mirror of
https://github.com/ceph/ceph-csi.git
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479 lines
16 KiB
Go
479 lines
16 KiB
Go
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// Copyright 2018 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package parser
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import (
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"sync"
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"github.com/antlr/antlr4/runtime/Go/antlr"
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"github.com/google/cel-go/common"
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exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
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)
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type parserHelper struct {
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source common.Source
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nextID int64
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positions map[int64]int32
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macroCalls map[int64]*exprpb.Expr
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}
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func newParserHelper(source common.Source) *parserHelper {
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return &parserHelper{
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source: source,
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nextID: 1,
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positions: make(map[int64]int32),
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macroCalls: make(map[int64]*exprpb.Expr),
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}
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}
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func (p *parserHelper) getSourceInfo() *exprpb.SourceInfo {
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return &exprpb.SourceInfo{
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Location: p.source.Description(),
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Positions: p.positions,
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LineOffsets: p.source.LineOffsets(),
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MacroCalls: p.macroCalls}
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}
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func (p *parserHelper) newLiteral(ctx interface{}, value *exprpb.Constant) *exprpb.Expr {
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exprNode := p.newExpr(ctx)
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exprNode.ExprKind = &exprpb.Expr_ConstExpr{ConstExpr: value}
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return exprNode
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}
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func (p *parserHelper) newLiteralBool(ctx interface{}, value bool) *exprpb.Expr {
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return p.newLiteral(ctx,
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&exprpb.Constant{ConstantKind: &exprpb.Constant_BoolValue{BoolValue: value}})
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}
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func (p *parserHelper) newLiteralString(ctx interface{}, value string) *exprpb.Expr {
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return p.newLiteral(ctx,
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&exprpb.Constant{ConstantKind: &exprpb.Constant_StringValue{StringValue: value}})
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}
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func (p *parserHelper) newLiteralBytes(ctx interface{}, value []byte) *exprpb.Expr {
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return p.newLiteral(ctx,
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&exprpb.Constant{ConstantKind: &exprpb.Constant_BytesValue{BytesValue: value}})
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}
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func (p *parserHelper) newLiteralInt(ctx interface{}, value int64) *exprpb.Expr {
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return p.newLiteral(ctx,
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&exprpb.Constant{ConstantKind: &exprpb.Constant_Int64Value{Int64Value: value}})
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}
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func (p *parserHelper) newLiteralUint(ctx interface{}, value uint64) *exprpb.Expr {
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return p.newLiteral(ctx, &exprpb.Constant{ConstantKind: &exprpb.Constant_Uint64Value{Uint64Value: value}})
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}
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func (p *parserHelper) newLiteralDouble(ctx interface{}, value float64) *exprpb.Expr {
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return p.newLiteral(ctx,
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&exprpb.Constant{ConstantKind: &exprpb.Constant_DoubleValue{DoubleValue: value}})
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}
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func (p *parserHelper) newIdent(ctx interface{}, name string) *exprpb.Expr {
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exprNode := p.newExpr(ctx)
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exprNode.ExprKind = &exprpb.Expr_IdentExpr{IdentExpr: &exprpb.Expr_Ident{Name: name}}
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return exprNode
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}
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func (p *parserHelper) newSelect(ctx interface{}, operand *exprpb.Expr, field string) *exprpb.Expr {
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exprNode := p.newExpr(ctx)
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exprNode.ExprKind = &exprpb.Expr_SelectExpr{
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SelectExpr: &exprpb.Expr_Select{Operand: operand, Field: field}}
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return exprNode
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}
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func (p *parserHelper) newPresenceTest(ctx interface{}, operand *exprpb.Expr, field string) *exprpb.Expr {
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exprNode := p.newExpr(ctx)
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exprNode.ExprKind = &exprpb.Expr_SelectExpr{
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SelectExpr: &exprpb.Expr_Select{Operand: operand, Field: field, TestOnly: true}}
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return exprNode
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}
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func (p *parserHelper) newGlobalCall(ctx interface{}, function string, args ...*exprpb.Expr) *exprpb.Expr {
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exprNode := p.newExpr(ctx)
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exprNode.ExprKind = &exprpb.Expr_CallExpr{
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CallExpr: &exprpb.Expr_Call{Function: function, Args: args}}
