git.go

  1// Package repository contains helper methods for working with the Git repo.
  2package repository
  3
  4import (
  5	"bytes"
  6	"crypto/sha1"
  7	"fmt"
  8	"github.com/MichaelMure/git-bug/util"
  9	"io"
 10	"os"
 11	"os/exec"
 12	"strings"
 13)
 14
 15// GitRepo represents an instance of a (local) git repository.
 16type GitRepo struct {
 17	Path string
 18}
 19
 20// Run the given git command with the given I/O reader/writers, returning an error if it fails.
 21func (repo *GitRepo) runGitCommandWithIO(stdin io.Reader, stdout, stderr io.Writer, args ...string) error {
 22	fmt.Println("Running git", strings.Join(args, " "))
 23
 24	cmd := exec.Command("git", args...)
 25	cmd.Dir = repo.Path
 26	cmd.Stdin = stdin
 27	cmd.Stdout = stdout
 28	cmd.Stderr = stderr
 29
 30	return cmd.Run()
 31}
 32
 33// Run the given git command and return its stdout, or an error if the command fails.
 34func (repo *GitRepo) runGitCommandRaw(stdin io.Reader, args ...string) (string, string, error) {
 35	var stdout bytes.Buffer
 36	var stderr bytes.Buffer
 37	err := repo.runGitCommandWithIO(stdin, &stdout, &stderr, args...)
 38	return strings.TrimSpace(stdout.String()), strings.TrimSpace(stderr.String()), err
 39}
 40
 41// Run the given git command and return its stdout, or an error if the command fails.
 42func (repo *GitRepo) runGitCommandWithStdin(stdin io.Reader, args ...string) (string, error) {
 43	stdout, stderr, err := repo.runGitCommandRaw(stdin, args...)
 44	if err != nil {
 45		if stderr == "" {
 46			stderr = "Error running git command: " + strings.Join(args, " ")
 47		}
 48		err = fmt.Errorf(stderr)
 49	}
 50	return stdout, err
 51}
 52
 53// Run the given git command and return its stdout, or an error if the command fails.
 54func (repo *GitRepo) runGitCommand(args ...string) (string, error) {
 55	return repo.runGitCommandWithStdin(nil, args...)
 56}
 57
 58// Run the given git command using the same stdin, stdout, and stderr as the review tool.
 59func (repo *GitRepo) runGitCommandInline(args ...string) error {
 60	return repo.runGitCommandWithIO(os.Stdin, os.Stdout, os.Stderr, args...)
 61}
 62
 63// NewGitRepo determines if the given working directory is inside of a git repository,
 64// and returns the corresponding GitRepo instance if it is.
 65func NewGitRepo(path string) (*GitRepo, error) {
 66	repo := &GitRepo{Path: path}
 67	_, err := repo.runGitCommand("rev-parse")
 68	if err == nil {
 69		return repo, nil
 70	}
 71	if _, ok := err.(*exec.ExitError); ok {
 72		return nil, err
 73	}
 74	return nil, err
 75}
 76
 77// GetPath returns the path to the repo.
 78func (repo *GitRepo) GetPath() string {
 79	return repo.Path
 80}
 81
 82// GetRepoStateHash returns a hash which embodies the entire current state of a repository.
 83func (repo *GitRepo) GetRepoStateHash() (string, error) {
 84	stateSummary, err := repo.runGitCommand("show-ref")
 85	return fmt.Sprintf("%x", sha1.Sum([]byte(stateSummary))), err
 86}
 87
 88// GetUserName returns the name the the user has used to configure git
 89func (repo *GitRepo) GetUserName() (string, error) {
 90	return repo.runGitCommand("config", "user.name")
 91}
 92
 93// GetUserEmail returns the email address that the user has used to configure git.
 94func (repo *GitRepo) GetUserEmail() (string, error) {
 95	return repo.runGitCommand("config", "user.email")
 96}
 97
 98// GetCoreEditor returns the name of the editor that the user has used to configure git.
