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gitea/vendor/code.gitea.io/git/commit_info.go
2017-12-22 09:00:30 +02:00

319 lines
9 KiB
Go

// Copyright 2017 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 git
import (
"bufio"
"context"
"fmt"
"os/exec"
"path"
"runtime"
"strconv"
"strings"
"sync"
"time"
)
const (
// parameters for searching for commit infos. If the untargeted search has
// not found any entries in the past 5 commits, and 12 or fewer entries
// remain, then we'll just let the targeted-searching threads finish off,
// and stop the untargeted search to not interfere.
deferToTargetedSearchColdStreak = 5
deferToTargetedSearchNumRemainingEntries = 12
)
// getCommitsInfoState shared state while getting commit info for entries
type getCommitsInfoState struct {
lock sync.Mutex
/* read-only fields, can be read without the mutex */
// entries and entryPaths are read-only after initialization, so they can
// safely be read without the mutex
entries []*TreeEntry
// set of filepaths to get info for
entryPaths map[string]struct{}
treePath string
headCommit *Commit
/* mutable fields, must hold mutex to read or write */
// map from filepath to commit
commits map[string]*Commit
// set of filepaths that have been or are being searched for in a target search
targetedPaths map[string]struct{}
}
func (state *getCommitsInfoState) numRemainingEntries() int {
state.lock.Lock()
defer state.lock.Unlock()
return len(state.entries) - len(state.commits)
}
// getTargetEntryPath Returns the next path for a targeted-searching thread to
// search for, or returns the empty string if nothing left to search for
func (state *getCommitsInfoState) getTargetedEntryPath() string {
var targetedEntryPath string
state.lock.Lock()
defer state.lock.Unlock()
for _, entry := range state.entries {
entryPath := path.Join(state.treePath, entry.Name())
if _, ok := state.commits[entryPath]; ok {
continue
} else if _, ok = state.targetedPaths[entryPath]; ok {
continue
}
targetedEntryPath = entryPath
state.targetedPaths[entryPath] = struct{}{}
break
}
return targetedEntryPath
}
// repeatedly perform targeted searches for unpopulated entries
func targetedSearch(state *getCommitsInfoState, done chan error) {
for {
entryPath := state.getTargetedEntryPath()
if len(entryPath) == 0 {
done <- nil
return
}
command := NewCommand("rev-list", "-1", state.headCommit.ID.String(), "--", entryPath)
output, err := command.RunInDir(state.headCommit.repo.Path)
if err != nil {
done <- err
return
}
id, err := NewIDFromString(strings.TrimSpace(output))
if err != nil {
done <- err
return
}
commit, err := state.headCommit.repo.getCommit(id)
if err != nil {
done <- err
return
}
state.update(entryPath, commit)
}
}
func initGetCommitInfoState(entries Entries, headCommit *Commit, treePath string) *getCommitsInfoState {
entryPaths := make(map[string]struct{}, len(entries))
for _, entry := range entries {
entryPaths[path.Join(treePath, entry.Name())] = struct{}{}
}
if treePath = path.Clean(treePath); treePath == "." {
treePath = ""
}
return &getCommitsInfoState{
entries: entries,
entryPaths: entryPaths,
commits: make(map[string]*Commit, len(entries)),
targetedPaths: make(map[string]struct{}, len(entries)),
treePath: treePath,
headCommit: headCommit,
}
}
// GetCommitsInfo gets information of all commits that are corresponding to these entries
func (tes Entries) GetCommitsInfo(commit *Commit, treePath string) ([][]interface{}, error) {
state := initGetCommitInfoState(tes, commit, treePath)
if err := getCommitsInfo(state); err != nil {
return nil, err
}
if len(state.commits) < len(state.entryPaths) {
return nil, fmt.Errorf("could not find commits for all entries")
}
commitsInfo := make([][]interface{}, len(tes))
for i, entry := range tes {
commit, ok := state.commits[path.Join(treePath, entry.Name())]
if !ok {
return nil, fmt.Errorf("could not find commit for %s", entry.Name())
}
switch entry.Type {
case ObjectCommit:
subModuleURL := ""
if subModule, err := state.headCommit.GetSubModule(entry.Name()); err != nil {
return nil, err
} else if subModule != nil {
subModuleURL = subModule.URL
}
subModuleFile := NewSubModuleFile(commit, subModuleURL, entry.ID.String())
commitsInfo[i] = []interface{}{entry, subModuleFile}
default:
commitsInfo[i] = []interface{}{entry, commit}
}
}
return commitsInfo, nil
}
func (state *getCommitsInfoState) cleanEntryPath(rawEntryPath string) (string, error) {
if rawEntryPath[0] == '"' {
var err error
rawEntryPath, err = strconv.Unquote(rawEntryPath)
if err != nil {
return rawEntryPath, err
}
}
var entryNameStartIndex int
if len(state.treePath) > 0 {
entryNameStartIndex = len(state.treePath) + 1
}
if index := strings.IndexByte(rawEntryPath[entryNameStartIndex:], '/'); index >= 0 {
return rawEntryPath[:entryNameStartIndex+index], nil
}
return rawEntryPath, nil
}
// update report that the given path was last modified by the given commit.
