85 lines
1.4 KiB
Go
85 lines
1.4 KiB
Go
package main
|
|
|
|
import "io"
|
|
|
|
type (
|
|
retrieveFunc func(io.Reader) ([]result, error)
|
|
filterFunc func(result) bool
|
|
groupFunc func(result) string
|
|
writeFunc func(io.Writer, []result) error
|
|
)
|
|
|
|
type report struct {
|
|
input io.Reader
|
|
output io.Writer
|
|
retrieve retrieveFunc
|
|
filter filterFunc
|
|
group groupFunc
|
|
write writeFunc
|
|
}
|
|
|
|
func newReport() *report {
|
|
return &report{
|
|
filter: noopFilter,
|
|
}
|
|
}
|
|
|
|
func (r *report) from(reader io.Reader) *report {
|
|
r.input = reader
|
|
return r
|
|
}
|
|
|
|
func (r *report) to(writer io.Writer) *report {
|
|
r.output = writer
|
|
return r
|
|
}
|
|
|
|
func (r *report) retrieveFrom(fn retrieveFunc) *report {
|
|
r.retrieve = fn
|
|
return r
|
|
}
|
|
|
|
func (r *report) filterBy(fn filterFunc) *report {
|
|
r.filter = fn
|
|
return r
|
|
}
|
|
|
|
func (r *report) groupBy(fn groupFunc) *report {
|
|
r.group = fn
|
|
return r
|
|
}
|
|
|
|
func (r *report) writeTo(fn writeFunc) *report {
|
|
r.write = fn
|
|
return r
|
|
}
|
|
|
|
func (r *report) run() ([]result, error) {
|
|
if r.retrieve == nil {
|
|
panic("report retrieve cannot be nil")
|
|
}
|
|
|
|
results, err := r.retrieve(r.input)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// noop if filter is nil
|
|
results = filterBy(results, r.filter)
|
|
|
|
// group func is more tricky
|
|
// you don't want to create an unnecessary map
|
|
if r.group != nil {
|
|
results = groupBy(results, r.group)
|
|
}
|
|
|
|
// TODO: prefer: noop writer
|
|
if r.write != nil {
|
|
if err := r.write(r.output, results); err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
return results, nil
|
|
}
|