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104 lines
2.5 KiB
Go
104 lines
2.5 KiB
Go
package libsq
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import (
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"fmt"
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"github.com/neilotoole/sq/libsq/core/loz"
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"github.com/neilotoole/sq/libsq/ast"
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"github.com/neilotoole/sq/libsq/core/errz"
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"golang.org/x/exp/slog"
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)
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// queryModel is a model of an SLQ query built from the AST.
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type queryModel struct {
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AST *ast.AST
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Table ast.Tabler
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Cols []ast.ResultColumn
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Range *ast.RowRangeNode
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Where *ast.WhereNode
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OrderBy *ast.OrderByNode
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GroupBy *ast.GroupByNode
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Distinct *ast.UniqueNode
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}
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func (qm *queryModel) String() string {
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return fmt.Sprintf("%v | %v | %v", qm.Table, qm.Cols, qm.Range)
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}
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// buildQueryModel creates a queryModel instance from the AST.
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func buildQueryModel(log *slog.Logger, a *ast.AST) (*queryModel, error) {
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if len(a.Segments()) == 0 {
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return nil, errz.Errorf("query model error: query does not have enough segments")
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}
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insp := ast.NewInspector(a)
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var tabler ast.Tabler
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var ok bool
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tablerSeg, err := insp.FindFinalTablerSegment()
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if err != nil {
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log.Debug("No Tabler segment.")
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}
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if tablerSeg != nil {
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if len(tablerSeg.Children()) != 1 {
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return nil, errz.Errorf(
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"the final selectable segment must have exactly one selectable element, but found %d elements",
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len(tablerSeg.Children()))
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}
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if tabler, ok = tablerSeg.Children()[0].(ast.Tabler); !ok {
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return nil, errz.Errorf(
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"the final selectable segment must have exactly one selectable element, but found element %T(%s)",
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tablerSeg.Children()[0], tablerSeg.Children()[0].Text())
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}
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}
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qm := &queryModel{AST: a, Table: tabler}
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if qm.Range, err = insp.FindRowRangeNode(); err != nil {
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return nil, err
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}
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seg, err := insp.FindColExprSegment()
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if err != nil {
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return nil, err
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}
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if seg != nil {
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var colExprs []ast.ResultColumn
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if colExprs, ok = loz.ToSliceType[ast.Node, ast.ResultColumn](seg.Children()...); !ok {
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return nil, errz.Errorf("segment children contained elements that were not of type %T: %s",
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ast.ResultColumn(nil), seg.Text())
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}
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qm.Cols = colExprs
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}
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whereClauses, err := insp.FindWhereClauses()
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if err != nil {
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return nil, err
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}
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if len(whereClauses) > 1 {
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return nil, errz.Errorf("only one WHERE clause is supported, but found %d", len(whereClauses))
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} else if len(whereClauses) == 1 {
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qm.Where = whereClauses[0]
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}
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if qm.OrderBy, err = insp.FindOrderByNode(); err != nil {
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return nil, err
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}
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if qm.GroupBy, err = insp.FindGroupByNode(); err != nil {
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return nil, err
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}
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if qm.Distinct, err = insp.FindUniqueNode(); err != nil {
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return nil, err
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}
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return qm, nil
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}
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