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return exprNode
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}
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func (p *parserHelper) newReceiverCall(ctx interface{}, function string, target *exprpb.Expr, args ...*exprpb.Expr) *exprpb.Expr {
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exprNode := p.newExpr(ctx)
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exprNode.ExprKind = &exprpb.Expr_CallExpr{
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CallExpr: &exprpb.Expr_Call{Function: function, Target: target, Args: args}}
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return exprNode
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}
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func (p *parserHelper) newList(ctx interface{}, elements ...*exprpb.Expr) *exprpb.Expr {
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exprNode := p.newExpr(ctx)
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exprNode.ExprKind = &exprpb.Expr_ListExpr{
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ListExpr: &exprpb.Expr_CreateList{Elements: elements}}
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return exprNode
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}
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func (p *parserHelper) newMap(ctx interface{}, entries ...*exprpb.Expr_CreateStruct_Entry) *exprpb.Expr {
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exprNode := p.newExpr(ctx)
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exprNode.ExprKind = &exprpb.Expr_StructExpr{
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StructExpr: &exprpb.Expr_CreateStruct{Entries: entries}}
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return exprNode
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}
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func (p *parserHelper) newMapEntry(entryID int64, key *exprpb.Expr, value *exprpb.Expr) *exprpb.Expr_CreateStruct_Entry {
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return &exprpb.Expr_CreateStruct_Entry{
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Id: entryID,
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KeyKind: &exprpb.Expr_CreateStruct_Entry_MapKey{MapKey: key},
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Value: value}
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}
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func (p *parserHelper) newObject(ctx interface{},
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typeName string,
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entries ...*exprpb.Expr_CreateStruct_Entry) *exprpb.Expr {
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exprNode := p.newExpr(ctx)
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exprNode.ExprKind = &exprpb.Expr_StructExpr{
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StructExpr: &exprpb.Expr_CreateStruct{
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MessageName: typeName,
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Entries: entries}}
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return exprNode
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}
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func (p *parserHelper) newObjectField(fieldID int64, field string, value *exprpb.Expr) *exprpb.Expr_CreateStruct_Entry {
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return &exprpb.Expr_CreateStruct_Entry{
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Id: fieldID,
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KeyKind: &exprpb.Expr_CreateStruct_Entry_FieldKey{FieldKey: field},
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Value: value}
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}
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func (p *parserHelper) newComprehension(ctx interface{}, iterVar string,
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iterRange *exprpb.Expr,
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accuVar string,
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accuInit *exprpb.Expr,
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condition *exprpb.Expr,
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step *exprpb.Expr,
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result *exprpb.Expr) *exprpb.Expr {
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exprNode := p.newExpr(ctx)
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exprNode.ExprKind = &exprpb.Expr_ComprehensionExpr{
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ComprehensionExpr: &exprpb.Expr_Comprehension{
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AccuVar: accuVar,
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AccuInit: accuInit,
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IterVar: iterVar,
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IterRange: iterRange,
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LoopCondition: condition,
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LoopStep: step,
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Result: result}}
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return exprNode
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}
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func (p *parserHelper) newExpr(ctx interface{}) *exprpb.Expr {
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id, isID := ctx.(int64)
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if isID {
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return &exprpb.Expr{Id: id}
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}
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return &exprpb.Expr{Id: p.id(ctx)}
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}
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func (p *parserHelper) id(ctx interface{}) int64 {
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var location common.Location
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switch ctx.(type) {
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case antlr.ParserRuleContext:
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token := (ctx.(antlr.ParserRuleContext)).GetStart()
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location = p.source.NewLocation(token.GetLine(), token.GetColumn())
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case antlr.Token:
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token := ctx.(antlr.Token)
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location = p.source.NewLocation(token.GetLine(), token.GetColumn())
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case common.Location:
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location = ctx.(common.Location)
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default:
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// This should only happen if the ctx is nil
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return -1
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}
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id := p.nextID
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p.positions[id], _ = p.source.LocationOffset(location)
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p.nextID++
