Before this change, attempting to copy a large google doc while using
the metadata mapper caused a panic. Google doc files use Rcat to
download as they have an unknown size, and when the size of the doc
file got above --streaming-upload-cutoff it used a
object.NewStaticObjectInfo with a `nil` Fs to upload the file which
caused the crash in the metadata mapper code.
This change makes sure that the Fs in object.NewStaticObjectInfo is
never nil, and it returns MemoryFs which is consistent with the Rcat
code when the source is sized below the --streaming-upload-cutoff
threshold.
Fixes#7845
- Change rclone/fs interfaces to accept context.Context
- Update interface implementations to use context.Context
- Change top level usage to propagate context to lover level functions
Context propagation is needed for stopping transfers and passing other
request-scoped values.
The purpose of this is to make it easier to maintain and eventually to
allow the rclone backends to be re-used in other projects without
having to use the rclone configuration system.
The new code layout is documented in CONTRIBUTING.