A fork of Gitea (see branch `mj`) adding Majority Judgment Polls 𐄷 over Issues and Merge Requests. https://git.mieuxvoter.fr
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// Copyright 2020 The Gitea Authors.
// All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package archiver
import (
"io"
"io/ioutil"
"os"
"path"
"regexp"
"strings"
"sync"
"time"
"code.gitea.io/gitea/modules/base"
"code.gitea.io/gitea/modules/context"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/graceful"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/util"
)
// ArchiveRequest defines the parameters of an archive request, which notably
// includes the specific repository being archived as well as the commit, the
// name by which it was requested, and the kind of archive being requested.
// This is entirely opaque to external entities, though, and mostly used as a
// handle elsewhere.
type ArchiveRequest struct {
uri string
repo *git.Repository
refName string
ext string
archivePath string
archiveType git.ArchiveType
archiveComplete bool
commit *git.Commit
cchan chan struct{}
}
var archiveInProgress []*ArchiveRequest
var archiveMutex sync.Mutex
// SHA1 hashes will only go up to 40 characters, but SHA256 hashes will go all
// the way to 64.
var shaRegex = regexp.MustCompile(`^[0-9a-f]{4,64}$`)
// These facilitate testing, by allowing the unit tests to control (to some extent)
// the goroutine used for processing the queue.
var archiveQueueMutex *sync.Mutex
var archiveQueueStartCond *sync.Cond
var archiveQueueReleaseCond *sync.Cond
// GetArchivePath returns the path from which we can serve this archive.
func (aReq *ArchiveRequest) GetArchivePath() string {
return aReq.archivePath
}
// GetArchiveName returns the name of the caller, based on the ref used by the
// caller to create this request.
func (aReq *ArchiveRequest) GetArchiveName() string {
return aReq.refName + aReq.ext
}
// IsComplete returns the completion status of this request.
func (aReq *ArchiveRequest) IsComplete() bool {
return aReq.archiveComplete
}
// WaitForCompletion will wait for this request to complete, with no timeout.
// It returns whether the archive was actually completed, as the channel could
// have also been closed due to an error.
func (aReq *ArchiveRequest) WaitForCompletion(ctx *context.Context) bool {
select {
case <-aReq.cchan:
case <-ctx.Req.Context().Done():
}
return aReq.IsComplete()
}
// TimedWaitForCompletion will wait for this request to complete, with timeout
// happening after the specified Duration. It returns whether the archive is
// now complete and whether we hit the timeout or not. The latter may not be
// useful if the request is complete or we started to shutdown.
func (aReq *ArchiveRequest) TimedWaitForCompletion(ctx *context.Context, dur time.Duration) (bool, bool) {
timeout := false
select {
case <-time.After(dur):
timeout = true
case <-aReq.cchan:
case <-ctx.Req.Context().Done():
}
return aReq.IsComplete(), timeout
}
// The caller must hold the archiveMutex across calls to getArchiveRequest.
func getArchiveRequest(repo *git.Repository, commit *git.Commit, archiveType git.ArchiveType) *ArchiveRequest {
for _, r := range archiveInProgress {
// Need to be referring to the same repository.
if r.repo.Path == repo.Path && r.commit.ID == commit.ID && r.archiveType == archiveType {
return r
}
}
return nil
}
// DeriveRequestFrom creates an archival request, based on the URI. The
// resulting ArchiveRequest is suitable for being passed to ArchiveRepository()
// if it's determined that the request still needs to be satisfied.
func DeriveRequestFrom(ctx *context.Context, uri string) *ArchiveRequest {
if ctx.Repo == nil || ctx.Repo.GitRepo == nil {
log.Trace("Repo not initialized")
return nil
}
r := &ArchiveRequest{
uri: uri,
repo: ctx.Repo.GitRepo,
}
switch {
case strings.HasSuffix(uri, ".zip"):
r.ext = ".zip"
r.archivePath = path.Join(r.repo.Path, "archives/zip")
r.archiveType = git.ZIP
case strings.HasSuffix(uri, ".tar.gz"):
r.ext = ".tar.gz"
r.archivePath = path.Join(r.repo.Path, "archives/targz")
r.archiveType = git.TARGZ
default:
log.Trace("Unknown format: %s", uri)
return nil
}
r.refName = strings.TrimSuffix(r.uri, r.ext)
isDir, err := util.IsDir(r.archivePath)
if err != nil {
ctx.ServerError("Download -> util.IsDir(archivePath)", err)
return nil
}
if !isDir {
if err := os.MkdirAll(r.archivePath, os.ModePerm); err != nil {
ctx.ServerError("Download -> os.MkdirAll(archivePath)", err)
return nil
}
}
// Get corresponding commit.
