GoToSocial/internal/db/bundb/util.go

229 lines
6.5 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 bundb
import (
"context"
"database/sql"
"slices"
"strings"
"github.com/superseriousbusiness/gotosocial/internal/cache"
"github.com/superseriousbusiness/gotosocial/internal/db"
"github.com/superseriousbusiness/gotosocial/internal/log"
"github.com/superseriousbusiness/gotosocial/internal/paging"
"github.com/uptrace/bun"
"github.com/uptrace/bun/dialect"
)
// likeEscaper is a thread-safe string replacer which escapes
// common SQLite + Postgres `LIKE` wildcard chars using the
// escape character `\`. Initialized as a var in this package
// so it can be reused.
var likeEscaper = strings.NewReplacer(
`\`, `\\`, // Escape char.
`%`, `\%`, // Zero or more char.
`_`, `\_`, // Exactly one char.
)
// likeOperator returns an appropriate LIKE or
// ILIKE operator for the given query's dialect.
func likeOperator(query *bun.SelectQuery) string {
const (
like = "LIKE"
ilike = "ILIKE"
)
d := query.Dialect().Name()
if d == dialect.SQLite {
return like
} else if d == dialect.PG {
return ilike
}
log.Panicf(nil, "db conn %s was neither pg nor sqlite", d)
return ""
}
// whereLike appends a WHERE clause to the
// given SelectQuery, which searches for
// matches of `search` in the given subQuery
// using LIKE (SQLite) or ILIKE (Postgres).
func whereLike(
query *bun.SelectQuery,
subject interface{},
search string,
) *bun.SelectQuery {
// Escape existing wildcard + escape
// chars in the search query string.
search = likeEscaper.Replace(search)
// Add our own wildcards back in; search
// zero or more chars around the query.
search = `%` + search + `%`
// Get appropriate operator.
like := likeOperator(query)
// Append resulting WHERE
// clause to the main query.
return query.Where(
"(?) ? ? ESCAPE ?",
subject, bun.Safe(like), search, `\`,
)
}
// whereStartsLike is like whereLike,
// but only searches for strings that
// START WITH `search`.
func whereStartsLike(
query *bun.SelectQuery,
subject interface{},
search string,
) *bun.SelectQuery {
// Escape existing wildcard + escape
// chars in the search query string.
search = likeEscaper.Replace(search)
// Add our own wildcards back in; search
// zero or more chars after the query.
search += `%`
// Get appropriate operator.
like := likeOperator(query)
// Append resulting WHERE
// clause to the main query.
return query.Where(
"(?) ? ? ESCAPE ?",
subject, bun.Safe(like), search, `\`,
)
}
// exists checks the results of a SelectQuery for the existence of the data in question, masking ErrNoEntries errors.
func exists(ctx context.Context, query *bun.SelectQuery) (bool, error) {
exists, err := query.Exists(ctx)
switch err {
case nil:
return exists, nil
case sql.ErrNoRows:
return false, nil
default:
return false, err
}
}
// notExists checks the results of a SelectQuery for the non-existence of the data in question, masking ErrNoEntries errors.
func notExists(ctx context.Context, query *bun.SelectQuery) (bool, error) {
exists, err := exists(ctx, query)
return !exists, err
}
// loadPagedIDs loads a page of IDs from given SliceCache by `key`, resorting to `loadDESC` if required. Uses `page` to sort + page resulting IDs.
// NOTE: IDs returned from `cache` / `loadDESC` MUST be in descending order, otherwise paging will not work correctly / return things out of order.
func loadPagedIDs(cache *cache.SliceCache[string], key string, page *paging.Page, loadDESC func() ([]string, error)) ([]string, error) {
// Check cache for IDs, else load.
ids, err := cache.Load(key, loadDESC)
if err != nil {
return nil, err
}
// Our cached / selected IDs are ALWAYS
// fetched from `loadDESC` in descending
// order. Depending on the paging requested
// this may be an unexpected order.
if page.GetOrder().Ascending() {
slices.Reverse(ids)
}
// Page the resulting IDs.
ids = page.Page(ids)
return ids, nil
}
// updateWhere parses []db.Where and adds it to the given update query.
func updateWhere(q *bun.UpdateQuery, where []db.Where) {
for _, w := range where {
query, args := parseWhere(w)
q = q.Where(query, args...)
}
}
// selectWhere parses []db.Where and adds it to the given select query.
func selectWhere(q *bun.SelectQuery, where []db.Where) {
for _, w := range where {
query, args := parseWhere(w)
q = q.Where(query, args...)
}
}
// deleteWhere parses []db.Where and adds it to the given where query.
func deleteWhere(q *bun.DeleteQuery, where []db.Where) {
for _, w := range where {
query, args := parseWhere(w)
q = q.Where(query, args...)
}
}
// parseWhere looks through the options on a single db.Where entry, and
// returns the appropriate query string and arguments.
func parseWhere(w db.Where) (query string, args []interface{}) {
if w.Not {
if w.Value == nil {
query = "? IS NOT NULL"
args = []interface{}{bun.Ident(w.Key)}
return
}
query = "? != ?"
args = []interface{}{bun.Ident(w.Key), w.Value}
return
}
if w.Value == nil {
query = "? IS NULL"
args = []interface{}{bun.Ident(w.Key)}
return
}
query = "? = ?"
args = []interface{}{bun.Ident(w.Key), w.Value}
return
}
// whereArrayIsNullOrEmpty extends a query with a where clause requiring an array to be null or empty.
// (The empty check varies by dialect; only PG has direct support for SQL array types.)
func whereArrayIsNullOrEmpty(query *bun.SelectQuery, subject interface{}) *bun.SelectQuery {
var arrayEmptySQL string
switch d := query.Dialect().Name(); d {
case dialect.SQLite:
arrayEmptySQL = "json_array_length(?) = 0"
case dialect.PG:
arrayEmptySQL = "CARDINALITY(?) = 0"
default:
log.Panicf(nil, "db conn %s was neither pg nor sqlite", d)
}
return query.WhereGroup(" AND ", func(q *bun.SelectQuery) *bun.SelectQuery {
return q.
Where("? IS NULL", subject).
WhereOr(arrayEmptySQL, subject)
})
}