1// Package repository contains helper methods for working with the Git repo.
  2package repository
  3
  4import (
  5	"bytes"
  6	"fmt"
  7	"io"
  8	"os/exec"
  9	"path"
 10	"strconv"
 11	"strings"
 12
 13	"github.com/blang/semver"
 14	"github.com/pkg/errors"
 15
 16	"github.com/MichaelMure/git-bug/util/git"
 17	"github.com/MichaelMure/git-bug/util/lamport"
 18)
 19
 20const createClockFile = "/git-bug/create-clock"
 21const editClockFile = "/git-bug/edit-clock"
 22
 23// ErrNotARepo is the error returned when the git repo root wan't be found
 24var ErrNotARepo = errors.New("not a git repository")
 25
 26var _ ClockedRepo = &GitRepo{}
 27
 28// GitRepo represents an instance of a (local) git repository.
 29type GitRepo struct {
 30	Path        string
 31	createClock *lamport.Persisted
 32	editClock   *lamport.Persisted
 33}
 34
 35// Run the given git command with the given I/O reader/writers, returning an error if it fails.
 36func (repo *GitRepo) runGitCommandWithIO(stdin io.Reader, stdout, stderr io.Writer, args ...string) error {
 37	// fmt.Printf("[%s] Running git %s\n", repo.Path, strings.Join(args, " "))
 38
 39	cmd := exec.Command("git", args...)
 40	cmd.Dir = repo.Path
 41	cmd.Stdin = stdin
 42	cmd.Stdout = stdout
 43	cmd.Stderr = stderr
 44
 45	return cmd.Run()
 46}
 47
 48// Run the given git command and return its stdout, or an error if the command fails.
 49func (repo *GitRepo) runGitCommandRaw(stdin io.Reader, args ...string) (string, string, error) {
 50	var stdout bytes.Buffer
 51	var stderr bytes.Buffer
 52	err := repo.runGitCommandWithIO(stdin, &stdout, &stderr, args...)
 53	return strings.TrimSpace(stdout.String()), strings.TrimSpace(stderr.String()), err
 54}
 55
 56// Run the given git command and return its stdout, or an error if the command fails.
 57func (repo *GitRepo) runGitCommandWithStdin(stdin io.Reader, args ...string) (string, error) {
 58	stdout, stderr, err := repo.runGitCommandRaw(stdin, args...)
 59	if err != nil {
 60		if stderr == "" {
 61			stderr = "Error running git command: " + strings.Join(args, " ")
 62		}
 63		err = fmt.Errorf(stderr)
 64	}
 65	return stdout, err
 66}
 67
 68// Run the given git command and return its stdout, or an error if the command fails.
 69func (repo *GitRepo) runGitCommand(args ...string) (string, error) {
 70	return repo.runGitCommandWithStdin(nil, args...)
 71}
 72
 73// NewGitRepo determines if the given working directory is inside of a git repository,
 74// and returns the corresponding GitRepo instance if it is.
 75func NewGitRepo(path string, witnesser Witnesser) (*GitRepo, error) {
 76	repo := &GitRepo{Path: path}
 77
 78	// Check the repo and retrieve the root path
 79	stdout, err := repo.runGitCommand("rev-parse", "--git-dir")
 80
 81	// Now dir is fetched with "git rev-parse --git-dir". May be it can
 82	// still return nothing in some cases. Then empty stdout check is
 83	// kept.
