Add `bt2_common::UuidView`

This patch adds the `bt2_common::UuidView` class which is like
`std::string_view`, but for UUIDs.

You cannot modify the underlying UUID (`const std::uint8_t *`).

Compare UUID views with operator==() and operator!=().

Get a UUID view's data with its data() method.

Get a UUID view's data size with its size() method.

Get the canonical string of a UUID view with its string() method, which
returns a new `std::string` instance.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Change-Id: Icc633b44b852383d223ff8e73034736f47b64579
Reviewed-on: https://review.lttng.org/c/babeltrace/+/4601

diff --git a/src/cpp-common/uuid-view.hpp b/src/cpp-common/uuid-view.hpp
new file mode 100644 (file)
index 0000000..7811664
--- /dev/null
+++ b/src/cpp-common/uuid-view.hpp
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2020 Philippe Proulx <pproulx@efficios.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef BABELTRACE_CPP_COMMON_UUID_VIEW_HPP
+#define BABELTRACE_CPP_COMMON_UUID_VIEW_HPP
+
+#include <cstdint>
+
+#include "common/assert.h"
+#include "common/uuid.h"
+
+namespace bt2_common {
+
+class UuidView
+{
+public:
+    explicit UuidView(const std::uint8_t * const uuid) noexcept : _mUuid {uuid}
+    {
+        BT_ASSERT_DBG(uuid);
+    }
+
+    UuidView(const UuidView&) noexcept = default;
+    UuidView& operator=(const UuidView&) noexcept = default;
+
+    bool operator==(const UuidView& other) const noexcept
+    {
+        return bt_uuid_compare(_mUuid, other._mUuid) == 0;
+    }
+
+    bool operator!=(const UuidView& other) const noexcept
+    {
+        return !(*this == other);
+    }
+
+    std::string string() const
+    {
+        std::array<char, BT_UUID_STR_LEN> buf;
+
+        bt_uuid_to_str(_mUuid, buf.data());
+        return {buf.data(), buf.size()};
+    }
+
+    static std::size_t size() noexcept
+    {
+        return BT_UUID_LEN;
+    }
+
+    const std::uint8_t *data() const noexcept
+    {
+        return _mUuid;
+    }
+
+private:
+    const std::uint8_t *_mUuid;
+};
+
+} // namespace bt2_common
+
+#endif // BABELTRACE_CPP_COMMON_UUID_VIEW_HPP