super-graph/psql/psql.go

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2019-03-24 14:57:29 +01:00
package psql
import (
"errors"
"fmt"
"io"
"github.com/dosco/super-graph/qcode"
"github.com/dosco/super-graph/util"
)
type Variables map[string]string
type Compiler struct {
schema *DBSchema
vars Variables
}
func NewCompiler(schema *DBSchema, vars Variables) *Compiler {
return &Compiler{schema, vars}
}
func (c *Compiler) Compile(w io.Writer, qc *qcode.QCode) error {
st := util.NewStack()
st.Push(&selectBlockClose{nil, qc.Query.Select})
st.Push(&selectBlock{nil, qc.Query.Select, c})
fmt.Fprintf(w, `SELECT json_object_agg('%s', %s) FROM (`,
qc.Query.Select.FieldName, qc.Query.Select.Table)
for {
if st.Len() == 0 {
break
}
intf := st.Pop()
switch v := intf.(type) {
case *selectBlock:
childCols, childIDs := c.relationshipColumns(v.sel)
v.render(w, c.schema, childCols, childIDs)
for i := range childIDs {
sub := v.sel.Joins[childIDs[i]]
st.Push(&joinClose{sub})
st.Push(&selectBlockClose{v.sel, sub})
st.Push(&selectBlock{v.sel, sub, c})
st.Push(&joinOpen{sub})
}
case *selectBlockClose:
v.render(w)
case *joinOpen:
v.render(w)
case *joinClose:
v.render(w)
}
}
io.WriteString(w, `) AS "done_1337";`)
return nil
}
func (c *Compiler) relationshipColumns(parent *qcode.Select) (
cols []*qcode.Column, childIDs []int) {
colmap := make(map[string]struct{}, len(parent.Cols))
for i := range parent.Cols {
colmap[parent.Cols[i].Name] = struct{}{}
}
for i, sub := range parent.Joins {
k := TTKey{sub.Table, parent.Table}
rel, ok := c.schema.RelMap[k]
if !ok {
continue
}
if rel.Type == RelBelongTo || rel.Type == RelOneToMany {
if _, ok := colmap[rel.Col2]; !ok {
cols = append(cols, &qcode.Column{parent.Table, rel.Col2, rel.Col2})
}
childIDs = append(childIDs, i)
}
if rel.Type == RelOneToManyThrough {
if _, ok := colmap[rel.Col1]; !ok {
cols = append(cols, &qcode.Column{parent.Table, rel.Col1, rel.Col1})
}
childIDs = append(childIDs, i)
}
}
return cols, childIDs
}
type selectBlock struct {
parent *qcode.Select
sel *qcode.Select
*Compiler
}
func (v *selectBlock) render(w io.Writer,
schema *DBSchema, childCols []*qcode.Column, childIDs []int) error {
isNotRoot := (v.parent != nil)
hasFilters := (v.sel.Where != nil)
hasOrder := len(v.sel.OrderBy) != 0
// SELECT
if v.sel.AsList {
fmt.Fprintf(w, `SELECT coalesce(json_agg("%s"`, v.sel.Table)
if hasOrder {
err := renderOrderBy(w, v.sel)
if err != nil {
return err
}
}
fmt.Fprintf(w, `), '[]') AS "%s" FROM (`, v.sel.Table)
}
// ROW-TO-JSON
io.WriteString(w, `SELECT `)
if len(v.sel.DistinctOn) != 0 {
v.renderDistinctOn(w)
}
io.WriteString(w, `row_to_json((`)
fmt.Fprintf(w, `SELECT "sel_%d" FROM (SELECT `, v.sel.ID)
// Combined column names
v.renderColumns(w)
err := v.renderJoinedColumns(w, childIDs)
if err != nil {
return err
}
fmt.Fprintf(w, `) AS "sel_%d"`, v.sel.ID)
fmt.Fprintf(w, `)) AS "%s"`, v.sel.Table)
// END-ROW-TO-JSON
if hasOrder {
v.renderOrderByColumns(w)
}
// END-SELECT
// FROM
io.WriteString(w, " FROM (SELECT ")
// Local column names
v.renderLocalColumns(w, append(v.sel.Cols, childCols...))
