A Range header requesting a suffix longer than the object (e.g.
"bytes=-90407" against a 5 byte object) caused RangeOption.Decode to
compute a negative offset (size - End), which serve.Object then used
directly as a slice/seek offset and panicked with "slice bounds out of
range". FixRangeOption (used by backends like OneDrive/Box that lack
native suffix-range support) had the same root cause: it produced a
RangeOption with a negative Start, which Header() silently dropped,
turning the request into the wrong byte range instead of erroring or
serving the whole object.
Per RFC 7233 section 2.1, when the suffix-length exceeds the
representation size, the entire representation should be served.
Clamp the computed offset/start to 0 in both places.
Fixes#6310
Cloudflare R2 doesn't support range options like `Range: bytes=21-`.
This patch makes FixRangeOption turn a SeekOption into an absolute
RangeOption like this `Range: bytes=21-25` to interoperate with R2.
See: #5642
Before this change FixRangeOption was leaving `Range: bytes=21-`
alone, thus not fulfilling its contract of making Range requests
absolute.
As it happens this form isn't supported by Cloudflare R2.
After this change the request is normalised to `Range: bytes=21-25`.
See: #5642
Nothing is added or removed and no package is renamed by this change.
Just rearrange definitions between source files in the fs directory.
New source files:
- types.go Filesystem types and interfaces
- features.go Features and optional interfaces
- registry.go Filesystem registry and backend options
- newfs.go NewFs and its helpers
- configmap.go Getters and Setters for ConfigMap
- pacer.go Pacer with logging and calculator
The final fs.go contains what is left.
Also rename options.go to open_options.go
to dissociate from registry options.