github.com/avfs/avfs@v0.33.1-0.20240303173310-c6ba67c33eb7/ostype.go (about)

     1  //
     2  //  Copyright 2023 The AVFS authors
     3  //
     4  //  Licensed under the Apache License, Version 2.0 (the "License");
     5  //  you may not use this file except in compliance with the License.
     6  //  You may obtain a copy of the License at
     7  //
     8  //  	http://www.apache.org/licenses/LICENSE-2.0
     9  //
    10  //  Unless required by applicable law or agreed to in writing, software
    11  //  distributed under the License is distributed on an "AS IS" BASIS,
    12  //  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  //  See the License for the specific language governing permissions and
    14  //  limitations under the License.
    15  //
    16  
    17  package avfs
    18  
    19  import (
    20  	"errors"
    21  	"runtime"
    22  )
    23  
    24  var ErrSetOSType = errors.New("can't set OS type, use build tag 'avfs_setostype' to set OS type")
    25  
    26  // OSType defines the operating system type.
    27  type OSType uint16
    28  
    29  //go:generate stringer -type OSType -linecomment -output ostype_string.go
    30  
    31  const (
    32  	OsUnknown OSType = iota // Unknown
    33  	OsLinux                 // Linux
    34  	OsWindows               // Windows
    35  	OsDarwin                // Darwin
    36  )
    37  
    38  // CurrentOSType returns the current OSType.
    39  func CurrentOSType() OSType {
    40  	return currentOSType
    41  }
    42  
    43  // currentOSType is the current OSType.
    44  var currentOSType = func() OSType { //nolint:gochecknoglobals // Store the current OS Type.
    45  	switch runtime.GOOS {
    46  	case "linux":
    47  		return OsLinux
    48  	case "darwin":
    49  		return OsDarwin
    50  	case "windows":
    51  		return OsWindows
    52  	default:
    53  		return OsUnknown
    54  	}
    55  }()
    56  
    57  // OSTyper is the interface that wraps the OS type related methods.
    58  type OSTyper interface {
    59  	// OSType returns the operating system type of the file system.
    60  	OSType() OSType
    61  }
    62  
    63  // OSTypeFn provides OS type functions to a file system or an identity manager.
    64  type OSTypeFn struct {
    65  	osType        OSType // OSType defines the operating system type.
    66  	pathSeparator uint8  // pathSeparator is the OS-specific path separator.
    67  }
    68  
    69  // OSType returns the operating system type of the file system.
    70  func (osf *OSTypeFn) OSType() OSType {
    71  	return osf.osType
    72  }
    73  
    74  // PathSeparator return the OS-specific path separator.
    75  func (osf *OSTypeFn) PathSeparator() uint8 {
    76  	return osf.pathSeparator
    77  }
    78  
    79  // SetOSType sets the operating system Type.
    80  // If the OS type can't be changed it returns an error.
    81  func (osf *OSTypeFn) SetOSType(osType OSType) error {
    82  	if osType == OsUnknown {
    83  		osType = CurrentOSType()
    84  	}
    85  
    86  	if BuildFeatures()&FeatSetOSType != 0 && osType != CurrentOSType() {
    87  		return ErrSetOSType
    88  	}
    89  
    90  	osf.osType = osType
    91  
    92  	sep := uint8('/')
    93  	if osType == OsWindows {
    94  		sep = '\\'
    95  	}
    96  
    97  	osf.pathSeparator = sep
    98  
    99  	return nil
   100  }