Import storage packages from c2FmZQ and re-license

* Import some internal packages from c2FmZQ/c2FmZQ/internal.
* Decouple the logging code from c2FmZQ/c2FmZQ/internal/log.
* Change the license to MIT.

Author: rthellend

.github/workflows/pr.yml

@@ -0,0 +1,21 @@
+name: PR
+on: 
+  - pull_request
+  - push
+jobs:
+  build-and-run-tests:
+    name: Build & run tests
+    if: github.ref_type == 'branch'
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Go
+      uses: actions/setup-go@v4
+      with:
+        go-version-file: go.mod
+    - name: Build
+      run: go build ./...
+    - name: Run go vet
+      run: go vet ./...
+    - name: Run go tests
+      run: go test -v ./...

.github/workflows/release.yml

@@ -0,0 +1,36 @@
+name: release
+on: 
+  push:
+    tags:
+      - "v*.*"
+
+jobs:
+  build-and-run-tests:
+    name: Build & run tests
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Go
+      uses: actions/setup-go@v4
+      with:
+        go-version-file: go.mod
+    - name: Build
+      run: go build ./...
+    - name: Run go vet
+      run: go vet ./...
+    - name: Run go tests
+      run: go test -v ./...
+
+  create-release:
+    name: Create release
+    needs: build-and-run-tests
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+    - uses: actions/checkout@v3
+    - name: Create release
+      uses: softprops/action-gh-release@v1
+      with:
+        draft: false
+        generate_release_notes: true

LICENSE

@@ -0,0 +1,22 @@
+MIT License
+
+Copyright (c) 2021-2023 TTBT Enterprises LLC
+Copyright (c) 2021-2023 Robin Thellend <rthellend@rthellend.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -0,0 +1,45 @@
+# Storage
+
+This go package is used to store data in encrypted files. It is designed for convenience and correctness, and may not be suitable for high volume or high throughput applications. It was refactored from internal [c2fmzq-server](https://github.com/c2FmZQ/c2FmZQ) code, and re-licenced, so that other projects can use it.
+
+GO objects can be saved, loaded, and atomically updated.
+
+```go
+mk, err := crypto.CreateMasterKey([]byte("<passphrase>"))
+if err != nil {
+    panic(err)
+}
+store := storage.New("<data dir>", mk)
+
+var obj1 Object
+// Populate obj1
+if err := store.SaveDataFile("<relative filename>", &obj1); err != nil {
+    panic(err)
+}
+
+var obj2 Object
+if err := store.ReadDataFile("<relative filename>", &obj2); err != nil {
+    panic(err)
+}
+// obj1 and obj2 have the same value
+```
+
+To update objects atomically:
+```go
+func foo() (retErr error) {
+    var obj Object
+    commit, err := store.OpenForUpdate("<relative filename>", &obj)
+    if err != nil {
+        panic(err)
+    }
+    defer commit(false, &retErr) // rollback unless first committed.
+    // modify obj
+    obj.Bar = X
+    return commit(true, nil) // commit
+}
+```
+
+Multiple objects can be updated atomically with `OpenManyForUpdate()`.
+
+Developers can also use `OpenBlobRead()` and `OpenBlobWrite()` to read and write encrypted BLOBs with a streaming API.
+

autocertcache/cache.go

@@ -0,0 +1,99 @@
+// MIT License
+//
+// Copyright (c) 2021-2023 TTBT Enterprises LLC
+// Copyright (c) 2021-2023 Robin Thellend <rthellend@rthellend.com>
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+package autocertcache
+
+import (
+	"context"
+	"encoding/base64"
+
+	"github.com/c2FmZQ/storage"
+	"golang.org/x/crypto/acme/autocert"
+)
+
+type cacheContent struct {
+	Entries map[string]string `json:"entries"`
+}
+
+var _ autocert.Cache = (*Cache)(nil)
+
+// New returns a new Autocert Cache stored in fileName and encrypted with storage.
+func New(fileName string, storage *storage.Storage) *Cache {
+	storage.CreateEmptyFile(fileName, cacheContent{})
+	return &Cache{fileName, storage}
+}
+
+// Cache implements autocert.Cache
+type Cache struct {
+	fileName string
+	storage  *storage.Storage
+}
+
+// Get returns a cached entry.
+func (c *Cache) Get(_ context.Context, key string) ([]byte, error) {
+	c.storage.Logger().Debugf("Cache.Get(%q)", key)
+	var cc cacheContent
+	if err := c.storage.ReadDataFile(c.fileName, &cc); err != nil {
+		return nil, err
+	}
+	if cc.Entries == nil {
+		cc.Entries = make(map[string]string)
+	}
+	e, ok := cc.Entries[key]
+	if !ok {
+		c.storage.Logger().Debugf("Cache.Get(%q) NOT found.", key)
+		return nil, autocert.ErrCacheMiss
+	}
+	c.storage.Logger().Debugf("Cache.Get(%q) found.", key)
+	return base64.StdEncoding.DecodeString(e)
+}
+
+// Put stores a cache entry.
+func (c *Cache) Put(_ context.Context, key string, data []byte) error {
+	c.storage.Logger().Debugf("Cache.Put(%q, ...)", key)
+	var cc cacheContent
+	commit, err := c.storage.OpenForUpdate(c.fileName, &cc)
+	if err != nil {
+		return err
+	}
+	if cc.Entries == nil {
+		cc.Entries = make(map[string]string)
+	}
+	cc.Entries[key] = base64.StdEncoding.EncodeToString(data)
+	return commit(true, nil)
+}
+
+// Delete deletes a cached entry.
+func (c *Cache) Delete(_ context.Context, key string) error {
+	c.storage.Logger().Debugf("Cache.Delete(%q)", key)
+	var cc cacheContent
+	commit, err := c.storage.OpenForUpdate(c.fileName, &cc)
+	if err != nil {
+		return err
+	}
+	if cc.Entries == nil {
+		cc.Entries = make(map[string]string)
+	}
+	delete(cc.Entries, key)
+	return commit(true, nil)
+}

