140 lines
3.2 KiB
Go
140 lines
3.2 KiB
Go
package rows
|
|
|
|
import (
|
|
"fmt"
|
|
|
|
"github.com/larvit/fejkdata/internal/invariant"
|
|
)
|
|
|
|
type pin[O any] struct {
|
|
t *Table[O]
|
|
row int
|
|
}
|
|
|
|
// Pins is the table rows fixed so far.
|
|
type Pins[O any] struct {
|
|
inline [8]pin[O] // sized so a render over a country's five-deep geo tree stays off the heap
|
|
used int
|
|
spill map[*Table[O]]int
|
|
}
|
|
|
|
func (p *Pins[O]) Pinned(t *Table[O]) (int, bool) {
|
|
for _, q := range p.inline[:p.used] {
|
|
if q.t == t {
|
|
return q.row, true
|
|
}
|
|
}
|
|
r, ok := p.spill[t]
|
|
return r, ok
|
|
}
|
|
|
|
// MustRow is the row pinned for t, which the caller pinned.
|
|
func (p *Pins[O]) MustRow(t *Table[O]) int {
|
|
r, ok := p.Pinned(t)
|
|
if !ok {
|
|
panic(invariant.Broken("no row of %s is pinned", t.segment))
|
|
}
|
|
return r
|
|
}
|
|
|
|
func (p *Pins[O]) add(t *Table[O], r int) {
|
|
if p.used < len(p.inline) {
|
|
p.inline[p.used] = pin[O]{t, r}
|
|
p.used++
|
|
return
|
|
}
|
|
if p.spill == nil {
|
|
p.spill = map[*Table[O]]int{}
|
|
}
|
|
p.spill[t] = r
|
|
}
|
|
|
|
// pin pins row r of t, and the rows of t's ancestors it links to. It checks nothing, so r must
|
|
// agree with the row p pins of nearestPinned(t): ask clash first, as PinRow does, or draw r inside
|
|
// it, as DrawIn does.
|
|
func (p *Pins[O]) pin(t *Table[O], r int) {
|
|
for stop := p.nearestPinned(t); t != stop; t = t.parent {
|
|
p.add(t, r)
|
|
if t.parent != stop {
|
|
r = t.parentRow(r)
|
|
}
|
|
}
|
|
}
|
|
|
|
// nearestPinned is the first of t and its ancestors p pins, where pinning a row of t stops; nil
|
|
// where none is.
|
|
func (p *Pins[O]) nearestPinned(t *Table[O]) *Table[O] {
|
|
for ; t != nil; t = t.parent {
|
|
if _, ok := p.Pinned(t); ok {
|
|
return t
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// clash is the table whose pinned row keeps row r of t out: t itself pinned to another row, or the
|
|
// nearest ancestor pinned to a row r is not inside; nil where none does.
|
|
func (p *Pins[O]) clash(t *Table[O], r int) *Table[O] {
|
|
if pr, ok := p.Pinned(t); ok && pr != r {
|
|
return t
|
|
}
|
|
for a := t.parent; a != nil; a = a.parent {
|
|
if pa, ok := p.Pinned(a); ok && !t.under(r, a, pa) {
|
|
return a
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// PinRow pins row r of t where it agrees with the rows pinned before it.
|
|
func (p *Pins[O]) PinRow(t *Table[O], r int) error {
|
|
switch a := p.clash(t, r); {
|
|
case a == t:
|
|
pr, _ := p.Pinned(t)
|
|
return fmt.Errorf("%s and %s are two rows of %s", t.selectorSpelling(pr), t.selectorSpelling(r), t.path)
|
|
case a != nil:
|
|
pa, _ := p.Pinned(a)
|
|
return fmt.Errorf("%s is not inside %s", t.selectorSpelling(r), a.selectorSpelling(pa))
|
|
}
|
|
p.pin(t, r)
|
|
return nil
|
|
}
|
|
|
|
// Select pins the row of t that sel names, and returns it.
|
|
func (p *Pins[O]) Select(t *Table[O], sel string) (int, error) {
|
|
r, err := t.find(sel, p)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
return r, p.PinRow(t, r)
|
|
}
|
|
|
|
// inside keeps the rows of t that sit inside every pinned ancestor.
|
|
func (p *Pins[O]) inside(t *Table[O], rows []int) []int {
|
|
for a := t.parent; a != nil; a = a.parent {
|
|
pa, ok := p.Pinned(a)
|
|
if !ok {
|
|
continue
|
|
}
|
|
var kept []int
|
|
for _, r := range rows {
|
|
if t.under(r, a, pa) {
|
|
kept = append(kept, r)
|
|
}
|
|
}
|
|
rows = kept
|
|
}
|
|
return rows
|
|
}
|
|
|
|
// Above is a pin set holding the rows p pins of t and its ancestors, and none below them.
|
|
func (p *Pins[O]) Above(t *Table[O]) *Pins[O] {
|
|
q := new(Pins[O])
|
|
for ; t != nil; t = t.parent {
|
|
if r, ok := p.Pinned(t); ok {
|
|
q.add(t, r)
|
|
}
|
|
}
|
|
return q
|
|
}
|