feat: Compare files side by side

[juliusknorr]

Contributes to nextcloud/server#39140

[juliusknorr]

@skjnldsv I'd much appreciate an early review even though still in draft.

One topic I was unsure about was how we want to determine which handlers support the comparison view. For now I keep a allow list in https://github.com/nextcloud/server/pull/39171/files#diff-8c16136a0fe1baf1357890af01439aebe1da2380f96f80afb1eab039157311b8R111 but was thinking if we should just have a supportsComparison property on the handler registration instead.

[skjnldsv]

if we should just have a supportsComparison property on the handler registration instead.

Defnitely!
Every handler should provide if they supports comparison or not 👍

[juliusknorr]

@jancborchardt @marcoambrosini Does it make sense to add images for side by side comparison? Videos/audio probably don't as per nextcloud/server#39140 (comment)

This would also give us at least one default handler we can use in server cypress tests for versions then. Otherwise I'd just cover this with tests in text.

[marcoambrosini]

@juliushaertl I don't think we have interesting use-cases for that, but I might be missing something :)

[juliusknorr]

Will push some tests in text then for this feature.

[juliusknorr]

/compile

[skjnldsv]

Cypress failure is also present on master, haven't found the time to adjust

[skjnldsv]

/backport to stable27

[backportbot-nextcloud]

The backport to stable27 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable27
git pull origin stable27

# Create the new backport branch
git checkout -b fix/foo-stable27

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable27

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[skjnldsv]

/backport to stable27

[backportbot-nextcloud]

The backport to stable27 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable27
git pull origin stable27

# Create the new backport branch
git checkout -b fix/foo-stable27

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable27

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[mejo-]

/backport 6b67e4e to stable27

[backportbot-nextcloud]

The backport to stable27 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable27
git pull origin stable27

# Create the new backport branch
git checkout -b fix/foo-stable27

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable27

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[juliusknorr]

/backport 6b67e4e to stable27

[backportbot-nextcloud]

The backport to stable27 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable27
git pull origin stable27

# Create the new backport branch
git checkout -b fix/foo-stable27

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable27

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport