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std: Fix using fs.Dir.Iterator twice

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This fixes the use of multiple `Iterator`s in a row on a directory.
Previously, on many platforms, using an `Iterator` on an
already-iterated directory would give no entries.

Fixing this involved seeking to the beginning of the directory on the
first call of `next()`.
This commit is contained in:
ominitay
2022-01-27 09:59:30 +00:00
parent c3ef85aa76
commit dc11fe4047
2 changed files with 29 additions and 7 deletions
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33
lib/std/fs.zig
View File

@@ -300,6 +300,7 @@ pub const Dir = struct {
buf: [8192]u8, // TODO align(@alignOf(os.system.dirent)),
index: usize,
end_index: usize,
first_iter: bool,
const Self = @This();
@@ -319,6 +320,10 @@ pub const Dir = struct {
fn nextDarwin(self: *Self) !?Entry {
start_over: while (true) {
if (self.index >= self.end_index) {
if (self.first_iter) {
std.os.lseek_SET(self.dir.fd, 0) catch unreachable; // EBADF here likely means that the Dir was not opened with iteration permissions
self.first_iter = false;
}
const rc = os.system.__getdirentries64(
self.dir.fd,
&self.buf,
@@ -369,6 +374,10 @@ pub const Dir = struct {
fn nextSolaris(self: *Self) !?Entry {
start_over: while (true) {
if (self.index >= self.end_index) {
if (self.first_iter) {
std.os.lseek_SET(self.dir.fd, 0) catch unreachable; // EBADF here likely means that the Dir was not opened with iteration permissions
self.first_iter = false;
}
const rc = os.system.getdents(self.dir.fd, &self.buf, self.buf.len);
switch (os.errno(rc)) {
.SUCCESS => {},
@@ -423,6 +432,10 @@ pub const Dir = struct {
fn nextBsd(self: *Self) !?Entry {
start_over: while (true) {
if (self.index >= self.end_index) {
if (self.first_iter) {
std.os.lseek_SET(self.dir.fd, 0) catch unreachable; // EBADF here likely means that the Dir was not opened with iteration permissions
self.first_iter = false;
}
const rc = if (builtin.os.tag == .netbsd)
os.system.__getdents30(self.dir.fd, &self.buf, self.buf.len)
else
@@ -479,6 +492,7 @@ pub const Dir = struct {
buf: [8192]u8, // TODO align(@alignOf(os.dirent64)),
index: usize,
end_index: usize,
first_iter: bool,
const Self = @This();
@@ -491,6 +505,10 @@ pub const Dir = struct {
// TODO: find a better max
const HAIKU_MAX_COUNT = 10000;
if (self.index >= self.end_index) {
if (self.first_iter) {
std.os.lseek_SET(self.dir.fd, 0) catch unreachable; // EBADF here likely means that the Dir was not opened with iteration permissions
self.first_iter = false;
}
const rc = os.system._kern_read_dir(
self.dir.fd,
&self.buf,
@@ -563,6 +581,7 @@ pub const Dir = struct {
buf: [8192]u8 align(if (builtin.os.tag != .linux) 1 else @alignOf(linux.dirent64)),
index: usize,
end_index: usize,
first_iter: bool,
const Self = @This();
const linux = os.linux;
@@ -574,6 +593,10 @@ pub const Dir = struct {
pub fn next(self: *Self) Error!?Entry {
start_over: while (true) {
if (self.index >= self.end_index) {
if (self.first_iter) {
std.os.lseek_SET(self.dir.fd, 0) catch unreachable; // EBADF here likely means that the Dir was not opened with iteration permissions
self.first_iter = false;
}
const rc = linux.getdents64(self.dir.fd, &self.buf, self.buf.len);
switch (linux.getErrno(rc)) {
.SUCCESS => {},
@@ -620,7 +643,7 @@ pub const Dir = struct {
buf: [8192]u8 align(@alignOf(os.windows.FILE_BOTH_DIR_INFORMATION)),
index: usize,
end_index: usize,
first: bool,
first_iter: bool,
name_data: [256]u8,
const Self = @This();
@@ -645,9 +668,9 @@ pub const Dir = struct {
.FileBothDirectoryInformation,
w.FALSE,
null,
if (self.first) @as(w.BOOLEAN, w.TRUE) else @as(w.BOOLEAN, w.FALSE),
if (self.first_iter) @as(w.BOOLEAN, w.TRUE) else @as(w.BOOLEAN, w.FALSE),
);
self.first = false;
self.first_iter = false;
if (io.Information == 0) return null;
self.index = 0;
self.end_index = io.Information;
@@ -769,18 +792,20 @@ pub const Dir = struct {
.index = 0,
.end_index = 0,
.buf = undefined,
.first_iter = true,
},
.linux, .haiku => return Iterator{
.dir = self,
.index = 0,
.end_index = 0,
.buf = undefined,
.first_iter = true,
},
.windows => return Iterator{
.dir = self,
.index = 0,
.end_index = 0,
.first = true,
.first_iter = true,
.buf = undefined,
.name_data = undefined,
},

3
lib/std/fs/test.zig
View File

@@ -180,10 +180,7 @@ test "Dir.Iterator" {
try testing.expect(contains(&entries, Dir.Entry{ .name = "some_dir", .kind = Dir.Entry.Kind.Directory }));
}
// TODO Only passes on Windows, see https://github.com/ziglang/zig/issues/10317
test "Dir.Iterator twice" {
if (builtin.os.tag != .windows) return error.SkipZigTest;
var tmp_dir = tmpDir(.{ .iterate = true });
defer tmp_dir.cleanup();