git-lfs/lfs/gitscanner_log.go
Lars Schneider aba51b679a move git log invocation to git package using gitNoLFSBuffered
The only side effect of this refactoring should be that the Git LFS
is disabled for the Git subprocess. No other functional changes are
intended.
2017-08-22 19:34:29 +02:00

272 lines
7.7 KiB
Go

package lfs
import (
"bufio"
"bytes"
"fmt"
"io"
"io/ioutil"
"regexp"
"time"
"github.com/git-lfs/git-lfs/filepathfilter"
"github.com/git-lfs/git-lfs/git"
"github.com/git-lfs/git-lfs/subprocess"
"github.com/rubyist/tracerx"
)
// When scanning diffs e.g. parseLogOutputToPointers, which direction of diff to include
// data from, i.e. '+' or '-'. Depending on what you're scanning for either might be useful
type LogDiffDirection byte
const (
LogDiffAdditions = LogDiffDirection('+') // include '+' diffs
LogDiffDeletions = LogDiffDirection('-') // include '-' diffs
)
var (
// Arguments to append to a git log call which will limit the output to
// lfs changes and format the output suitable for parseLogOutput.. method(s)
logLfsSearchArgs = []string{
"-G", "oid sha256:", // only diffs which include an lfs file SHA change
"-p", // include diff so we can read the SHA
"-U12", // Make sure diff context is always big enough to support 10 extension lines to get whole pointer
`--format=lfs-commit-sha: %H %P`, // just a predictable commit header we can detect
}
)
type gitscannerResult struct {
Pointer *WrappedPointer
Err error
}
func scanUnpushed(cb GitScannerFoundPointer, remote string) error {
logArgs := []string{
"--branches", "--tags", // include all locally referenced commits
"--not"} // but exclude everything that comes after
if len(remote) == 0 {
logArgs = append(logArgs, "--remotes")
} else {
logArgs = append(logArgs, fmt.Sprintf("--remotes=%v", remote))
}
// Add standard search args to find lfs references
logArgs = append(logArgs, logLfsSearchArgs...)
cmd, err := git.Log(logArgs...)
if err != nil {
return err
}
parseScannerLogOutput(cb, LogDiffAdditions, cmd)
return nil
}
func parseScannerLogOutput(cb GitScannerFoundPointer, direction LogDiffDirection, cmd *subprocess.BufferedCmd) {
ch := make(chan gitscannerResult, chanBufSize)
go func() {
scanner := newLogScanner(direction, cmd.Stdout)
for scanner.Scan() {
if p := scanner.Pointer(); p != nil {
ch <- gitscannerResult{Pointer: p}
}
}
stderr, _ := ioutil.ReadAll(cmd.Stderr)
err := cmd.Wait()
if err != nil {
ch <- gitscannerResult{Err: fmt.Errorf("Error in git log: %v %v", err, string(stderr))}
}
close(ch)
}()
cmd.Stdin.Close()
for result := range ch {
cb(result.Pointer, result.Err)
}
}
// logPreviousVersions scans history for all previous versions of LFS pointers
// from 'since' up to (but not including) the final state at ref
func logPreviousSHAs(cb GitScannerFoundPointer, ref string, since time.Time) error {
logArgs := []string{
fmt.Sprintf("--since=%v", git.FormatGitDate(since)),
}
// Add standard search args to find lfs references
logArgs = append(logArgs, logLfsSearchArgs...)
// ending at ref
logArgs = append(logArgs, ref)
cmd, err := git.Log(logArgs...)
if err != nil {
return err
}
parseScannerLogOutput(cb, LogDiffDeletions, cmd)
return nil
}
func parseLogOutputToPointers(log io.Reader, dir LogDiffDirection,
includePaths, excludePaths []string, results chan *WrappedPointer) {
scanner := newLogScanner(dir, log)
if len(includePaths)+len(excludePaths) > 0 {
scanner.Filter = filepathfilter.New(includePaths, excludePaths)
}
for scanner.Scan() {
if p := scanner.Pointer(); p != nil {
results <- p
}
}
}
// logScanner parses log output formatted as per logLfsSearchArgs & returns
// pointers.
type logScanner struct {
// Filter will ensure file paths matching the include patterns, or not matchin
// the exclude patterns are skipped.
