1 files changed, 212 insertions, 0 deletions
diff --git a/models/user/setting.go b/models/user/setting.go
new file mode 100644
index 0000000..b4af0e5
--- /dev/null
+++ b/models/user/setting.go
@@ -0,0 +1,212 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package user
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/modules/cache"
+	setting_module "code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
+
+	"xorm.io/builder"
+)
+
+// Setting is a key value store of user settings
+type Setting struct {
+	ID           int64  `xorm:"pk autoincr"`
+	UserID       int64  `xorm:"index unique(key_userid)"`              // to load all of someone's settings
+	SettingKey   string `xorm:"varchar(255) index unique(key_userid)"` // ensure key is always lowercase
+	SettingValue string `xorm:"text"`
+}
+
+// TableName sets the table name for the settings struct
+func (s *Setting) TableName() string {
+	return "user_setting"
+}
+
+func init() {
+	db.RegisterModel(new(Setting))
+}
+
+// ErrUserSettingIsNotExist represents an error that a setting is not exist with special key
+type ErrUserSettingIsNotExist struct {
+	Key string
+}
+
+// Error implements error
+func (err ErrUserSettingIsNotExist) Error() string {
+	return fmt.Sprintf("Setting[%s] is not exist", err.Key)
+}
+
+func (err ErrUserSettingIsNotExist) Unwrap() error {
+	return util.ErrNotExist
+}
+
+// IsErrUserSettingIsNotExist return true if err is ErrSettingIsNotExist
+func IsErrUserSettingIsNotExist(err error) bool {
+	_, ok := err.(ErrUserSettingIsNotExist)
+	return ok
+}
+
+// genSettingCacheKey returns the cache key for some configuration
+func genSettingCacheKey(userID int64, key string) string {
+	return fmt.Sprintf("user_%d.setting.%s", userID, key)
+}
+
+// GetSetting returns the setting value via the key
+func GetSetting(ctx context.Context, uid int64, key string) (string, error) {
+	return cache.GetString(genSettingCacheKey(uid, key), func() (string, error) {
+		res, err := GetSettingNoCache(ctx, uid, key)
+		if err != nil {
+			return "", err
+		}
+		return res.SettingValue, nil
+	})
+}
+
+// GetSettingNoCache returns specific setting without using the cache
+func GetSettingNoCache(ctx context.Context, uid int64, key string) (*Setting, error) {
+	v, err := GetSettings(ctx, uid, []string{key})
+	if err != nil {
+		return nil, err
+	}
+	if len(v) == 0 {
+		return nil, ErrUserSettingIsNotExist{key}
+	}
+	return v[key], nil
+}
+
+// GetSettings returns specific settings from user
+func GetSettings(ctx context.Context, uid int64, keys []string) (map[string]*Setting, error) {
+	settings := make([]*Setting, 0, len(keys))
+	if err := db.GetEngine(ctx).
+		Where("user_id=?", uid).
+		And(builder.In("setting_key", keys)).
+		Find(&settings); err != nil {
+		return nil, err
+	}
+	settingsMap := make(map[string]*Setting)
+	for _, s := range settings {
+		settingsMap[s.SettingKey] = s
+	}
+	return settingsMap, nil
+}
+
+// GetUserAllSettings returns all settings from user
+func GetUserAllSettings(ctx context.Context, uid int64) (map[string]*Setting, error) {
+	settings := make([]*Setting, 0, 5)
+	if err := db.GetEngine(ctx).
+		Where("user_id=?", uid).
+		Find(&settings); err != nil {
+		return nil, err
+	}
+	settingsMap := make(map[string]*Setting)
+	for _, s := range settings {
+		settingsMap[s.SettingKey] = s
+	}
+	return settingsMap, nil
+}
+
+func validateUserSettingKey(key string) error {
+	if len(key) == 0 {
+		return fmt.Errorf("setting key must be set")
+	}
+	if strings.ToLower(key) != key {
+		return fmt.Errorf("setting key should be lowercase")
+	}
+	return nil
+}
+
+// GetUserSetting gets a specific setting for a user
+func GetUserSetting(ctx context.Context, userID int64, key string, def ...string) (string, error) {
+	if err := validateUserSettingKey(key); err != nil {
+		return "", err
+	}
+
+	setting := &Setting{UserID: userID, SettingKey: key}
+	has, err := db.GetEngine(ctx).Get(setting)
+	if err != nil {
+		return "", err
+	}
+	if !has {
+		if len(def) == 1 {
+			return def[0], nil
+		}
+		return "", nil
+	}
+	return setting.SettingValue, nil
+}
+
+// DeleteUserSetting deletes a specific setting for a user
+func DeleteUserSetting(ctx context.Context, userID int64, key string) error {
+	if err := validateUserSettingKey(key); err != nil {
+		return err
+	}
+
+	cache.Remove(genSettingCacheKey(userID, key))
+	_, err := db.GetEngine(ctx).Delete(&Setting{UserID: userID, SettingKey: key})
+
+	return err
+}
+
+// SetUserSetting updates a users' setting for a specific key
+func SetUserSetting(ctx context.Context, userID int64, key, value string) error {
+	if err := validateUserSettingKey(key); err != nil {
+		return err
+	}
+
+	if err := upsertUserSettingValue(ctx, userID, key, value); err != nil {
+		return err
+	}
+
+	cc := cache.GetCache()
+	if cc != nil {
+		return cc.Put(genSettingCacheKey(userID, key), value, setting_module.CacheService.TTLSeconds())
+	}
+
+	return nil
+}
+
+func upsertUserSettingValue(ctx context.Context, userID int64, key, value string) error {
+	return db.WithTx(ctx, func(ctx context.Context) error {
+		e := db.GetEngine(ctx)
+
+		// here we use a general method to do a safe upsert for different databases (and most transaction levels)
+		// 1. try to UPDATE the record and acquire the transaction write lock
+		//    if UPDATE returns non-zero rows are changed, OK, the setting is saved correctly
+		//    if UPDATE returns "0 rows changed", two possibilities: (a) record doesn't exist  (b) value is not changed
+		// 2. do a SELECT to check if the row exists or not (we already have the transaction lock)
+		// 3. if the row doesn't exist, do an INSERT (we are still protected by the transaction lock, so it's safe)
+		//
+		// to optimize the SELECT in step 2, we can use an extra column like `revision=revision+1`
+		//    to make sure the UPDATE always returns a non-zero value for existing (unchanged) records.
+
+		res, err := e.Exec("UPDATE user_setting SET setting_value=? WHERE setting_key=? AND user_id=?", value, key, userID)
+		if err != nil {
+			return err
+		}
+		rows, _ := res.RowsAffected()
+		if rows > 0 {
+			// the existing row is updated, so we can return
+			return nil
+		}
+
+		// in case the value isn't changed, update would return 0 rows changed, so we need this check
+		has, err := e.Exist(&Setting{UserID: userID, SettingKey: key})
+		if err != nil {
+			return err
+		}
+		if has {
+			return nil
+		}
+
+		// if no existing row, insert a new row
+		_, err = e.Insert(&Setting{UserID: userID, SettingKey: key, SettingValue: value})
+		return err
+	})
+}