[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, 146 deletions

diff --git a/internal/timeline/prepare.go b/internal/timeline/prepare.go
deleted file mode 100644
index ec595ce42..000000000
--- a/internal/timeline/prepare.go
+++ /dev/null
@@ -1,146 +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"
-	"errors"
-
-	"codeberg.org/gruf/go-kv"
-	"github.com/superseriousbusiness/gotosocial/internal/db"
-	statusfilter "github.com/superseriousbusiness/gotosocial/internal/filter/status"
-	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
-	"github.com/superseriousbusiness/gotosocial/internal/log"
-)
-
-func (t *timeline) prepareXBetweenIDs(ctx context.Context, amount int, behindID string, beforeID string, frontToBack bool) error {
-	l := log.
-		WithContext(ctx).
-		WithFields(kv.Fields{
-			{"amount", amount},
-			{"behindID", behindID},
-			{"beforeID", beforeID},
-			{"frontToBack", frontToBack},
-		}...)
-	l.Trace("entering prepareXBetweenIDs")
-
-	if beforeID >= behindID {
-		// This is an impossible situation, we
-		// can't prepare anything between these.
-		return nil
-	}
-
-	if err := t.indexXBetweenIDs(ctx, amount, behindID, beforeID, frontToBack); err != nil {
-		// An error here doesn't necessarily mean we
-		// can't prepare anything, so log + keep going.
-		l.Debugf("error calling prepareXBetweenIDs: %s", err)
-	}
-
-	t.Lock()
-	defer t.Unlock()
-
-	// Try to prepare everything between (and including) the two points.
-	var (
-		toPrepare      = make(map[*list.Element]*indexedItemsEntry)
-		foundToPrepare int
-	)
-
-	if frontToBack {
-		// Paging forwards / down.
-		for e := t.items.data.Front(); e != nil; e = e.Next() {
-			entry := e.Value.(*indexedItemsEntry)
-
-			if entry.itemID > behindID {
-				l.Trace("item is too new, continuing")
-				continue
-			}
-
-			if entry.itemID < beforeID {
-				// We've gone beyond the bounds of
-				// items we're interested in; stop.
-				l.Trace("reached older items, breaking")
-				break
-			}
-
-			// Only prepare entry if it's not
-			// already prepared, save db calls.
-			if entry.prepared == nil {
-				toPrepare[e] = entry
-			}
-
-			foundToPrepare++
-			if foundToPrepare >= amount {
-				break
-			}
-		}
-	} else {
-		// Paging backwards / up.
-		for e := t.items.data.Back(); e != nil; e = e.Prev() {
-			entry := e.Value.(*indexedItemsEntry)
-
-			if entry.itemID < beforeID {
-				l.Trace("item is too old, continuing")
-				continue
-			}
-
-			if entry.itemID > behindID {
-				// We've gone beyond the bounds of
-				// items we're interested in; stop.
-				l.Trace("reached newer items, breaking")
-				break
-			}
-
-			if entry.prepared == nil {
-				toPrepare[e] = entry
-			}
-
-			// Only prepare entry if it's not
-			// already prepared, save db calls.
-			foundToPrepare++
-			if foundToPrepare >= amount {
-				break
-			}
-		}
-	}
-
-	for e, entry := range toPrepare {
-		prepared, err := t.prepareFunction(ctx, t.timelineID, entry.itemID)
-		if err != nil {
-			if errors.Is(err, statusfilter.ErrHideStatus) {
-				// This item has been filtered out by the requesting user's filters.
-				// Remove it and skip past it.
-				t.items.data.Remove(e)
-				continue
-			}
-			if errors.Is(err, db.ErrNoEntries) {
-				// ErrNoEntries means something has been deleted,
-				// so we'll likely not be able to ever prepare this.
-				// This means we can remove it and skip past it.
-				l.Debugf("db.ErrNoEntries while trying to prepare %s; will remove from timeline", entry.itemID)
-				t.items.data.Remove(e)
-				continue
-			}
-			// We've got a proper db error.
-			return gtserror.Newf("db error while trying to prepare %s: %w", entry.itemID, err)
-		}
-		entry.prepared = prepared
-	}
-
-	return nil
-}