmills/R.jpg: (No IPTC data found in the file)
     177     837   12153
582 rmills@rmillsmbp:~/gnu/exiv2/trunk/test $ echo $?
0
583 rmills@rmillsmbp:~/gnu/exiv2/trunk/test $ 

I am very happy with the return code of 0. I think the semantics of -pa are "give me all you can find" and no message "(No IPTC data found in the file)" should be reported by default. The options -pa --verbose should report "No IPTC data found in the file" and set a return code of -3/253. I'd also like to see us return -3 (and not 253). The man page src/exiv2.1 should be updated with a section "EXIT STATUS" and the return codes documented as recommended here: https://wiki.archlinux.org/index.php/Man_page

There are other related matters here. The man page documents -pa as being the same as -Pkyct and -pt as -PEkyct. There's something inconsistent about this (and may simply be a man page error). We should also add the option -pe to report only Exif data (to correspond to options -pi and -px which report IPTC and XMP respectively.

When we do this, we're going to change return codes and error messages. We'll need to update the reference files in the test file. This usually only involves copying output files from test/tmp/ to test/data. For example, if bugfixes.sh reports something you understand, you can silence him with:

cp tmp/bugfixes-test.out-stripped data/bugfixes-test.out

1. We should set a return code != 0 if we write to stderr
2. We should always return a code != 0 if we write to stderr
3. Fix odd codes such as 253 to be -3
4. Add option -pe to only report Exif metadata
5. Change semantics of -pa to be silent when the file does not contain any metadata sections (Exif, IPTC, XMP)
6. Change semantics of -pa --verbose to complain when a metadata section is missing (and set return != 0)
7. Add a section EXIT STATUS to the man page
8. Review if the man page -pa == -Pkyct is true
9. Update the man page about -pe (both Command Summary and Options)
10. Clean up the reference files in the test suite

I'll leave this assigned to Thomas S. Thomas, if you're too busy to work on this, please assign it to me and I'll take care of it.

This behaviour has been in exiv2 for years. There is insufficient time in v0.25 to undertake this work. Punted to v0.26.

1. We should set a return code != 0 if we write to stderr
2. We should always return a code != 0 if we write to stderr

That's difficult to implement and not practical imho. (The library may write to stderr without the utility knowing.)

3. Fix odd codes such as 253 to be -3

I don't know how to do that. It may be better to return small positive values instead.

4. Add option -pe to only report Exif metadata

There are several options to only report Exif metadata: -pt, -pv and -ph. Maybe we should rename -pt to -pe.

5. Change semantics of -pa to be silent when the file does not contain any metadata sections (Exif, IPTC, XMP)
6. Change semantics of -pa --verbose to complain when a metadata section is missing (and set return != 0)

Changed back to original: silent without -v, inform about absence of metadata with -v. In accordance with the "give me all you can find" comment I also see this as just an info message, not a complaint (warning or error), thus it now returns 0 in either case.

7. Add a section EXIT STATUS to the man page
8. Review if the man page -pa == -Pkyct is true

Yes, it is.

9. Update the man page about -pe (both Command Summary and Options)
10. Clean up the reference files in the test suite

Further, with -g or -K, exiv2 now returns 1 if no matching tags were found. That's in-line with UNIX grep.

I believe this is closed.