[common] clipboard: define streamed clipboard ABIs

idd/LGCommon/ClipboardRing.h

@@ -0,0 +1,64 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2026 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#pragma once
+
+#include "common/KVMFRClipboard.h"
+
+#include <stddef.h>
+#include <stdint.h>
+
+static constexpr uint32_t LG_CLIPBOARD_MAPPING_MAGIC = 0x4c474342U;
+static constexpr uint32_t LG_CLIPBOARD_MAPPING_VERSION = 1U;
+
+struct ClipboardRingSlot
+{
+  KVMFRClipboardSlotHeader header;
+  uint8_t data[KVMFR_CLIPBOARD_DATA_BYTES];
+};
+
+struct alignas(64) ClipboardRing
+{
+  uint32_t produced;
+  uint32_t consumed;
+  uint32_t reserved[14];
+  ClipboardRingSlot slots[KVMFR_CLIPBOARD_SLOT_COUNT];
+};
+
+struct alignas(64) ClipboardMapping
+{
+  uint32_t magic;
+  uint32_t version;
+  uint32_t size;
+  uint32_t slotBytes;
+  uint32_t slotCount;
+  uint32_t reserved0;
+  uint64_t epoch;
+  uint8_t reserved1[32];
+  ClipboardRing helperToIdd;
+  ClipboardRing iddToHelper;
+};
+
+static_assert(sizeof(KVMFRClipboardSlotHeader) == 64,
+  "clipboard slot header alignment changed");
+static_assert(offsetof(ClipboardMapping, helperToIdd) == 64,
+  "clipboard mapping header layout changed");
+static_assert(offsetof(ClipboardMapping, iddToHelper) % 64 == 0,
+  "clipboard rings must remain cache-line aligned");