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return id
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}
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func (p *parserHelper) getLocation(id int64) common.Location {
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characterOffset := p.positions[id]
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location, _ := p.source.OffsetLocation(characterOffset)
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return location
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}
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// buildMacroCallArg iterates the expression and returns a new expression
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// where all macros have been replaced by their IDs in MacroCalls
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func (p *parserHelper) buildMacroCallArg(expr *exprpb.Expr) *exprpb.Expr {
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if _, found := p.macroCalls[expr.GetId()]; found {
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return &exprpb.Expr{Id: expr.GetId()}
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}
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switch expr.GetExprKind().(type) {
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case *exprpb.Expr_CallExpr:
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// Iterate the AST from `expr` recursively looking for macros. Because we are at most
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// starting from the top level macro, this recursion is bounded by the size of the AST. This
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// means that the depth check on the AST during parsing will catch recursion overflows
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// before we get to here.
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macroTarget := expr.GetCallExpr().GetTarget()
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if macroTarget != nil {
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macroTarget = p.buildMacroCallArg(macroTarget)
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}
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macroArgs := make([]*exprpb.Expr, len(expr.GetCallExpr().GetArgs()))
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for index, arg := range expr.GetCallExpr().GetArgs() {
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macroArgs[index] = p.buildMacroCallArg(arg)
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}
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return &exprpb.Expr{
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Id: expr.GetId(),
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ExprKind: &exprpb.Expr_CallExpr{
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CallExpr: &exprpb.Expr_Call{
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Target: macroTarget,
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Function: expr.GetCallExpr().GetFunction(),
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Args: macroArgs,
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},
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},
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}
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case *exprpb.Expr_ListExpr:
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listExpr := expr.GetListExpr()
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macroListArgs := make([]*exprpb.Expr, len(listExpr.GetElements()))
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for i, elem := range listExpr.GetElements() {
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macroListArgs[i] = p.buildMacroCallArg(elem)
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}
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return &exprpb.Expr{
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Id: expr.GetId(),
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ExprKind: &exprpb.Expr_ListExpr{
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ListExpr: &exprpb.Expr_CreateList{
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Elements: macroListArgs,
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},
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},
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}
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}
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return expr
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}
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// addMacroCall adds the macro the the MacroCalls map in source info. If a macro has args/subargs/target
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// that are macros, their ID will be stored instead for later self-lookups.
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func (p *parserHelper) addMacroCall(exprID int64, function string, target *exprpb.Expr, args ...*exprpb.Expr) {
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macroTarget := target
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if target != nil {
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if _, found := p.macroCalls[target.GetId()]; found {
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macroTarget = &exprpb.Expr{Id: target.GetId()}
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} else {
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macroTarget = p.buildMacroCallArg(target)
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}
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}
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macroArgs := make([]*exprpb.Expr, len(args))
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for index, arg := range args {
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macroArgs[index] = p.buildMacroCallArg(arg)
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}
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p.macroCalls[exprID] = &exprpb.Expr{
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ExprKind: &exprpb.Expr_CallExpr{
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CallExpr: &exprpb.Expr_Call{
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Target: macroTarget,
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Function: function,
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Args: macroArgs,
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},
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},
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}
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}
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// balancer performs tree balancing on operators whose arguments are of equal precedence.
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//
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// The purpose of the balancer is to ensure a compact serialization format for the logical &&, ||
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// operators which have a tendency to create long DAGs which are skewed in one direction. Since the
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// operators are commutative re-ordering the terms *must not* affect the evaluation result.
