0
Fork 0
mirror of https://codeberg.org/forgejo/forgejo.git synced 2024-12-22 23:33:15 -05:00
forgejo/modules/csv/csv.go

101 lines
2.6 KiB
Go
Raw Normal View History

// Copyright 2021 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package csv
import (
"bytes"
stdcsv "encoding/csv"
"errors"
"io"
"regexp"
"strings"
"code.gitea.io/gitea/modules/translation"
"code.gitea.io/gitea/modules/util"
)
var quoteRegexp = regexp.MustCompile(`["'][\s\S]+?["']`)
// CreateReader creates a csv.Reader with the given delimiter.
func CreateReader(input io.Reader, delimiter rune) *stdcsv.Reader {
rd := stdcsv.NewReader(input)
rd.Comma = delimiter
rd.TrimLeadingSpace = true
return rd
}
// CreateReaderAndGuessDelimiter tries to guess the field delimiter from the content and creates a csv.Reader.
// Reads at most 10k bytes.
func CreateReaderAndGuessDelimiter(rd io.Reader) (*stdcsv.Reader, error) {
var data = make([]byte, 1e4)
size, err := util.ReadAtMost(rd, data)
if err != nil {
return nil, err
}
return CreateReader(
io.MultiReader(bytes.NewReader(data[:size]), rd),
guessDelimiter(data[:size]),
), nil
}
// guessDelimiter scores the input CSV data against delimiters, and returns the best match.
func guessDelimiter(data []byte) rune {
maxLines := 10
text := quoteRegexp.ReplaceAllLiteralString(string(data), "")
lines := strings.SplitN(text, "\n", maxLines+1)
lines = lines[:util.Min(maxLines, len(lines))]
delimiters := []rune{',', ';', '\t', '|', '@'}
bestDelim := delimiters[0]
bestScore := 0.0
for _, delim := range delimiters {
score := scoreDelimiter(lines, delim)
if score > bestScore {
bestScore = score
bestDelim = delim
}
}
return bestDelim
}
// scoreDelimiter uses a count & regularity metric to evaluate a delimiter against lines of CSV.
func scoreDelimiter(lines []string, delim rune) float64 {
countTotal := 0
countLineMax := 0
linesNotEqual := 0
for _, line := range lines {
if len(line) == 0 {
continue
}
countLine := strings.Count(line, string(delim))
countTotal += countLine
if countLine != countLineMax {
if countLineMax != 0 {
linesNotEqual++
}
countLineMax = util.Max(countLine, countLineMax)
}
}
return float64(countTotal) * (1 - float64(linesNotEqual)/float64(len(lines)))
}
// FormatError converts csv errors into readable messages.
func FormatError(err error, locale translation.Locale) (string, error) {
var perr *stdcsv.ParseError
if errors.As(err, &perr) {
if perr.Err == stdcsv.ErrFieldCount {
return locale.Tr("repo.error.csv.invalid_field_count", perr.Line), nil
}
return locale.Tr("repo.error.csv.unexpected", perr.Line, perr.Column), nil
}
return "", err
}