mirror of
https://github.com/go-sylixos/elvish.git
synced 2024-12-15 11:57:55 +08:00
92 lines
2.2 KiB
Go
92 lines
2.2 KiB
Go
package edit
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import (
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"errors"
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"io"
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"os"
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"strings"
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"unicode/utf8"
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"github.com/elves/elvish/edit/ui"
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"github.com/elves/elvish/util"
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)
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// PreviewBytes is the maximum number of bytes to preview a file.
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const PreviewBytes = 64 * 1024
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// Errors displayed in the preview area of navigation mode.
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var (
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ErrNotRegular = errors.New("no preview for non-regular file")
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ErrNotValidUTF8 = errors.New("no preview for non-utf8 file")
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)
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type navFilePreview struct {
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lines []ui.Styled
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fullWidth int
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beginLine int
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}
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func newNavFilePreview(lines []string) *navFilePreview {
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width := 0
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convertedLines := make([]ui.Styled, len(lines))
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for i, line := range lines {
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// BUG: Handle tabstops correctly
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convertedLine := strings.Replace(line, "\t", " ", -1)
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convertedLines[i] = ui.Unstyled(convertedLine)
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width = max(width, util.Wcswidth(convertedLine))
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}
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return &navFilePreview{convertedLines, width, 0}
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}
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func (fp *navFilePreview) FullWidth(h int) int {
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width := fp.fullWidth
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if h < len(fp.lines) {
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return width + 1
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}
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return width
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}
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func (fp *navFilePreview) List(h int) ui.Renderer {
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if len(fp.lines) <= h {
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logger.Printf("Height %d fit all lines", h)
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return listingRenderer{fp.lines}
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}
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shown := fp.lines[fp.beginLine:]
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if len(shown) > h {
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shown = shown[:h]
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}
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logger.Printf("Showing lines %d to %d", fp.beginLine, fp.beginLine+len(shown))
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return listingWithScrollBarRenderer{
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listingRenderer{shown}, len(fp.lines),
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fp.beginLine, fp.beginLine + len(shown), h}
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}
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func makeNavFilePreview(fname string) navPreview {
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file, err := os.Open(fname)
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if err != nil {
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return newErrNavColumn(err)
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}
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info, err := file.Stat()
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if err != nil {
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return newErrNavColumn(err)
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}
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if (info.Mode() & (os.ModeDevice | os.ModeNamedPipe | os.ModeSocket | os.ModeCharDevice)) != 0 {
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return newErrNavColumn(ErrNotRegular)
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}
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// BUG: when the file is bigger than the buffer, the scrollbar is wrong.
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var buf [PreviewBytes]byte
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nr, err := file.Read(buf[:])
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if err != nil && err != io.EOF {
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return newErrNavColumn(err)
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}
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content := buf[:nr]
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if !utf8.Valid(content) {
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return newErrNavColumn(ErrNotValidUTF8)
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}
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return newNavFilePreview(strings.Split(string(content), "\n"))
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}
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