frame.go RawHistoryFolder

1package ansi
2
3import (
4	"fmt"
5	"reflect"
6
7	"github.com/bnema/vev-vt/core"
8)
9
10// Frame is an alias for the frontend-neutral terminal grid. ANSI rendering
11// consumes it but does not own its model or storage policy.
12type Frame = core.Frame
13
14// CellSource is the read-only semantic grid consumed by ANSI rendering.
15type CellSource = core.CellSource
16
17var NewFrame = core.NewFrame
18
19func validateCellSource(source CellSource) error {
20	if source == nil {
21		return fmt.Errorf("nil cell source")
22	}
23	value := reflect.ValueOf(source)
24	switch value.Kind() {
25	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Pointer, reflect.Slice:
26		if value.IsNil() {
27			return fmt.Errorf("nil cell source")
28		}
29	}
30	if source.Columns() <= 0 || source.Rows() <= 0 {
31		return fmt.Errorf("invalid cell source size %dx%d", source.Columns(), source.Rows())
32	}
33	if frame, ok := asFrame(source); ok {
34		return frame.Validate()
35	}
36	return nil
37}
38
39// snapshotCellSource returns an independent Frame holding source's cells. When
40// scratch is non-nil the snapshot is written into scratch's existing storage
41// (allocating only to grow or on first use) and the returned Frame shares that
42// storage; the caller owns scratch and must not hand it to anyone else while
43// the snapshot is live. A nil scratch allocates a fresh frame.
44func snapshotCellSource(scratch *Frame, source CellSource) Frame {
45	if scratch == nil {
46		return cloneCellSource(source)
47	}
48	if frame, ok := asFrame(source); ok {
49		scratch.CopyFrom(frame)
50		return *scratch
51	}
52	columns, rows := source.Columns(), source.Rows()
53	if scratch.Width != columns || scratch.Height != rows || scratch.Validate() != nil {
54		*scratch = NewFrame(columns, rows)
55	}
56	for y := range rows {
57		for x := range columns {
58			scratch.Set(x, y, source.Cell(x, y))
59		}
60	}
61	return *scratch
62}
63
64// asFrame reports whether source is a compact core.Frame, directly or through
65// a non-nil pointer, enabling stored-cell paths that bypass CellSource.
66func asFrame(source CellSource) (Frame, bool) {
67	switch frame := source.(type) {
68	case Frame:
69		return frame, true
70	case *Frame:
71		if frame != nil {
72			return *frame, true
73		}
74	}
75	return Frame{}, false
76}
77
78func cloneCellSource(source CellSource) Frame {
79	if frame, ok := asFrame(source); ok {
80		return frame.Clone()
81	}
82	clone := NewFrame(source.Columns(), source.Rows())
83	for y := range source.Rows() {
84		for x := range source.Columns() {
85			clone.Set(x, y, source.Cell(x, y))
86		}
87	}
88	return clone
89}