61 lines
1.4 KiB
Go
61 lines
1.4 KiB
Go
package util
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import (
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"time"
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"fyne.io/fyne/v2"
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)
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type WidgetType int
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const (
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WidgetTypeAlbumPageHeader WidgetType = iota
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WidgetTypeArtistPageHeader
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WidgetTypePlaylistPageHeader
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WidgetTypeTracklist
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)
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// A pool to share commonly-used widgets across pages to reduce
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// creation of new widgets and memory allocations.
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// It is not thread-safe, which is fine for its current use.
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type WidgetPool struct {
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cache map[WidgetType][]cachedWidget
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}
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type cachedWidget struct {
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widget fyne.CanvasObject
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releasedAt int64 // unixMillis
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}
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func NewWidgetPool() WidgetPool {
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return WidgetPool{
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cache: make(map[WidgetType][]cachedWidget),
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}
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}
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// Obtain obtains a widget of the given type from the pool, if one exists.
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// Returns nil if there is no available widget.
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func (w *WidgetPool) Obtain(typ WidgetType) fyne.CanvasObject {
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var widget fyne.CanvasObject
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if ws, ok := w.cache[typ]; ok && len(ws) > 0 {
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i := len(ws) - 1
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widget = ws[i].widget
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ws[i].widget = nil
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w.cache[typ] = ws[:i]
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}
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return widget
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}
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// Release releases a widget into the pool.
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// The widget must not be modified by the releaser after release,
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// since it may be Obtained for a new use at any time.
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func (w *WidgetPool) Release(typ WidgetType, wid fyne.CanvasObject) {
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if _, ok := w.cache[typ]; !ok {
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w.cache[typ] = make([]cachedWidget, 0)
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}
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w.cache[typ] = append(w.cache[typ], cachedWidget{
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widget: wid,
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releasedAt: time.Now().UnixMilli(),
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})
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}
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