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ignorefs.go
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ignorefs.go
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// Package ignorefs implements a wrapper that hides ignored files listed in '.kopiaignore' and in policies attached to directories.
package ignorefs
import (
"bufio"
"context"
"strings"
"github.com/pkg/errors"
"github.com/kopia/kopia/fs"
"github.com/kopia/kopia/internal/ignore"
"github.com/kopia/kopia/snapshot/policy"
)
// IgnoreCallback is a function called by ignorefs to report whenever a file or directory is being ignored while listing its parent.
type IgnoreCallback func(path string, metadata fs.Entry)
type ignoreContext struct {
parent *ignoreContext
onIgnore []IgnoreCallback
dotIgnoreFiles []string // which files to look for more ignore rules
matchers []ignore.Matcher // current set of rules to ignore files
maxFileSize int64 // maximum size of file allowed
}
func (c *ignoreContext) shouldIncludeByName(path string, e fs.Entry) bool {
for _, m := range c.matchers {
if m(path, e.IsDir()) {
for _, oi := range c.onIgnore {
oi(path, e)
}
return false
}
}
if c.parent == nil {
return true
}
return c.parent.shouldIncludeByName(path, e)
}
type ignoreDirectory struct {
relativePath string
parentContext *ignoreContext
policyTree *policy.Tree
fs.Directory
}
func (d *ignoreDirectory) Readdir(ctx context.Context) (fs.Entries, error) {
entries, err := d.Directory.Readdir(ctx)
if err != nil {
return nil, err
}
thisContext, err := d.buildContext(ctx, entries)
if err != nil {
return nil, err
}
result := make(fs.Entries, 0, len(entries))
for _, e := range entries {
if !thisContext.shouldIncludeByName(d.relativePath+"/"+e.Name(), e) {
continue
}
if maxSize := thisContext.maxFileSize; maxSize > 0 && e.Size() > maxSize {
continue
}
if dir, ok := e.(fs.Directory); ok {
e = &ignoreDirectory{d.relativePath + "/" + e.Name(), thisContext, d.policyTree.Child(e.Name()), dir}
}
result = append(result, e)
}
return result, nil
}
func (d *ignoreDirectory) buildContext(ctx context.Context, entries fs.Entries) (*ignoreContext, error) {
var effectiveDotIgnoreFiles = d.parentContext.dotIgnoreFiles
pol := d.policyTree.DefinedPolicy()
if pol != nil {
effectiveDotIgnoreFiles = pol.FilesPolicy.DotIgnoreFiles
}
var foundDotIgnoreFiles bool
for _, dotfile := range effectiveDotIgnoreFiles {
if e := entries.FindByName(dotfile); e != nil {
foundDotIgnoreFiles = true
}
}
if !foundDotIgnoreFiles && pol == nil {
// no dotfiles and no policy at this level, reuse parent ignore rules
return d.parentContext, nil
}
newic := &ignoreContext{
parent: d.parentContext,
onIgnore: d.parentContext.onIgnore,
dotIgnoreFiles: effectiveDotIgnoreFiles,
maxFileSize: d.parentContext.maxFileSize,
}
if pol != nil {
if err := newic.overrideFromPolicy(pol.FilesPolicy, d.relativePath); err != nil {
return nil, err
}
}
if err := newic.loadDotIgnoreFiles(ctx, d.relativePath, entries, effectiveDotIgnoreFiles); err != nil {
return nil, err
}
return newic, nil
}
func (c *ignoreContext) overrideFromPolicy(fp policy.FilesPolicy, dirPath string) error {
if fp.NoParentDotIgnoreFiles {
c.dotIgnoreFiles = nil
}
if fp.NoParentIgnoreRules {
c.matchers = nil
}
c.dotIgnoreFiles = combineAndDedupe(c.dotIgnoreFiles, fp.DotIgnoreFiles)
if fp.MaxFileSize != 0 {
c.maxFileSize = fp.MaxFileSize
}
// append policy-level rules
for _, rule := range fp.IgnoreRules {
m, err := ignore.ParseGitIgnore(dirPath, rule)
if err != nil {
return errors.Wrapf(err, "unable to parse ignore entry %v", dirPath)
}
c.matchers = append(c.matchers, m)
}
return nil
}
func (c *ignoreContext) loadDotIgnoreFiles(ctx context.Context, dirPath string, entries fs.Entries, dotIgnoreFiles []string) error {
for _, dotIgnoreFile := range dotIgnoreFiles {
e := entries.FindByName(dotIgnoreFile)
if e == nil {
// no dotfile
continue
}
f, ok := e.(fs.File)
if !ok {
// not a file
continue
}
matchers, err := parseIgnoreFile(ctx, dirPath, f)
if err != nil {
return errors.Wrapf(err, "unable to parse ignore file %v", f.Name())
}
c.matchers = append(c.matchers, matchers...)
}
return nil
}
func combineAndDedupe(slices ...[]string) []string {
var result []string
existing := map[string]bool{}
for _, slice := range slices {
for _, it := range slice {
if existing[it] {
continue
}
existing[it] = true
result = append(result, it)
}
}
return result
}
func parseIgnoreFile(ctx context.Context, baseDir string, file fs.File) ([]ignore.Matcher, error) {
f, err := file.Open(ctx)
if err != nil {
return nil, errors.Wrap(err, "unable to open ignore file")
}
defer f.Close() //nolint:errcheck
var matchers []ignore.Matcher
s := bufio.NewScanner(f)
for s.Scan() {
line := s.Text()
if strings.HasPrefix(line, "#") {
// ignore comments
continue
}
if strings.TrimSpace(line) == "" {
// ignore empty lines
continue
}
m, err := ignore.ParseGitIgnore(baseDir, line)
if err != nil {
return nil, errors.Wrapf(err, "unable to parse ignore entry %v", line)
}
matchers = append(matchers, m)
}
return matchers, nil
}
// Option modifies the behavior of ignorefs
type Option func(parentContext *ignoreContext)
// New returns a fs.Directory that wraps another fs.Directory and hides files specified in the ignore dotfiles.
func New(dir fs.Directory, policyTree *policy.Tree, options ...Option) fs.Directory {
rootContext := &ignoreContext{}
for _, opt := range options {
opt(rootContext)
}
return &ignoreDirectory{".", rootContext, policyTree, dir}
}
var _ fs.Directory = &ignoreDirectory{}
// ReportIgnoredFiles returns an Option causing ignorefs to call the provided function whenever a file or directory is ignored.
func ReportIgnoredFiles(f IgnoreCallback) Option {
return func(ic *ignoreContext) {
if f != nil {
ic.onIgnore = append(ic.onIgnore, f)
}
}
}