Bool expression refactoring.
This commit is contained in:
zer0sub
parent
5a7563d4af
commit
38007810c1
15 changed files with 818 additions and 583 deletions
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@ -1,179 +1,56 @@
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// Query building functions for expression components
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package sqlbuilder
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import (
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"bytes"
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"strconv"
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"strings"
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"time"
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"github.com/dropbox/godropbox/database/sqltypes"
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"github.com/dropbox/godropbox/errors"
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)
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type orderByClause struct {
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isOrderByClause
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expression Expression
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ascent bool
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// An expression
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type Expression interface {
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Clause
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As(alias string) Clause
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IsDistinct(expression Expression) BoolExpression
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IsNull(expression Expression) BoolExpression
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}
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func (o *orderByClause) SerializeSql(out *bytes.Buffer) error {
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if o.expression == nil {
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return errors.Newf(
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"nil order by clause. Generated sql: %s",
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out.String())
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}
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type expressionInterfaceImpl struct {
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parent Expression
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}
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if err := o.expression.SerializeSql(out); err != nil {
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return err
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}
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if o.ascent {
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_, _ = out.WriteString(" ASC")
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} else {
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_, _ = out.WriteString(" DESC")
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}
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func (e *expressionInterfaceImpl) As(alias string) Clause {
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return NewAlias(e.parent, alias)
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}
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func (e *expressionInterfaceImpl) IsDistinct(expression Expression) BoolExpression {
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return nil
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}
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func Asc(expression Expression) OrderByClause {
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return &orderByClause{expression: expression, ascent: true}
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}
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func Desc(expression Expression) OrderByClause {
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return &orderByClause{expression: expression, ascent: false}
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}
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// Representation of an escaped literal
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type literalExpression struct {
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isExpression
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value sqltypes.Value
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}
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func (c literalExpression) SerializeSql(out *bytes.Buffer) error {
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sqltypes.Value(c.value).EncodeSql(out)
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return nil
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}
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func serializeClauses(
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clauses []Clause,
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separator []byte,
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out *bytes.Buffer) (err error) {
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if clauses == nil || len(clauses) == 0 {
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return errors.Newf("Empty clauses. Generated sql: %s", out.String())
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}
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if clauses[0] == nil {
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return errors.Newf("nil clause. Generated sql: %s", out.String())
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}
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if err = clauses[0].SerializeSql(out); err != nil {
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return
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}
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for _, c := range clauses[1:] {
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_, _ = out.Write(separator)
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if c == nil {
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return errors.Newf("nil clause. Generated sql: %s", out.String())
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}
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if err = c.SerializeSql(out); err != nil {
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return
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}
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}
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return nil
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}
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// Representation of n-ary arithmetic (+ - * /)
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type arithmeticExpression struct {
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isExpression
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expressions []Expression
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operator []byte
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}
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func (arith *arithmeticExpression) SerializeSql(out *bytes.Buffer) (err error) {
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if len(arith.expressions) == 0 {
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return errors.Newf(
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"Empty arithmetic expression. Generated sql: %s",
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out.String())
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}
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clauses := make([]Clause, len(arith.expressions), len(arith.expressions))
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for i, expr := range arith.expressions {
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clauses[i] = expr
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}
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useParentheses := len(clauses) > 1
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if useParentheses {
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_ = out.WriteByte('(')
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}
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if err = serializeClauses(clauses, arith.operator, out); err != nil {
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return
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}
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if useParentheses {
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_ = out.WriteByte(')')
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}
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return nil
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}
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type tupleExpression struct {
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isExpression
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elements listClause
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}
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func (tuple *tupleExpression) SerializeSql(out *bytes.Buffer) error {
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if len(tuple.elements.clauses) < 1 {
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return errors.Newf("Tuples must include at least one element")
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}
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return tuple.elements.SerializeSql(out)
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}
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func Tuple(exprs ...Expression) Expression {
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clauses := make([]Clause, 0, len(exprs))
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for _, expr := range exprs {
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clauses = append(clauses, expr)
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}
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return &tupleExpression{
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elements: listClause{
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clauses: clauses,
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includeParentheses: true,
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},
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}
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}
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// Representation of a tuple enclosed, comma separated list of clauses
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type listClause struct {
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clauses []Clause
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includeParentheses bool
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}
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func (list *listClause) SerializeSql(out *bytes.Buffer) error {
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if list.includeParentheses {
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_ = out.WriteByte('(')
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}
