gotosocial/internal/processing/status/get.go
Vyr Cossont c675d47a8c
Improve context descendant sorting (#2579)
* Improve context descendant sorting

Topologically sort replies, then move self-replies to top of list

* Unify descendant sort passes

* Correct test package name

* Preallocate maps
2024-01-31 13:40:41 +00:00

224 lines
7.2 KiB
Go

// 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 status
import (
"context"
"slices"
"strings"
apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
"github.com/superseriousbusiness/gotosocial/internal/gtserror"
"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
)
// Get gets the given status, taking account of privacy settings and blocks etc.
func (p *Processor) Get(ctx context.Context, requestingAccount *gtsmodel.Account, targetStatusID string) (*apimodel.Status, gtserror.WithCode) {
targetStatus, errWithCode := p.c.GetVisibleTargetStatus(ctx,
requestingAccount,
targetStatusID,
false, // refresh
)
if errWithCode != nil {
return nil, errWithCode
}
return p.c.GetAPIStatus(ctx, requestingAccount, targetStatus)
}
// WebGet gets the given status for web use, taking account of privacy settings.
func (p *Processor) WebGet(ctx context.Context, targetStatusID string) (*apimodel.Status, gtserror.WithCode) {
targetStatus, errWithCode := p.c.GetVisibleTargetStatus(ctx,
nil, // requester
targetStatusID,
false, // refresh
)
if errWithCode != nil {
return nil, errWithCode
}
webStatus, err := p.converter.StatusToWebStatus(ctx, targetStatus, nil)
if err != nil {
err = gtserror.Newf("error converting status: %w", err)
return nil, gtserror.NewErrorInternalError(err)
}
return webStatus, nil
}
func (p *Processor) contextGet(
ctx context.Context,
requestingAccount *gtsmodel.Account,
targetStatusID string,
convert func(context.Context, *gtsmodel.Status, *gtsmodel.Account) (*apimodel.Status, error),
) (*apimodel.Context, gtserror.WithCode) {
targetStatus, errWithCode := p.c.GetVisibleTargetStatus(ctx,
requestingAccount,
targetStatusID,
false, // refresh
)
if errWithCode != nil {
return nil, errWithCode
}
parents, err := p.state.DB.GetStatusParents(ctx, targetStatus)
if err != nil {
return nil, gtserror.NewErrorInternalError(err)
}
var ancestors []*apimodel.Status
for _, status := range parents {
if v, err := p.filter.StatusVisible(ctx, requestingAccount, status); err == nil && v {
apiStatus, err := convert(ctx, status, requestingAccount)
if err == nil {
ancestors = append(ancestors, apiStatus)
}
}
}
slices.SortFunc(ancestors, func(lhs, rhs *apimodel.Status) int {
return strings.Compare(lhs.ID, rhs.ID)
})
children, err := p.state.DB.GetStatusChildren(ctx, targetStatus.ID)
if err != nil {
return nil, gtserror.NewErrorInternalError(err)
}
var descendants []*apimodel.Status
for _, status := range children {
if v, err := p.filter.StatusVisible(ctx, requestingAccount, status); err == nil && v {
apiStatus, err := convert(ctx, status, requestingAccount)
if err == nil {
descendants = append(descendants, apiStatus)
}
}
}
TopoSort(descendants, targetStatus.AccountID)
//goland:noinspection GoImportUsedAsName
context := &apimodel.Context{
Ancestors: make([]apimodel.Status, 0, len(ancestors)),
Descendants: make([]apimodel.Status, 0, len(descendants)),
}
for _, ancestor := range ancestors {
context.Ancestors = append(context.Ancestors, *ancestor)
}
for _, descendant := range descendants {
context.Descendants = append(context.Descendants, *descendant)
}
return context, nil
}
// TopoSort sorts statuses topologically, by self-reply, and by ID.
// Can handle cycles but the output order will be arbitrary.
// (But if there are cycles, something went wrong upstream.)
func TopoSort(apiStatuses []*apimodel.Status, targetAccountID string) {
if len(apiStatuses) == 0 {
return
}
// Map of status IDs to statuses.
lookup := make(map[string]*apimodel.Status, len(apiStatuses))
for _, apiStatus := range apiStatuses {
lookup[apiStatus.ID] = apiStatus
}
// Tree of statuses to their children.
// The nil status may have children: any who don't have a parent, or whose parent isn't in the input.
tree := make(map[*apimodel.Status][]*apimodel.Status, len(apiStatuses))
for _, apiStatus := range apiStatuses {
var parent *apimodel.Status
if apiStatus.InReplyToID != nil {
parent = lookup[*apiStatus.InReplyToID]
}
tree[parent] = append(tree[parent], apiStatus)
}
// Sort children of each status by self-reply status and then ID, *in reverse*.
isSelfReply := func(apiStatus *apimodel.Status) bool {
return apiStatus.GetAccountID() == targetAccountID &&
apiStatus.InReplyToAccountID != nil &&
*apiStatus.InReplyToAccountID == targetAccountID
}
for id, children := range tree {
slices.SortFunc(children, func(lhs, rhs *apimodel.Status) int {
lhsIsContextSelfReply := isSelfReply(lhs)
rhsIsContextSelfReply := isSelfReply(rhs)
if lhsIsContextSelfReply && !rhsIsContextSelfReply {
return 1
} else if !lhsIsContextSelfReply && rhsIsContextSelfReply {
return -1
}
return -strings.Compare(lhs.ID, rhs.ID)
})
tree[id] = children
}
// Traverse the tree using preorder depth-first search, topologically sorting the statuses.
stack := make([]*apimodel.Status, 1, len(tree))
apiStatusIndex := 0
for len(stack) > 0 {
parent := stack[len(stack)-1]
children := tree[parent]
if len(children) == 0 {
// Remove this node from the tree.
delete(tree, parent)
// Go back to this node's parent.
stack = stack[:len(stack)-1]
continue
}
// Remove the last child entry (the first in sorted order).
child := children[len(children)-1]
tree[parent] = children[:len(children)-1]
// Explore its children next.
stack = append(stack, child)
// Overwrite the next entry of the input slice.
apiStatuses[apiStatusIndex] = child
apiStatusIndex++
}
// There should only be nodes left in the tree in the event of a cycle.
// Append them to the end in arbitrary order.
// This ensures that the slice of statuses has no duplicates.
for node := range tree {
apiStatuses[apiStatusIndex] = node
apiStatusIndex++
}
}
// ContextGet returns the context (previous and following posts) from the given status ID.
func (p *Processor) ContextGet(ctx context.Context, requestingAccount *gtsmodel.Account, targetStatusID string) (*apimodel.Context, gtserror.WithCode) {
return p.contextGet(ctx, requestingAccount, targetStatusID, p.converter.StatusToAPIStatus)
}
// WebContextGet is like ContextGet, but is explicitly
// for viewing statuses via the unauthenticated web UI.
//
// TODO: a more advanced threading model could be implemented here.
func (p *Processor) WebContextGet(ctx context.Context, targetStatusID string) (*apimodel.Context, gtserror.WithCode) {
return p.contextGet(ctx, nil, targetStatusID, p.converter.StatusToWebStatus)
}