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- // Copyright 2023 The Gitea Authors. All rights reserved.
- // SPDX-License-Identifier: MIT
-
- package db
-
- import (
- "errors"
- "fmt"
- "strings"
-
- "code.gitea.io/gitea/modules/container"
- "code.gitea.io/gitea/modules/log"
- "code.gitea.io/gitea/modules/setting"
-
- "xorm.io/xorm"
- "xorm.io/xorm/schemas"
- )
-
- type CheckCollationsResult struct {
- ExpectedCollation string
- AvailableCollation container.Set[string]
- DatabaseCollation string
- IsCollationCaseSensitive func(s string) bool
- CollationEquals func(a, b string) bool
- ExistingTableNumber int
-
- InconsistentCollationColumns []string
- }
-
- func findAvailableCollationsMySQL(x *xorm.Engine) (ret container.Set[string], err error) {
- var res []struct {
- Collation string
- }
- if err = x.SQL("SHOW COLLATION WHERE (Collation = 'utf8mb4_bin') OR (Collation LIKE '%\\_as\\_cs%')").Find(&res); err != nil {
- return nil, err
- }
- ret = make(container.Set[string], len(res))
- for _, r := range res {
- ret.Add(r.Collation)
- }
- return ret, nil
- }
-
- func findAvailableCollationsMSSQL(x *xorm.Engine) (ret container.Set[string], err error) {
- var res []struct {
- Name string
- }
- if err = x.SQL("SELECT * FROM sys.fn_helpcollations() WHERE name LIKE '%[_]CS[_]AS%'").Find(&res); err != nil {
- return nil, err
- }
- ret = make(container.Set[string], len(res))
- for _, r := range res {
- ret.Add(r.Name)
- }
- return ret, nil
- }
-
- func CheckCollations(x *xorm.Engine) (*CheckCollationsResult, error) {
- dbTables, err := x.DBMetas()
- if err != nil {
- return nil, err
- }
-
- res := &CheckCollationsResult{
- ExistingTableNumber: len(dbTables),
- CollationEquals: func(a, b string) bool { return a == b },
- }
-
- var candidateCollations []string
- if x.Dialect().URI().DBType == schemas.MYSQL {
- if _, err = x.SQL("SELECT @@collation_database").Get(&res.DatabaseCollation); err != nil {
- return nil, err
- }
- res.IsCollationCaseSensitive = func(s string) bool {
- return s == "utf8mb4_bin" || strings.HasSuffix(s, "_as_cs")
- }
- candidateCollations = []string{"utf8mb4_0900_as_cs", "uca1400_as_cs", "utf8mb4_bin"}
- res.AvailableCollation, err = findAvailableCollationsMySQL(x)
- if err != nil {
- return nil, err
- }
- res.CollationEquals = func(a, b string) bool {
- // MariaDB adds the "utf8mb4_" prefix, eg: "utf8mb4_uca1400_as_cs", but not the name "uca1400_as_cs" in "SHOW COLLATION"
- // At the moment, it's safe to ignore the database difference, just trim the prefix and compare. It could be fixed easily if there is any problem in the future.