 84	if err != nil || stdout == "" {
 85		return nil, ErrNotARepo
 86	}
 87
 88	// Fix the path to be sure we are at the root
 89	repo.Path = stdout
 90
 91	err = repo.LoadClocks()
 92
 93	if err != nil {
 94		// No clock yet, trying to initialize them
 95		err = repo.createClocks()
 96		if err != nil {
 97			return nil, err
 98		}
 99
100		err = witnesser(repo)
101		if err != nil {
102			return nil, err
103		}
104
105		err = repo.WriteClocks()
106		if err != nil {
107			return nil, err
108		}
109
110		return repo, nil
111	}
112
113	return repo, nil
114}
115
116// InitGitRepo create a new empty git repo at the given path
117func InitGitRepo(path string) (*GitRepo, error) {
118	repo := &GitRepo{Path: path}
119	err := repo.createClocks()
120	if err != nil {
121		return nil, err
122	}
123
124	_, err = repo.runGitCommand("init", path)
125	if err != nil {
126		return nil, err
127	}
128
129	return repo, nil
130}
131
132// InitBareGitRepo create a new --bare empty git repo at the given path
133func InitBareGitRepo(path string) (*GitRepo, error) {
134	repo := &GitRepo{Path: path}
135	err := repo.createClocks()
136	if err != nil {
137		return nil, err
138	}
139
140	_, err = repo.runGitCommand("init", "--bare", path)
141	if err != nil {
142		return nil, err
143	}
144
145	return repo, nil
146}
147
148// GetPath returns the path to the repo.
149func (repo *GitRepo) GetPath() string {
150	return repo.Path
151}
152
153// GetUserName returns the name the the user has used to configure git
154func (repo *GitRepo) GetUserName() (string, error) {
155	return repo.runGitCommand("config", "user.name")
156}
157
158// GetUserEmail returns the email address that the user has used to configure git.
159func (repo *GitRepo) GetUserEmail() (string, error) {
160	return repo.runGitCommand("config", "user.email")
161}
162
163// GetCoreEditor returns the name of the editor that the user has used to configure git.
164func (repo *GitRepo) GetCoreEditor() (string, error) {
165	return repo.runGitCommand("var", "GIT_EDITOR")
166}
167
168// GetRemotes returns the configured remotes repositories.
169func (repo *GitRepo) GetRemotes() (map[string]string, error) {
170	stdout, err := repo.runGitCommand("remote", "--verbose")
171	if err != nil {
172		return nil, err
173	}
174
175	lines := strings.Split(stdout, "\n")
176	remotes := make(map[string]string, len(lines))
177
178	for _, line := range lines {
179		elements := strings.Fields(line)
180		if len(elements) != 3 {
181			return nil, fmt.Errorf("unexpected output format: %s", line)
182		}
183
184		remotes[elements[0]] = elements[1]
185	}
186
187	return remotes, nil
188}
189
190// StoreConfig store a single key/value pair in the config of the repo
191func (repo *GitRepo) StoreConfig(key string, value string) error {
192	_, err := repo.runGitCommand("config", "--replace-all", key, value)
193
194	return err
195}
196
197// ReadConfigs read all key/value pair matching the key prefix
198func (repo *GitRepo) ReadConfigs(keyPrefix string) (map[string]string, error) {
199	stdout, err := repo.runGitCommand("config", "--get-regexp", keyPrefix)
200
201	//   / \
202	//  / ! \
203	// -------
204	//
205	// There can be a legitimate error here, but I see no portable way to
206	// distinguish them from the git error that say "no matching value exist"
207	if err != nil {
208		return nil, nil
209	}
210
211	lines := strings.Split(stdout, "\n")
212
213	result := make(map[string]string, len(lines))
214
215	for _, line := range lines {
216		if strings.TrimSpace(line) == "" {
217			continue
218		}
219
220		parts := strings.Fields(line)
221		if len(parts) != 2 {
222			return nil, fmt.Errorf("bad git config: %s", line)
223		}
224
225		result[parts[0]] = parts[1]
226	}
227
228	return result, nil
229}
230
231func (repo *GitRepo) ReadConfigBool(key string) (bool, error) {
232	val, err := repo.ReadConfigString(key)
233	if err != nil {
234		return false, err
235	}
236
237	return strconv.ParseBool(val)
238}
239
240func (repo *GitRepo) ReadConfigString(key string) (string, error) {
241	stdout, err := repo.runGitCommand("config", "--get-all", key)
242
243	//   / \
244	//  / ! \
245	// -------
246	//
247	// There can be a legitimate error here, but I see no portable way to
248	// distinguish them from the git error that say "no matching value exist"
249	if err != nil {
250		return "", ErrNoConfigEntry
251	}
252
253	lines := strings.Split(stdout, "\n")
254
255	if len(lines) == 0 {
256		return "", ErrNoConfigEntry
257	}
258	if len(lines) > 1 {
259		return "", ErrMultipleConfigEntry
260	}
261
262	return lines[0], nil
263}
264
265func (repo *GitRepo) rmSection(keyPrefix string) error {
266	_, err := repo.runGitCommand("config", "--remove-section", keyPrefix)
267	return err
268}
269
270func (repo *GitRepo) unsetAll(keyPrefix string) error {
271	_, err := repo.runGitCommand("config", "--unset-all", keyPrefix)
272	return err
273}
274
275// return keyPrefix section
276// example: sectionFromKey(a.b.c.d) return a.b.c
277func sectionFromKey(keyPrefix string) string {
278	s := strings.Split(keyPrefix, ".")
