Refactor code indexer (#9313)

* Refactor code indexer

* fix test

* fix test

* refactor code indexer

* fix import

* improve code

* fix typo

* fix test and make code clean

* fix lint

modules/indexer/code/search.go

@@ -0,0 +1,130 @@
+// Copyright 2017 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 code
+
+import (
+	"bytes"
+	"html"
+	gotemplate "html/template"
+	"strings"
+
+	"code.gitea.io/gitea/modules/highlight"
+	"code.gitea.io/gitea/modules/util"
+)
+
+// Result a search result to display
+type Result struct {
+	RepoID         int64
+	Filename       string
+	HighlightClass string
+	LineNumbers    []int
+	FormattedLines gotemplate.HTML
+}
+
+func indices(content string, selectionStartIndex, selectionEndIndex int) (int, int) {
+	startIndex := selectionStartIndex
+	numLinesBefore := 0
+	for ; startIndex > 0; startIndex-- {
+		if content[startIndex-1] == '\n' {
+			if numLinesBefore == 1 {
+				break
+			}
+			numLinesBefore++
+		}
+	}
+
+	endIndex := selectionEndIndex
+	numLinesAfter := 0
+	for ; endIndex < len(content); endIndex++ {
+		if content[endIndex] == '\n' {
+			if numLinesAfter == 1 {
+				break
+			}
+			numLinesAfter++
+		}
+	}
+
+	return startIndex, endIndex
+}
+
+func writeStrings(buf *bytes.Buffer, strs ...string) error {
+	for _, s := range strs {
+		_, err := buf.WriteString(s)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func searchResult(result *SearchResult, startIndex, endIndex int) (*Result, error) {
+	startLineNum := 1 + strings.Count(result.Content[:startIndex], "\n")
+
+	var formattedLinesBuffer bytes.Buffer
+
+	contentLines := strings.SplitAfter(result.Content[startIndex:endIndex], "\n")
+	lineNumbers := make([]int, len(contentLines))
+	index := startIndex
+	for i, line := range contentLines {
+		var err error
+		if index < result.EndIndex &&
+			result.StartIndex < index+len(line) &&
+			result.StartIndex < result.EndIndex {
+			openActiveIndex := util.Max(result.StartIndex-index, 0)
+			closeActiveIndex := util.Min(result.EndIndex-index, len(line))
+			err = writeStrings(&formattedLinesBuffer,
+				`<li>`,
+				html.EscapeString(line[:openActiveIndex]),
+				`<span class='active'>`,
+				html.EscapeString(line[openActiveIndex:closeActiveIndex]),
+				`</span>`,
+				html.EscapeString(line[closeActiveIndex:]),
+				`</li>`,
+			)
+		} else {
+			err = writeStrings(&formattedLinesBuffer,
+				`<li>`,
+				html.EscapeString(line),
+				`</li>`,
+			)
+		}
+		if err != nil {
+			return nil, err
+		}
+
+		lineNumbers[i] = startLineNum + i
+		index += len(line)
+	}
+	return &Result{
+		RepoID:         result.RepoID,
+		Filename:       result.Filename,
+		HighlightClass: highlight.FileNameToHighlightClass(result.Filename),
+		LineNumbers:    lineNumbers,
+		FormattedLines: gotemplate.HTML(formattedLinesBuffer.String()),
+	}, nil
+}
+
+// PerformSearch perform a search on a repository
+func PerformSearch(repoIDs []int64, keyword string, page, pageSize int) (int, []*Result, error) {
+	if len(keyword) == 0 {
+		return 0, nil, nil
+	}
+
+	total, results, err := indexer.Search(repoIDs, keyword, page, pageSize)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	displayResults := make([]*Result, len(results))
+
+	for i, result := range results {
+		startIndex, endIndex := indices(result.Content, result.StartIndex, result.EndIndex)
+		displayResults[i], err = searchResult(result, startIndex, endIndex)
+		if err != nil {
+			return 0, nil, err
+		}
+	}
+	return int(total), displayResults, nil
+}