File resumption requires keeping partial files around for some time,
but we must still eventually delete them if never resumed.
Thus, we implement asynchronous file deletion, which could
spawn a background goroutine to delete the files.
We also use the same mechanism for deleting files on Windows,
where a file can't be deleted if there is still an open file handle.
We can enqueue those with the asynchronous file deleter as well.
Updates tailscale/corp#14772
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
Changes made:
* Move all HTTP related functionality from taildrop to ipnlocal.
* Add two arguments to taildrop.Manager.PutFile to specify
an opaque client ID and a resume offset (both unused for now).
* Cleanup the logic of taildrop.Manager.PutFile
to be easier to follow.
* Implement file conflict handling where duplicate files are renamed
(e.g., "IMG_1234.jpg" -> "IMG_1234 (2).jpg").
* Implement file de-duplication where "renaming" a partial file
simply deletes it if it already exists with the same contents.
* Detect conflicting active puts where a second concurrent put
results in an error.
Updates tailscale/corp#14772
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
Co-authored-by: Rhea Ghosh <rhea@tailscale.com>
Changes made:
* Unexport declarations specific to internal taildrop functionality.
* Document all exported functionality.
* Move TestRedactErr to the taildrop package.
* Rename and invert Handler.DirectFileDoFinalRename as AvoidFinalRename.
Updates tailscale/corp#14772
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
