Merge lp:~stolowski/unity8-session-snap/thumbnailer-fixes into lp:unity8-session-snap

[Paweł Stołowski]

Fixes to make thumbnailer-service work in the snap. Without them thumbnailer considers images to be of text/plain type and also cannot process them because of missing pixbuf loaders.

There are two aspects of this fix:
- usr/share/mime files are genereted when the snap is created.
- gdk-pixbuf-loaders.cache is created by snappyenv script on first run (based on snappy-playpen/plank).

I'm not totally happy with the way the mime part works, i.e. the need to copy generated files from stage to install dir. The main problem is that update-mime-database doesn't support arbitrary target directories. I tried different approaches in snapcraft.yaml and x-mime plugin without success, but perhaps I missed something. Any suggestions for making this cleaner will be appreciated.

To test this branch you need scopes wich actually trigger thumbnailer with image://thumbnailer/ uris. I've tested it with unity-scope-fake from ppa:unity-team/scopes-dev (e.g with Fake Music scope).

[Michael Terry (mterry)]

OK, I'm going to test this, but a couple quick comments:

- You might want to use post-process.mk instead of a custom plugin. Should be simpler overall and be consistent with existing post processing like gsettings schemas.

- To avoid polluting the stage directory, maybe copy ./stage/usr/share/mime to a working dir, run update-mime-database, then copy the result into the install dir and delete the working dir.

- Why do you set XDG_CACHE_HOME? HOME will be set to SNAP_USER_DATA already, so the default will be the same as the one you set. If you were just trying to be explicit (to avoid typing HOME/.cache elsewhere), at least use the correct value of HOME/.cache (since HOME will actually be different based on whether the wrapper script is running for a system daemon we install, like cgmanager, or a user command like unity8).

[Michael Terry (mterry)]

What normally runs gdk-pixbuf-query-loaders in a user session? Can we adjust them to know about SNAP instead of pulling that logic into our wrapper script?

[Paweł Stołowski (stolowski)]

> What normally runs gdk-pixbuf-query-loaders in a user session? Can we adjust
> them to know about SNAP instead of pulling that logic into our wrapper script?

It's normally run on per-system basis by dpkg hooks (/var/lib/dpkg/info/libgdk-pixbuf2.0-0*postinst). I'm not aware of doing this in user session. In snap world however it's been done like that for the plank launcher in snappy-playpen (I borrowed it from there).

As for your earlier suggestion sure, I will try doing that, thanks for the review!

[Michael Terry (mterry)]

OK, I took your mime bits and added them to post-process.mk in trunk. And verified it got picked up by the snap.

So thanks for that bit! You can drop that part of this MP now.

That leaves the pixbuf loaders...

[Michael Terry (mterry)]

Don't bother looking at the pixbuf loaders either actually. I'm trying to integrate the desktop-loader script from snappy land and it should address that for us...

[Paweł Stołowski (stolowski)]

I got it working in the meantime, but indeed using existing desktop-loaders is definately a better idea. Closing this MR.

Unmerged revisions

54. By Paweł Stołowski on 2016-11-15

Actually create loaders cache file

53. By Paweł Stołowski on 2016-11-15

Remove mime plugin since it's now handled by post-process.mk.
Update gdk pixbuf loaders cache if snap gets upgraded.

52. By Paweł Stołowski on 2016-11-15

Merged trunk

51. By Paweł Stołowski on 2016-11-14

Merged trunk.

50. By Paweł Stołowski on 2016-11-14

Generate mime data in usr/share/mime and initialize gdk-pixbuf loaders cache to make thumbnailer-service work in the snap.

49. By Paweł Stołowski on 2016-11-10

Added x-mime.

=== modified file 'overlay/snappyenv'
--- overlay/snappyenv	2016-11-14 16:25:42 +0000
+++ overlay/snappyenv	2016-11-15 14:13:35 +0000
@@ -80,6 +80,18 @@
 export FONTCONFIG_PATH=$SNAP/etc/fonts
 export FONTCONFIG_FILE=$SNAP_USER_DATA/fonts.conf
 
+# Setup GDK pixbuf loaders
+export GDK_PIXBUF_MODULE_FILE=$HOME/.cache/gdk-pixbuf-loaders.cache
+export GDK_PIXBUF_MODULEDIR=$SNAP/usr/lib/$ARCH/gdk-pixbuf-2.0/2.10.0/loaders
+if [ -f $GDK_PIXBUF_MODULE_FILE ] && ! grep -q $SNAP $GDK_PIXBUF_MODULE_FILE; then
+    # This is an old version of the file that points to another snap location.
+    # Delete it and then recreate.
+    rm $GDK_PIXBUF_MODULE_FILE
+fi
+if [ ! -e $GDK_PIXBUF_MODULE_FILE ]; then
+    $SNAP/usr/lib/$ARCH/gdk-pixbuf-2.0/gdk-pixbuf-query-loaders > $GDK_PIXBUF_MODULE_FILE
+fi
+
 if [ -f $FONTCONFIG_FILE ] && ! grep -q $SNAP $FONTCONFIG_FILE; then
     # This is an old version of the file that points to another snap location.
     # Delete it and we'll recreate it in a second.

=== added directory 'parts'
=== added directory 'parts/plugins'
=== modified file 'snapcraft.yaml'
--- snapcraft.yaml	2016-11-14 16:53:00 +0000
+++ snapcraft.yaml	2016-11-15 14:13:35 +0000
@@ -71,6 +71,7 @@
       - unity-scope-click
       - unity-scope-mediascanner2
       - url-dispatcher
+      - libgdk-pixbuf2.0-0
       - thumbnailer-service
       - webbrowser-app
       - webapp-container