git-bug/cache/repo_cache.go

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package cache
import (
"bytes"
"encoding/gob"
"fmt"
"io"
"io/ioutil"
"os"
"path"
"sort"
"strconv"
"strings"
"github.com/MichaelMure/git-bug/bug"
"github.com/MichaelMure/git-bug/operations"
"github.com/MichaelMure/git-bug/repository"
"github.com/MichaelMure/git-bug/util/git"
"github.com/MichaelMure/git-bug/util/process"
)
const cacheFile = "cache"
const formatVersion = 1
type RepoCache struct {
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// the underlying repo
repo repository.ClockedRepo
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// excerpt of bugs data for all bugs
excerpts map[string]*BugExcerpt
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// bug loaded in memory
bugs map[string]*BugCache
}
func NewRepoCache(r repository.ClockedRepo) (*RepoCache, error) {
c := &RepoCache{
repo: r,
bugs: make(map[string]*BugCache),
}
err := c.lock()
if err != nil {
return &RepoCache{}, err
}
err = c.load()
if err == nil {
return c, nil
}
err = c.buildCache()
if err != nil {
return nil, err
}
return c, c.write()
}
// GetPath returns the path to the repo.
func (c *RepoCache) GetPath() string {
return c.repo.GetPath()
}
// GetPath returns the path to the repo.
func (c *RepoCache) GetCoreEditor() (string, error) {
return c.repo.GetCoreEditor()
}
// GetUserName returns the name the the user has used to configure git
func (c *RepoCache) GetUserName() (string, error) {
return c.repo.GetUserName()
}
// GetUserEmail returns the email address that the user has used to configure git.
func (c *RepoCache) GetUserEmail() (string, error) {
return c.repo.GetUserEmail()
}
func (c *RepoCache) lock() error {
lockPath := repoLockFilePath(c.repo)
err := repoIsAvailable(c.repo)
if err != nil {
return err
}
f, err := os.Create(lockPath)
if err != nil {
return err
}
pid := fmt.Sprintf("%d", os.Getpid())
_, err = f.WriteString(pid)
if err != nil {
return err
}
return f.Close()
}
func (c *RepoCache) Close() error {
lockPath := repoLockFilePath(c.repo)
return os.Remove(lockPath)
}
// bugUpdated is a callback to trigger when the excerpt of a bug changed,
// that is each time a bug is updated
func (c *RepoCache) bugUpdated(id string) error {
b, ok := c.bugs[id]
if !ok {
panic("missing bug in the cache")
}
c.excerpts[id] = NewBugExcerpt(b.bug, b.Snapshot())
return c.write()
}
// load will try to read from the disk the bug cache file
func (c *RepoCache) load() error {
f, err := os.Open(cacheFilePath(c.repo))
if err != nil {
return err
}
decoder := gob.NewDecoder(f)
aux := struct {
Version uint
Excerpts map[string]*BugExcerpt
}{}
err = decoder.Decode(&aux)
if err != nil {
return err
}
if aux.Version != 1 {
return fmt.Errorf("unknown cache format version %v", aux.Version)
}
c.excerpts = aux.Excerpts
return nil
}
// write will serialize on disk the bug cache file
func (c *RepoCache) write() error {
var data bytes.Buffer
aux := struct {
Version uint
Excerpts map[string]*BugExcerpt
}{
Version: formatVersion,
Excerpts: c.excerpts,
}
encoder := gob.NewEncoder(&data)
err := encoder.Encode(aux)
if err != nil {
return err
}
f, err := os.Create(cacheFilePath(c.repo))
if err != nil {
return err
}
_, err = f.Write(data.Bytes())
if err != nil {
return err
}
return f.Close()
}
func cacheFilePath(repo repository.Repo) string {
return path.Join(repo.GetPath(), ".git", "git-bug", cacheFile)
}
func (c *RepoCache) buildCache() error {
fmt.Printf("Building bug cache... ")
c.excerpts = make(map[string]*BugExcerpt)
allBugs := bug.ReadAllLocalBugs(c.repo)
for b := range allBugs {
if b.Err != nil {
return b.Err
}
snap := b.Bug.Compile()
c.excerpts[b.Bug.Id()] = NewBugExcerpt(b.Bug, &snap)
}
fmt.Println("Done.")
