mirror of
https://github.com/gohugoio/hugo.git
synced 2024-12-27 19:41:49 +00:00
376 lines
8.1 KiB
Go
376 lines
8.1 KiB
Go
// Copyright 2018 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package filecache
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import (
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"bytes"
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"errors"
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"io"
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"io/ioutil"
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"os"
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"path/filepath"
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"strings"
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"sync"
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"time"
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"github.com/gohugoio/hugo/common/hugio"
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"github.com/gohugoio/hugo/helpers"
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"github.com/BurntSushi/locker"
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"github.com/spf13/afero"
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)
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// ErrFatal can be used to signal an unrecoverable error.
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var ErrFatal = errors.New("fatal filecache error")
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const (
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filecacheRootDirname = "filecache"
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)
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// Cache caches a set of files in a directory. This is usually a file on
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// disk, but since this is backed by an Afero file system, it can be anything.
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type Cache struct {
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Fs afero.Fs
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// Max age for items in this cache. Negative duration means forever,
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// 0 is effectively turning this cache off.
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maxAge time.Duration
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// When set, we just remove this entire root directory on expiration.
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pruneAllRootDir string
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nlocker *lockTracker
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}
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type lockTracker struct {
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seenMu sync.RWMutex
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seen map[string]struct{}
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*locker.Locker
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}
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// Lock tracks the ids in use. We use this information to do garbage collection
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// after a Hugo build.
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func (l *lockTracker) Lock(id string) {
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l.seenMu.RLock()
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if _, seen := l.seen[id]; !seen {
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l.seenMu.RUnlock()
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l.seenMu.Lock()
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l.seen[id] = struct{}{}
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l.seenMu.Unlock()
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} else {
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l.seenMu.RUnlock()
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}
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l.Locker.Lock(id)
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}
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// ItemInfo contains info about a cached file.
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type ItemInfo struct {
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// This is the file's name relative to the cache's filesystem.
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Name string
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}
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// NewCache creates a new file cache with the given filesystem and max age.
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func NewCache(fs afero.Fs, maxAge time.Duration, pruneAllRootDir string) *Cache {
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return &Cache{
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Fs: fs,
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nlocker: &lockTracker{Locker: locker.NewLocker(), seen: make(map[string]struct{})},
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maxAge: maxAge,
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pruneAllRootDir: pruneAllRootDir,
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}
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}
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// lockedFile is a file with a lock that is released on Close.
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type lockedFile struct {
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afero.File
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unlock func()
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}
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func (l *lockedFile) Close() error {
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defer l.unlock()
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return l.File.Close()
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}
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// WriteCloser returns a transactional writer into the cache.
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// It's important that it's closed when done.
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func (c *Cache) WriteCloser(id string) (ItemInfo, io.WriteCloser, error) {
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id = cleanID(id)
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c.nlocker.Lock(id)
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info := ItemInfo{Name: id}
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f, err := helpers.OpenFileForWriting(c.Fs, id)
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if err != nil {
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c.nlocker.Unlock(id)
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return info, nil, err
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}
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return info, &lockedFile{
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File: f,
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unlock: func() { c.nlocker.Unlock(id) },
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}, nil
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}
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// ReadOrCreate tries to lookup the file in cache.
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// If found, it is passed to read and then closed.
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// If not found a new file is created and passed to create, which should close
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// it when done.
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func (c *Cache) ReadOrCreate(id string,
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read func(info ItemInfo, r io.ReadSeeker) error,
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create func(info ItemInfo, w io.WriteCloser) error) (info ItemInfo, err error) {
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id = cleanID(id)
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c.nlocker.Lock(id)
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defer c.nlocker.Unlock(id)
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info = ItemInfo{Name: id}
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if r := c.getOrRemove(id); r != nil {
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err = read(info, r)
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defer r.Close()
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if err == nil || err == ErrFatal {
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// See https://github.com/gohugoio/hugo/issues/6401
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// To recover from file corruption we handle read errors
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// as the cache item was not found.
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// Any file permission issue will also fail in the next step.
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return
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}
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}
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f, err := helpers.OpenFileForWriting(c.Fs, id)
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if err != nil {
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return
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}
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err = create(info, f)
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return
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}
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// GetOrCreate tries to get the file with the given id from cache. If not found or expired, create will
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// be invoked and the result cached.
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// This method is protected by a named lock using the given id as identifier.
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func (c *Cache) GetOrCreate(id string, create func() (io.ReadCloser, error)) (ItemInfo, io.ReadCloser, error) {
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id = cleanID(id)
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c.nlocker.Lock(id)
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defer c.nlocker.Unlock(id)
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info := ItemInfo{Name: id}
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if r := c.getOrRemove(id); r != nil {
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return info, r, nil
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}
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r, err := create()
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if err != nil {
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return info, nil, err
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}
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if c.maxAge == 0 {
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// No caching.