Filter *filepathfilter.Filter
s *bufio.Scanner
dir LogDiffDirection
pointer *WrappedPointer
pointerData *bytes.Buffer
currentFilename string
currentFileIncluded bool
commitHeaderRegex *regexp.Regexp
fileHeaderRegex *regexp.Regexp
fileMergeHeaderRegex *regexp.Regexp
pointerDataRegex *regexp.Regexp
}
// dir: whether to include results from + or - diffs
// r: a stream of output from git log with at least logLfsSearchArgs specified
func newLogScanner(dir LogDiffDirection, r io.Reader) *logScanner {
return &logScanner{
s: bufio.NewScanner(r),
dir: dir,
pointerData: &bytes.Buffer{},
currentFileIncluded: true,
// no need to compile these regexes on every `git-lfs` call, just ones that
// use the scanner.
commitHeaderRegex: regexp.MustCompile(`^lfs-commit-sha: ([A-Fa-f0-9]{40})(?: ([A-Fa-f0-9]{40}))*`),
fileHeaderRegex: regexp.MustCompile(`diff --git a\/(.+?)\s+b\/(.+)`),
fileMergeHeaderRegex: regexp.MustCompile(`diff --cc (.+)`),
pointerDataRegex: regexp.MustCompile(`^([\+\- ])(version https://git-lfs|oid sha256|size|ext-).*$`),
}
}
func (s *logScanner) Pointer() *WrappedPointer {
return s.pointer
}
func (s *logScanner) Err() error {
return s.s.Err()
}
func (s *logScanner) Scan() bool {
s.pointer = nil
p, canScan := s.scan()
s.pointer = p
return canScan
}
// Utility func used at several points below (keep in narrow scope)
func (s *logScanner) finishLastPointer() *WrappedPointer {
if s.pointerData.Len() == 0 || !s.currentFileIncluded {
return nil
}
p, err := DecodePointer(s.pointerData)
s.pointerData.Reset()
if err == nil {
return &WrappedPointer{Name: s.currentFilename, Pointer: p}
} else {
tracerx.Printf("Unable to parse pointer from log: %v", err)
return nil
}
}
// For each commit we'll get something like this:
/*
lfs-commit-sha: 60fde3d23553e10a55e2a32ed18c20f65edd91e7 e2eaf1c10b57da7b98eb5d722ec5912ddeb53ea1
diff --git a/1D_Noise.png b/1D_Noise.png
new file mode 100644
index 0000000..2622b4a
--- /dev/null
+++ b/1D_Noise.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:f5d84da40ab1f6aa28df2b2bf1ade2cdcd4397133f903c12b4106641b10e1ed6
+size 1289
*/
// There can be multiple diffs per commit (multiple binaries)
// Also when a binary is changed the diff will include a '-' line for the old SHA
func (s *logScanner) scan() (*WrappedPointer, bool) {
for s.s.Scan() {
line := s.s.Text()
if match := s.commitHeaderRegex.FindStringSubmatch(line); match != nil {
// Currently we're not pulling out commit groupings, but could if we wanted
// This just acts as a delimiter for finishing a multiline pointer
if p := s.finishLastPointer(); p != nil {
return p, true
}
} else if match := s.fileHeaderRegex.FindStringSubmatch(line); match != nil {
// Finding a regular file header
p := s.finishLastPointer()
// Pertinent file name depends on whether we're listening to additions or removals
if s.dir == LogDiffAdditions {
s.setFilename(match[2])
} else {
s.setFilename(match[1])
}
if p != nil {
return p, true
}
} else if match := s.fileMergeHeaderRegex.FindStringSubmatch(line); match != nil {
// Git merge file header is a little different, only one file
p := s.finishLastPointer()
s.setFilename(match[1])
if p != nil {
return p, true
}
} else if s.currentFileIncluded {
if match := s.pointerDataRegex.FindStringSubmatch(line); match != nil {
// An LFS pointer data line
// Include only the entirety of one side of the diff
// -U3 will ensure we always get all of it, even if only
// the SHA changed (version & size the same)
changeType := match[1][0]
// Always include unchanged context lines (normally just the version line)
if LogDiffDirection(changeType) == s.dir || changeType == ' ' {
// Must skip diff +/- marker
s.pointerData.WriteString(line[1:])
s.pointerData.WriteString("\n") // newline was stripped off by scanner
}
}
}
}
if p := s.finishLastPointer(); p != nil {
return p, true
}
return nil, false
}
func (s *logScanner) setFilename(name string) {
s.currentFilename = name
s.currentFileIncluded = s.Filter.Allows(name)
}