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105 lines
2.4 KiB
Go
105 lines
2.4 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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)
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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.TblSelectorNode
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Joins []*ast.JoinNode
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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(qc *QueryContext, a *ast.AST) (*queryModel, error) {
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if len(a.Segments()) == 0 {
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return nil, errz.Errorf("invalid query: no segments")
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}
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var (
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ok bool
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err error
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insp = ast.NewInspector(a)
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qm = &queryModel{AST: a}
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)
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qm.Table = insp.FindFirstTableSelector()
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if qm.Table != nil {
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// If the table selector doesn't specify a handle, set the
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// table's handle to the active handle.
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if qm.Table.Handle() == "" {
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// It's possible that there's no active source: this
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// is effectively a no-op in that case.
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qm.Table.SetHandle(qc.Collection.ActiveHandle())
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}
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}
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if qm.Joins, err = insp.FindJoins(); err != nil {
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return nil, err
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}
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if len(qm.Joins) > 0 && qm.Table == nil {
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return nil, errz.Errorf("invalid query: join doesn't have a preceding table selector")
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}
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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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