 99func (repo *GitRepo) GetCoreEditor() (string, error) {
100	return repo.runGitCommand("var", "GIT_EDITOR")
101}
102
103// FetchRefs fetch git refs from a remote
104func (repo *GitRepo) FetchRefs(remote, refSpec string) error {
105	err := repo.runGitCommandInline("fetch", remote, "\""+refSpec+"\"")
106
107	if err != nil {
108		return fmt.Errorf("failed to fetch from the remote '%s': %v", remote, err)
109	}
110
111	return err
112}
113
114// PushRefs push git refs to a remote
115func (repo *GitRepo) PushRefs(remote string, refSpec string) error {
116	err := repo.runGitCommandInline("push", remote, refSpec)
117
118	if err != nil {
119		return fmt.Errorf("failed to push to the remote '%s': %v", remote, err)
120	}
121	return nil
122}
123
124// StoreData will store arbitrary data and return the corresponding hash
125func (repo *GitRepo) StoreData(data []byte) (util.Hash, error) {
126	var stdin = bytes.NewReader(data)
127
128	stdout, err := repo.runGitCommandWithStdin(stdin, "hash-object", "--stdin", "-w")
129
130	return util.Hash(stdout), err
131}
132
133// ReadData will attempt to read arbitrary data from the given hash
134func (repo *GitRepo) ReadData(hash util.Hash) ([]byte, error) {
135	var stdout bytes.Buffer
136	var stderr bytes.Buffer
137
138	err := repo.runGitCommandWithIO(nil, &stdout, &stderr, "cat-file", "-p", string(hash))
139
140	if err != nil {
141		return []byte{}, err
142	}
143
144	return stdout.Bytes(), nil
145}
146
147// StoreTree will store a mapping key-->Hash as a Git tree
148func (repo *GitRepo) StoreTree(entries []TreeEntry) (util.Hash, error) {
149	buffer := prepareTreeEntries(entries)
150
151	stdout, err := repo.runGitCommandWithStdin(&buffer, "mktree")
152
153	if err != nil {
154		return "", err
155	}
156
157	return util.Hash(stdout), nil
158}
159
160// StoreCommit will store a Git commit with the given Git tree
161func (repo *GitRepo) StoreCommit(treeHash util.Hash) (util.Hash, error) {
162	stdout, err := repo.runGitCommand("commit-tree", string(treeHash))
163
164	if err != nil {
165		return "", err
166	}
167
168	return util.Hash(stdout), nil
169}
170
171// StoreCommitWithParent will store a Git commit with the given Git tree
172func (repo *GitRepo) StoreCommitWithParent(treeHash util.Hash, parent util.Hash) (util.Hash, error) {
173	stdout, err := repo.runGitCommand("commit-tree", string(treeHash),
174		"-p", string(parent))
175
176	if err != nil {
177		return "", err
178	}
179
180	return util.Hash(stdout), nil
181}
182
183// UpdateRef will create or update a Git reference
184func (repo *GitRepo) UpdateRef(ref string, hash util.Hash) error {
185	_, err := repo.runGitCommand("update-ref", ref, string(hash))
186
187	return err
188}
189
190// ListRefs will return a list of Git ref matching the given refspec
191func (repo *GitRepo) ListRefs(refspec string) ([]string, error) {
192	// the format option will strip the ref name to keep only the last part (ie, the bug id)
193	stdout, err := repo.runGitCommand("for-each-ref", "--format=%(refname:lstrip=-1)", refspec)
194
195	if err != nil {
196		return nil, err
197	}
198
199	splitted := strings.Split(stdout, "\n")
200
201	if len(splitted) == 1 && splitted[0] == "" {
202		return []string{}, nil
203	}
204
205	return splitted, nil
206}
207
208// RefExist will check if a reference exist in Git
209func (repo *GitRepo) RefExist(ref string) (bool, error) {
210	stdout, err := repo.runGitCommand("for-each-ref", ref)
211
212	if err != nil {
213		return false, err
214	}
215
216	return stdout != "", nil
217}
218
219// CopyRef will create a new reference with the same value as another one
220func (repo *GitRepo) CopyRef(source string, dest string) error {
221	_, err := repo.runGitCommand("update-ref", dest, source)
222
223	return err
224}
225
226// ListCommits will return the list of commit hashes of a ref, in chronological order
227func (repo *GitRepo) ListCommits(ref string) ([]util.Hash, error) {
228	stdout, err := repo.runGitCommand("rev-list", "--first-parent", "--reverse", ref)
229
230	if err != nil {
231		return nil, err
232	}
233
234	splitted := strings.Split(stdout, "\n")
235
236	casted := make([]util.Hash, len(splitted))
237	for i, line := range splitted {
238		casted[i] = util.Hash(line)
239	}
240
241	return casted, nil
242
243}
244
245// ListEntries will return the list of entries in a Git tree
246func (repo *GitRepo) ListEntries(hash util.Hash) ([]TreeEntry, error) {
247	stdout, err := repo.runGitCommand("ls-tree", string(hash))
248
249	if err != nil {
250		return nil, err
251	}
252
253	return readTreeEntries(stdout)
254}
255
256// FindCommonAncestor will return the last common ancestor of two chain of commit
257func (repo *GitRepo) FindCommonAncestor(hash1 util.Hash, hash2 util.Hash) (util.Hash, error) {
258	stdout, err := repo.runGitCommand("merge-base", string(hash1), string(hash2))
259
260	if err != nil {
261		return "", nil
262	}
263
264	return util.Hash(stdout), nil
265}
266
267// Return the git tree hash referenced in a commit
268func (repo *GitRepo) GetTreeHash(commit util.Hash) (util.Hash, error) {
269	stdout, err := repo.runGitCommand("rev-parse", string(commit)+"^{tree}")
270
271	if err != nil {
272		return "", nil
273	}
274
275	return util.Hash(stdout), nil
276}