diff options
Diffstat (limited to 'libgo/go/os/file.go')
| -rw-r--r-- | libgo/go/os/file.go | 49 |
1 files changed, 42 insertions, 7 deletions
diff --git a/libgo/go/os/file.go b/libgo/go/os/file.go index 85f151e2840..1c3d0172d34 100644 --- a/libgo/go/os/file.go +++ b/libgo/go/os/file.go @@ -7,11 +7,33 @@ // Go-like; failing calls return values of type error rather than error numbers. // Often, more information is available within the error. For example, // if a call that takes a file name fails, such as Open or Stat, the error -// will include failing file name when printed and will be of type *PathError, -// which may be unpacked for more information. +// will include the failing file name when printed and will be of type +// *PathError, which may be unpacked for more information. // // The os interface is intended to be uniform across all operating systems. // Features not generally available appear in the system-specific package syscall. +// +// Here is a simple example, opening a file and reading some of it. +// +// file, err := os.Open("file.go") // For read access. +// if err != nil { +// log.Fatal(err) +// } +// +// If the open fails, the error string will be self-explanatory, like +// +// open file.go: no such file or directory +// +// The file's data can then be read into a slice of bytes. Read and +// Write take their byte counts from the length of the artument slice. +// +// data := make([]byte, 100) +// count, err := file.Read(data) +// if err != nil { +// log.Fatal(err) +// } +// fmt.Printf("read %d bytes: %q\n", count, data[:count]) +// package os import ( @@ -50,12 +72,25 @@ const ( SEEK_END int = 2 // seek relative to the end ) +// LinkError records an error during a link or symlink or rename +// system call and the paths that caused it. +type LinkError struct { + Op string + Old string + New string + Err error +} + +func (e *LinkError) Error() string { + return e.Op + " " + e.Old + " " + e.New + ": " + e.Err.Error() +} + // Read reads up to len(b) bytes from the File. // It returns the number of bytes read and an error, if any. // EOF is signaled by a zero count with err set to io.EOF. func (f *File) Read(b []byte) (n int, err error) { if f == nil { - return 0, EINVAL + return 0, ErrInvalid } n, e := f.read(b) if n < 0 { @@ -76,7 +111,7 @@ func (f *File) Read(b []byte) (n int, err error) { // At end of file, that error is io.EOF. func (f *File) ReadAt(b []byte, off int64) (n int, err error) { if f == nil { - return 0, EINVAL + return 0, ErrInvalid } for len(b) > 0 { m, e := f.pread(b, off) @@ -99,7 +134,7 @@ func (f *File) ReadAt(b []byte, off int64) (n int, err error) { // Write returns a non-nil error when n != len(b). func (f *File) Write(b []byte) (n int, err error) { if f == nil { - return 0, EINVAL + return 0, ErrInvalid } n, e := f.write(b) if n < 0 { @@ -119,7 +154,7 @@ func (f *File) Write(b []byte) (n int, err error) { // WriteAt returns a non-nil error when n != len(b). func (f *File) WriteAt(b []byte, off int64) (n int, err error) { if f == nil { - return 0, EINVAL + return 0, ErrInvalid } for len(b) > 0 { m, e := f.pwrite(b, off) @@ -153,7 +188,7 @@ func (f *File) Seek(offset int64, whence int) (ret int64, err error) { // an array of bytes. func (f *File) WriteString(s string) (ret int, err error) { if f == nil { - return 0, EINVAL + return 0, ErrInvalid } return f.Write([]byte(s)) } |