cpp-common/bt2: rework `bt2::CommonIterator` (now `bt2::BorrowedObjectIterator`)

[babeltrace.git] / src / cpp-common / bt2 / borrowed-object-iterator.hpp

diff --git a/src/cpp-common/bt2/borrowed-object-iterator.hpp b/src/cpp-common/bt2/borrowed-object-iterator.hpp
new file mode 100644 (file)
index 0000000..46e68c1
--- /dev/null
+++ b/src/cpp-common/bt2/borrowed-object-iterator.hpp
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2022 Francis Deslauriers <francis.deslauriers@efficios.com>
+ * Copyright (c) 2023 Philippe Proulx <pproulx@efficios.com>
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#ifndef BABELTRACE_CPP_COMMON_BT2_BORROWED_OBJECT_ITERATOR_HPP
+#define BABELTRACE_CPP_COMMON_BT2_BORROWED_OBJECT_ITERATOR_HPP
+
+#include <cstdint>
+#include <type_traits>
+#include <utility>
+
+#include "common/assert.h"
+
+#include "borrowed-object-proxy.hpp"
+
+namespace bt2 {
+
+/*
+ * An iterator class to iterate an instance of a borrowed object
+ * container of type `ContainerT`.
+ *
+ * `ContainerT` must implement:
+ *
+ *     // Returns the number of contained borrowed objects.
+ *     std::uint64_t length() const noexcept;
+ *
+ *     // Returns the borrowed object at index `i`.
+ *     SomeObject operator[](std::uint64_t i) const noexcept;
+ */
+template <typename ContainerT>
+class BorrowedObjectIterator final
+{
+    friend ContainerT;
+
+public:
+    using Object = typename std::remove_reference<
+        decltype(std::declval<ContainerT>()[std::declval<std::uint64_t>()])>::type;
+
+private:
+    explicit BorrowedObjectIterator(const ContainerT container, const uint64_t idx) :
+        _mContainer {container}, _mIdx {idx}
+    {
+    }
+
+public:
+    BorrowedObjectIterator& operator++() noexcept
+    {
+        ++_mIdx;
+        return *this;
+    }
+
+    BorrowedObjectIterator operator++(int) noexcept
+    {
+        const auto tmp = *this;
+
+        ++(*this);
+        return tmp;
+    }
+
+    bool operator==(const BorrowedObjectIterator& other) const noexcept
+    {
+        BT_ASSERT_DBG(_mContainer.isSame(other._mContainer));
+        return _mIdx == other._mIdx;
+    }
+
+    bool operator!=(const BorrowedObjectIterator& other) const noexcept
+    {
+        return !(*this == other);
+    }
+
+    Object operator*() const noexcept
+    {
+        BT_ASSERT_DBG(_mIdx < _mContainer.length());
+        return _mContainer[_mIdx];
+    }
+
+    BorrowedObjectProxy<Object> operator->() const noexcept
+    {
+        return BorrowedObjectProxy<Object> {(**this).libObjPtr()};
+    }
+
+private:
+    ContainerT _mContainer;
+    std::uint64_t _mIdx;
+};
+
+} /* namespace bt2 */
+
+#endif /* BABELTRACE_CPP_COMMON_BT2_BORROWED_OBJECT_ITERATOR_HPP */