std.windows: use posix semantics to delete files, if available

lib/std/fs/test.zig

@@ -1416,23 +1416,42 @@ test "File.PermissionsUnix" {
     try testing.expect(!permissions_unix.unixHas(.other, .execute));
 }
 
-test "delete a read-only file on windows" {
-    if (builtin.os.tag != .windows) return error.SkipZigTest;
+test "delete a read-only file on windows with file pending semantics" {
+    if (builtin.os.tag != .windows or builtin.target.os.version_range.windows.min.isAtLeast(.win10_rs1))
+        return error.SkipZigTest;
+
+    var tmp = tmpDir(.{});
+    defer tmp.cleanup();
+    {
+        const file = try tmp.dir.createFile("test_file", .{ .read = true });
+        defer file.close();
+        // Create a file and make it read-only
+        const metadata = try file.metadata();
+        var permissions = metadata.permissions();
+        permissions.setReadOnly(true);
+        try file.setPermissions(permissions);
+        try testing.expectError(error.AccessDenied, tmp.dir.deleteFile("test_file"));
+        // Now make the file not read-only
+        permissions.setReadOnly(false);
+        try file.setPermissions(permissions);
+    }
+    try tmp.dir.deleteFile("test_file");
+}
+
+test "delete a read-only file on windows with posix semantis" {
+    if (builtin.os.tag != .windows or !builtin.target.os.version_range.windows.min.isAtLeast(.win10_rs1))
+        return error.SkipZigTest;
 
     var tmp = tmpDir(.{});
     defer tmp.cleanup();
     const file = try tmp.dir.createFile("test_file", .{ .read = true });
+    defer file.close();
     // Create a file and make it read-only
     const metadata = try file.metadata();
     var permissions = metadata.permissions();
     permissions.setReadOnly(true);
     try file.setPermissions(permissions);
-    try testing.expectError(error.AccessDenied, tmp.dir.deleteFile("test_file"));
-    // Now make the file not read-only
-    permissions.setReadOnly(false);
-    try file.setPermissions(permissions);
-    file.close();
-    try tmp.dir.deleteFile("test_file");
+    try tmp.dir.deleteFile("test_file"); // file is unmapped and deleted once last handle closed
 }
 
 test "delete a setAsCwd directory on Windows" {

lib/std/os/windows.zig

@@ -937,19 +937,40 @@ pub fn DeleteFile(sub_path_w: []const u16, options: DeleteFileOptions) DeleteFil
         .DELETE_PENDING => return,
         else => return unexpectedStatus(rc),
     }
-    var file_dispo = FILE_DISPOSITION_INFORMATION{
-        .DeleteFile = TRUE,
-    };
-    rc = ntdll.NtSetInformationFile(
-        tmp_handle,
-        &io,
-        &file_dispo,
-        @sizeOf(FILE_DISPOSITION_INFORMATION),
-        .FileDispositionInformation,
-    );
-    CloseHandle(tmp_handle);
+    defer CloseHandle(tmp_handle);
+
+    if (comptime builtin.target.os.version_range.windows.min.isAtLeast(.win10_rs1)) {
+        // Deletion with posix semantics.
+        var info = FILE_DISPOSITION_INFORMATION_EX{
+            .Flags = FILE_DISPOSITION_DELETE |
+                FILE_DISPOSITION_POSIX_SEMANTICS |
+                FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE,
+        };
+
+        rc = ntdll.NtSetInformationFile(
+            tmp_handle,
+            &io,
+            &info,
+            @sizeOf(FILE_DISPOSITION_INFORMATION_EX),
+            .FileDispositionInformationEx,
+        );
+    } else {
+        // Deletion with file pending semantics, which requires waiting or moving
+        // files to get them removed (from here).
+        var file_dispo = FILE_DISPOSITION_INFORMATION{
+            .DeleteFile = TRUE,
+        };
+
+        rc = ntdll.NtSetInformationFile(
+            tmp_handle,
+            &io,
+            &file_dispo,
+            @sizeOf(FILE_DISPOSITION_INFORMATION),
+            .FileDispositionInformation,
+        );
+    }
     switch (rc) {
-        .SUCCESS => return,
+        .SUCCESS => {},
         .DIRECTORY_NOT_EMPTY => return error.DirNotEmpty,
         .INVALID_PARAMETER => unreachable,
         .CANNOT_DELETE => return error.AccessDenied,
@@ -2397,6 +2418,18 @@ pub const FILE_NAME_INFORMATION = extern struct {
     FileName: [1]WCHAR,
 };
 
+pub const FILE_DISPOSITION_INFORMATION_EX = extern struct {
+    /// combination of FILE_DISPOSITION_* flags
+    Flags: ULONG,
+};
+
+const FILE_DISPOSITION_DO_NOT_DELETE: ULONG = 0x00000000;
+const FILE_DISPOSITION_DELETE: ULONG = 0x00000001;
+const FILE_DISPOSITION_POSIX_SEMANTICS: ULONG = 0x00000002;
+const FILE_DISPOSITION_FORCE_IMAGE_SECTION_CHECK: ULONG = 0x00000004;
+const FILE_DISPOSITION_ON_CLOSE: ULONG = 0x00000008;
+const FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE: ULONG = 0x00000010;
+
 pub const FILE_RENAME_INFORMATION = extern struct {
     ReplaceIfExists: BOOLEAN,
     RootDirectory: ?HANDLE,