mediocre-go-lib/mcmp/series.go

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package mcmp
const (
seriesEls int = iota
seriesNumValueEls
)
type seriesKey struct {
userKey interface{}
mod int
}
// SeriesElement is used to describe a single element in a series, as
// implemented by AddSeriesValue. A SeriesElement can either be a Child which
// was spawned from the Component, or a Value which was added via
// AddSeriesValue.
type SeriesElement struct {
Child *Component
Value interface{}
}
func seriesKeys(key interface{}) (seriesKey, seriesKey) {
return seriesKey{userKey: key, mod: seriesEls},
seriesKey{userKey: key, mod: seriesNumValueEls}
}
func getSeriesElements(c *Component, key interface{}) ([]SeriesElement, int) {
elsKey, numValueElsKey := seriesKeys(key)
lastEls, _ := c.Value(elsKey).([]SeriesElement)
lastNumValueEls, _ := c.Value(numValueElsKey).(int)
children := c.Children()
lastNumChildrenEls := len(lastEls) - lastNumValueEls
els := lastEls
for _, child := range children[lastNumChildrenEls:] {
els = append(els, SeriesElement{Child: child})
}
return els, lastNumValueEls
}
// AddSeriesValue is a helper which adds a value to a series which is being
// stored under the given key on the given Component. The series of values added
// under any key can be retrieved with GetSeriesValues.
//
// Additionally, AddSeriesValue keeps track of the order of calls to itself and
// children spawned from the Component. By using GetSeriesElements you can
// retrieve the sequence of values and children in the order they were added to
// the Component.
func AddSeriesValue(c *Component, key, value interface{}) {
lastEls, lastNumValueEls := getSeriesElements(c, key)
els := append(lastEls, SeriesElement{Value: value})
elsKey, numValueElsKey := seriesKeys(key)
c.SetValue(elsKey, els)
c.SetValue(numValueElsKey, lastNumValueEls+1)
}
// SeriesElements returns the sequence of values that have been added to the
// Component under the given key via AddSeriesValue, interlaced with children
// which have been spawned from the Component, in the same respective order the
// events originally happened.
func SeriesElements(c *Component, key interface{}) []SeriesElement {
els, _ := getSeriesElements(c, key)
return els
}
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// SeriesGetElement returns the ith element in the series at the given key.
func SeriesGetElement(c *Component, key interface{}, i int) (SeriesElement, bool) {
els, _ := getSeriesElements(c, key)
if i >= len(els) {
return SeriesElement{}, false
}
return els[i], true
}
// SeriesValues returns the sequence of values that have been added to the
// Component under the given key via AddSeriesValue, in the same order the
// values were added.
func SeriesValues(c *Component, key interface{}) []interface{} {
elsKey, numValueElsKey := seriesKeys(key)
els, _ := c.Value(elsKey).([]SeriesElement)
numValueEls, _ := c.Value(numValueElsKey).(int)
values := make([]interface{}, 0, numValueEls)
for _, el := range els {
if el.Child != nil {
continue
}
values = append(values, el.Value)
}
return values
}