- return a == b || strings.TrimPrefix(a, "utf8mb4_") == strings.TrimPrefix(b, "utf8mb4_")
- }
- } else if x.Dialect().URI().DBType == schemas.MSSQL {
- if _, err = x.SQL("SELECT DATABASEPROPERTYEX(DB_NAME(), 'Collation')").Get(&res.DatabaseCollation); err != nil {
- return nil, err
- }
- res.IsCollationCaseSensitive = func(s string) bool {
- return strings.HasSuffix(s, "_CS_AS")
- }
- candidateCollations = []string{"Latin1_General_CS_AS"}
- res.AvailableCollation, err = findAvailableCollationsMSSQL(x)
- if err != nil {
- return nil, err
- }
- } else {
- return nil, nil
- }
-
- if res.DatabaseCollation == "" {
- return nil, errors.New("unable to get collation for current database")
- }
-
- res.ExpectedCollation = setting.Database.CharsetCollation
- if res.ExpectedCollation == "" {
- for _, collation := range candidateCollations {
- if res.AvailableCollation.Contains(collation) {
- res.ExpectedCollation = collation
- break
- }
- }
- }
-
- if res.ExpectedCollation == "" {
- return nil, errors.New("unable to find a suitable collation for current database")
- }
-
- allColumnsMatchExpected := true
- allColumnsMatchDatabase := true
- for _, table := range dbTables {
- for _, col := range table.Columns() {
- if col.Collation != "" {
- allColumnsMatchExpected = allColumnsMatchExpected && res.CollationEquals(col.Collation, res.ExpectedCollation)
- allColumnsMatchDatabase = allColumnsMatchDatabase && res.CollationEquals(col.Collation, res.DatabaseCollation)
- if !res.IsCollationCaseSensitive(col.Collation) || !res.CollationEquals(col.Collation, res.DatabaseCollation) {
- res.InconsistentCollationColumns = append(res.InconsistentCollationColumns, fmt.Sprintf("%s.%s", table.Name, col.Name))
- }
- }
- }
- }
- // if all columns match expected collation or all match database collation, then it could also be considered as "consistent"
- if allColumnsMatchExpected || allColumnsMatchDatabase {
- res.InconsistentCollationColumns = nil
- }
- return res, nil
- }
-
- func CheckCollationsDefaultEngine() (*CheckCollationsResult, error) {
- return CheckCollations(x)
- }
-
- func alterDatabaseCollation(x *xorm.Engine, collation string) error {
- if x.Dialect().URI().DBType == schemas.MYSQL {
- _, err := x.Exec("ALTER DATABASE CHARACTER SET utf8mb4 COLLATE " + collation)
- return err
- } else if x.Dialect().URI().DBType == schemas.MSSQL {
- // TODO: MSSQL has many limitations on changing database collation, it could fail in many cases.
- _, err := x.Exec("ALTER DATABASE CURRENT COLLATE " + collation)
- return err
- }
- return errors.New("unsupported database type")
- }
-
- // preprocessDatabaseCollation checks database & table column collation, and alter the database collation if needed
- func preprocessDatabaseCollation(x *xorm.Engine) {
- r, err := CheckCollations(x)
- if err != nil {
- log.Error("Failed to check database collation: %v", err)
- }
- if r == nil {
- return // no check result means the database doesn't need to do such check/process (at the moment ....)
- }
-
- // try to alter database collation to expected if the database is empty, it might fail in some cases (and it isn't necessary to succeed)
- // at the moment, there is no "altering" solution for MSSQL, site admin should manually change the database collation
- if !r.CollationEquals(r.DatabaseCollation, r.ExpectedCollation) && r.ExistingTableNumber == 0 {
- if err = alterDatabaseCollation(x, r.ExpectedCollation); err != nil {
- log.Error("Failed to change database collation to %q: %v", r.ExpectedCollation, err)
- } else {
- _, _ = x.Exec("SELECT 1") // after "altering", MSSQL's session becomes invalid, so make a simple query to "refresh" the session
- if r, err = CheckCollations(x); err != nil {
- log.Error("Failed to check database collation again after altering: %v", err) // impossible case
- return
- }
- log.Warn("Current database has been altered to use collation %q", r.DatabaseCollation)
- }
- }
-
- // check column collation, and show warning/error to end users -- no need to fatal, do not block the startup
- if !r.IsCollationCaseSensitive(r.DatabaseCollation) {
- log.Warn("Current database is using a case-insensitive collation %q, although Gitea could work with it, there might be some rare cases which don't work as expected.", r.DatabaseCollation)
- }
-
- if len(r.InconsistentCollationColumns) > 0 {
- log.Error("There are %d table columns using inconsistent collation, they should use %q. Please go to admin panel Self Check page", len(r.InconsistentCollationColumns), r.DatabaseCollation)
- }
- }
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