fmt.Fprintf(w, ` FROM "%s"`, v.sel.Table)
if isNotRoot || hasFilters {
if isNotRoot {
v.renderJoinTable(w, schema, childIDs)
}
io.WriteString(w, ` WHERE (`)
if isNotRoot {
v.renderRelationship(w, schema)
}
if hasFilters {
err := v.renderWhere(w)
if err != nil {
return err
}
}
io.WriteString(w, ` ) `)
}
if len(v.sel.Paging.Limit) != 0 {
fmt.Fprintf(w, ` LIMIT ('%s') :: integer`, v.sel.Paging.Limit)
} else {
io.WriteString(w, ` LIMIT ('20') :: integer`)
}
if len(v.sel.Paging.Offset) != 0 {
fmt.Fprintf(w, ` OFFSET ('%s') :: integer`, v.sel.Paging.Offset)
}
fmt.Fprintf(w, `) AS "%s_%d"`, v.sel.Table, v.sel.ID)
// END-FROM
return nil
}
type selectBlockClose struct {
parent *qcode.Select
sel *qcode.Select
}
func (v *selectBlockClose) render(w io.Writer) error {
hasOrder := len(v.sel.OrderBy) != 0
if hasOrder {
err := renderOrderBy(w, v.sel)
if err != nil {
return err
}
}
if len(v.sel.Paging.Limit) != 0 {
fmt.Fprintf(w, ` LIMIT ('%s') :: integer`, v.sel.Paging.Limit)
} else {
io.WriteString(w, ` LIMIT ('20') :: integer`)
}
if len(v.sel.Paging.Offset) != 0 {
fmt.Fprintf(w, ` OFFSET ('%s') :: integer`, v.sel.Paging.Offset)
}
if v.sel.AsList {
fmt.Fprintf(w, `) AS "%s_%d"`, v.sel.Table, v.sel.ID)
}
return nil
}
type joinOpen struct {
sel *qcode.Select
}
func (v joinOpen) render(w io.Writer) error {
io.WriteString(w, ` LEFT OUTER JOIN LATERAL (`)
return nil
}
type joinClose struct {
sel *qcode.Select
}
func (v *joinClose) render(w io.Writer) error {
fmt.Fprintf(w, `) AS "%s_%d.join" ON ('true') `, v.sel.Table, v.sel.ID)
return nil
}
func (v *selectBlock) renderJoinTable(w io.Writer, schema *DBSchema, childIDs []int) {
k := TTKey{v.sel.Table, v.parent.Table}
rel, ok := schema.RelMap[k]
if !ok {
panic(errors.New("no relationship found"))
}
if rel.Type != RelOneToManyThrough {
return
}
fmt.Fprintf(w, ` LEFT OUTER JOIN "%s" ON (("%s"."%s") = ("%s_%d"."%s"))`,
rel.Through, rel.Through, rel.ColT, v.parent.Table, v.parent.ID, rel.Col1)
}
func (v *selectBlock) renderColumns(w io.Writer) {
for i, col := range v.sel.Cols {
fmt.Fprintf(w, `"%s_%d"."%s" AS "%s"`,
v.sel.Table, v.sel.ID, col.Name, col.FieldName)
if i < len(v.sel.Cols)-1 {
io.WriteString(w, ", ")
}
}
}
func (v *selectBlock) renderJoinedColumns(w io.Writer, childIDs []int) error {
if len(v.sel.Cols) != 0 && len(childIDs) != 0 {
io.WriteString(w, ", ")
}
for i := range childIDs {
s := v.sel.Joins[childIDs[i]]
fmt.Fprintf(w, `"%s_%d.join"."%s" AS "%s"`,
s.Table, s.ID, s.Table, s.FieldName)
if i < len(childIDs)-1 {
io.WriteString(w, ", ")
}
}
return nil
}
func (v *selectBlock) renderLocalColumns(w io.Writer, columns []*qcode.Column) {