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if err := serializeClauses(list.clauses, []byte(","), out); err != nil {
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return err
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}
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if list.includeParentheses {
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_ = out.WriteByte(')')
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}
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func (e *expressionInterfaceImpl) IsNull(expression Expression) BoolExpression {
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return nil
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}
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// Representation of binary operations (e.g. comparisons, arithmetic)
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type binaryExpression struct {
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isExpression
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expressionInterfaceImpl
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lhs, rhs Expression
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operator []byte
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}
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func NewBinaryExpression(lhs, rhs Expression, operator []byte, parent ...Expression) *binaryExpression {
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binaryExpression := binaryExpression{
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lhs: lhs,
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rhs: rhs,
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operator: operator,
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}
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if len(parent) > 0 {
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binaryExpression.parent = parent[0]
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}
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return &binaryExpression
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}
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func (c *binaryExpression) SerializeSql(out *bytes.Buffer) (err error) {
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if c.lhs == nil {
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return errors.Newf("nil lhs. Generated sql: %s", out.String())
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@ -194,220 +71,90 @@ func (c *binaryExpression) SerializeSql(out *bytes.Buffer) (err error) {
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return nil
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}
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type funcExpression struct {
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isExpression
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funcName string
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args *listClause
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// A not expression which negates a expression value
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type prefixExpression struct {
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expressionInterfaceImpl
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expression Expression
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operator []byte
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}
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func (c *funcExpression) SerializeSql(out *bytes.Buffer) (err error) {
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if !validIdentifierName(c.funcName) {
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func NewPrefixExpression(expression Expression, operator []byte, parent ...Expression) *prefixExpression {
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prefixExpression := prefixExpression{
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expression: expression,
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operator: operator,
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}
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if len(parent) > 0 {
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prefixExpression.parent = parent[0]
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}
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return &prefixExpression
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}
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func (p *prefixExpression) SerializeSql(out *bytes.Buffer) (err error) {
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_, _ = out.Write(p.operator)
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if p.expression == nil {
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return errors.Newf("nil prefix expression. Generated sql: %s", out.String())
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}
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if err = p.expression.SerializeSql(out); err != nil {
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return
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}
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return nil
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}
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// Representation of n-ary conjunctions (AND/OR)
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type conjunctExpression struct {
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expressionInterfaceImpl
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expressions []BoolExpression
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conjunction []byte
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}
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func (conj *conjunctExpression) SerializeSql(out *bytes.Buffer) (err error) {
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if len(conj.expressions) == 0 {
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return errors.Newf(
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"Invalid function name: %s. Generated sql: %s",
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c.funcName,
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"Empty conjunction. Generated sql: %s",
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out.String())
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}
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_, _ = out.WriteString(c.funcName)
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if c.args == nil {
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_, _ = out.WriteString("()")
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} else {
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return c.args.SerializeSql(out)
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clauses := make([]Clause, len(conj.expressions), len(conj.expressions))
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for i, expr := range conj.expressions {
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clauses[i] = expr
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}
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useParentheses := len(clauses) > 1
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if useParentheses {
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_ = out.WriteByte('(')
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}
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if err = serializeClauses(clauses, conj.conjunction, out); err != nil {
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return
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}
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if useParentheses {
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_ = out.WriteByte(')')
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}
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return nil
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}
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// Returns a representation of sql function call "func_call(c[0], ..., c[n-1])
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func SqlFunc(funcName string, expressions ...Expression) Expression {
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f := &funcExpression{
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funcName: funcName,
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}
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if len(expressions) > 0 {
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args := make([]Clause, len(expressions), len(expressions))
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for i, expr := range expressions {
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args[i] = expr
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}
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//--------------------------------------------------------------
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f.args = &listClause{
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clauses: args,
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includeParentheses: true,
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}
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}
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return f
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// Representation of an escaped literal
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type literalExpression struct {
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expressionInterfaceImpl
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value sqltypes.Value
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}
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type intervalExpression struct {
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isExpression
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duration time.Duration
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negative bool
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func NewLiteralExpression(value sqltypes.Value) *literalExpression {
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exp := literalExpression{value: value}
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exp.expressionInterfaceImpl.parent = &exp
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return &exp
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}
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var intervalSep = ":"
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func (c *intervalExpression) SerializeSql(out *bytes.Buffer) (err error) {
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hours := c.duration / time.Hour
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minutes := (c.duration % time.Hour) / time.Minute
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sec := (c.duration % time.Minute) / time.Second
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msec := (c.duration % time.Second) / time.Microsecond
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_, _ = out.WriteString("INTERVAL '")
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if c.negative {
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_, _ = out.WriteString("-")
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}
