Refactor config provider (#24245)

This PR introduces more abstract about `ConfigProvider` and hides more `ini` references.

---------

Co-authored-by: delvh <dev.lh@web.de>

modules/setting/config_provider.go

@@ -4,20 +4,157 @@
 package setting
 
 import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/util"
 
 	ini "gopkg.in/ini.v1"
 )
 
+type ConfigSection interface {
+	Name() string
+	MapTo(interface{}) error
+	HasKey(key string) bool
+	NewKey(name, value string) (*ini.Key, error)
+	Key(key string) *ini.Key
+	Keys() []*ini.Key
+	ChildSections() []*ini.Section
+}
+
 // ConfigProvider represents a config provider
 type ConfigProvider interface {
-	Section(section string) *ini.Section
-	NewSection(name string) (*ini.Section, error)
-	GetSection(name string) (*ini.Section, error)
+	Section(section string) ConfigSection
+	NewSection(name string) (ConfigSection, error)
+	GetSection(name string) (ConfigSection, error)
+	DeleteSection(name string) error
+	Save() error
+}
+
+type iniFileConfigProvider struct {
+	*ini.File
+	filepath   string // the ini file path
+	newFile    bool   // whether the file has not existed previously
+	allowEmpty bool   // whether not finding configuration files is allowed (only true for the tests)
+}
+
+// NewEmptyConfigProvider create a new empty config provider
+func NewEmptyConfigProvider() ConfigProvider {
+	cp, _ := newConfigProviderFromData("")
+	return cp
+}
+
+// newConfigProviderFromData this function is only for testing
+func newConfigProviderFromData(configContent string) (ConfigProvider, error) {
+	var cfg *ini.File
+	var err error
+	if configContent == "" {
+		cfg = ini.Empty()
+	} else {
+		cfg, err = ini.Load(strings.NewReader(configContent))
+		if err != nil {
+			return nil, err
+		}
+	}
+	cfg.NameMapper = ini.SnackCase
+	return &iniFileConfigProvider{
+		File:    cfg,
+		newFile: true,
+	}, nil
+}
+
+// newConfigProviderFromFile load configuration from file.
+// NOTE: do not print any log except error.
+func newConfigProviderFromFile(customConf string, allowEmpty bool, extraConfig string) (*iniFileConfigProvider, error) {
+	cfg := ini.Empty()
+	newFile := true
+
+	if customConf != "" {
+		isFile, err := util.IsFile(customConf)
+		if err != nil {
+			return nil, fmt.Errorf("unable to check if %s is a file. Error: %v", customConf, err)
+		}
+		if isFile {
+			if err := cfg.Append(customConf); err != nil {
+				return nil, fmt.Errorf("failed to load custom conf '%s': %v", customConf, err)
+			}
+			newFile = false
+		}
+	}
+
+	if newFile && !allowEmpty {
+		return nil, fmt.Errorf("unable to find configuration file: %q, please ensure you are running in the correct environment or set the correct configuration file with -c", CustomConf)
+	}
+
+	if extraConfig != "" {
+		if err := cfg.Append([]byte(extraConfig)); err != nil {
+			return nil, fmt.Errorf("unable to append more config: %v", err)
+		}
+	}
+
+	cfg.NameMapper = ini.SnackCase
+	return &iniFileConfigProvider{
+		File:       cfg,
+		filepath:   customConf,
+		newFile:    newFile,
+		allowEmpty: allowEmpty,
+	}, nil
+}
+
+func (p *iniFileConfigProvider) Section(section string) ConfigSection {
+	return p.File.Section(section)
+}
+
+func (p *iniFileConfigProvider) NewSection(name string) (ConfigSection, error) {
+	return p.File.NewSection(name)
+}
+
+func (p *iniFileConfigProvider) GetSection(name string) (ConfigSection, error) {
+	return p.File.GetSection(name)
+}
+
+func (p *iniFileConfigProvider) DeleteSection(name string) error {
+	p.File.DeleteSection(name)
+	return nil
+}
+
+// Save save the content into file
+func (p *iniFileConfigProvider) Save() error {
+	if p.filepath == "" {
+		if !p.allowEmpty {
+			return fmt.Errorf("custom config path must not be empty")
+		}
+		return nil
+	}
+
+	if p.newFile {
+		if err := os.MkdirAll(filepath.Dir(CustomConf), os.ModePerm); err != nil {
+			return fmt.Errorf("failed to create '%s': %v", CustomConf, err)
+		}
+	}
+	if err := p.SaveTo(p.filepath); err != nil {
+		return fmt.Errorf("failed to save '%s': %v", p.filepath, err)
+	}
+
+	// Change permissions to be more restrictive
+	fi, err := os.Stat(CustomConf)
+	if err != nil {
+		return fmt.Errorf("failed to determine current conf file permissions: %v", err)
+	}
+
+	if fi.Mode().Perm() > 0o600 {
+		if err = os.Chmod(CustomConf, 0o600); err != nil {
+			log.Warn("Failed changing conf file permissions to -rw-------. Consider changing them manually.")
+		}
+	}
+	return nil
 }
 
 // a file is an implementation ConfigProvider and other implementations are possible, i.e. from docker, k8s, …
-var _ ConfigProvider = &ini.File{}
+var _ ConfigProvider = &iniFileConfigProvider{}
 
 func mustMapSetting(rootCfg ConfigProvider, sectionName string, setting interface{}) {
 	if err := rootCfg.Section(sectionName).MapTo(setting); err != nil {