add Readdir: returns an array of Dir structures

R=rsc
DELTA=200  (176 added, 12 deleted, 12 changed)
OCL=24680
CL=24680

src/lib/os/dir_amd64_darwin.go

@@ -37,9 +37,9 @@ 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);
+			dirent := unsafe.Pointer((uintptr(unsafe.Pointer(&buf[0])) + i)).(*syscall.Dirent);
-			w = uintptr(dir.Reclen);
+			w = uintptr(dirent.Reclen);
-			if dir.Ino == 0 {
+			if dirent.Ino == 0 {
 				continue
 			}
 			count--;
@@ -51,8 +51,68 @@ 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:dir.Namlen]);
+			names[len(names)-1] = string(dirent.Name[0:dirent.Namlen]);
 		}
 	}
 	return names, nil;
 }
+
+// TODO(r): see comment in dir_amd64_linux.go
+
+// Negative count means read until EOF.
+func Readdir(fd *FD, count int) (dirs []Dir, err *os.Error) {
+	dirname := fd.name;
+	if dirname == "" {
+		dirname = ".";
+	}
+	dirname += "/";
+	// Getdirentries needs the file offset - it's too hard for the kernel to remember
+	// a number it already has written down.
+	base, err1 := syscall.Seek(fd.fd, 0, 1);
+	if err1 != 0 {
+		return nil, os.ErrnoToError(err1)
+	}
+	// The buffer must be at least a block long.
+	// TODO(r): use fstatfs to find fs block size.
+	var buf = make([]byte, 8192);
+	dirs = make([]Dir, 0, 100);	// TODO: could be smarter about size
+	for {
+		if count == 0 {
+			break
+		}
+		ret, err2 := syscall.Getdirentries(fd.fd, &buf[0], int64(len(buf)), &base);
+		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:dirent.Namlen]);
+			dirp, err := Stat(dirname + filename);
+			if dir == nil || err != nil {
+				dirs[len(dirs)-1].Name = filename;	// rest will be zeroed out
+			} else {
+				dirs[len(dirs)-1] = *dirp;
+			}
+		}
+	}
+	return dirs, nil;
+}

src/lib/os/dir_amd64_linux.go

@@ -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);
+			dirent := unsafe.Pointer((uintptr(unsafe.Pointer(&buf[0])) + i)).(*syscall.Dirent);
-			w = uintptr(dir.Reclen);
+			w = uintptr(dirent.Reclen);
-			if dir.Ino == 0 {
+			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;
+}

src/lib/os/os_test.go

@@ -10,6 +10,25 @@ import (
 	"testing";
 )
 
+var dot = []string{
+	"dir_amd64_darwin.go",
+	"dir_amd64_linux.go",
+	"os_env.go",
+	"os_error.go",
+	"os_file.go",
+	"os_test.go",
+	"os_time.go",
+	"os_types.go",
+	"stat_amd64_darwin.go",
+	"stat_amd64_linux.go"
+}
+
+var etc = []string{
+	"group",
+	"hosts",
+	"passwd",
+}
+
 func size(file string, t *testing.T) uint64 {
 	fd, err := Open(file, O_RDONLY, 0);
 	defer fd.Close();
@@ -78,29 +97,17 @@ func TestLstat(t *testing.T) {
 	}
 }
 
-func TestReaddirnames(t *testing.T) {
+func testReaddirnames(dir string, contents []string, t *testing.T) {
-	fd, err := Open(".", O_RDONLY, 0);
+	fd, err := Open(dir, O_RDONLY, 0);
 	defer fd.Close();
 	if err != nil {
-		t.Fatal("open . failed:", err);
+		t.Fatalf("open %q failed: %s\n", dir, err.String());
 	}
 	s, err2 := Readdirnames(fd, -1);
 	if err2 != nil {
 		t.Fatal("readdirnames . failed:", err);
 	}
-	a := []string{
+	for i, m := range contents {
-		"dir_amd64_darwin.go",
-		"dir_amd64_linux.go",
-		"os_env.go",
-		"os_error.go",
-		"os_file.go",
-		"os_test.go",
-		"os_time.go",
-		"os_types.go",
-		"stat_amd64_darwin.go",
-		"stat_amd64_linux.go"
-	};
-	for i, m := range a {
 		found := false;
 		for j, n := range s {
 			if m == n {
@@ -115,3 +122,39 @@ func TestReaddirnames(t *testing.T) {
 		}
 	}
 }
+
+func testReaddir(dir string, contents []string, t *testing.T) {
+	fd, err := Open(dir, O_RDONLY, 0);
+	defer fd.Close();
+	if err != nil {
+		t.Fatalf("open %q failed: %s\n", dir, err.String());
+	}
+	s, err2 := Readdir(fd, -1);
+	if err2 != nil {
+		t.Fatal("readdir . failed:", err);
+	}
+	for i, m := range contents {
+		found := false;
+		for j, n := range s {
+			if m == n.Name {
+				if found {
+					t.Error("present twice:", m);
+				}
+				found = true
+			}
+		}
+		if !found {
+			t.Error("could not find", m);
+		}
+	}
+}
+
+func TestReaddirnames(t *testing.T) {
+	testReaddirnames(".", dot, t);
+	testReaddirnames("/etc", etc, t);
+}
+
+func TestReaddir(t *testing.T) {
+	testReaddir(".", dot, t);
+	testReaddir("/etc", etc, t);
+}