When an update is available, a big frame is visible, proposing to go to
the download page. Now a button is also available to explicitly request
for an update check in other cases (bypassing the wait delay for a
future startup).
First, let's make the check happen at each startup on unstable (still
once a week on stable).
Second, make it parse gimp.org's gimp_versions.json on stable, but
testing's one on unstable and also check environment variable
GIMP_DEV_VERSIONS_JSON (unstable only) to allow setting a local path
(allowing to tweak the file and test various cases).
Unrelated to testing, some improvements:
- save a timestamp in seconds (really no need to keep microseconds
precision here).
- just in case, check that the saved timestamp is not in the future.
This fixes the following warning when compiling with Mingw:
> warning: integer overflow in expression of type 'long int' results in '-694967296' [-Woverflow]
GIMP will now process the remote gimp_versions json file to look if one
is using the last version of GIMP. This initial code doesn't act up yet
on this information. This will come in further commits.
Here are the characteristics:
- Since this requires internet access, a new checkbox is available in
the Preferences dialog, allowing to disable version checks. Note that
it is enabled by default as it is an important security feature, but
it has to be deactivatable.
- The remote access is done as an async operation because we don't want
it to block the startup in any way (for whatever reason). Also it
doesn't output errors if it fails to not be a bother (you don't
technically need internet access for an image program).
- We don't check at every startup. At each successful check, we save a
timestamp to prevent too frequent useless checks (I set it the timer
to a week or more for now).
Jehan