71 lines
1.7 KiB
Go
71 lines
1.7 KiB
Go
package timeline
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import (
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"container/list"
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"errors"
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)
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type postIndex struct {
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data *list.List
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}
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type postIndexEntry struct {
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statusID string
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boostOfID string
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}
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func (p *postIndex) insertIndexed(i *postIndexEntry) (bool, error) {
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if p.data == nil {
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p.data = &list.List{}
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}
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// if we have no entries yet, this is both the newest and oldest entry, so just put it in the front
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if p.data.Len() == 0 {
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p.data.PushFront(i)
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return true, nil
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}
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var insertMark *list.Element
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var position int
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// We need to iterate through the index to make sure we put this post in the appropriate place according to when it was created.
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// We also need to make sure we're not inserting a duplicate post -- this can happen sometimes and it's not nice UX (*shudder*).
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for e := p.data.Front(); e != nil; e = e.Next() {
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position = position + 1
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entry, ok := e.Value.(*postIndexEntry)
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if !ok {
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return false, errors.New("index: could not parse e as a postIndexEntry")
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}
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// don't insert this if it's a boost of a status we've seen recently
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if i.boostOfID != "" {
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if i.boostOfID == entry.boostOfID || i.boostOfID == entry.statusID {
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if position < boostReinsertionDepth {
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return false, nil
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}
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}
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}
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// if the post to index is newer than e, insert it before e in the list
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if insertMark == nil {
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if i.statusID > entry.statusID {
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insertMark = e
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}
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}
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// make sure we don't insert a duplicate
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if entry.statusID == i.statusID {
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return false, nil
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}
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}
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if insertMark != nil {
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p.data.InsertBefore(i, insertMark)
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return true, nil
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}
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// if we reach this point it's the oldest post we've seen so put it at the back
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p.data.PushBack(i)
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return true, nil
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}
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