279	if len(s) == 1 {
280		return keyPrefix
281	}
282
283	return strings.Join(s[:len(s)-1], ".")
284}
285
286// rmConfigs with git version lesser than 2.18
287func (repo *GitRepo) rmConfigsGitVersionLT218(keyPrefix string) error {
288	// try to remove key/value pair by key
289	err := repo.unsetAll(keyPrefix)
290	if err != nil {
291		return repo.rmSection(keyPrefix)
292	}
293
294	m, err := repo.ReadConfigs(sectionFromKey(keyPrefix))
295	if err != nil {
296		return err
297	}
298
299	// if section doesn't have any left key/value remove the section
300	if len(m) == 0 {
301		return repo.rmSection(sectionFromKey(keyPrefix))
302	}
303
304	return nil
305}
306
307// RmConfigs remove all key/value pair matching the key prefix
308func (repo *GitRepo) RmConfigs(keyPrefix string) error {
309	// starting from git 2.18.0 sections are automatically deleted when the last existing
310	// key/value is removed. Before 2.18.0 we should remove the section
311	// see https://github.com/git/git/blob/master/Documentation/RelNotes/2.18.0.txt#L379
312	lt218, err := repo.gitVersionLT218()
313	if err != nil {
314		return errors.Wrap(err, "getting git version")
315	}
316
317	if lt218 {
318		return repo.rmConfigsGitVersionLT218(keyPrefix)
319	}
320
321	err = repo.unsetAll(keyPrefix)
322	if err != nil {
323		return repo.rmSection(keyPrefix)
324	}
325
326	return nil
327}
328
329func (repo *GitRepo) gitVersionLT218() (bool, error) {
330	versionOut, err := repo.runGitCommand("version")
331	if err != nil {
332		return false, err
333	}
334
335	versionString := strings.Fields(versionOut)[2]
336	version, err := semver.Make(versionString)
337	if err != nil {
338		return false, err
339	}
340
341	version218string := "2.18.0"
342	gitVersion218, err := semver.Make(version218string)
343	if err != nil {
344		return false, err
345	}
346
347	return version.LT(gitVersion218), nil
348}
349
350// FetchRefs fetch git refs from a remote
351func (repo *GitRepo) FetchRefs(remote, refSpec string) (string, error) {
352	stdout, err := repo.runGitCommand("fetch", remote, refSpec)
353
354	if err != nil {
355		return stdout, fmt.Errorf("failed to fetch from the remote '%s': %v", remote, err)
356	}
357
358	return stdout, err
359}
360
361// PushRefs push git refs to a remote
362func (repo *GitRepo) PushRefs(remote string, refSpec string) (string, error) {
363	stdout, stderr, err := repo.runGitCommandRaw(nil, "push", remote, refSpec)
364
365	if err != nil {
366		return stdout + stderr, fmt.Errorf("failed to push to the remote '%s': %v", remote, stderr)
367	}
368	return stdout + stderr, nil
369}
370
371// StoreData will store arbitrary data and return the corresponding hash
372func (repo *GitRepo) StoreData(data []byte) (git.Hash, error) {
373	var stdin = bytes.NewReader(data)
374
375	stdout, err := repo.runGitCommandWithStdin(stdin, "hash-object", "--stdin", "-w")
376
377	return git.Hash(stdout), err
378}
379
380// ReadData will attempt to read arbitrary data from the given hash
381func (repo *GitRepo) ReadData(hash git.Hash) ([]byte, error) {
382	var stdout bytes.Buffer
383	var stderr bytes.Buffer
384
385	err := repo.runGitCommandWithIO(nil, &stdout, &stderr, "cat-file", "-p", string(hash))