return nil
}
func (c *RepoCache) ResolveBug(id string) (*BugCache, error) {
cached, ok := c.bugs[id]
if ok {
return cached, nil
}
b, err := bug.ReadLocalBug(c.repo, id)
if err != nil {
return nil, err
}
cached = NewBugCache(c, b)
c.bugs[id] = cached
return cached, nil
}
func (c *RepoCache) ResolveBugPrefix(prefix string) (*BugCache, error) {
// preallocate but empty
matching := make([]string, 0, 5)
for id := range c.excerpts {
if strings.HasPrefix(id, prefix) {
matching = append(matching, id)
}
}
if len(matching) > 1 {
return nil, fmt.Errorf("Multiple matching bug found:\n%s", strings.Join(matching, "\n"))
}
if len(matching) == 0 {
return nil, bug.ErrBugNotExist
}
return c.ResolveBug(matching[0])
}
func (c *RepoCache) QueryBugs(query *Query) []string {
if query == nil {
return c.AllBugsIds()
}
var filtered []*BugExcerpt
for _, excerpt := range c.excerpts {
if query.Match(excerpt) {
filtered = append(filtered, excerpt)
}
}
var sorter sort.Interface
switch query.OrderBy {
case OrderById:
sorter = BugsById(filtered)
case OrderByCreation:
sorter = BugsByCreationTime(filtered)
case OrderByEdit:
sorter = BugsByEditTime(filtered)
default:
panic("missing sort type")
}
if query.OrderDirection == OrderDescending {
sorter = sort.Reverse(sorter)
}
sort.Sort(sorter)
result := make([]string, len(filtered))
for i, val := range filtered {
result[i] = val.Id
}
return result
}
// AllBugsIds return all known bug ids
func (c *RepoCache) AllBugsIds() []string {
result := make([]string, len(c.excerpts))
i := 0
for _, excerpt := range c.excerpts {
result[i] = excerpt.Id
i++
}
return result
}
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// ClearAllBugs clear all bugs kept in memory
func (c *RepoCache) ClearAllBugs() {
c.bugs = make(map[string]*BugCache)
}
// ValidLabels list valid labels
//
// Note: in the future, a proper label policy could be implemented where valid
// labels are defined in a configuration file. Until that, the default behavior
// is to return the list of labels already used.
func (c *RepoCache) ValidLabels() []bug.Label {
set := map[bug.Label]interface{}{}
for _, excerpt := range c.excerpts {
for _, l := range excerpt.Labels {
set[l] = nil
}
}
result := make([]bug.Label, len(set))
i := 0
for l := range set {
result[i] = l
i++
}
// Sort
sort.Slice(result, func(i, j int) bool {
return string(result[i]) < string(result[j])
})
return result
}
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// NewBug create a new bug
// The new bug is written in the repository (commit)
func (c *RepoCache) NewBug(title string, message string) (*BugCache, error) {
return c.NewBugWithFiles(title, message, nil)
}
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// NewBugWithFiles create a new bug with attached files for the message
// The new bug is written in the repository (commit)
func (c *RepoCache) NewBugWithFiles(title string, message string, files []git.Hash) (*BugCache, error) {
author, err := bug.GetUser(c.repo)
if err != nil {
return nil, err
}
b, err := operations.CreateWithFiles(author, title, message, files)
if err != nil {
return nil, err
}
err = b.Commit(c.repo)
if err != nil {
return nil, err
}
cached := NewBugCache(c, b)
c.bugs[b.Id()] = cached
err = c.bugUpdated(b.Id())
if err != nil {
return nil, err
}
return cached, nil
}
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// Fetch retrieve update from a remote
// This does not change the local bugs state
func (c *RepoCache) Fetch(remote string) (string, error) {
return bug.Fetch(c.repo, remote)
}
// MergeAll will merge all the available remote bug
func (c *RepoCache) MergeAll(remote string) <-chan bug.MergeResult {
out := make(chan bug.MergeResult)
// Intercept merge results to update the cache properly
go func() {
defer close(out)
results := bug.MergeAll(c.repo, remote)
for result := range results {
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out <- result
if result.Err != nil {
continue
}
id := result.Id
switch result.Status {
case bug.MergeStatusNew, bug.MergeStatusUpdated:
b := result.Bug
snap := b.Compile()
c.excerpts[id] = NewBugExcerpt(b, &snap)
}
}
err := c.write()
// No easy way out here ..
if err != nil {
panic(err)
}
}()
return out
}
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// Push update a remote with the local changes
func (c *RepoCache) Push(remote string) (string, error) {
return bug.Push(c.repo, remote)
}
func repoLockFilePath(repo repository.Repo) string {
return path.Join(repo.GetPath(), ".git", "git-bug", lockfile)
}
// repoIsAvailable check is the given repository is locked by a Cache.
// Note: this is a smart function that will cleanup the lock file if the
// corresponding process is not there anymore.
// If no error is returned, the repo is free to edit.
func repoIsAvailable(repo repository.Repo) error {
lockPath := repoLockFilePath(repo)
// Todo: this leave way for a racey access to the repo between the test
// if the file exist and the actual write. It's probably not a problem in
// practice because using a repository will be done from user interaction
// or in a context where a single instance of git-bug is already guaranteed
// (say, a server with the web UI running). But still, that might be nice to
// have a mutex or something to guard that.
// Todo: this will fail if somehow the filesystem is shared with another
// computer. Should add a configuration that prevent the cleaning of the
// lock file
f, err := os.Open(lockPath)
if err != nil && !os.IsNotExist(err) {
return err
}
if err == nil {
// lock file already exist
buf, err := ioutil.ReadAll(io.LimitReader(f, 10))
if err != nil {
return err
}
if len(buf) == 10 {
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return fmt.Errorf("the lock file should be < 10 bytes")
}
pid, err := strconv.Atoi(string(buf))
if err != nil {
return err
}
if process.IsRunning(pid) {
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return fmt.Errorf("the repository you want to access is already locked by the process pid %d", pid)
}
// The lock file is just laying there after a crash, clean it
fmt.Println("A lock file is present but the corresponding process is not, removing it.")
err = f.Close()
if err != nil {
return err
}
os.Remove(lockPath)
if err != nil {
return err
}
}
return nil
}