windows: handles can't have multiple completion keys

This kinda sucks, but oh well ...
Cloudef · Aug 29, 2024 · 9161f2a · 9161f2a
1 parent 48c66c2
commit 9161f2a
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Showing 2 changed files with 29 additions and 10 deletions.
diff --git a/src/aio/Windows.zig b/src/aio/Windows.zig
@@ -40,7 +40,7 @@ const INVALID_SOCKET = win_sock.INVALID_SOCKET;
 const threading = win32.system.threading;
 
 const IoContext = struct {
-    overlapped: io.OVERLAPPED = undefined,
+    overlapped: io.OVERLAPPED = std.mem.zeroes(io.OVERLAPPED),
 
     // needs to be cleaned up
     owned: union(enum) {
@@ -127,6 +127,20 @@ fn iocpDrainThread(self: *@This()) void {
         var key: Iocp.Key = undefined;
         var maybe_ovl: ?*io.OVERLAPPED = null;
         const res = io.GetQueuedCompletionStatus(self.iocp.port, &transferred, @ptrCast(&key), &maybe_ovl, INFINITE);
+        if (res != 1 and maybe_ovl == null) {
+            break;
+        }
+
+        const id: u16 = switch (key.type) {
+            .shutdown,
+            .event_source,
+            .child_exit => key.id,
+            .overlapped => blk: {
+                const parent: *IoContext = @fieldParentPtr("overlapped", maybe_ovl.?);
+                break :blk @intCast((@intFromPtr(parent) - @intFromPtr(self.ovls.ptr)) / @sizeOf(IoContext));
+            }
+        };
+
         if (res == 1) {
             switch (key.type) {
                 .shutdown => break,
@@ -139,7 +153,7 @@ fn iocpDrainThread(self: *@This()) void {
                         win32.system.system_services.JOB_OBJECT_MSG_EXIT_PROCESS, win32.system.system_services.JOB_OBJECT_MSG_ABNORMAL_EXIT_PROCESS => {},
                         else => continue,
                     }
-                    const op = &self.uringlator.ops.nodes[key.id].used.child_exit;
+                    const op = &self.uringlator.ops.nodes[id].used.child_exit;
                     if (op.out_term) |term| {
                         var code: u32 = undefined;
                         if (win32.system.threading.GetExitCodeProcess(op.child, &code) == 0) {
@@ -149,14 +163,12 @@ fn iocpDrainThread(self: *@This()) void {
                         }
                     }
                 },
-                .overlapped => self.ovls[key.id].res = transferred,
+                .overlapped => self.ovls[id].res = transferred,
             }
-            self.uringlator.finish(key.id, error.Success);
-        } else if (maybe_ovl) |_| {
-            std.debug.assert(key.type != .shutdown);
-            self.uringlator.finish(key.id, werr(0));
+            self.uringlator.finish(id, error.Success);
         } else {
-            break;
+            std.debug.assert(key.type != .shutdown);
+            self.uringlator.finish(id, werr(0));
         }
     }
 }

diff --git a/src/aio/posix/windows.zig b/src/aio/posix/windows.zig
@@ -52,6 +52,13 @@ pub const Iocp = struct {
             child_exit,
             overlapped,
         },
+        // The ID is only used for custom events, for CreateIoCompletionPort assocations its useless,
+        // as it prevents from having multiple keys for a single handle:
+        // > Use the CompletionKey parameter to help your application track which I/O operations have completed.
+        // > This value is not used by CreateIoCompletionPort for functional control; rather, it is attached to
+        // > the file handle specified in the FileHandle parameter at the time of association with an I/O completion port.
+        // > This completion key should be unique for each file handle, and it accompanies the file handle throughout the
+        // > internal completion queuing process.
         id: u16,
         _: @Type(.{ .Int = .{ .bits = @bitSizeOf(usize) - @bitSizeOf(u16) * 2, .signedness = .unsigned } }) = undefined,
     };
@@ -80,8 +87,8 @@ pub const Iocp = struct {
         self.* = undefined;
     }
 
-    pub fn associateHandle(self: *@This(), id: u16, handle: HANDLE) !void {
-        const key: Key = .{ .type = .overlapped, .id = id };
+    pub fn associateHandle(self: *@This(), _: u16, handle: HANDLE) !void {
+        const key: Key = .{ .type = .overlapped, .id = undefined };
         const res = io.CreateIoCompletionPort(handle, self.port, @bitCast(key), 0);
         if (res == null or res.? == INVALID_HANDLE) {
             // ignore 87 as it may mean that we just re-registered the handle