path: root/hugolib/filesystems/basefs.go

// 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 filesystems provides the fine grained file systems used by Hugo. These
// are typically virtual filesystems that are composites of project and theme content.
package filesystems

import (
	"errors"
	"io"
	"os"
	"path/filepath"
	"strings"

	"github.com/gohugoio/hugo/config"

	"github.com/gohugoio/hugo/hugofs"

	"fmt"

	"github.com/gohugoio/hugo/hugolib/paths"
	"github.com/gohugoio/hugo/langs"
	"github.com/spf13/afero"
)

// When we create a virtual filesystem with data and i18n bundles for the project and the themes,
// this is the name of the project's virtual root. It got it's funky name to make sure
// (or very unlikely) that it collides with a theme name.
const projectVirtualFolder = "__h__project"

var filePathSeparator = string(filepath.Separator)

// BaseFs contains the core base filesystems used by Hugo. The name "base" is used
// to underline that even if they can be composites, they all have a base path set to a specific
// resource folder, e.g "/my-project/content". So, no absolute filenames needed.
type BaseFs struct {

	// SourceFilesystems contains the different source file systems.
	*SourceFilesystems

	// The filesystem used to publish the rendered site.
	// This usually maps to /my-project/public.
	PublishFs afero.Fs

	themeFs afero.Fs

	// TODO(bep) improve the "theme interaction"
	AbsThemeDirs []string
}

// RelContentDir tries to create a path relative to the content root from
// the given filename. The return value is the path and language code.
func (b *BaseFs) RelContentDir(filename string) string {
	for _, dirname := range b.SourceFilesystems.Content.Dirnames {
		if strings.HasPrefix(filename, dirname) {
			rel := strings.TrimPrefix(filename, dirname)
			return strings.TrimPrefix(rel, filePathSeparator)
		}
	}
	// Either not a content dir or already relative.
	return filename
}

// SourceFilesystems contains the different source file systems. These can be
// composite file systems (theme and project etc.), and they have all root
// set to the source type the provides: data, i18n, static, layouts.
type SourceFilesystems struct {
	Content    *SourceFilesystem
	Data       *SourceFilesystem
	I18n       *SourceFilesystem
	Layouts    *SourceFilesystem
	Archetypes *SourceFilesystem
	Assets     *SourceFilesystem
	Resources  *SourceFilesystem

	// This is a unified read-only view of the project's and themes' workdir.
	Work *SourceFilesystem

	// When in multihost we have one static filesystem per language. The sync
	// static files is currently done outside of the Hugo build (where there is
	// a concept of a site per language).
	// When in non-multihost mode there will be one entry in this map with a blank key.
	Static map[string]*SourceFilesystem
}

// A SourceFilesystem holds the filesystem for a given source type in Hugo (data,
// i18n, layouts, static) and additional metadata to be able to use that filesystem
// in server mode.
type SourceFilesystem struct {
	// This is a virtual composite filesystem. It expects path relative to a context.
	Fs afero.Fs

	// This is the base source filesystem. In real Hugo, this will be the OS filesystem.
	// Use this if you need to resolve items in Dirnames below.
	SourceFs afero.Fs

	// Dirnames is absolute filenames to the directories in this filesystem.
	Dirnames []string

	// When syncing a source folder to the target (e.g. /public), this may
	// be set to publish into a subfolder. This is used for static syncing
	// in multihost mode.
	PublishFolder string
}

// ContentStaticAssetFs will create a new composite filesystem from the content,
// static, and asset filesystems. The site language is needed to pick the correct static filesystem.
// The order is content, static and then assets.
// TODO(bep) check usage
func (s SourceFilesystems) ContentStaticAssetFs(lang string) afero.Fs {
	staticFs := s.StaticFs(lang)

	base := afero.NewCopyOnWriteFs(s.Assets.Fs, staticFs)
	return afero.NewCopyOnWriteFs(base, s.Content.Fs)

}

// StaticFs returns the static filesystem for the given language.
// This can be a composite filesystem.
func (s SourceFilesystems) StaticFs(lang string) afero.Fs {
	var staticFs afero.Fs = hugofs.NoOpFs

	if fs, ok := s.Static[lang]; ok {
		staticFs = fs.Fs
	} else if fs, ok := s.Static[""]; ok {
		staticFs = fs.Fs
	}

	return staticFs
}

// StatResource looks for a resource in these filesystems in order: static, assets and finally content.
// If found in any of them, it returns FileInfo and the relevant filesystem.
// Any non os.IsNotExist error will be returned.
// An os.IsNotExist error wil be returned only if all filesystems return such an error.
// Note that if we only wanted to find the file, we could create a composite Afero fs,
// but we also need to know which filesystem root it lives in.
func (s SourceFilesystems) StatResource(lang, filename string) (fi os.FileInfo, fs afero.Fs, err error) {
	for _, fsToCheck := range []afero.Fs{s.StaticFs(lang), s.Assets.Fs, s.Content.Fs} {
		fs = fsToCheck
		fi, err = fs.Stat(filename)
		if err == nil || !os.IsNotExist(err) {
			return
		}
	}
	// Not found.
	return
}

// IsStatic returns true if the given filename is a member of one of the static
// filesystems.
func (s SourceFilesystems) IsStatic(filename