Merge loaders package into git_commands package

pkg/commands/git_commands/commit_file_loader.go

@@ -0,0 +1,56 @@
+package git_commands
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/jesseduffield/generics/slices"
+	"github.com/jesseduffield/lazygit/pkg/commands/models"
+	"github.com/jesseduffield/lazygit/pkg/commands/oscommands"
+	"github.com/jesseduffield/lazygit/pkg/common"
+	"github.com/samber/lo"
+)
+
+type CommitFileLoader struct {
+	*common.Common
+	cmd oscommands.ICmdObjBuilder
+}
+
+func NewCommitFileLoader(common *common.Common, cmd oscommands.ICmdObjBuilder) *CommitFileLoader {
+	return &CommitFileLoader{
+		Common: common,
+		cmd:    cmd,
+	}
+}
+
+// GetFilesInDiff get the specified commit files
+func (self *CommitFileLoader) GetFilesInDiff(from string, to string, reverse bool) ([]*models.CommitFile, error) {
+	reverseFlag := ""
+	if reverse {
+		reverseFlag = " -R "
+	}
+
+	filenames, err := self.cmd.New(fmt.Sprintf("git diff --submodule --no-ext-diff --name-status -z --no-renames %s %s %s", reverseFlag, from, to)).DontLog().RunWithOutput()
+	if err != nil {
+		return nil, err
+	}
+
+	return getCommitFilesFromFilenames(filenames), nil
+}
+
+// filenames string is something like "MM\x00file1\x00MU\x00file2\x00AA\x00file3\x00"
+// so we need to split it by the null character and then map each status-name pair to a commit file
+func getCommitFilesFromFilenames(filenames string) []*models.CommitFile {
+	lines := strings.Split(strings.TrimRight(filenames, "\x00"), "\x00")
+	if len(lines) == 1 {
+		return []*models.CommitFile{}
+	}
+
+	// typical result looks like 'A my_file' meaning my_file was added
+	return slices.Map(lo.Chunk(lines, 2), func(chunk []string) *models.CommitFile {
+		return &models.CommitFile{
+			ChangeStatus: chunk[0],
+			Name:         chunk[1],
+		}
+	})
+}