[performance] rewrite timelines to rely on new timeline cache type (#3941)

* start work rewriting timeline cache type

* further work rewriting timeline caching

* more work integration new timeline code

* remove old code

* add local timeline, fix up merge conflicts

* remove old use of go-bytes

* implement new timeline code into more areas of codebase, pull in latest go-mangler, go-mutexes, go-structr

* remove old timeline package, add local timeline cache

* remove references to old timeline types that needed starting up in tests

* start adding page validation

* fix test-identified timeline cache package issues

* fix up more tests, fix missing required changes, etc

* add exclusion for test.out in gitignore

* clarify some things better in code comments

* tweak cache size limits

* fix list timeline cache fetching

* further list timeline fixes

* linter, ssssssssshhhhhhhhhhhh please

* fix linter hints

* reslice the output if it's beyond length of 'lim'

* remove old timeline initialization code, bump go-structr to v0.9.4

* continued from previous commit

* improved code comments

* don't allow multiple entries for BoostOfID values to prevent repeated boosts of same boosts

* finish writing more code comments

* some variable renaming, for ease of following

* change the way we update lo,hi paging values during timeline load

* improved code comments for updated / returned lo , hi paging values

* finish writing code comments for the StatusTimeline{} type itself

* fill in more code comments

* update go-structr version to latest with changed timeline unique indexing logic

* have a local and public timeline *per user*

* rewrite calls to public / local timeline calls

* remove the zero length check, as lo, hi values might still be set

* simplify timeline cache loading, fix lo/hi returns, fix timeline invalidation side-effects missing for some federated actions

* swap the lo, hi values :facepalm:

* add (now) missing slice reverse of tag timeline statuses when paging ASC

* remove local / public caches (is out of scope for this work), share more timeline code

* remove unnecessary change

* again, remove more unused code

* remove unused function to appease the linter

* move boost checking to prepare function

* fix use of timeline.lastOrder, fix incorrect range functions used

* remove comments for repeat code

* remove the boost logic from prepare function

* do a maximum of 5 loads, not 10

* add repeat boost filtering logic, update go-structr, general improvements

* more code comments

* add important note

* fix timeline tests now that timelines are returned in page order

* remove unused field

* add StatusTimeline{} tests

* add more status timeline tests

* start adding preloading support

* ensure repeat boosts are marked in preloaded entries

* share a bunch of the database load code in timeline cache, don't clear timelines on relationship change

* add logic to allow dynamic clear / preloading of timelines

* comment-out unused functions, but leave in place as we might end-up using them

* fix timeline preload state check

* much improved status timeline code comments

* more code comments, don't bother inserting statuses if timeline not preloaded

* shift around some logic to make sure things aren't accidentally left set

* finish writing code comments

* remove trim-after-insert behaviour

* fix-up some comments referring to old logic

* remove unsetting of lo, hi

* fix preload repeatBoost checking logic

* don't return on status filter errors, these are usually transient

* better concurrency safety in Clear() and Done()

* fix test broken due to addition of preloader

* fix repeatBoost logic that doesn't account for already-hidden repeatBoosts

* ensure edit submodels are dropped on cache insertion

* update code-comment to expand CAS accronym

* use a plus1hULID() instead of 24h

* remove unused functions

* add note that public / local timeline requester can be nil

* fix incorrect visibility filtering of tag timeline statuses

* ensure we filter home timeline statuses on local only

* some small re-orderings to confirm query params in correct places

* fix the local only home timeline filter func

1 files changed, 0 insertions, 120 deletions

diff --git a/internal/timeline/indexeditems.go b/internal/timeline/indexeditems.go
deleted file mode 100644
index 9b75e7256..000000000
--- a/internal/timeline/indexeditems.go
+++ /dev/null
@@ -1,120 +0,0 @@
-// GoToSocial
-// Copyright (C) GoToSocial Authors admin@gotosocial.org
-// SPDX-License-Identifier: AGPL-3.0-or-later
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-package timeline
-
-import (
-	"container/list"
-	"context"
-
-	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
-)
-
-type indexedItems struct {
-	data       *list.List
-	skipInsert SkipInsertFunction
-}
-
-type indexedItemsEntry struct {
-	itemID           string
-	boostOfID        string
-	accountID        string
-	boostOfAccountID string
-	prepared         Preparable
-}
-
-// WARNING: ONLY CALL THIS FUNCTION IF YOU ALREADY HAVE
-// A LOCK ON THE TIMELINE CONTAINING THIS INDEXEDITEMS!
-func (i *indexedItems) insertIndexed(ctx context.Context, newEntry *indexedItemsEntry) (bool, error) {
-	// Lazily init indexed items.
-	if i.data == nil {
-		i.data = &list.List{}
-		i.data.Init()
-	}
-
-	if i.data.Len() == 0 {
-		// We have no entries yet, meaning this is both the
-		// newest + oldest entry, so just put it in the front.
-		i.data.PushFront(newEntry)
-		return true, nil
-	}
-
-	var (
-		insertMark      *list.Element
-		currentPosition int
-	)
-
-	// We need to iterate through the index to make sure we put
-	// this item in the appropriate place according to its id.
-	// We also need to make sure we're not inserting a duplicate
-	// item -- this can happen sometimes and it's sucky UX.
-	for e := i.data.Front(); e != nil; e = e.Next() {
-		currentPosition++
-
-		currentEntry := e.Value.(*indexedItemsEntry)
-
-		// Check if we need to skip inserting this item based on
-		// the current item.
-		//
-		// For example, if the new item is a boost, and the current
-		// item is the original, we may not want to insert the boost
-		// if it would appear very shortly after the original.
-		if skip, err := i.skipInsert(
-			ctx,
-			newEntry.itemID,
-			newEntry.accountID,
-			newEntry.boostOfID,
-			newEntry.boostOfAccountID,
-			currentEntry.itemID,
-			currentEntry.accountID,
-			currentEntry.boostOfID,
-			currentEntry.boostOfAccountID,
-			currentPosition,
-		); err != nil {
-			return false, gtserror.Newf("error calling skipInsert: %w", err)
-		} else if skip {
-			// We don't need to insert this at all,
-			// so we can safely bail.
-			return false, nil
-		}
-
-		if insertMark != nil {
-			// We already found our mark.
-			continue
-		}
-
-		if currentEntry.itemID > newEntry.itemID {
-			// We're still in items newer than
-			// the one we're trying to insert.
-			continue
-		}
-
-		// We found our spot!
-		insertMark = e
-	}
-
-	if insertMark == nil {
-		// We looked through the whole timeline and didn't find
-		// a mark, so the new item is the oldest item we've seen;
-		// insert it at the back.
-		i.data.PushBack(newEntry)
-		return true, nil
-	}
-
-	i.data.InsertBefore(newEntry, insertMark)
-	return true, nil
-}