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return info, hugio.ToReadCloser(r), nil
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}
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var buff bytes.Buffer
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return info,
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hugio.ToReadCloser(&buff),
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afero.WriteReader(c.Fs, id, io.TeeReader(r, &buff))
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}
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// GetOrCreateBytes is the same as GetOrCreate, but produces a byte slice.
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func (c *Cache) GetOrCreateBytes(id string, create func() ([]byte, error)) (ItemInfo, []byte, error) {
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id = cleanID(id)
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c.nlocker.Lock(id)
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defer c.nlocker.Unlock(id)
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info := ItemInfo{Name: id}
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if r := c.getOrRemove(id); r != nil {
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defer r.Close()
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b, err := ioutil.ReadAll(r)
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return info, b, err
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}
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b, err := create()
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if err != nil {
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return info, nil, err
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}
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if c.maxAge == 0 {
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return info, b, nil
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}
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if err := afero.WriteReader(c.Fs, id, bytes.NewReader(b)); err != nil {
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return info, nil, err
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}
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return info, b, nil
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}
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// GetBytes gets the file content with the given id from the cahce, nil if none found.
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func (c *Cache) GetBytes(id string) (ItemInfo, []byte, error) {
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id = cleanID(id)
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c.nlocker.Lock(id)
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defer c.nlocker.Unlock(id)
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info := ItemInfo{Name: id}
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if r := c.getOrRemove(id); r != nil {
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defer r.Close()
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b, err := ioutil.ReadAll(r)
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return info, b, err
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}
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return info, nil, nil
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}
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// Get gets the file with the given id from the cahce, nil if none found.
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func (c *Cache) Get(id string) (ItemInfo, io.ReadCloser, error) {
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id = cleanID(id)
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c.nlocker.Lock(id)
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defer c.nlocker.Unlock(id)
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info := ItemInfo{Name: id}
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r := c.getOrRemove(id)
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return info, r, nil
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}
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// getOrRemove gets the file with the given id. If it's expired, it will
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// be removed.
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func (c *Cache) getOrRemove(id string) hugio.ReadSeekCloser {
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if c.maxAge == 0 {
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// No caching.
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return nil
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}
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if c.maxAge > 0 {
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fi, err := c.Fs.Stat(id)
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if err != nil {
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return nil
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}
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if c.isExpired(fi.ModTime()) {
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c.Fs.Remove(id)
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return nil
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}
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}
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f, err := c.Fs.Open(id)
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if err != nil {
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return nil
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}
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return f
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}
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func (c *Cache) isExpired(modTime time.Time) bool {
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if c.maxAge < 0 {
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return false
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}
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return c.maxAge == 0 || time.Since(modTime) > c.maxAge
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}
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// For testing
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func (c *Cache) getString(id string) string {
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id = cleanID(id)
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c.nlocker.Lock(id)
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defer c.nlocker.Unlock(id)
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f, err := c.Fs.Open(id)
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if err != nil {
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return ""
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}
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defer f.Close()
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b, _ := ioutil.ReadAll(f)
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return string(b)
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}
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// Caches is a named set of caches.
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type Caches map[string]*Cache
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// Get gets a named cache, nil if none found.
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func (f Caches) Get(name string) *Cache {
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return f[strings.ToLower(name)]
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}
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// NewCaches creates a new set of file caches from the given
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// configuration.
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func NewCaches(p *helpers.PathSpec) (Caches, error) {
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var dcfg Configs
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if c, ok := p.Cfg.Get("filecacheConfigs").(Configs); ok {
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dcfg = c
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} else {
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var err error
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dcfg, err = DecodeConfig(p.Fs.Source, p.Cfg)
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if err != nil {
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return nil, err
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}
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}
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fs := p.Fs.Source
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m := make(Caches)
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for k, v := range dcfg {
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var cfs afero.Fs
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if v.isResourceDir {
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cfs = p.BaseFs.ResourcesCache
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} else {
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cfs = fs
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}
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if cfs == nil {
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// TODO(bep) we still have some places that do not initialize the
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// full dependencies of a site, e.g. the import Jekyll command.
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// That command does not need these caches, so let us just continue
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// for now.
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continue
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}
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baseDir := v.Dir
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if err := cfs.MkdirAll(baseDir, 0777); err != nil && !os.IsExist(err) {
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return nil, err
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}
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bfs := afero.NewBasePathFs(cfs, baseDir)
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var pruneAllRootDir string
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if k == cacheKeyModules {
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pruneAllRootDir = "pkg"
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}
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m[k] = NewCache(bfs, v.MaxAge, pruneAllRootDir)
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}
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return m, nil
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}
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func cleanID(name string) string {
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return strings.TrimPrefix(filepath.Clean(name), helpers.FilePathSeparator)
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}
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