if r.repo.IsBranchExist(r.refName) {
r.commit, err = r.repo.GetBranchCommit(r.refName)
if err != nil {
ctx.ServerError("GetBranchCommit", err)
return nil
}
} else if r.repo.IsTagExist(r.refName) {
r.commit, err = r.repo.GetTagCommit(r.refName)
if err != nil {
ctx.ServerError("GetTagCommit", err)
return nil
}
} else if shaRegex.MatchString(r.refName) {
r.commit, err = r.repo.GetCommit(r.refName)
if err != nil {
ctx.NotFound("GetCommit", nil)
return nil
}
} else {
ctx.NotFound("DeriveRequestFrom", nil)
return nil
}
archiveMutex.Lock()
defer archiveMutex.Unlock()
if rExisting := getArchiveRequest(r.repo, r.commit, r.archiveType); rExisting != nil {
return rExisting
}
r.archivePath = path.Join(r.archivePath, base.ShortSha(r.commit.ID.String())+r.ext)
r.archiveComplete, err = util.IsFile(r.archivePath)
if err != nil {
ctx.ServerError("util.IsFile", err)
return nil
}
return r
}
func doArchive(r *ArchiveRequest) {
var (
err error
tmpArchive *os.File
destArchive *os.File
)
// Close the channel to indicate to potential waiters that this request
// has finished.
defer close(r.cchan)
// It could have happened that we enqueued two archival requests, due to
// race conditions and difficulties in locking. Do one last check that
// the archive we're referring to doesn't already exist. If it does exist,
// then just mark the request as complete and move on.
isFile, err := util.IsFile(r.archivePath)
if err != nil {
log.Error("Unable to check if %s util.IsFile: %v. Will ignore and recreate.", r.archivePath, err)
}
if isFile {
r.archiveComplete = true
return
}
// Create a temporary file to use while the archive is being built. We
// will then copy it into place (r.archivePath) once it's fully
// constructed.
tmpArchive, err = ioutil.TempFile("", "archive")
if err != nil {
log.Error("Unable to create a temporary archive file! Error: %v", err)
return
}
defer func() {
tmpArchive.Close()
os.Remove(tmpArchive.Name())
}()
if err = r.commit.CreateArchive(graceful.GetManager().ShutdownContext(), tmpArchive.Name(), git.CreateArchiveOpts{
Format: r.archiveType,
Prefix: setting.Repository.PrefixArchiveFiles,
}); err != nil {
log.Error("Download -> CreateArchive "+tmpArchive.Name(), err)
return
}
// Now we copy it into place
if destArchive, err = os.Create(r.archivePath); err != nil {
log.Error("Unable to open archive " + r.archivePath)
return
}
_, err = io.Copy(destArchive, tmpArchive)
destArchive.Close()
if err != nil {
log.Error("Unable to write archive " + r.archivePath)
return
}
// Block any attempt to finalize creating a new request if we're marking
r.archiveComplete = true
}
// ArchiveRepository satisfies the ArchiveRequest being passed in. Processing
// will occur in a separate goroutine, as this phase may take a while to
// complete. If the archive already exists, ArchiveRepository will not do
// anything. In all cases, the caller should be examining the *ArchiveRequest
// being returned for completion, as it may be different than the one they passed
// in.
func ArchiveRepository(request *ArchiveRequest) *ArchiveRequest {
// We'll return the request that's already been enqueued if it has been
// enqueued, or we'll immediately enqueue it if it has not been enqueued
// and it is not marked complete.
archiveMutex.Lock()
defer archiveMutex.Unlock()
if rExisting := getArchiveRequest(request.repo, request.commit, request.archiveType); rExisting != nil {
return rExisting
}
if request.archiveComplete {
return request
}
request.cchan = make(chan struct{})
archiveInProgress = append(archiveInProgress, request)
go func() {
// Wait to start, if we have the Cond for it. This is currently only
// useful for testing, so that the start and release of queued entries
// can be controlled to examine the queue.
if archiveQueueStartCond != nil {
archiveQueueMutex.Lock()
archiveQueueStartCond.Wait()
archiveQueueMutex.Unlock()
}
// Drop the mutex while we process the request. This may take a long
// time, and it's not necessary now that we've added the reequest to
// archiveInProgress.
doArchive(request)
if archiveQueueReleaseCond != nil {
archiveQueueMutex.Lock()
archiveQueueReleaseCond.Wait()
archiveQueueMutex.Unlock()
}
// Purge this request from the list. To do so, we'll just take the
// index at which we ended up at and swap the final element into that
// position, then chop off the now-redundant final element. The slice
// may have change in between these two segments and we may have moved,
// so we search for it here. We could perhaps avoid this search
// entirely if len(archiveInProgress) == 1, but we should verify
// correctness.
archiveMutex.Lock()
defer archiveMutex.Unlock()
idx := -1
for _idx, req := range archiveInProgress {
if req == request {
idx = _idx
break
}
}
if idx == -1 {
log.Error("ArchiveRepository: Failed to find request for removal.")
return
}
archiveInProgress = append(archiveInProgress[:idx], archiveInProgress[idx+1:]...)
}()
return request
}