55 lines
2.3 KiB
Text
55 lines
2.3 KiB
Text
|
Working on building [[design/metadata]] filtered branches.
|
||
|
|
|
||
|
|
Spent most of the day on types and pure code. Finally at the end
|
||
|
|
I wrote down two actions that I still need to implement to make
|
||
|
|
it all work:
|
||
|
|
|
||
|
|
[[!format haskell """
|
||
|
|
applyView' :: MkFileView -> View -> Annex Git.Branch
|
||
|
|
updateView :: View -> Git.Ref -> Git.Ref -> Annex Git.Branch
|
||
|
|
"""]]
|
||
|
|
|
||
|
|
I know how to implement these, more or less. And in most cases
|
||
|
|
they will be pretty fast.
|
||
|
|
|
||
|
|
The more interesting part is already done. That was the issue of how to
|
||
|
|
generate filenames in the filter branches. That depends on the `View` being
|
||
|
|
used to filter and organize the branch, but also on the original filename used
|
||
|
|
in the reference branch. Each filter branch has a reference branch (such as
|
||
|
|
"master"), and displays a filtered and metadata-driven reorganized tree
|
||
|
|
of files from its reference branch.
|
||
|
|
|
||
|
|
[[!format haskell """
|
||
|
|
fileViews :: View -> (FilePath -> FileView) -> FilePath -> MetaData -> Maybe [FileView]
|
||
|
|
"""]]
|
||
|
|
|
||
|
|
So, a view that matches files tagged "haskell" or "git-annex"
|
||
|
|
and with an author of "J\*" will generate filenames like
|
||
|
|
"haskell/Joachim/interesting_theoretical_talk.ogg" and
|
||
|
|
"git-annex/Joey/mytalk.ogg".
|
||
|
|
|
||
|
|
It can also work backwards from these
|
||
|
|
filenames to derive the MetaData that is encoded in them.
|
||
|
|
|
||
|
|
[[!format haskell """
|
||
|
|
fromView :: View -> FileView -> MetaData
|
||
|
|
"""]]
|
||
|
|
|
||
|
|
So, copying a file to "haskell/Joey/mytalk.ogg" lets it know that
|
||
|
|
it's gained a "haskell" tag. I knew I was on the right track when
|
||
|
|
`fromView` turned out to be only 6 lines of code!
|
||
|
|
|
||
|
|
The trickiest part of all this, which I spent most of yesterday thinking
|
||
|
|
about, is what to do if the master branch has files in subdirectories. It
|
||
|
|
probably does not makes sense to retain that hierarchical directory
|
||
|
|
structure in the filtered branch, because we instead have a
|
||
|
|
non-hierarchical metadata structure to express. (And there would probably
|
||
|
|
be a lot of deep directory structures containing only one file.) But
|
||
|
|
throwing away the subdirectory information entirely means that two files
|
||
|
|
with the same basename and same metadata would have colliding names.
|
||
|
|
|
||
|
|
I eventually decided to embed the subdirectory information into the filenames
|
||
|
|
used on the filter branch. Currently that is done by converting
|
||
|
|
`dir/subdir/file.foo` to `file(dir)(subdir).foo`. We'll see how this works
|
||
|
|
out in practice..
|