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/services/docextractor/combine.go

@@ -0,0 +1,42 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package docextractor
+
+import (
+	"io"
+
+	"github.com/mattermost/mattermost-server/v6/server/platform/shared/mlog"
+)
+
+type combineExtractor struct {
+	SubExtractors []Extractor
+}
+
+func (ce *combineExtractor) Add(extractor Extractor) {
+	ce.SubExtractors = append(ce.SubExtractors, extractor)
+}
+
+func (ce *combineExtractor) Match(filename string) bool {
+	for _, extractor := range ce.SubExtractors {
+		if extractor.Match(filename) {
+			return true
+		}
+	}
+	return false
+}
+
+func (ce *combineExtractor) Extract(filename string, r io.ReadSeeker) (string, error) {
+	for _, extractor := range ce.SubExtractors {
+		if extractor.Match(filename) {
+			r.Seek(0, io.SeekStart)
+			text, err := extractor.Extract(filename, r)
+			if err != nil {
+				mlog.Warn("unable to extract file content", mlog.Err(err))
+				continue
+			}
+			return text, nil
+		}
+	}
+	return "", nil
+}