1 files changed, 442 insertions, 0 deletions
diff --git a/cache/filecache/filecache.go b/cache/filecache/filecache.go
new file mode 100644
index 000000000..45359f574
--- /dev/null
+++ b/cache/filecache/filecache.go
@@ -0,0 +1,442 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package filecache
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+	"path"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/gohugoio/hugo/common/hugio"
+
+	"github.com/gohugoio/hugo/helpers"
+
+	"github.com/gohugoio/hugo/hugolib/paths"
+
+	"github.com/pkg/errors"
+
+	"github.com/BurntSushi/locker"
+	"github.com/bep/mapstructure"
+	"github.com/spf13/afero"
+)
+
+const (
+	cachesConfigKey = "caches"
+
+	resourcesGenDir = ":resourceDir/_gen"
+)
+
+var defaultCacheConfig = cacheConfig{
+	MaxAge: -1, // Never expire
+	Dir:    ":cacheDir",
+}
+
+const (
+	cacheKeyGetJSON = "getjson"
+	cacheKeyGetCSV  = "getcsv"
+	cacheKeyImages  = "images"
+	cacheKeyAssets  = "assets"
+)
+
+var defaultCacheConfigs = map[string]cacheConfig{
+	cacheKeyGetJSON: defaultCacheConfig,
+	cacheKeyGetCSV:  defaultCacheConfig,
+	cacheKeyImages: cacheConfig{
+		MaxAge: -1,
+		Dir:    resourcesGenDir,
+	},
+	cacheKeyAssets: cacheConfig{
+		MaxAge: -1,
+		Dir:    resourcesGenDir,
+	},
+}
+
+type cachesConfig map[string]cacheConfig
+
+type cacheConfig struct {
+	// Maxe age of ache entries in this cache. Any items older than this will
+	// be removed and not returned from the cache.
+	// -1 means forever, 0 means cache is disabled.
+	MaxAge int
+
+	// The directory where files are stored.
+	Dir string
+}
+
+// Cache caches a set of files in a directory. This is usually a file on
+// disk, but since this is backed by an Afero file system, it can be anything.
+type Cache struct {
+	Fs afero.Fs
+
+	// Max age in seconds.
+	maxAge int
+
+	nlocker *locker.Locker
+}
+
+// ItemInfo contains info about a cached file.
+type ItemInfo struct {
+	// This is the file's name relative to the cache's filesystem.
+	Name string
+}
+
+// NewCache creates a new file cache with the given filesystem and max age.
+func NewCache(fs afero.Fs, maxAge int) *Cache {
+	return &Cache{
+		Fs:      fs,
+		nlocker: locker.NewLocker(),
+		maxAge:  maxAge,
+	}
+}
+
+// lockedFile is a file with a lock that is released on Close.
+type lockedFile struct {
+	afero.File
+	unlock func()
+}
+
+func (l *lockedFile) Close() error {
+	defer l.unlock()
+	return l.File.Close()
+}
+
+// GetWriteCloser returns a transactional writer into the cache.
+// It's important that it's closed when done.
+func (c *Cache) WriteCloser(id string) (ItemInfo, io.WriteCloser, error) {
+	id = cleanID(id)
+	c.nlocker.Lock(id)
+
+	info := ItemInfo{Name: id}
+
+	f, err := helpers.OpenFileForWriting(c.Fs, id)
+	if err != nil {
+		c.nlocker.Unlock(id)
+		return info, nil, err
+	}
+
+	return info, &lockedFile{
+		File:   f,
+		unlock: func() { c.nlocker.Unlock(id) },
+	}, nil
+}
+
+// ReadOrCreate tries to lookup the file in cache.
+// If found, it is passed to read and then closed.
+// If not found a new file is created and passed to create, which should close
+// it when done.
+func (c *Cache) ReadOrCreate(id string,
+	read func(info ItemInfo, r io.Reader) error,
+	create func(info ItemInfo, w io.WriteCloser) error) (info ItemInfo, err error) {
+	id = cleanID(id)
+
+	c.nlocker.Lock(id)
+	defer c.nlocker.Unlock(id)
+
+	info = ItemInfo{Name: id}
+
+	if r := c.getOrRemove(id); r != nil {
+		err = read(info, r)
+		defer r.Close()
+		return
+	}
+
+	f, err := helpers.OpenFileForWriting(c.Fs, id)
+	if err != nil {
+		return
+	}
+
+	err = create(info, f)
+
+	return
+
+}
+
+// GetOrCreate tries to get the file with the given id from cache. If not found or expired, create will
+// be invoked and the result cached.
