[Development] Mime database size

Arnaud Vrac rawoul at gmail.com
Tue Feb 17 11:51:04 CET 2015

Commit fbeeaf2 in qtbase adds QT_NO_MIMETYPE:

"The mime type stuff generates one of the biggest translation units in
QtCore due to the compressed 1.7MB freedesktop.org.xml resource. With
QT_NO_MIMETYPE, libQt5Core.so is almost 400Kb smaller (4.8MB->4.4MB gcc 4.9
stripped release build)"

It would be nice to be able to find a middle ground between disabling the
mime database completely and adding 1.7MB of data to Qt. The
update-mime-database binary from the shared-mime-info package can generate
a binary file from the XML, which is 100KB large and still allows finding
the mimetype of any file. The only difference with the XML is that you
don't have the translated pretty string for the mime type. The binary file
can also be mmapped and used for every request very efficiently, instead of
allocating all mime types data in memory.

Arnaud Vrac
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