386
387	if err != nil {
388		return []byte{}, err
389	}
390
391	return stdout.Bytes(), nil
392}
393
394// StoreTree will store a mapping key-->Hash as a Git tree
395func (repo *GitRepo) StoreTree(entries []TreeEntry) (git.Hash, error) {
396	buffer := prepareTreeEntries(entries)
397
398	stdout, err := repo.runGitCommandWithStdin(&buffer, "mktree")
399
400	if err != nil {
401		return "", err
402	}
403
404	return git.Hash(stdout), nil
405}
406
407// StoreCommit will store a Git commit with the given Git tree
408func (repo *GitRepo) StoreCommit(treeHash git.Hash) (git.Hash, error) {
409	stdout, err := repo.runGitCommand("commit-tree", string(treeHash))
410
411	if err != nil {
412		return "", err
413	}
414
415	return git.Hash(stdout), nil
416}
417
418// StoreCommitWithParent will store a Git commit with the given Git tree
419func (repo *GitRepo) StoreCommitWithParent(treeHash git.Hash, parent git.Hash) (git.Hash, error) {
420	stdout, err := repo.runGitCommand("commit-tree", string(treeHash),
421		"-p", string(parent))
422
423	if err != nil {
424		return "", err
425	}
426
427	return git.Hash(stdout), nil
428}
429
430// UpdateRef will create or update a Git reference
431func (repo *GitRepo) UpdateRef(ref string, hash git.Hash) error {
432	_, err := repo.runGitCommand("update-ref", ref, string(hash))
433
434	return err
435}
436
437// ListRefs will return a list of Git ref matching the given refspec
438func (repo *GitRepo) ListRefs(refspec string) ([]string, error) {
439	stdout, err := repo.runGitCommand("for-each-ref", "--format=%(refname)", refspec)
440
441	if err != nil {
442		return nil, err
443	}
444
445	split := strings.Split(stdout, "\n")
446
447	if len(split) == 1 && split[0] == "" {
448		return []string{}, nil
449	}
450
451	return split, nil
452}
453
454// RefExist will check if a reference exist in Git
455func (repo *GitRepo) RefExist(ref string) (bool, error) {
456	stdout, err := repo.runGitCommand("for-each-ref", ref)
457
458	if err != nil {
459		return false, err
460	}
461
462	return stdout != "", nil
463}
464
465// CopyRef will create a new reference with the same value as another one
466func (repo *GitRepo) CopyRef(source string, dest string) error {
467	_, err := repo.runGitCommand("update-ref", dest, source)
468
469	return err
470}
471
472// ListCommits will return the list of commit hashes of a ref, in chronological order
473func (repo *GitRepo) ListCommits(ref string) ([]git.Hash, error) {
474	stdout, err := repo.runGitCommand("rev-list", "--first-parent", "--reverse", ref)
475
476	if err != nil {
477		return nil, err
478	}
479
480	split := strings.Split(stdout, "\n")
481
482	casted := make([]git.Hash, len(split))
483	for i, line := range split {
484		casted[i] = git.Hash(line)
485	}
486
487	return casted, nil
488
489}
490
491// ListEntries will return the list of entries in a Git tree
492func (repo *GitRepo) ListEntries(hash git.Hash) ([]TreeEntry, error) {
493	stdout, err := repo.runGitCommand("ls-tree", string(hash))
494
495	if err != nil {
496		return nil, err
497	}
498
499	return readTreeEntries(stdout)
500}
501
502// FindCommonAncestor will return the last common ancestor of two chain of commit
