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add Readdir: returns an array of Dir structures

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R=rsc
DELTA=200  (176 added, 12 deleted, 12 changed)
OCL=24680
CL=24680
This commit is contained in:
Rob Pike 2009-02-09 11:24:35 -08:00
parent c8d59c1fb2
commit aba4c75408
3 changed files with 188 additions and 24 deletions
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69
src/lib/os/dir_amd64_linux.go
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@ -40,9 +40,9 @@ func Readdirnames(fd *FD, count int) (names []string, err *os.Error) {
if count == 0 {
break
}
dir := unsafe.Pointer((uintptr(unsafe.Pointer(&buf[0])) + i)).(*syscall.Dirent);
w = uintptr(dir.Reclen);
if dir.Ino == 0 {
dirent := unsafe.Pointer((uintptr(unsafe.Pointer(&buf[0])) + i)).(*syscall.Dirent);
w = uintptr(dirent.Reclen);
if dirent.Ino == 0 {
continue
}
count--;
@ -54,8 +54,69 @@ func Readdirnames(fd *FD, count int) (names []string, err *os.Error) {
names = nnames;
}
names = names[0:len(names)+1];
names[len(names)-1] = string(dir.Name[0:clen(dir.Name)]);
names[len(names)-1] = string(dirent.Name[0:clen(dirent.Name)]);
}
}
return names, nil;
}
// TODO(r): Readdir duplicates a lot of Readdirnames. The other way would
// be to have Readdir (which could then be portable) call Readdirnames and
// then do the Stats. The existing design was chosen to avoid allocating a
// throwaway names array, but the issue should be revisited once we have
// a better handle on what that overhead is with a strong garbage collector.
// Also, it's possible given the nature of the Unix kernel that interleaving
// reads of the directory with stats (as done here) would work better than
// one big read of the directory followed by a long run of Stat calls.
// Negative count means read until EOF.
func Readdir(fd *FD, count int) (dirs []Dir, err *os.Error) {
dirname := fd.name;
if dirname == "" {
dirname = ".";
}
dirname += "/";
// The buffer must be at least a block long.
// TODO(r): use fstatfs to find fs block size.
var buf = make([]syscall.Dirent, 8192/unsafe.Sizeof(*new(syscall.Dirent)));
dirs = make([]Dir, 0, 100); // TODO: could be smarter about size
for {
if count == 0 {
break
}
ret, err2 := syscall.Getdents(fd.fd, &buf[0], int64(len(buf) * unsafe.Sizeof(buf[0])));
if ret < 0 || err2 != 0 {
return dirs, os.ErrnoToError(err2)
}
if ret == 0 {
break
}
for w, i := uintptr(0),uintptr(0); i < uintptr(ret); i += w {
if count == 0 {
break
}
dirent := unsafe.Pointer((uintptr(unsafe.Pointer(&buf[0])) + i)).(*syscall.Dirent);
w = uintptr(dirent.Reclen);
if dirent.Ino == 0 {
continue
}
count--;
if len(dirs) == cap(dirs) {
ndirs := make([]Dir, len(dirs), 2*len(dirs));
for i := 0; i < len(dirs); i++ {
ndirs[i] = dirs[i]
}
dirs = ndirs;
}
dirs = dirs[0:len(dirs)+1];
filename := string(dirent.Name[0:clen(dirent.Name)]);
dirp, err := Stat(dirname + filename);
if dirp == nil || err != nil {
dirs[len(dirs)-1].Name = filename; // rest will be zeroed out
} else {
dirs[len(dirs)-1] = *dirp;
}
}
}
return dirs, nil;
}