+// This method is protected by a named lock using the given id as identifier.
+func (c *Cache) GetOrCreate(id string, create func() (io.ReadCloser, error)) (ItemInfo, io.ReadCloser, error) {
+	id = cleanID(id)
+
+	c.nlocker.Lock(id)
+	defer c.nlocker.Unlock(id)
+
+	info := ItemInfo{Name: id}
+
+	if r := c.getOrRemove(id); r != nil {
+		return info, r, nil
+	}
+
+	r, err := create()
+	if err != nil {
+		return info, nil, err
+	}
+
+	if c.maxAge == 0 {
+		// No caching.
+		return info, hugio.ToReadCloser(r), nil
+	}
+
+	var buff bytes.Buffer
+	return info,
+		hugio.ToReadCloser(&buff),
+		afero.WriteReader(c.Fs, id, io.TeeReader(r, &buff))
+}
+
+// GetOrCreateBytes is the same as GetOrCreate, but produces a byte slice.
+func (c *Cache) GetOrCreateBytes(id string, create func() ([]byte, error)) (ItemInfo, []byte, error) {
+	id = cleanID(id)
+
+	c.nlocker.Lock(id)
+	defer c.nlocker.Unlock(id)
+
+	info := ItemInfo{Name: id}
+
+	if r := c.getOrRemove(id); r != nil {
+		defer r.Close()
+		b, err := ioutil.ReadAll(r)
+		return info, b, err
+	}
+
+	b, err := create()
+	if err != nil {
+		return info, nil, err
+	}
+
+	if c.maxAge == 0 {
+		return info, b, nil
+	}
+
+	if err := afero.WriteReader(c.Fs, id, bytes.NewReader(b)); err != nil {
+		return info, nil, err
+	}
+	return info, b, nil
+
+}
+
+// GetBytes gets the file content with the given id from the cahce, nil if none found.
+func (c *Cache) GetBytes(id string) (ItemInfo, []byte, error) {
+	id = cleanID(id)
+
+	c.nlocker.Lock(id)
+	defer c.nlocker.Unlock(id)
+
+	info := ItemInfo{Name: id}
+
+	if r := c.getOrRemove(id); r != nil {
+		defer r.Close()
+		b, err := ioutil.ReadAll(r)
+		return info, b, err
+	}
+
+	return info, nil, nil
+}
+
+// Get gets the file with the given id from the cahce, nil if none found.
+func (c *Cache) Get(id string) (ItemInfo, io.ReadCloser, error) {
+	id = cleanID(id)
+
+	c.nlocker.Lock(id)
+	defer c.nlocker.Unlock(id)
+
+	info := ItemInfo{Name: id}
+
+	r := c.getOrRemove(id)
+
+	return info, r, nil
+}
+
+// get gets the file with the given id. If it's expired, it will
+// be removed.
+func (c *Cache) getOrRemove(id string) hugio.ReadSeekCloser {
+	if c.maxAge == 0 {
+		// No caching.
+		return nil
+	}
+
+	if c.maxAge > 0 {
+		fi, err := c.Fs.Stat(id)
+		if err != nil {
+			return nil
+		}
+
+		expiry := time.Now().Add(-time.Duration(c.maxAge) * time.Second)
+		expired := fi.ModTime().Before(expiry)
+		if expired {
+			c.Fs.Remove(id)
+			return nil
+		}
+	}
+
+	f, err := c.Fs.Open(id)
+
+	if err != nil {
+		return nil
+	}
+
+	return f
+}
+
+// For testing
+func (c *Cache) getString(id string) string {
+	id = cleanID(id)
+
+	c.nlocker.Lock(id)
+	defer c.nlocker.Unlock(id)
+
+	if r := c.getOrRemove(id); r != nil {
+		defer r.Close()
+		b, _ := ioutil.ReadAll(r)
+		return string(b)
+	}
+
+	return ""
+
+}
+
+// Caches is a named set of caches.