503func (repo *GitRepo) FindCommonAncestor(hash1 git.Hash, hash2 git.Hash) (git.Hash, error) {
504	stdout, err := repo.runGitCommand("merge-base", string(hash1), string(hash2))
505
506	if err != nil {
507		return "", err
508	}
509
510	return git.Hash(stdout), nil
511}
512
513// GetTreeHash return the git tree hash referenced in a commit
514func (repo *GitRepo) GetTreeHash(commit git.Hash) (git.Hash, error) {
515	stdout, err := repo.runGitCommand("rev-parse", string(commit)+"^{tree}")
516
517	if err != nil {
518		return "", err
519	}
520
521	return git.Hash(stdout), nil
522}
523
524// AddRemote add a new remote to the repository
525// Not in the interface because it's only used for testing
526func (repo *GitRepo) AddRemote(name string, url string) error {
527	_, err := repo.runGitCommand("remote", "add", name, url)
528
529	return err
530}
531
532func (repo *GitRepo) createClocks() error {
533	createPath := path.Join(repo.Path, createClockFile)
534	createClock, err := lamport.NewPersisted(createPath)
535	if err != nil {
536		return err
537	}
538
539	editPath := path.Join(repo.Path, editClockFile)
540	editClock, err := lamport.NewPersisted(editPath)
541	if err != nil {
542		return err
543	}
544
545	repo.createClock = createClock
546	repo.editClock = editClock
547
548	return nil
549}
550
551// LoadClocks read the clocks values from the on-disk repo
552func (repo *GitRepo) LoadClocks() error {
553	createClock, err := lamport.LoadPersisted(repo.GetPath() + createClockFile)
554	if err != nil {
555		return err
556	}
557
558	editClock, err := lamport.LoadPersisted(repo.GetPath() + editClockFile)
559	if err != nil {
560		return err
561	}
562
563	repo.createClock = createClock
564	repo.editClock = editClock
565	return nil
566}
567
568// WriteClocks write the clocks values into the repo
569func (repo *GitRepo) WriteClocks() error {
570	err := repo.createClock.Write()
571	if err != nil {
572		return err
573	}
574
575	err = repo.editClock.Write()
576	if err != nil {
577		return err
578	}
579
580	return nil
581}
582
583// CreateTime return the current value of the creation clock
584func (repo *GitRepo) CreateTime() lamport.Time {
585	return repo.createClock.Time()
586}
587
588// CreateTimeIncrement increment the creation clock and return the new value.
589func (repo *GitRepo) CreateTimeIncrement() (lamport.Time, error) {
590	return repo.createClock.Increment()
591}
592
593// EditTime return the current value of the edit clock
594func (repo *GitRepo) EditTime() lamport.Time {
595	return repo.editClock.Time()
596}
597
598// EditTimeIncrement increment the edit clock and return the new value.
599func (repo *GitRepo) EditTimeIncrement() (lamport.Time, error) {
600	return repo.editClock.Increment()
601}
602
603// CreateWitness witness another create time and increment the corresponding clock
604// if needed.
605func (repo *GitRepo) CreateWitness(time lamport.Time) error {
606	return repo.createClock.Witness(time)
607}
608
609// EditWitness witness another edition time and increment the corresponding clock
610// if needed.
611func (repo *GitRepo) EditWitness(time lamport.Time) error {
612	return repo.editClock.Witness(time)
613}