[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, 172 deletions

diff --git a/internal/timeline/timeline.go b/internal/timeline/timeline.go
deleted file mode 100644
index e7c609638..000000000
--- a/internal/timeline/timeline.go
+++ /dev/null
@@ -1,172 +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 (
-	"context"
-	"sync"
-	"time"
-)
-
-// GrabFunction is used by a Timeline to grab more items to index.
-//
-// It should be provided to NewTimeline when the caller is creating a timeline
-// (of statuses, notifications, etc).
-//
-//   - timelineID: ID of the timeline.
-//   - maxID: the maximum item ID desired.
-//   - sinceID: the minimum item ID desired.
-//   - minID: see sinceID
-//   - limit: the maximum amount of items to be returned
-//
-// If an error is returned, the timeline will stop processing whatever request called GrabFunction,
-// and return the error. If no error is returned, but stop = true, this indicates to the caller of GrabFunction
-// that there are no more items to return, and processing should continue with the items already grabbed.
-type GrabFunction func(ctx context.Context, timelineID string, maxID string, sinceID string, minID string, limit int) (items []Timelineable, stop bool, err error)
-
-// FilterFunction is used by a Timeline to filter whether or not a grabbed item should be indexed.
-type FilterFunction func(ctx context.Context, timelineID string, item Timelineable) (shouldIndex bool, err error)
-
-// PrepareFunction converts a Timelineable into a Preparable.
-//
-// For example, this might result in the converstion of a *gtsmodel.Status with the given itemID into a serializable *apimodel.Status.
-type PrepareFunction func(ctx context.Context, timelineID string, itemID string) (Preparable, error)
-
-// SkipInsertFunction indicates whether a new item about to be inserted in the prepared list should be skipped,
-// based on the item itself, the next item in the timeline, and the depth at which nextItem has been found in the list.
-//
-// This will be called for every item found while iterating through a timeline, so callers should be very careful
-// not to do anything expensive here.
-type SkipInsertFunction func(ctx context.Context,
-	newItemID string,
-	newItemAccountID string,
-	newItemBoostOfID string,
-	newItemBoostOfAccountID string,
-	nextItemID string,
-	nextItemAccountID string,
-	nextItemBoostOfID string,
-	nextItemBoostOfAccountID string,
-	depth int) (bool, error)
-
-// Timeline represents a timeline for one account, and contains indexed and prepared items.
-type Timeline interface {
-	/*
-		RETRIEVAL FUNCTIONS
-	*/
-
-	// Get returns an amount of prepared items with the given parameters.
-	// If prepareNext is true, then the next predicted query will be prepared already in a goroutine,
-	// to make the next call to Get faster.
-	Get(ctx context.Context, amount int, maxID string, sinceID string, minID string, prepareNext bool) ([]Preparable, error)
-
-	/*
-		INDEXING + PREPARATION FUNCTIONS
-	*/
-
-	// IndexAndPrepareOne puts a item into the timeline at the appropriate place
-	// according to its id, and then immediately prepares it.
-	//
-	// The returned bool indicates whether or not the item was actually inserted
-	// into the timeline. This will be false if the item is a boost and the original
-	// item, or a boost of it, already exists recently in the timeline.
-	IndexAndPrepareOne(ctx context.Context, itemID string, boostOfID string, accountID string, boostOfAccountID string) (bool, error)
-
-	// Unprepare clears the prepared version of the given item (and any boosts
-	// thereof) from the timeline, but leaves the indexed version in place.
-	//
-	// This is useful for cache invalidation when the prepared version of the
-	// item has changed for some reason (edits, updates, etc), but the item does
-	// not need to be removed: it will be prepared again next time Get is called.
-	Unprepare(ctx context.Context, itemID string) error
-
-	/*
-		INFO FUNCTIONS
-	*/
-
-	// TimelineID returns the id of this timeline.
-	TimelineID() string
-
-	// Len returns the length of the item index at this point in time.
-	Len() int
-
-	// OldestIndexedItemID returns the id of the rearmost (ie., the oldest) indexed item.
-	// If there's no oldest item, an empty string will be returned so make sure to check for this.
-	OldestIndexedItemID() string
-
-	/*
-		UTILITY FUNCTIONS
-	*/
-
-	// LastGot returns the time that Get was last called.
-	LastGot() time.Time
-
-	// Prune prunes prepared and indexed items in this timeline to the desired lengths.
-	// This will be a no-op if the lengths are already < the desired values.
-	//
-	// The returned int indicates the amount of entries that were removed or unprepared.
-	Prune(desiredPreparedItemsLength int, desiredIndexedItemsLength int) int
-
-	// Remove removes an item with the given ID.
-	//
-	// If a item has multiple entries in a timeline, they will all be removed.
-	//
-	// The returned int indicates the amount of entries that were removed.
-	Remove(ctx context.Context, itemID string) (int, error)
-
-	// RemoveAllByOrBoosting removes all items created by or boosting the given accountID.
-	//
-	// The returned int indicates the amount of entries that were removed.
-	RemoveAllByOrBoosting(ctx context.Context, accountID string) (int, error)
-}
-
-// timeline fulfils the Timeline interface
-type timeline struct {
-	items           *indexedItems
-	grabFunction    GrabFunction
-	filterFunction  FilterFunction
-	prepareFunction PrepareFunction
-	timelineID      string
-	lastGot         time.Time
-	sync.Mutex
-}
-
-func (t *timeline) TimelineID() string {
-	return t.timelineID
-}
-
-// NewTimeline returns a new Timeline with
-// the given ID, using the given functions.
-func NewTimeline(
-	ctx context.Context,
-	timelineID string,
-	grabFunction GrabFunction,
-	filterFunction FilterFunction,
-	prepareFunction PrepareFunction,
-	skipInsertFunction SkipInsertFunction,
-) Timeline {
-	return &timeline{
-		items: &indexedItems{
-			skipInsert: skipInsertFunction,
-		},
-		grabFunction:    grabFunction,
-		filterFunction:  filterFunction,
-		prepareFunction: prepareFunction,
-		timelineID:      timelineID,
-		lastGot:         time.Time{},
-	}
-}