+type Caches map[string]*Cache
+
+// Get gets a named cache, nil if none found.
+func (f Caches) Get(name string) *Cache {
+	return f[strings.ToLower(name)]
+}
+
+// GetJSOnCache gets the file cache for getJSON.
+func (f Caches) GetJSONCache() *Cache {
+	return f[cacheKeyGetJSON]
+}
+
+// GetCSVCache gets the file cache for getCSV.
+func (f Caches) GetCSVCache() *Cache {
+	return f[cacheKeyGetCSV]
+}
+
+// ImageCache gets the file cache for processed images.
+func (f Caches) ImageCache() *Cache {
+	return f[cacheKeyImages]
+}
+
+// AssetsCache gets the file cache for assets (processed resources, SCSS etc.).
+func (f Caches) AssetsCache() *Cache {
+	return f[cacheKeyAssets]
+}
+
+// NewCachesFromPaths creates a new set of file caches from the given
+// configuration.
+func NewCachesFromPaths(p *paths.Paths) (Caches, error) {
+	dcfg, err := decodeConfig(p)
+	if err != nil {
+		return nil, err
+	}
+
+	fs := p.Fs.Source
+
+	m := make(Caches)
+	for k, v := range dcfg {
+		baseDir := filepath.Join(v.Dir, k)
+		if err = fs.MkdirAll(baseDir, 0777); err != nil {
+			return nil, err
+		}
+		bfs := afero.NewBasePathFs(fs, baseDir)
+		m[k] = NewCache(bfs, v.MaxAge)
+	}
+
+	return m, nil
+}
+
+func decodeConfig(p *paths.Paths) (cachesConfig, error) {
+	c := make(cachesConfig)
+	valid := make(map[string]bool)
+	// Add defaults
+	for k, v := range defaultCacheConfigs {
+		c[k] = v
+		valid[k] = true
+	}
+
+	cfg := p.Cfg
+
+	m := cfg.GetStringMap(cachesConfigKey)
+
+	_, isOsFs := p.Fs.Source.(*afero.OsFs)
+
+	for k, v := range m {
+		cc := defaultCacheConfig
+
+		if err := mapstructure.WeakDecode(v, &cc); err != nil {
+			return nil, err
+		}
+
+		if cc.Dir == "" {
+			return c, errors.New("must provide cache Dir")
+		}
+
+		name := strings.ToLower(k)
+		if !valid[name] {
+			return nil, errors.Errorf("%q is not a valid cache name", name)
+		}
+
+		c[name] = cc
+	}
+
+	// This is a very old flag in Hugo, but we need to respect it.
+	disabled := cfg.GetBool("ignoreCache")
+
+	for k, v := range c {
+		v.Dir = filepath.Clean(v.Dir)
+		dir := filepath.ToSlash(v.Dir)
+		parts := strings.Split(dir, "/")
+		first := parts[0]
+
+		if strings.HasPrefix(first, ":") {
+			resolved, err := resolveDirPlaceholder(p, first)
+			if err != nil {
+				return c, err
+			}
+			resolved = filepath.ToSlash(resolved)
+
+			v.Dir = filepath.FromSlash(path.Join((append([]string{resolved}, parts[1:]...))...))
+
+		} else if isOsFs && !path.IsAbs(dir) {
+			return c, errors.Errorf("%q must either start with a placeholder (e.g. :cacheDir, :resourceDir) or be absolute", v.Dir)
+		}
+
+		if disabled {
+			v.MaxAge = 0
+		}
+
+		c[k] = v
+	}
+
+	return c, nil
+}
+
+// Resolves :resourceDir => /myproject/resources etc., :cacheDir => ...
+func resolveDirPlaceholder(p *paths.Paths, placeholder string) (string, error) {
+	switch strings.ToLower(placeholder) {
+	case ":resourcedir":
+		return p.AbsResourcesDir, nil
+	case ":cachedir":
+		return helpers.GetCacheDir(p.Fs.Source, p.Cfg)
+	}
+
+	return "", errors.Errorf("%q is not a valid placeholder (valid values are :cacheDir or :resourceDir)", placeholder)
+}
+
+func cleanID(name string) string {
+	return filepath.Clean(name)
+}