Add new Insertion datastructures

core/translate/insert.rs

@@ -949,6 +949,123 @@ fn populate_column_registers(
     Ok(())
 }
 
+/// Represents how a table should be populated during an INSERT.
+#[derive(Debug)]
+struct Insertion<'a> {
+    /// The integer key ("rowid") provided to the VDBE.
+    key: InsertionKey<'a>,
+    /// The column values that will be fed to the MakeRecord instruction to insert the row.
+    /// If the table has a rowid alias column, it will also be included in this record,
+    /// but a NULL will be stored for it.
+    col_mappings: Vec<ColMapping<'a>>,
+    /// The register that will contain the record built using the MakeRecord instruction.
+    record_reg: usize,
+}
+
+impl<'a> Insertion<'a> {
+    /// Return the register that contains the rowid.
+    pub fn key_register(&self) -> usize {
+        self.key.register()
+    }
+
+    /// Return the first register of the values that used to build the record
+    /// for the main table insert.
+    pub fn first_col_register(&self) -> usize {
+        self.col_mappings
+            .first()
+            .expect("columns must be present")
+            .register
+    }
+
+    /// Return the register that contains the record built using the MakeRecord instruction.
+    pub fn record_register(&self) -> usize {
+        self.record_reg
+    }
+
+    /// Returns the column mapping for a given column name.
+    pub fn get_col_mapping_by_name(&self, name: &str) -> &ColMapping<'a> {
+        if let InsertionKey::RowidAlias(mapping) = &self.key {
+            // If the key is a rowid alias, a NULL is emitted as the column value,
+            // so we need to return the key mapping instead so that the non-NULL rowid is used
+            // for the index insert.
+            if mapping
+                .column
+                .name
+                .as_ref()
+                .is_some_and(|n| n.eq_ignore_ascii_case(name))
+            {
+                return mapping;
+            }
+        }
+        self.col_mappings
+            .iter()
+            .find(|col| {
+                col.column
+                    .name
+                    .as_ref()
+                    .is_some_and(|n| n.eq_ignore_ascii_case(name))
+            })
+            .unwrap_or_else(|| panic!("column {name} not found in insertion"))
+    }
+}
+
+#[derive(Debug)]
+enum InsertionKey<'a> {
+    /// Rowid is not provided by user and will be autogenerated.
+    Autogenerated { register: usize },
+    /// Rowid is provided via the 'rowid' keyword.
+    LiteralRowid {
+        value_index: Option<usize>,
+        register: usize,
+    },
+    /// Rowid is provided via a rowid alias column.
+    RowidAlias(ColMapping<'a>),
+}
+
+impl InsertionKey<'_> {
+    fn register(&self) -> usize {
+        match self {
+            InsertionKey::Autogenerated { register } => *register,
+            InsertionKey::LiteralRowid { register, .. } => *register,
+            InsertionKey::RowidAlias(x) => x.register,
+        }
+    }
+    fn is_provided_by_user(&self) -> bool {
+        !matches!(self, InsertionKey::Autogenerated { .. })
+    }
+
+    fn column_name(&self) -> &str {
+        match self {
+            InsertionKey::RowidAlias(x) => x
+                .column
+                .name
+                .as_ref()
+                .expect("rowid alias column must be present")
+                .as_str(),
+            InsertionKey::LiteralRowid { .. } => ROWID,
+            InsertionKey::Autogenerated { .. } => ROWID,
+        }
+    }
+}
+
+/// Represents how a column in a table should be populated during an INSERT.
+/// In a vector of [ColMapping], the index of a given [ColMapping] is
+/// the position of the column in the table.
+#[derive(Debug)]
+struct ColMapping<'a> {
+    /// Column definition
+    column: &'a Column,
+    /// Index of the value to use from a tuple in the insert statement.
+    /// This is needed because the values in the insert statement are not necessarily
+    /// in the same order as the columns in the table, nor do they necessarily contain
+    /// all of the columns in the table.
+    /// If None, a NULL will be emitted for the column, unless it has a default value.
+    /// A NULL rowid alias column's value will be autogenerated.
+    value_index: Option<usize>,
+    /// Register where the value will be stored for insertion into the table.
+    register: usize,
+}
+
 // TODO: comeback here later to apply the same improvements on select
 fn translate_virtual_table_insert(
     mut program: ProgramBuilder,