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//
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// Re-balancing the terms is a safe, if somewhat controversial choice. A better solution would be
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// to make these functions variadic and update both the checker and interpreter to understand this;
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// however, this is a more complex change.
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//
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// TODO: Consider replacing tree-balancing with variadic logical &&, || within the parser, checker,
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// and interpreter.
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type balancer struct {
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helper *parserHelper
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function string
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terms []*exprpb.Expr
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ops []int64
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}
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// newBalancer creates a balancer instance bound to a specific function and its first term.
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func newBalancer(h *parserHelper, function string, term *exprpb.Expr) *balancer {
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return &balancer{
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helper: h,
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function: function,
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terms: []*exprpb.Expr{term},
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ops: []int64{},
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}
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}
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// addTerm adds an operation identifier and term to the set of terms to be balanced.
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func (b *balancer) addTerm(op int64, term *exprpb.Expr) {
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b.terms = append(b.terms, term)
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b.ops = append(b.ops, op)
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}
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// balance creates a balanced tree from the sub-terms and returns the final Expr value.
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func (b *balancer) balance() *exprpb.Expr {
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if len(b.terms) == 1 {
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return b.terms[0]
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}
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return b.balancedTree(0, len(b.ops)-1)
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}
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// balancedTree recursively balances the terms provided to a commutative operator.
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func (b *balancer) balancedTree(lo, hi int) *exprpb.Expr {
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mid := (lo + hi + 1) / 2
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var left *exprpb.Expr
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if mid == lo {
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left = b.terms[mid]
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} else {
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left = b.balancedTree(lo, mid-1)
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}
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var right *exprpb.Expr
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if mid == hi {
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right = b.terms[mid+1]
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} else {
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right = b.balancedTree(mid+1, hi)
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}
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return b.helper.newGlobalCall(b.ops[mid], b.function, left, right)
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}
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type exprHelper struct {
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*parserHelper
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id int64
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}
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func (e *exprHelper) nextMacroID() int64 {
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return e.parserHelper.id(e.parserHelper.getLocation(e.id))
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}
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// LiteralBool implements the ExprHelper interface method.
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func (e *exprHelper) LiteralBool(value bool) *exprpb.Expr {
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return e.parserHelper.newLiteralBool(e.nextMacroID(), value)
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}
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// LiteralBytes implements the ExprHelper interface method.
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func (e *exprHelper) LiteralBytes(value []byte) *exprpb.Expr {
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return e.parserHelper.newLiteralBytes(e.nextMacroID(), value)
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}
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// LiteralDouble implements the ExprHelper interface method.
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func (e *exprHelper) LiteralDouble(value float64) *exprpb.Expr {
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return e.parserHelper.newLiteralDouble(e.nextMacroID(), value)
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}
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// LiteralInt implements the ExprHelper interface method.
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func (e *exprHelper) LiteralInt(value int64) *exprpb.Expr {
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return e.parserHelper.newLiteralInt(e.nextMacroID(), value)
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}
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// LiteralString implements the ExprHelper interface method.
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func (e *exprHelper) LiteralString(value string) *exprpb.Expr {
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return e.parserHelper.newLiteralString(e.nextMacroID(), value)
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}
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// LiteralUint implements the ExprHelper interface method.
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func (e *exprHelper) LiteralUint(value uint64) *exprpb.Expr {
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return e.parserHelper.newLiteralUint(e.nextMacroID(), value)
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}
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// NewList implements the ExprHelper interface method.
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func (e *exprHelper) NewList(elems ...*exprpb.Expr) *exprpb.Expr {
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return e.parserHelper.newList(e.nextMacroID(), elems...)
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}
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// NewMap implements the ExprHelper interface method.
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func (e *exprHelper) NewMap(entries ...*exprpb.Expr_CreateStruct_Entry) *exprpb.Expr {
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return e.parserHelper.newMap(e.nextMacroID(), entries...)
