| 1 | package store |
| 2 | |
| 3 | import "fmt" |
| 4 | |
| 5 | // Formats reads every formatted cell in the tab in two queries. |
| 6 | // |
| 7 | // Handle.Format answers for one cell with two round trips, which was |
| 8 | // right while formatting was a thing only the XLSX importer wrote and |
| 9 | // only the contrast check read. It stops being right the moment the |
| 10 | // grid paints formats: snapshot walks a whole window, so a hundred |
| 11 | // formatted cells became two hundred queries per page load — and the |
| 12 | // cost is invisible in every test, because the tests all use tabs with |
| 13 | // a handful of cells. |
| 14 | // |
| 15 | // Two queries and not one: the join would return the interned Format's |
| 16 | // columns once per cell using it, which is exactly the duplication |
| 17 | // interning exists to avoid. A column of 5,000 identically styled cells |
| 18 | // is one Format row here, and this reads it once. |
| 19 | // |
| 20 | // The returned pointers are shared — several coordinates map to the |
| 21 | // same *Format, because that is what interning means. Callers read |
| 22 | // them; nothing mutates one in place. |
| 23 | func (h *Handle) Formats() (map[CellCoord]*Format, error) { |
| 24 | var cells []Cell |
| 25 | if err := h.db.Select("row_id", "col_id", "format_id"). |
| 26 | Where("tab_id = ? AND format_id IS NOT NULL", h.tabID). |
| 27 | Find(&cells).Error; err != nil { |
| 28 | return nil, fmt.Errorf("store: list formatted cells: %w", err) |
| 29 | } |
| 30 | if len(cells) == 0 { |
| 31 | return map[CellCoord]*Format{}, nil |
| 32 | } |
| 33 | |
| 34 | ids := make([]uint64, 0, len(cells)) |
| 35 | seen := make(map[uint64]bool, len(cells)) |
| 36 | for _, c := range cells { |
| 37 | if c.FormatID == nil || seen[*c.FormatID] { |
| 38 | continue |
| 39 | } |
| 40 | seen[*c.FormatID] = true |
| 41 | ids = append(ids, *c.FormatID) |
| 42 | } |
| 43 | |
| 44 | var rows []Format |
| 45 | if err := h.db.Where("id IN ?", ids).Find(&rows).Error; err != nil { |
| 46 | return nil, fmt.Errorf("store: read formats: %w", err) |
| 47 | } |
| 48 | byID := make(map[uint64]*Format, len(rows)) |
| 49 | for i := range rows { |
| 50 | byID[rows[i].ID] = &rows[i] |
| 51 | } |
| 52 | |
| 53 | out := make(map[CellCoord]*Format, len(cells)) |
| 54 | for _, c := range cells { |
| 55 | // A cell pointing at a Format row that is not there is dropped |
| 56 | // rather than defaulted. It cannot happen through any path this |
| 57 | // package offers — formats are interned before they are |
| 58 | // assigned and never deleted — and if it ever does, an unstyled |
| 59 | // cell is a better answer than a styled one we invented. |
| 60 | if c.FormatID == nil { |
| 61 | continue |
| 62 | } |
| 63 | if f, ok := byID[*c.FormatID]; ok { |
| 64 | out[CellCoord{RowID: c.RowID, ColID: c.ColID}] = f |
| 65 | } |
| 66 | } |
| 67 | return out, nil |
| 68 | } |
| 69 | |
amadan