for i, col := range columns {
if len(col.Table) != 0 {
fmt.Fprintf(w, `"%s"."%s"`, col.Table, col.Name)
} else {
fmt.Fprintf(w, `"%s"."%s"`, v.sel.Table, col.Name)
}
if i < len(columns)-1 {
io.WriteString(w, ", ")
}
}
}
func (v *selectBlock) renderOrderByColumns(w io.Writer) {
if len(v.sel.Cols) != 0 {
io.WriteString(w, ", ")
}
for i := range v.sel.OrderBy {
c := v.sel.OrderBy[i].Col
fmt.Fprintf(w, `"%s_%d"."%s" AS "%s_%d.ob.%s"`,
v.sel.Table, v.sel.ID, c,
v.sel.Table, v.sel.ID, c)
if i < len(v.sel.OrderBy)-1 {
io.WriteString(w, ", ")
}
}
}
func (v *selectBlock) renderRelationship(w io.Writer, schema *DBSchema) {
hasFilters := (v.sel.Where != nil)
k := TTKey{v.sel.Table, v.parent.Table}
rel, ok := schema.RelMap[k]
if !ok {
panic(errors.New("no relationship found"))
}
switch rel.Type {
case RelBelongTo:
fmt.Fprintf(w, ` (("%s"."%s") = ("%s_%d"."%s"))`,
v.sel.Table, rel.Col1, v.parent.Table, v.parent.ID, rel.Col2)
case RelOneToMany:
fmt.Fprintf(w, ` (("%s"."%s") = ("%s_%d"."%s"))`,
v.sel.Table, rel.Col1, v.parent.Table, v.parent.ID, rel.Col2)
case RelOneToManyThrough:
fmt.Fprintf(w, ` (("%s"."%s") = ("%s"."%s"))`,
v.sel.Table, rel.Col1, rel.Through, rel.Col2)
}
if hasFilters {
io.WriteString(w, ` AND `)
}
}
func (v *selectBlock) renderWhere(w io.Writer) error {
st := util.NewStack()
if v.sel.Where == nil {
return nil
}
st.Push(v.sel.Where)
for {
if st.Len() == 0 {
break
}
intf := st.Pop()
switch val := intf.(type) {
case qcode.ExpOp:
switch val {
case qcode.OpAnd:
io.WriteString(w, ` AND `)
case qcode.OpOr:
io.WriteString(w, ` OR `)
case qcode.OpNot:
io.WriteString(w, ` NOT `)
default:
return fmt.Errorf("[Where] unexpected value encountered %v", intf)
}
case *qcode.Exp:
switch val.Op {
case qcode.OpAnd:
st.Push(val.Children[1])
st.Push(qcode.OpAnd)
st.Push(val.Children[0])
continue
case qcode.OpOr:
st.Push(val.Children[1])
st.Push(qcode.OpOr)
st.Push(val.Children[0])
continue
case qcode.OpNot:
st.Push(qcode.OpNot)
st.Push(val.Children[0])
continue
}
if val.NestedCol {
fmt.Fprintf(w, `(("%s") `, val.Col)
} else {
fmt.Fprintf(w, `(("%s"."%s") `, v.sel.Table, val.Col)
}
switch val.Op {
case qcode.OpEquals:
io.WriteString(w, `=`)
case qcode.OpNotEquals:
io.WriteString(w, `!=`)
case qcode.OpGreaterOrEquals:
io.WriteString(w, `>=`)
case qcode.OpLesserOrEquals:
io.WriteString(w, `<=`)
case qcode.OpGreaterThan:
io.WriteString(w, `>`)
case qcode.OpLesserThan:
io.WriteString(w, `<`)
case qcode.OpIn:
io.WriteString(w, `IN`)
case qcode.OpNotIn:
io.WriteString(w, `NOT IN`)
case qcode.OpLike:
io.WriteString(w, `LIKE`)