// Returns whether state.commits was updated
func (state *getCommitsInfoState) update(entryPath string, commit *Commit) bool {
if _, ok := state.entryPaths[entryPath]; !ok {
return false
}
var updated bool
state.lock.Lock()
defer state.lock.Unlock()
if _, ok := state.commits[entryPath]; !ok {
state.commits[entryPath] = commit
updated = true
}
return updated
}
const getCommitsInfoPretty = "--pretty=format:%H %ct %s"
func getCommitsInfo(state *getCommitsInfoState) error {
ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
defer cancel()
args := []string{"log", state.headCommit.ID.String(), getCommitsInfoPretty, "--name-status", "-c"}
if len(state.treePath) > 0 {
args = append(args, "--", state.treePath)
}
cmd := exec.CommandContext(ctx, "git", args...)
cmd.Dir = state.headCommit.repo.Path
readCloser, err := cmd.StdoutPipe()
if err != nil {
return err
}
if err := cmd.Start(); err != nil {
return err
}
// it's okay to ignore the error returned by cmd.Wait(); we expect the
// subprocess to sometimes have a non-zero exit status, since we may
// prematurely close stdout, resulting in a broken pipe.
defer cmd.Wait()
numThreads := runtime.NumCPU()
done := make(chan error, numThreads)
for i := 0; i < numThreads; i++ {
go targetedSearch(state, done)
}
scanner := bufio.NewScanner(readCloser)
err = state.processGitLogOutput(scanner)
// it is important that we close stdout here; if we do not close
// stdout, the subprocess will keep running, and the deffered call
// cmd.Wait() may block for a long time.
if closeErr := readCloser.Close(); closeErr != nil && err == nil {
err = closeErr
}
for i := 0; i < numThreads; i++ {
doneErr := <-done
if doneErr != nil && err == nil {
err = doneErr
}
}
return err
}
func (state *getCommitsInfoState) processGitLogOutput(scanner *bufio.Scanner) error {
// keep a local cache of seen paths to avoid acquiring a lock for paths
// we've already seen
seenPaths := make(map[string]struct{}, len(state.entryPaths))
// number of consecutive commits without any finds
coldStreak := 0
var commit *Commit
var err error
for scanner.Scan() {
line := scanner.Text()
if len(line) == 0 { // in-between commits
numRemainingEntries := state.numRemainingEntries()
if numRemainingEntries == 0 {
break
}
if coldStreak >= deferToTargetedSearchColdStreak &&
numRemainingEntries <= deferToTargetedSearchNumRemainingEntries {
// stop this untargeted search, and let the targeted-search threads
// finish the work
break
}
continue
}
if line[0] >= 'A' && line[0] <= 'X' { // a file was changed by the current commit
// look for the last tab, since for copies (C) and renames (R) two
// filenames are printed: src, then dest
tabIndex := strings.LastIndexByte(line, '\t')
if tabIndex < 1 {
return fmt.Errorf("misformatted line: %s", line)
}
entryPath, err := state.cleanEntryPath(line[tabIndex+1:])
if err != nil {
return err
}
if _, ok := seenPaths[entryPath]; !ok {
if state.update(entryPath, commit) {
coldStreak = 0
}
seenPaths[entryPath] = struct{}{}
}
continue
}
// a new commit
commit, err = parseCommitInfo(line)
if err != nil {
return err
}
coldStreak++
}
return scanner.Err()
}
// parseCommitInfo parse a commit from a line of `git log` output. Expects the
// line to be formatted according to getCommitsInfoPretty.
func parseCommitInfo(line string) (*Commit, error) {
if len(line) < 43 {
return nil, fmt.Errorf("invalid git output: %s", line)
}
ref, err := NewIDFromString(line[:40])
if err != nil {
return nil, err
}
spaceIndex := strings.IndexByte(line[41:], ' ')
if spaceIndex < 0 {
return nil, fmt.Errorf("invalid git output: %s", line)
}
unixSeconds, err := strconv.Atoi(line[41 : 41+spaceIndex])
if err != nil {
return nil, err
}
message := line[spaceIndex+42:]
return &Commit{
ID: ref,
CommitMessage: message,
Committer: &Signature{
When: time.Unix(int64(unixSeconds), 0),
},
}, nil
}