Initial commit (#1)

* initial

pkg/git/git.go

@@ -0,0 +1,188 @@
+package git
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/briandowns/spinner"
+	"github.com/knqyf263/trivy/pkg/log"
+	"github.com/knqyf263/trivy/pkg/utils"
+	"golang.org/x/xerrors"
+	git "gopkg.in/src-d/go-git.v4"
+	"gopkg.in/src-d/go-git.v4/plumbing/object"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
+)
+
+func CloneOrPull(url, repoPath string) (map[string]struct{}, error) {
+	exists, err := utils.Exists(filepath.Join(repoPath, ".git"))
+	if err != nil {
+		return nil, xerrors.Errorf("failed to check if a file exists: %w", err)
+	}
+
+	updatedFiles := map[string]struct{}{}
+	if exists {
+		log.Logger.Debug("git pull")
+		files, err := pull(repoPath)
+		if err != nil {
+			return nil, xerrors.Errorf("failed to pull repository: %w", err)
+		}
+
+		for _, filename := range files {
+			updatedFiles[strings.TrimSpace(filename)] = struct{}{}
+		}
+	} else {
+		log.Logger.Debug("remove an existed directory")
+
+		s := spinner.New(spinner.CharSets[36], 100*time.Millisecond)
+		s.Suffix = " The first time will take a while..."
+		s.Start()
+		defer s.Stop()
+
+		if err = os.RemoveAll(repoPath); err != nil {
+			return nil, xerrors.Errorf("failed to remove an existed directory: %w", err)
+		}
+
+		if err = os.MkdirAll(repoPath, 0700); err != nil {
+			return nil, xerrors.Errorf("failed to mkdir: %w", err)
+		}
+		if err := clone(url, repoPath); err != nil {
+			return nil, xerrors.Errorf("failed to clone repository: %w", err)
+		}
+
+		err = filepath.Walk(repoPath, func(path string, info os.FileInfo, err error) error {
+			if info.IsDir() {
+				return nil
+			}
+			rel, err := filepath.Rel(repoPath, path)
+			if err != nil {
+				return xerrors.Errorf("failed to get a relative path: %w", err)
+			}
+			updatedFiles[rel] = struct{}{}
+			return nil
+		})
+		if err != nil {
+			return nil, xerrors.Errorf("error in file walk: %w", err)
+		}
+	}
+
+	return updatedFiles, nil
+}
+
+func clone(url, repoPath string) error {
+	if utils.IsCommandAvailable("git") {
+		return cloneByOSCommand(url, repoPath)
+	}
+	log.Logger.Warn("Recommend installing git (if not, DB update is very slow)")
+
+	_, err := git.PlainClone(repoPath, false, &git.CloneOptions{
+		URL: url,
+	})
+	if err != nil && err != git.ErrRepositoryAlreadyExists {
+		return xerrors.Errorf("unexpected error in git clone: %w", err)
+	}
+	return nil
+}
+
+func cloneByOSCommand(url, repoPath string) error {
+	commandAndArgs := []string{"clone", url, repoPath}
+	_, err := utils.Exec("git", commandAndArgs)
+	if err != nil {
+		return xerrors.Errorf("error in git clone: %w", err)
+	}
+	return nil
+}
+
+func pull(repoPath string) ([]string, error) {
+	if utils.IsCommandAvailable("git") {
+		return pullByOSCommand(repoPath)
+	}
+
+	r, err := git.PlainOpen(repoPath)
+	if err != nil {
+		return nil, xerrors.Errorf("failed to open repository: %w", err)
+	}
+
+	log.Logger.Debug("Retrieve the branch being pointed by HEAD")
+	ref, err := r.Head()
+	if err != nil {
+		return nil, xerrors.Errorf("failed to get HEAD: %w", err)
+	}
+
+	log.Logger.Debug("Get the working directory for the repository")
+	w, err := r.Worktree()
+	if err != nil {
+		return nil, xerrors.Errorf("failed to get the working directory: %w", err)
+	}
+
+	log.Logger.Debug("Pull the latest changes from the origin remote and merge into the current branch")
+	err = w.Pull(&git.PullOptions{RemoteName: "origin"})
+	if err != nil && err != git.NoErrAlreadyUpToDate {
+		return nil, err
+	} else if err == git.NoErrAlreadyUpToDate {
+		return []string{}, nil
+	}
+
+	log.Logger.Debug("Retrieve the commit history")
+	commits, err := r.Log(&git.LogOptions{})
+	if err != nil {
+		return nil, xerrors.Errorf("error in git log: %w", err)
+	}
+
+	log.Logger.Debug("Detect the updated files")
+	var prevCommit *object.Commit
+	var updatedFiles []string
+	err = commits.ForEach(func(commit *object.Commit) error {
+		if prevCommit == nil {
+			prevCommit = commit
+			return nil
+		}
+
+		patch, err := commit.Patch(prevCommit)
+		if err != nil {
+			return xerrors.Errorf("error in patch: %w", err)
+		}
+		for _, stat := range patch.Stats() {
+			updatedFiles = append(updatedFiles, stat.Name)
+		}
+
+		if commit.Hash == ref.Hash() {
+			return storer.ErrStop
+		}
+
+		prevCommit = commit
+		return nil
+	})
+	if err != nil {
+		return nil, xerrors.Errorf("error in commit foreach: %w", err)
+	}
+
+	return updatedFiles, nil
+}
+
+func pullByOSCommand(repoPath string) ([]string, error) {
+	gitDir := filepath.Join(repoPath, ".git")
+	commandArgs := []string{"--git-dir", gitDir, "--work-tree", repoPath}
+
+	revParseCmd := []string{"rev-parse", "HEAD"}
+	output, err := utils.Exec("git", append(commandArgs, revParseCmd...))
+	if err != nil {
+		return nil, xerrors.Errorf("error in git rev-parse: %w", err)
+	}
+	commitHash := strings.TrimSpace(output)
+
+	pullCmd := []string{"pull", "origin", "master"}
+	_, err = utils.Exec("git", append(commandArgs, pullCmd...))
+	if err != nil {
+		return nil, xerrors.Errorf("error in git pull: %w", err)
+	}
+
+	diffCmd := []string{"diff", commitHash, "HEAD", "--name-only"}
+	output, err = utils.Exec("git", append(commandArgs, diffCmd...))
+	if err != nil {
+		return nil, xerrors.Errorf("error in git diff: %w", err)
+	}
+	updatedFiles := strings.Split(strings.TrimSpace(output), "\n")
+	return updatedFiles, nil
+}