--- /dev/null
+/*************************************************************************
+ *
+ * Copyright 2016 Realm Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ **************************************************************************/
+
+#ifndef REALM_COLUMN_LINK_HPP
+#define REALM_COLUMN_LINK_HPP
+
+#include <realm/column.hpp>
+#include <realm/column_linkbase.hpp>
+#include <realm/column_backlink.hpp>
+
+namespace realm {
+
+/// A link column is an extension of an integer column (Column) and maintains
+/// its node structure.
+///
+/// The individual values in a link column are indexes of rows in the target
+/// table (offset with one to allow zero to indicate null links.) The target
+/// table is specified by the table descriptor.
+class LinkColumn : public LinkColumnBase {
+public:
+ using LinkColumnBase::LinkColumnBase;
+ ~LinkColumn() noexcept override;
+
+ static ref_type create(Allocator&, size_t size = 0);
+
+ bool is_nullable() const noexcept override;
+
+ //@{
+
+ /// is_null_link() is shorthand for `get_link() == realm::npos`,
+ /// nullify_link() is shorthand foe `set_link(realm::npos)`, and
+ /// insert_null_link() is shorthand for
+ /// `insert_link(realm::npos)`. set_link() returns the original link, with
+ /// `realm::npos` indicating that it was null.
+
+ size_t get_link(size_t row_ndx) const noexcept;
+ bool is_null(size_t row_ndx) const noexcept override;
+ bool is_null_link(size_t row_ndx) const noexcept;
+ size_t set_link(size_t row_ndx, size_t target_row_ndx);
+ void set_null(size_t row_ndx) override;
+ void nullify_link(size_t row_ndx);
+ void insert_link(size_t row_ndx, size_t target_row_ndx);
+ void insert_null_link(size_t row_ndx);
+
+ //@}
+
+ void insert_rows(size_t, size_t, size_t, bool) override;
+ void erase_rows(size_t, size_t, size_t, bool) override;
+ void move_last_row_over(size_t, size_t, bool) override;
+ void swap_rows(size_t, size_t) override;
+ void clear(size_t, bool) override;
+ void cascade_break_backlinks_to(size_t, CascadeState&) override;
+ void cascade_break_backlinks_to_all_rows(size_t, CascadeState&) override;
+
+ void verify(const Table&, size_t) const override;
+
+protected:
+ friend class BacklinkColumn;
+ void do_nullify_link(size_t row_ndx, size_t old_target_row_ndx) override;
+ void do_update_link(size_t row_ndx, size_t old_target_row_ndx, size_t new_target_row_ndx) override;
+ void do_swap_link(size_t row_ndx, size_t target_row_ndx_1, size_t target_row_ndx_2) override;
+
+private:
+ void remove_backlinks(size_t row_ndx);
+};
+
+
+// Implementation
+
+inline LinkColumn::~LinkColumn() noexcept
+{
+}
+
+inline bool LinkColumn::is_nullable() const noexcept
+{
+ return true;
+}
+
+inline ref_type LinkColumn::create(Allocator& alloc, size_t size)
+{
+ return IntegerColumn::create(alloc, Array::type_Normal, size); // Throws
+}
+
+inline bool LinkColumn::is_null(size_t row_ndx) const noexcept
+{
+ // Null is represented by zero
+ return LinkColumnBase::get(row_ndx) == 0;
+}
+
+inline size_t LinkColumn::get_link(size_t row_ndx) const noexcept
+{
+ // Map zero to realm::npos, and `n+1` to `n`, where `n` is a target row index.
+ return to_size_t(LinkColumnBase::get(row_ndx)) - size_t(1);
+}
+
+inline bool LinkColumn::is_null_link(size_t row_ndx) const noexcept
+{
+ return is_null(row_ndx);
+}
+
+inline size_t LinkColumn::set_link(size_t row_ndx, size_t target_row_ndx)
+{
+ int_fast64_t old_value = LinkColumnBase::get(row_ndx);
+ size_t old_target_row_ndx = to_size_t(old_value) - size_t(1);
+ if (old_value != 0)
+ m_backlink_column->remove_one_backlink(old_target_row_ndx, row_ndx); // Throws
+
+ int_fast64_t new_value = int_fast64_t(size_t(1) + target_row_ndx);
+ LinkColumnBase::set(row_ndx, new_value); // Throws
+
+ if (target_row_ndx != realm::npos)
+ m_backlink_column->add_backlink(target_row_ndx, row_ndx); // Throws
+
+ return old_target_row_ndx;
+}
+
+inline void LinkColumn::set_null(size_t row_ndx)
+{
+ set_link(row_ndx, realm::npos); // Throws
+}
+
+inline void LinkColumn::nullify_link(size_t row_ndx)
+{
+ set_null(row_ndx); // Throws
+}
+
+inline void LinkColumn::insert_link(size_t row_ndx, size_t target_row_ndx)
+{
+ int_fast64_t value = int_fast64_t(size_t(1) + target_row_ndx);
+ LinkColumnBase::insert(row_ndx, value); // Throws
+
+ if (target_row_ndx != realm::npos)
+ m_backlink_column->add_backlink(target_row_ndx, row_ndx); // Throws
+}
+
+inline void LinkColumn::insert_null_link(size_t row_ndx)
+{
+ insert_link(row_ndx, realm::npos); // Throws
+}
+
+inline void LinkColumn::do_update_link(size_t row_ndx, size_t, size_t new_target_row_ndx)
+{
+ // Row pos is offset by one, to allow null refs
+ LinkColumnBase::set(row_ndx, new_target_row_ndx + 1);
+}
+
+inline void LinkColumn::do_swap_link(size_t row_ndx, size_t target_row_ndx_1, size_t target_row_ndx_2)
+{
+ // Row pos is offset by one, to allow null refs
+ ++target_row_ndx_1;
+ ++target_row_ndx_2;
+
+ uint64_t value = LinkColumnBase::get_uint(row_ndx);
+ if (value == target_row_ndx_1) {
+ LinkColumnBase::set_uint(row_ndx, target_row_ndx_2);
+ }
+ else if (value == target_row_ndx_2) {
+ LinkColumnBase::set_uint(row_ndx, target_row_ndx_1);
+ }
+}
+
+} // namespace realm
+
+#endif // REALM_COLUMN_LINK_HPP
fnp / wl-app.git / blobdiff