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MediaGallery: remove "isSubstantialRequest" optimization

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MediaGallery tried to avoid loading just a few items at a time,
because database queries are expensive and it's better to do work in
bulk. But the logic to do so was complicated and not entirely correct
(swiping very quickly through the detail view could run out of loaded
items while still considering the "next few" to be "not substantial").
Just remove it.
This commit is contained in:
Jordan Rose 2022-04-25 17:16:47 -07:00
parent 8c2bd109dd
commit ecd0740c7d
1 changed files with 0 additions and 80 deletions
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80
Signal/src/ViewControllers/MediaGallery/MediaGallery.swift
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@ -393,86 +393,6 @@ class MediaGallery: Dependencies {
return range
}()
func isSubstantialRequest() -> Bool {
// If we have not loaded the item at the given path yet, it's substantial.
guard let item = anchorItem else {
return true
}
let sectionItems = sections[sectionIndex].value
// If we're loading the remainder of an album, check to see if any items in the album are not loaded yet.
if shouldLoadAlbumRemainder {
let albumStart = (itemIndex - item.albumIndex)
.clamp(sectionItems.startIndex, sectionItems.endIndex)
let albumEnd = (albumStart + item.message.attachmentIds.count)
.clamp(sectionItems.startIndex, sectionItems.endIndex)
if sectionItems[albumStart..<albumEnd].contains(nil) { return true }
}
// Count unfetched items forward and backward.
func countUnfetched(in slice: ArraySlice<MediaGalleryItem?>) -> Int {
return slice.lazy.filter { $0 == nil }.count
}
owsAssertDebug(naiveRequestRange.lowerBound < sectionItems.count)
let sectionSliceStart = naiveRequestRange.lowerBound
.clamp(sectionItems.startIndex, sectionItems.endIndex)
let sectionSliceEnd = naiveRequestRange.upperBound
.clamp(sectionItems.startIndex, sectionItems.endIndex)
let sectionSlice = sectionItems[sectionSliceStart..<sectionSliceEnd]
var unfetchedCount = countUnfetched(in: sectionSlice)
if naiveRequestRange.upperBound > sectionItems.count {
var currentSectionIndex = sectionIndex + 1
var remainingForward = naiveRequestRange.upperBound - sectionItems.count
repeat {
guard let currentSectionItems = sections[safe: currentSectionIndex]?.value else {
// We've reached the end of the fetched sections. If there are more sections, or the last item
// isn't fetched yet, assume it's substantial.
if !hasFetchedMostRecent || (sections.last?.value.last ?? nil) == nil {
return true
}
break
}
unfetchedCount += countUnfetched(in: currentSectionItems.prefix(remainingForward))
if remainingForward <= currentSectionItems.count {
break
}
remainingForward -= currentSectionItems.count
currentSectionIndex += 1
} while true
}
if naiveRequestRange.lowerBound < 0 {
var currentSectionIndex = sectionIndex - 1
var remainingBackward = -naiveRequestRange.lowerBound
repeat {
guard let currentSectionItems = sections[safe: currentSectionIndex]?.value else {
// We've reached the start of the fetched sections. If there are more sections, or the first
// item isn't fetched yet, assume it's substantial.
if !hasFetchedOldest || (sections.first?.value.first ?? nil) == nil {
return true
}
break
}
unfetchedCount += countUnfetched(in: currentSectionItems.suffix(remainingBackward))
if remainingBackward <= currentSectionItems.count {
break
}
remainingBackward -= currentSectionItems.count
currentSectionIndex -= 1
} while true
}
// If we haven't hit the start or end, and more than half the items are unfetched, it's substantial.
return unfetchedCount > (naiveRequestRange.count / 2)
}
guard isSubstantialRequest() else {
return
}
var numNewlyLoadedEarlierSections: Int = 0
var numNewlyLoadedLaterSections: Int = 0