1 files changed, 140 insertions, 0 deletions
diff --git a/modules/git/repo_index.go b/modules/git/repo_index.go
new file mode 100644
index 00000000..6aaab242
--- /dev/null
+++ b/modules/git/repo_index.go
@@ -0,0 +1,140 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package git
+
+import (
+	"bytes"
+	"context"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/util"
+)
+
+// ReadTreeToIndex reads a treeish to the index
+func (repo *Repository) ReadTreeToIndex(treeish string, indexFilename ...string) error {
+	objectFormat, err := repo.GetObjectFormat()
+	if err != nil {
+		return err
+	}
+
+	if len(treeish) != objectFormat.FullLength() {
+		res, _, err := NewCommand(repo.Ctx, "rev-parse", "--verify").AddDynamicArguments(treeish).RunStdString(&RunOpts{Dir: repo.Path})
+		if err != nil {
+			return err
+		}
+		if len(res) > 0 {
+			treeish = res[:len(res)-1]
+		}
+	}
+	id, err := NewIDFromString(treeish)
+	if err != nil {
+		return err
+	}
+	return repo.readTreeToIndex(id, indexFilename...)
+}
+
+func (repo *Repository) readTreeToIndex(id ObjectID, indexFilename ...string) error {
+	var env []string
+	if len(indexFilename) > 0 {
+		env = append(os.Environ(), "GIT_INDEX_FILE="+indexFilename[0])
+	}
+	_, _, err := NewCommand(repo.Ctx, "read-tree").AddDynamicArguments(id.String()).RunStdString(&RunOpts{Dir: repo.Path, Env: env})
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// ReadTreeToTemporaryIndex reads a treeish to a temporary index file
+func (repo *Repository) ReadTreeToTemporaryIndex(treeish string) (filename, tmpDir string, cancel context.CancelFunc, err error) {
+	tmpDir, err = os.MkdirTemp("", "index")
+	if err != nil {
+		return filename, tmpDir, cancel, err
+	}
+
+	filename = filepath.Join(tmpDir, ".tmp-index")
+	cancel = func() {
+		err := util.RemoveAll(tmpDir)
+		if err != nil {
+			log.Error("failed to remove tmp index file: %v", err)
+		}
+	}
+	err = repo.ReadTreeToIndex(treeish, filename)
+	if err != nil {
+		defer cancel()
+		return "", "", func() {}, err
+	}
+	return filename, tmpDir, cancel, err
+}
+
+// EmptyIndex empties the index
+func (repo *Repository) EmptyIndex() error {
+	_, _, err := NewCommand(repo.Ctx, "read-tree", "--empty").RunStdString(&RunOpts{Dir: repo.Path})
+	return err
+}
+
+// LsFiles checks if the given filenames are in the index
+func (repo *Repository) LsFiles(filenames ...string) ([]string, error) {
+	cmd := NewCommand(repo.Ctx, "ls-files", "-z").AddDashesAndList(filenames...)
+	res, _, err := cmd.RunStdBytes(&RunOpts{Dir: repo.Path})
+	if err != nil {
+		return nil, err
+	}
+	filelist := make([]string, 0, len(filenames))
+	for _, line := range bytes.Split(res, []byte{'\000'}) {
+		filelist = append(filelist, string(line))
+	}
+
+	return filelist, err
+}
+
+// RemoveFilesFromIndex removes given filenames from the index - it does not check whether they are present.
+func (repo *Repository) RemoveFilesFromIndex(filenames ...string) error {
+	objectFormat, err := repo.GetObjectFormat()
+	if err != nil {
+		return err
+	}
+	cmd := NewCommand(repo.Ctx, "update-index", "--remove", "-z", "--index-info")
+	stdout := new(bytes.Buffer)
+	stderr := new(bytes.Buffer)
+	buffer := new(bytes.Buffer)
+	for _, file := range filenames {
+		if file != "" {
+			buffer.WriteString("0 ")
+			buffer.WriteString(objectFormat.EmptyObjectID().String())
+			buffer.WriteByte('\t')
+			buffer.WriteString(file)
+			buffer.WriteByte('\000')
+		}
+	}
+	return cmd.Run(&RunOpts{
+		Dir:    repo.Path,
+		Stdin:  bytes.NewReader(buffer.Bytes()),
+		Stdout: stdout,
+		Stderr: stderr,
+	})
+}
+
+// AddObjectToIndex adds the provided object hash to the index at the provided filename
+func (repo *Repository) AddObjectToIndex(mode string, object ObjectID, filename string) error {
+	cmd := NewCommand(repo.Ctx, "update-index", "--add", "--replace", "--cacheinfo").AddDynamicArguments(mode, object.String(), filename)
+	_, _, err := cmd.RunStdString(&RunOpts{Dir: repo.Path})
+	return err
+}
+
+// WriteTree writes the current index as a tree to the object db and returns its hash
+func (repo *Repository) WriteTree() (*Tree, error) {
+	stdout, _, runErr := NewCommand(repo.Ctx, "write-tree").RunStdString(&RunOpts{Dir: repo.Path})
+	if runErr != nil {
+		return nil, runErr
+	}
+	id, err := NewIDFromString(strings.TrimSpace(stdout))
+	if err != nil {
+		return nil, err
+	}
+	return NewTree(repo, id), nil
+}