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forgejo/modules/assetfs/layered.go

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// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package assetfs
import (
"context"
"fmt"
"io"
"io/fs"
"net/http"
"os"
"path/filepath"
"sort"
"time"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/process"
"code.gitea.io/gitea/modules/util"
"github.com/fsnotify/fsnotify"
)
// Layer represents a layer in a layered asset file-system. It has a name and works like http.FileSystem
type Layer struct {
name string
fs http.FileSystem
localPath string
}
func (l *Layer) Name() string {
return l.name
}
// Open opens the named file. The caller is responsible for closing the file.
func (l *Layer) Open(name string) (http.File, error) {
return l.fs.Open(name)
}
// Local returns a new Layer with the given name, it serves files from the given local path.
func Local(name, base string, sub ...string) *Layer {
// TODO: the old behavior (StaticRootPath might not be absolute), not ideal, just keep the same as before
// Ideally, the caller should guarantee the base is absolute, guessing a relative path based on the current working directory is unreliable.
base, err := filepath.Abs(base)
if err != nil {
// This should never happen in a real system. If it happens, the user must have already been in trouble: the system is not able to resolve its own paths.
panic(fmt.Sprintf("Unable to get absolute path for %q: %v", base, err))
}
root := util.FilePathJoinAbs(base, sub...)
return &Layer{name: name, fs: http.Dir(root), localPath: root}
}
// Bindata returns a new Layer with the given name, it serves files from the given bindata asset.
func Bindata(name string, fs http.FileSystem) *Layer {
return &Layer{name: name, fs: fs}
}
// LayeredFS is a layered asset file-system. It works like http.FileSystem, but it can have multiple layers.
// The first layer is the top layer, and it will be used first.
// If the file is not found in the top layer, it will be searched in the next layer.
type LayeredFS struct {
layers []*Layer
}
// Layered returns a new LayeredFS with the given layers. The first layer is the top layer.
func Layered(layers ...*Layer) *LayeredFS {
return &LayeredFS{layers: layers}
}
// Open opens the named file. The caller is responsible for closing the file.
func (l *LayeredFS) Open(name string) (http.File, error) {
for _, layer := range l.layers {
f, err := layer.Open(name)
if err == nil || !os.IsNotExist(err) {
return f, err
}
}
return nil, fs.ErrNotExist
}
// ReadFile reads the named file.
func (l *LayeredFS) ReadFile(elems ...string) ([]byte, error) {
bs, _, err := l.ReadLayeredFile(elems...)
return bs, err
}
// ReadLayeredFile reads the named file, and returns the layer name.
func (l *LayeredFS) ReadLayeredFile(elems ...string) ([]byte, string, error) {
name := util.PathJoinRel(elems...)
for _, layer := range l.layers {
f, err := layer.Open(name)
if os.IsNotExist(err) {
continue
} else if err != nil {
return nil, layer.name, err
}
bs, err := io.ReadAll(f)
_ = f.Close()
return bs, layer.name, err
}
return nil, "", fs.ErrNotExist
}
func shouldInclude(info fs.FileInfo, fileMode ...bool) bool {
if util.CommonSkip(info.Name()) {
return false
}
if len(fileMode) == 0 {
return true
} else if len(fileMode) == 1 {
return fileMode[0] == !info.Mode().IsDir()
}
panic("too many arguments for fileMode in shouldInclude")
}
func readDir(layer *Layer, name string) ([]fs.FileInfo, error) {
f, err := layer.Open(name)
if os.IsNotExist(err) {
return nil, nil
} else if err != nil {
return nil, err
}
defer f.Close()
return f.Readdir(-1)
}
// ListFiles lists files/directories in the given directory. The fileMode controls the returned files.
// * omitted: all files and directories will be returned.
// * true: only files will be returned.
// * false: only directories will be returned.
// The returned files are sorted by name.
func (l *LayeredFS) ListFiles(name string, fileMode ...bool) ([]string, error) {
fileMap := map[string]bool{}
for _, layer := range l.layers {
infos, err := readDir(layer, name)
if err != nil {
return nil, err
}
for _, info := range infos {
if shouldInclude(info, fileMode...) {
fileMap[info.Name()] = true
}
}
}
files := make([]string, 0, len(fileMap))
for file := range fileMap {
files = append(files, file)
}
sort.Strings(files)
return files, nil
}
// ListAllFiles returns files/directories in the given directory, including subdirectories, recursively.
// The fileMode controls the returned files:
// * omitted: all files and directories will be returned.
// * true: only files will be returned.
// * false: only directories will be returned.
// The returned files are sorted by name.
func (l *LayeredFS) ListAllFiles(name string, fileMode ...bool) ([]string, error) {
return listAllFiles(l.layers, name, fileMode...)
}
func listAllFiles(layers []*Layer, name string, fileMode ...bool) ([]string, error) {
fileMap := map[string]bool{}
var list func(dir string) error
list = func(dir string) error {
for _, layer := range layers {
infos, err := readDir(layer, dir)
if err != nil {
return err
}
for _, info := range infos {
path := util.PathJoinRelX(dir, info.Name())
if shouldInclude(info, fileMode...) {
fileMap[path] = true
}
if info.IsDir() {
if err = list(path); err != nil {
return err
}
}
}
}
return nil
}
if err := list(name); err != nil {
return nil, err
}
var files []string
for file := range fileMap {
files = append(files, file)
}
sort.Strings(files)
return files, nil
}
// WatchLocalChanges watches local changes in the file-system. It's used to help to reload assets when the local file-system changes.
func (l *LayeredFS) WatchLocalChanges(ctx context.Context, callback func()) {
ctx, _, finished := process.GetManager().AddTypedContext(ctx, "Asset Local FileSystem Watcher", process.SystemProcessType, true)
defer finished()
watcher, err := fsnotify.NewWatcher()
if err != nil {
log.Error("Unable to create watcher for asset local file-system: %v", err)
return
}
defer watcher.Close()
for _, layer := range l.layers {
if layer.localPath == "" {
continue
}
layerDirs, err := listAllFiles([]*Layer{layer}, ".", false)
if err != nil {
log.Error("Unable to list directories for asset local file-system %q: %v", layer.localPath, err)
continue
}
layerDirs = append(layerDirs, ".")
for _, dir := range layerDirs {
if err = watcher.Add(util.FilePathJoinAbs(layer.localPath, dir)); err != nil {
log.Error("Unable to watch directory %s: %v", dir, err)
}
}
}
debounce := util.Debounce(100 * time.Millisecond)
for {
select {
case <-ctx.Done():
return
case event, ok := <-watcher.Events:
if !ok {
return
}
log.Trace("Watched asset local file-system had event: %v", event)
debounce(callback)
case err, ok := <-watcher.Errors:
if !ok {
return
}
log.Error("Watched asset local file-system had error: %v", err)
}
}
}
// GetFileLayerName returns the name of the first-seen layer that contains the given file.
func (l *LayeredFS) GetFileLayerName(elems ...string) string {
name := util.PathJoinRel(elems...)
for _, layer := range l.layers {
f, err := layer.Open(name)
if os.IsNotExist(err) {
continue
} else if err != nil {
return ""
}
_ = f.Close()
return layer.name
}
return ""
}