[feature] List replies policy, refactor async workers (#2087)

* Add/update some DB functions.

* move async workers into subprocessor

* rename FromFederator -> FromFediAPI

* update home timeline check to include check for current status first before moving to parent status

* change streamMap to pointer to mollify linter

* update followtoas func signature

* fix merge

* remove errant debug log

* don't use separate errs.Combine() check to wrap errs

* wrap parts of workers functionality in sub-structs

* populate report using new db funcs

* embed federator (tiny bit tidier)

* flesh out error msg, add continue(!)

* fix other error messages to be more specific

* better, nicer

* give parseURI util function a bit more util

* missing headers

* use pointers for subprocessors

1 files changed, 26 insertions, 21 deletions

diff --git a/internal/visibility/home_timeline.go b/internal/visibility/home_timeline.go
index e3af03d83..d8bbc3979 100644
--- a/internal/visibility/home_timeline.go
+++ b/internal/visibility/home_timeline.go
@@ -24,6 +24,7 @@ import (
 
 	"github.com/superseriousbusiness/gotosocial/internal/cache"
 	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 	"github.com/superseriousbusiness/gotosocial/internal/log"
 )
@@ -97,33 +98,17 @@ func (f *Filter) isStatusHomeTimelineable(ctx context.Context, owner *gtsmodel.A
 	}
 
 	var (
-		next      *gtsmodel.Status
+		next      = status
 		oneAuthor = true // Assume one author until proven otherwise.
 		included  bool
 		converstn bool
 	)
 
-	for next = status; next.InReplyToURI != ""; {
-		// Fetch next parent to lookup.
-		parentID := next.InReplyToID
-		if parentID == "" {
-			log.Warnf(ctx, "status not yet deref'd: %s", next.InReplyToURI)
-			return false, cache.SentinelError
-		}
-
-		// Get the next parent in the chain from DB.
-		next, err = f.state.DB.GetStatusByID(
-			gtscontext.SetBarebones(ctx),
-			parentID,
-		)
-		if err != nil {
-			return false, fmt.Errorf("isStatusHomeTimelineable: error getting status parent %s: %w", parentID, err)
-		}
-
+	for {
 		// Populate account mention objects before account mention checks.
 		next.Mentions, err = f.state.DB.GetMentions(ctx, next.MentionIDs)
 		if err != nil {
-			return false, fmt.Errorf("isStatusHomeTimelineable: error populating status parent %s mentions: %w", parentID, err)
+			return false, gtserror.Newf("error populating status %s mentions: %w", next.ID, err)
 		}
 
 		if (next.AccountID == owner.ID) ||
@@ -139,7 +124,7 @@ func (f *Filter) isStatusHomeTimelineable(ctx context.Context, owner *gtsmodel.A
 		// is it between accounts on owner timeline that they follow?
 		converstn, err = f.isVisibleConversation(ctx, owner, next)
 		if err != nil {
-			return false, fmt.Errorf("isStatusHomeTimelineable: error checking conversation visibility: %w", err)
+			return false, gtserror.Newf("error checking conversation visibility: %w", err)
 		}
 
 		if converstn {
@@ -152,6 +137,26 @@ func (f *Filter) isStatusHomeTimelineable(ctx context.Context, owner *gtsmodel.A
 			// Check if this continues to be a single-author thread.
 			oneAuthor = (next.AccountID == status.AccountID)
 		}
+
+		if next.InReplyToURI == "" {
+			// Reached the top of the thread.
+			break
+		}
+
+		// Fetch next parent in thread.
+		parentID := next.InReplyToID
+		if parentID == "" {
+			log.Warnf(ctx, "status not yet deref'd: %s", next.InReplyToURI)
+			return false, cache.SentinelError
+		}
+
+		next, err = f.state.DB.GetStatusByID(
+			gtscontext.SetBarebones(ctx),
+			parentID,
+		)
+		if err != nil {
+			return false, gtserror.Newf("error getting status parent %s: %w", parentID, err)
+		}
 	}
 
 	if next != status && !oneAuthor && !included && !converstn {
@@ -177,7 +182,7 @@ func (f *Filter) isStatusHomeTimelineable(ctx context.Context, owner *gtsmodel.A
 		status.AccountID,
 	)
 	if err != nil {
-		return false, fmt.Errorf("isStatusHomeTimelineable: error checking follow %s->%s: %w", owner.ID, status.AccountID, err)
+		return false, gtserror.Newf("error checking follow %s->%s: %w", owner.ID, status.AccountID, err)
 	}
 
 	if !follow {