Make database install/upgrade provider aware

Ground work for installing and upgrading database schema based upon DB provider (MySQL, PostgresSQL, SQL Server, etc.)

Cleaned up legacy cruft, refactored, commented and made simpler for to support additional database providers.

core/database/scripts.go

@@ -0,0 +1,80 @@
+// Copyright 2016 Documize Inc. <legal@documize.com>. All rights reserved.
+//
+// This software (Documize Community Edition) is licensed under
+// GNU AGPL v3 http://www.gnu.org/licenses/agpl-3.0.en.html
+//
+// You can operate outside the AGPL restrictions by purchasing
+// Documize Enterprise Edition and obtaining a commercial license
+// by contacting <sales@documize.com>.
+//
+// https://documize.com
+
+package database
+
+import (
+	"fmt"
+	"github.com/documize/community/core/env"
+	"sort"
+
+	"github.com/documize/community/server/web"
+)
+
+// Scripts holds all .SQL files for all supported database providers.
+type Scripts struct {
+	MySQLScripts       []Script
+	PostgresSQLScripts []Script
+	SQLServerScripts   []Script
+}
+
+// Script holds SQL script and it's associated version number.
+type Script struct {
+	Version int
+	Script  []byte
+}
+
+// LoadScripts returns .SQL scripts for supported database providers.
+func LoadScripts() (s Scripts, err error) {
+	assetDir := "bindata/scripts"
+
+	// MySQL
+	s.MySQLScripts, err = loadFiles(fmt.Sprintf("%s/mysql", assetDir))
+	if err != nil {
+		return
+	}
+
+	return s, nil
+}
+
+// SpecificScripts returns SQL scripts for current databasse provider.
+func SpecificScripts(runtime *env.Runtime, all Scripts) (s []Script) {
+	switch runtime.Storage.Type {
+	case env.StoreTypeMySQL, env.StoreTypeMariaDB, env.StoreTypePercona:
+		return all.MySQLScripts
+	case env.StoreTypePostgreSQL:
+		return all.PostgresSQLScripts
+	case env.StoreTypeMSSQL:
+		return all.SQLServerScripts
+	}
+
+	return
+}
+
+// loadFiles returns all SQL scripts in specified folder as [][]byte.
+func loadFiles(path string) (b []Script, err error) {
+	buf := []byte{}
+	scripts, err := web.AssetDir(path)
+	if err != nil {
+		return
+	}
+	sort.Strings(scripts)
+	for _, file := range scripts {
+		buf, err = web.Asset(fmt.Sprintf("%s/%s", path, file))
+		if err != nil {
+			return
+		}
+
+		b = append(b, Script{Version: extractVersionNumber(file), Script: buf})
+	}
+
+	return b, nil
+}