case qcode.OpNotLike:
io.WriteString(w, `NOT LIKE`)
case qcode.OpILike:
io.WriteString(w, `ILIKE`)
case qcode.OpNotILike:
io.WriteString(w, `NOT ILIKE`)
case qcode.OpSimilar:
io.WriteString(w, `SIMILAR TO`)
case qcode.OpNotSimilar:
io.WriteString(w, `NOT SIMILAR TO`)
case qcode.OpContains:
io.WriteString(w, `CONTAINS`)
case qcode.OpContainedIn:
io.WriteString(w, `CONTAINED IN`)
case qcode.OpHasKey:
io.WriteString(w, `HAS KEY`)
default:
return fmt.Errorf("[Where] unexpected op code %d", val.Op)
}
if val.Type == qcode.ValList {
renderList(w, val)
} else {
renderVal(w, val, v.vars)
}
io.WriteString(w, `)`)
default:
return fmt.Errorf("[Where] unexpected value encountered %v", intf)
}
}
return nil
}
func renderOrderBy(w io.Writer, sel *qcode.Select) error {
io.WriteString(w, ` ORDER BY `)
for i := range sel.OrderBy {
ob := sel.OrderBy[i]
switch ob.Order {
case qcode.OrderAsc:
fmt.Fprintf(w, `"%s_%d.ob.%s" ASC`, sel.Table, sel.ID, ob.Col)
case qcode.OrderDesc:
fmt.Fprintf(w, `"%s_%d.ob.%s" DESC`, sel.Table, sel.ID, ob.Col)
case qcode.OrderAscNullsFirst:
fmt.Fprintf(w, `"%s_%d.ob.%s" ASC NULLS FIRST`, sel.Table, sel.ID, ob.Col)
case qcode.OrderDescNullsFirst:
fmt.Fprintf(w, `%s_%d.ob.%s DESC NULLS FIRST`, sel.Table, sel.ID, ob.Col)
case qcode.OrderAscNullsLast:
fmt.Fprintf(w, `"%s_%d.ob.%s ASC NULLS LAST`, sel.Table, sel.ID, ob.Col)
case qcode.OrderDescNullsLast:
fmt.Fprintf(w, `%s_%d.ob.%s DESC NULLS LAST`, sel.Table, sel.ID, ob.Col)
default:
return fmt.Errorf("[qcode.Order By] unexpected value encountered %v", ob.Order)
}
if i < len(sel.OrderBy)-1 {
io.WriteString(w, ", ")
}
}
return nil
}
func (v selectBlock) renderDistinctOn(w io.Writer) {
io.WriteString(w, ` DISTINCT ON (`)
for i := range v.sel.DistinctOn {
fmt.Fprintf(w, `"%s"`, v.sel.DistinctOn[i])
if i < len(v.sel.DistinctOn)-1 {
io.WriteString(w, ", ")
}
}
io.WriteString(w, `) `)
}
func renderList(w io.Writer, ex *qcode.Exp) {
io.WriteString(w, ` (`)
for i := range ex.ListVal {
switch ex.ListType {
case qcode.ValBool, qcode.ValInt, qcode.ValFloat:
io.WriteString(w, ex.ListVal[i])
case qcode.ValStr:
fmt.Fprintf(w, `'%s'`, ex.ListVal[i])
}
if i < len(ex.ListVal)-1 {
io.WriteString(w, ", ")
}
}
io.WriteString(w, `)`)
}
func renderVal(w io.Writer, ex *qcode.Exp, vars Variables) {
io.WriteString(w, ` (`)
switch ex.Type {
case qcode.ValBool, qcode.ValInt, qcode.ValFloat:
io.WriteString(w, ex.Val)
case qcode.ValStr:
fmt.Fprintf(w, `'%s'`, ex.Val)
case qcode.ValVar:
if val, ok := vars[ex.Val]; ok {
io.WriteString(w, val)
} else {
fmt.Fprintf(w, `'{{%s}}'`, ex.Val)
}
}
io.WriteString(w, `)`)
}