readfs.go

Documentation: github.com/tetratelabs/wazero/internal/sysfs

     1  package sysfs
     2  
     3  import (
     4  	"io/fs"
     5  
     6  	experimentalsys "github.com/tetratelabs/wazero/experimental/sys"
     7  )
     8  
     9  type ReadFS struct {
    10  	experimentalsys.FS
    11  }
    12  
    13  // OpenFile implements the same method as documented on sys.FS
    14  func (r *ReadFS) OpenFile(path string, flag experimentalsys.Oflag, perm fs.FileMode) (experimentalsys.File, experimentalsys.Errno) {
    15  	// Mask the mutually exclusive bits as they determine write mode.
    16  	switch flag & (experimentalsys.O_RDONLY | experimentalsys.O_WRONLY | experimentalsys.O_RDWR) {
    17  	case experimentalsys.O_WRONLY, experimentalsys.O_RDWR:
    18  		// Return the correct error if a directory was opened for write.
    19  		if flag&experimentalsys.O_DIRECTORY != 0 {
    20  			return nil, experimentalsys.EISDIR
    21  		}
    22  		return nil, experimentalsys.ENOSYS
    23  	default: // sys.O_RDONLY (integer zero) so we are ok!
    24  	}
    25  
    26  	f, errno := r.FS.OpenFile(path, flag, perm)
    27  	if errno != 0 {
    28  		return nil, errno
    29  	}
    30  	return &readFile{f}, 0
    31  }
    32  
    33  // Mkdir implements the same method as documented on sys.FS
    34  func (r *ReadFS) Mkdir(path string, perm fs.FileMode) experimentalsys.Errno {
    35  	return experimentalsys.EROFS
    36  }
    37  
    38  // Chmod implements the same method as documented on sys.FS
    39  func (r *ReadFS) Chmod(path string, perm fs.FileMode) experimentalsys.Errno {
    40  	return experimentalsys.EROFS
    41  }
    42  
    43  // Rename implements the same method as documented on sys.FS
    44  func (r *ReadFS) Rename(from, to string) experimentalsys.Errno {
    45  	return experimentalsys.EROFS
    46  }
    47  
    48  // Rmdir implements the same method as documented on sys.FS
    49  func (r *ReadFS) Rmdir(path string) experimentalsys.Errno {
    50  	return experimentalsys.EROFS
    51  }
    52  
    53  // Link implements the same method as documented on sys.FS
    54  func (r *ReadFS) Link(_, _ string) experimentalsys.Errno {
    55  	return experimentalsys.EROFS
    56  }
    57  
    58  // Symlink implements the same method as documented on sys.FS
    59  func (r *ReadFS) Symlink(_, _ string) experimentalsys.Errno {
    60  	return experimentalsys.EROFS
    61  }
    62  
    63  // Unlink implements the same method as documented on sys.FS
    64  func (r *ReadFS) Unlink(path string) experimentalsys.Errno {
    65  	return experimentalsys.EROFS
    66  }
    67  
    68  // Utimens implements the same method as documented on sys.FS
    69  func (r *ReadFS) Utimens(path string, atim, mtim int64) experimentalsys.Errno {
    70  	return experimentalsys.EROFS
    71  }
    72  
    73  // compile-time check to ensure readFile implements api.File.
    74  var _ experimentalsys.File = (*readFile)(nil)
    75  
    76  type readFile struct {
    77  	experimentalsys.File
    78  }
    79  
    80  // Write implements the same method as documented on sys.File.
    81  func (r *readFile) Write([]byte) (int, experimentalsys.Errno) {
    82  	return 0, r.writeErr()
    83  }
    84  
    85  // Pwrite implements the same method as documented on sys.File.
    86  func (r *readFile) Pwrite([]byte, int64) (n int, errno experimentalsys.Errno) {
    87  	return 0, r.writeErr()
    88  }
    89  
    90  // Truncate implements the same method as documented on sys.File.
    91  func (r *readFile) Truncate(int64) experimentalsys.Errno {
    92  	return r.writeErr()
    93  }
    94  
    95  // Sync implements the same method as documented on sys.File.
    96  func (r *readFile) Sync() experimentalsys.Errno {
    97  	return experimentalsys.EBADF
    98  }
    99  
   100  // Datasync implements the same method as documented on sys.File.
   101  func (r *readFile) Datasync() experimentalsys.Errno {
   102  	return experimentalsys.EBADF
   103  }
   104  
   105  // Utimens implements the same method as documented on sys.File.
   106  func (r *readFile) Utimens(int64, int64) experimentalsys.Errno {
   107  	return experimentalsys.EBADF
   108  }
   109  
   110  func (r *readFile) writeErr() experimentalsys.Errno {
   111  	if isDir, errno := r.IsDir(); errno != 0 {
   112  		return errno
   113  	} else if isDir {
   114  		return experimentalsys.EISDIR
   115  	}
   116  	return experimentalsys.EBADF
   117  }
   118
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