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_, _ = out.WriteString(strconv.FormatInt(int64(hours), 10))
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_, _ = out.WriteString(intervalSep)
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_, _ = out.WriteString(strconv.FormatInt(int64(minutes), 10))
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_, _ = out.WriteString(intervalSep)
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_, _ = out.WriteString(strconv.FormatInt(int64(sec), 10))
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_, _ = out.WriteString(intervalSep)
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_, _ = out.WriteString(strconv.FormatInt(int64(msec), 10))
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_, _ = out.WriteString("' HOUR_MICROSECOND")
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return nil
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}
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// Interval returns a representation of duration
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// in a form "INTERVAL `hour:min:sec:microsec` HOUR_MICROSECOND"
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func Interval(duration time.Duration) Expression {
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negative := false
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if duration < 0 {
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negative = true
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duration = -duration
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}
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return &intervalExpression{
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duration: duration,
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negative: negative,
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}
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}
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var likeEscaper = strings.NewReplacer("_", "\\_", "%", "\\%")
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func EscapeForLike(s string) string {
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return likeEscaper.Replace(s)
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}
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// Returns an escaped literal string
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func Literal(v interface{}) Expression {
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value, err := sqltypes.BuildValue(v)
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if err != nil {
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panic(errors.Wrap(err, "Invalid literal value"))
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}
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return &literalExpression{value: value}
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}
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// Returns a representation of "c[0] + ... + c[n-1]" for c in clauses
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func Add(expressions ...Expression) Expression {
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return &arithmeticExpression{
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expressions: expressions,
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operator: []byte(" + "),
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}
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}
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// Returns a representation of "c[0] - ... - c[n-1]" for c in clauses
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func Sub(expressions ...Expression) Expression {
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return &arithmeticExpression{
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expressions: expressions,
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operator: []byte(" - "),
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}
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}
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// Returns a representation of "c[0] * ... * c[n-1]" for c in clauses
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func Mul(expressions ...Expression) Expression {
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return &arithmeticExpression{
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expressions: expressions,
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operator: []byte(" * "),
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}
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}
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// Returns a representation of "c[0] / ... / c[n-1]" for c in clauses
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func Div(expressions ...Expression) Expression {
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return &arithmeticExpression{
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expressions: expressions,
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operator: []byte(" / "),
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}
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}
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func BitOr(lhs, rhs Expression) Expression {
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return &binaryExpression{
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lhs: lhs,
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rhs: rhs,
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operator: []byte(" | "),
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}
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}
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func BitAnd(lhs, rhs Expression) Expression {
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return &binaryExpression{
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lhs: lhs,
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rhs: rhs,
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operator: []byte(" & "),
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}
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}
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func BitXor(lhs, rhs Expression) Expression {
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return &binaryExpression{
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lhs: lhs,
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rhs: rhs,
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operator: []byte(" ^ "),
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}
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}
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func Plus(lhs, rhs Expression) Expression {
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return &binaryExpression{
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lhs: lhs,
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rhs: rhs,
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operator: []byte(" + "),
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}
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}
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func Minus(lhs, rhs Expression) Expression {
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return &binaryExpression{
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lhs: lhs,
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rhs: rhs,
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operator: []byte(" - "),
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}
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}
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type ifExpression struct {
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isExpression
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conditional BoolExpression
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trueExpression Expression
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falseExpression Expression
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}
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func (exp *ifExpression) SerializeSql(out *bytes.Buffer) error {
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_, _ = out.WriteString("IF(")
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_ = exp.conditional.SerializeSql(out)
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_, _ = out.WriteString(",")
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_ = exp.trueExpression.SerializeSql(out)
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_, _ = out.WriteString(",")
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_ = exp.falseExpression.SerializeSql(out)
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_, _ = out.WriteString(")")
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return nil
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}
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// Returns a representation of an if-expression, of the form:
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// IF (BOOLEAN TEST, VALUE-IF-TRUE, VALUE-IF-FALSE)
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func If(conditional BoolExpression,
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trueExpression Expression,
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falseExpression Expression) Expression {
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return &ifExpression{
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conditional: conditional,
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trueExpression: trueExpression,
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falseExpression: falseExpression,
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}
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}
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type columnValueExpression struct {
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isExpression
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column NonAliasColumn
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}
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func ColumnValue(col NonAliasColumn) Expression {
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return &columnValueExpression{
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column: col,
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}
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}
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func (cv *columnValueExpression) SerializeSql(out *bytes.Buffer) error {
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_, _ = out.WriteString("VALUES(")
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_ = cv.column.SerializeSqlForColumnList(out)
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_ = out.WriteByte(')')
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func (c literalExpression) SerializeSql(out *bytes.Buffer) error {
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sqltypes.Value(c.value).EncodeSql(out)
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return nil
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}
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