Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/platform/shared/filestore/filesstore.go

@@ -0,0 +1,102 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package filestore
+
+import (
+	"context"
+	"io"
+	"time"
+
+	"github.com/pkg/errors"
+)
+
+const (
+	driverS3    = "amazons3"
+	driverLocal = "local"
+)
+
+type ReadCloseSeeker interface {
+	io.ReadCloser
+	io.Seeker
+}
+
+type FileBackend interface {
+	TestConnection() error
+
+	Reader(path string) (ReadCloseSeeker, error)
+	ReadFile(path string) ([]byte, error)
+	FileExists(path string) (bool, error)
+	FileSize(path string) (int64, error)
+	CopyFile(oldPath, newPath string) error
+	MoveFile(oldPath, newPath string) error
+	WriteFile(fr io.Reader, path string) (int64, error)
+	AppendFile(fr io.Reader, path string) (int64, error)
+	RemoveFile(path string) error
+	FileModTime(path string) (time.Time, error)
+
+	ListDirectory(path string) ([]string, error)
+	ListDirectoryRecursively(path string) ([]string, error)
+	RemoveDirectory(path string) error
+}
+
+type FileBackendSettings struct {
+	DriverName                         string
+	Directory                          string
+	AmazonS3AccessKeyId                string
+	AmazonS3SecretAccessKey            string
+	AmazonS3Bucket                     string
+	AmazonS3PathPrefix                 string
+	AmazonS3Region                     string
+	AmazonS3Endpoint                   string
+	AmazonS3SSL                        bool
+	AmazonS3SignV2                     bool
+	AmazonS3SSE                        bool
+	AmazonS3Trace                      bool
+	SkipVerify                         bool
+	AmazonS3RequestTimeoutMilliseconds int64
+}
+
+func (settings *FileBackendSettings) CheckMandatoryS3Fields() error {
+	if settings.AmazonS3Bucket == "" {
+		return errors.New("missing s3 bucket settings")
+	}
+
+	// if S3 endpoint is not set call the set defaults to set that
+	if settings.AmazonS3Endpoint == "" {
+		settings.AmazonS3Endpoint = "s3.amazonaws.com"
+	}
+
+	return nil
+}
+
+func NewFileBackend(settings FileBackendSettings) (FileBackend, error) {
+	switch settings.DriverName {
+	case driverS3:
+		backend, err := NewS3FileBackend(settings)
+		if err != nil {
+			return nil, errors.Wrap(err, "unable to connect to the s3 backend")
+		}
+		return backend, nil
+	case driverLocal:
+		return &LocalFileBackend{
+			directory: settings.Directory,
+		}, nil
+	}
+	return nil, errors.New("no valid filestorage driver found")
+}
+
+// TryWriteFileContext checks if the file backend supports context writes and passes the context in that case.
+// Should the file backend not support contexts, it just calls WriteFile instead. This can be used to disable
+// the timeouts for long writes (like exports).
+func TryWriteFileContext(fb FileBackend, ctx context.Context, fr io.Reader, path string) (int64, error) {
+	type ContextWriter interface {
+		WriteFileContext(context.Context, io.Reader, string) (int64, error)
+	}
+
+	if cw, ok := fb.(ContextWriter); ok {
+		return cw.WriteFileContext(ctx, fr, path)
+	}
+
+	return fb.WriteFile(fr, path)
+}