backup.go

@@ -0,0 +1,171 @@
+// MIT License
+//
+// Copyright (c) 2021-2023 TTBT Enterprises LLC
+// Copyright (c) 2021-2023 Robin Thellend <rthellend@rthellend.com>
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+package storage
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+func (s *Storage) createBackup(files []string) (*backup, error) {
+	b := &backup{dir: s.dir, TS: time.Now(), Files: files}
+	if err := b.backup(); err != nil {
+		return nil, err
+	}
+	b.pending = filepath.Join("pending", fmt.Sprintf("%d", b.TS.UnixNano()))
+	if err := s.SaveDataFile(b.pending, b); err != nil {
+		return nil, err
+	}
+	return b, nil
+}
+
+func (s *Storage) rollbackPendingOps() error {
+	m, err := filepath.Glob(filepath.Join(s.dir, "pending", "*"))
+	if err != nil {
+		return err
+	}
+	for _, f := range m {
+		rel, err := filepath.Rel(s.dir, f)
+		if err != nil {
+			return err
+		}
+		var b backup
+		if err := s.ReadDataFile(rel, &b); err != nil {
+			return err
+		}
+		b.dir = s.dir
+		b.pending = rel
+		// Make sure pending is this backup is really abandoned.
+		time.Sleep(time.Until(b.TS.Add(5 * time.Second)))
+		if err := b.restore(); err != nil {
+			return err
+		}
+		s.Logger().Infof("Rolled back pending operation %d [%v]", b.TS.UnixNano(), b.Files)
+		// The abandoned files were most likely locked.
+		s.UnlockMany(b.Files)
+	}
+	return nil
+}
+
+type backup struct {
+	// The timestamp of the backup.
+	TS time.Time `json:"ts"`
+	// Relative file names.
+	Files []string `json:"files"`
+
+	// The root of the data directory.
+	dir string
+	// The relative file name of the pending ops file.
+	pending string
+}
+
+func (b *backup) backup() error {
+	ch := make(chan error)
+	for _, f := range b.Files {
+		go func(fn string) { ch <- copyFile(b.backupFileName(fn), fn) }(filepath.Join(b.dir, f))
+	}
+	var errList []error
+	for _ = range b.Files {
+		if err := <-ch; err != nil && !errors.Is(err, os.ErrNotExist) {
+			errList = append(errList, err)
+		}
+	}
+	if errList != nil {
+		return fmt.Errorf("%w %v", errList[0], errList[1:])
+	}
+	return nil
+}
+
+func (b *backup) restore() error {
+	ch := make(chan error)
+	for _, f := range b.Files {
+		go func(fn string) { ch <- os.Rename(b.backupFileName(fn), fn) }(filepath.Join(b.dir, f))
+	}
+	var errList []error
+	for _ = range b.Files {
+		if err := <-ch; err != nil && !errors.Is(err, os.ErrNotExist) {
+			errList = append(errList, err)
+		}
+	}
+	if errList != nil {
+		return fmt.Errorf("%w %v", errList[0], errList[1:])
+	}
+	if err := os.Remove(filepath.Join(b.dir, b.pending)); err != nil && !errors.Is(err, os.ErrNotExist) {
+		return err
+	}
+	return nil
+}
+
+func (b *backup) delete() error {
+	ch := make(chan error)
+	for _, f := range b.Files {
+		go func(fn string) { ch <- os.Remove(b.backupFileName(fn)) }(filepath.Join(b.dir, f))
+	}
+	var errList []error
+	for _ = range b.Files {
+		if err := <-ch; err != nil && !errors.Is(err, os.ErrNotExist) {
+			errList = append(errList, err)
+		}
+	}
+	if errList != nil {
+		return fmt.Errorf("%w %v", errList[0], errList[1:])
+	}
+	if err := os.Remove(filepath.Join(b.dir, b.pending)); err != nil && !errors.Is(err, os.ErrNotExist) {
+		return err
+	}
+	return nil
+}
+
+func (b *backup) backupFileName(f string) string {
+	return fmt.Sprintf("%s.bck-%d", f, b.TS.UnixNano())
+}
+
+func copyFile(dst, src string) error {
+	if err := os.Link(src, dst); err == nil {
+		return nil
+	}
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	out, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0600)
+	if err != nil {
+		in.Close()
+		return err
+	}
+	if _, err := io.Copy(out, in); err != nil {
+		in.Close()
+		out.Close()
+		return err
+	}
+	if err := out.Close(); err != nil {
+		in.Close()
+		return err
+	}
+	return in.Close()
+}