refactor: prepare to decouple the "model migration" package and "models" package (#38533)

Migrations should never use model structs directly, because the model
structs can be different in different releases. e.g. if one migration uses
"User" model, it works in the early releases, then one day, when the
User model changes, the migration breaks because it will use the
new (incorrect) User model, it should only use the old User model.

The same to "modules/structs".

---------

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>

modelmigration/v1_9/v85.go

@@ -0,0 +1,113 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_9
+
+import (
+	"fmt"
+
+	"gitea.dev/modelmigration/base"
+	"gitea.dev/modules/log"
+	"gitea.dev/modules/timeutil"
+	"gitea.dev/modules/util"
+)
+
+func HashAppToken(x base.EngineMigration) error {
+	// AccessToken see models/token.go
+	type AccessToken struct {
+		ID             int64 `xorm:"pk autoincr"`
+		UID            int64 `xorm:"INDEX"`
+		Name           string
+		Sha1           string
+		Token          string `xorm:"-"`
+		TokenHash      string // sha256 of token - we will ensure UNIQUE later
+		TokenSalt      string
+		TokenLastEight string `xorm:"token_last_eight"`
+
+		CreatedUnix       timeutil.TimeStamp `xorm:"INDEX created"`
+		UpdatedUnix       timeutil.TimeStamp `xorm:"INDEX updated"`
+		HasRecentActivity bool               `xorm:"-"`
+		HasUsed           bool               `xorm:"-"`
+	}
+
+	// First remove the index
+	sess := x.NewSession()
+	defer sess.Close()
+
+	if err := sess.Begin(); err != nil {
+		return err
+	}
+
+	if err := sess.Sync(new(AccessToken)); err != nil {
+		return fmt.Errorf("Sync: %w", err)
+	}
+
+	if err := sess.Commit(); err != nil {
+		return err
+	}
+
+	if err := sess.Begin(); err != nil {
+		return err
+	}
+
+	// transform all tokens to hashes
+	const batchSize = 100
+	for start := 0; ; start += batchSize {
+		tokens := make([]*AccessToken, 0, batchSize)
+		if err := sess.Limit(batchSize, start).Find(&tokens); err != nil {
+			return err
+		}
+		if len(tokens) == 0 {
+			break
+		}
+
+		for _, token := range tokens {
+			// generate salt
+			salt := util.CryptoRandomString(10)
+			token.TokenSalt = salt
+			token.TokenHash = base.HashToken(token.Sha1, salt)
+			if len(token.Sha1) < 8 {
+				log.Warn("Unable to transform token %s with name %s belonging to user ID %d, skipping transformation", token.Sha1, token.Name, token.UID)
+				continue
+			}
+			token.TokenLastEight = token.Sha1[len(token.Sha1)-8:]
+			token.Sha1 = "" // ensure to blank out column in case drop column doesn't work
+
+			if _, err := sess.ID(token.ID).Cols("token_hash, token_salt, token_last_eight, sha1").Update(token); err != nil {
+				return fmt.Errorf("couldn't add in sha1, token_hash, token_salt and token_last_eight: %w", err)
+			}
+		}
+	}
+
+	// Commit and begin new transaction for dropping columns
+	if err := sess.Commit(); err != nil {
+		return err
+	}
+	if err := sess.Begin(); err != nil {
+		return err
+	}
+
+	if err := base.DropTableColumns(sess, "access_token", "sha1"); err != nil {
+		return err
+	}
+	if err := sess.Commit(); err != nil {
+		return err
+	}
+	return resyncHashAppTokenWithUniqueHash(x)
+}
+
+func resyncHashAppTokenWithUniqueHash(x base.EngineMigration) error {
+	// AccessToken see models/token.go
+	type AccessToken struct {
+		TokenHash string `xorm:"UNIQUE"` // sha256 of token - we will ensure UNIQUE later
+	}
+	sess := x.NewSession()
+	defer sess.Close()
+	if err := sess.Begin(); err != nil {
+		return err
+	}
+	if err := sess.Sync(new(AccessToken)); err != nil {
+		return fmt.Errorf("Sync: %w", err)
+	}
+	return sess.Commit()
+}