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}
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// NewMapEntry implements the ExprHelper interface method.
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func (e *exprHelper) NewMapEntry(key *exprpb.Expr,
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val *exprpb.Expr) *exprpb.Expr_CreateStruct_Entry {
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return e.parserHelper.newMapEntry(e.nextMacroID(), key, val)
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}
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// NewObject implements the ExprHelper interface method.
|
||
|
func (e *exprHelper) NewObject(typeName string,
|
||
|
fieldInits ...*exprpb.Expr_CreateStruct_Entry) *exprpb.Expr {
|
||
|
return e.parserHelper.newObject(e.nextMacroID(), typeName, fieldInits...)
|
||
|
}
|
||
|
|
||
|
// NewObjectFieldInit implements the ExprHelper interface method.
|
||
|
func (e *exprHelper) NewObjectFieldInit(field string,
|
||
|
init *exprpb.Expr) *exprpb.Expr_CreateStruct_Entry {
|
||
|
return e.parserHelper.newObjectField(e.nextMacroID(), field, init)
|
||
|
}
|
||
|
|
||
|
// Fold implements the ExprHelper interface method.
|
||
|
func (e *exprHelper) Fold(iterVar string,
|
||
|
iterRange *exprpb.Expr,
|
||
|
accuVar string,
|
||
|
accuInit *exprpb.Expr,
|
||
|
condition *exprpb.Expr,
|
||
|
step *exprpb.Expr,
|
||
|
result *exprpb.Expr) *exprpb.Expr {
|
||
|
return e.parserHelper.newComprehension(
|
||
|
e.nextMacroID(), iterVar, iterRange, accuVar, accuInit, condition, step, result)
|
||
|
}
|
||
|
|
||
|
// Ident implements the ExprHelper interface method.
|
||
|
func (e *exprHelper) Ident(name string) *exprpb.Expr {
|
||
|
return e.parserHelper.newIdent(e.nextMacroID(), name)
|
||
|
}
|
||
|
|
||
|
// AccuIdent implements the ExprHelper interface method.
|
||
|
func (e *exprHelper) AccuIdent() *exprpb.Expr {
|
||
|
return e.parserHelper.newIdent(e.nextMacroID(), AccumulatorName)
|
||
|
}
|
||
|
|
||
|
// GlobalCall implements the ExprHelper interface method.
|
||
|
func (e *exprHelper) GlobalCall(function string, args ...*exprpb.Expr) *exprpb.Expr {
|
||
|
return e.parserHelper.newGlobalCall(e.nextMacroID(), function, args...)
|
||
|
}
|
||
|
|
||
|
// ReceiverCall implements the ExprHelper interface method.
|
||
|
func (e *exprHelper) ReceiverCall(function string,
|
||
|
target *exprpb.Expr, args ...*exprpb.Expr) *exprpb.Expr {
|
||
|
return e.parserHelper.newReceiverCall(e.nextMacroID(), function, target, args...)
|
||
|
}
|
||
|
|
||
|
// PresenceTest implements the ExprHelper interface method.
|
||
|
func (e *exprHelper) PresenceTest(operand *exprpb.Expr, field string) *exprpb.Expr {
|
||
|
return e.parserHelper.newPresenceTest(e.nextMacroID(), operand, field)
|
||
|
}
|
||
|
|
||
|
// Select implements the ExprHelper interface method.
|
||
|
func (e *exprHelper) Select(operand *exprpb.Expr, field string) *exprpb.Expr {
|
||
|
return e.parserHelper.newSelect(e.nextMacroID(), operand, field)
|
||
|
}
|
||
|
|
||
|
// OffsetLocation implements the ExprHelper interface method.
|
||
|
func (e *exprHelper) OffsetLocation(exprID int64) common.Location {
|
||
|
offset := e.parserHelper.positions[exprID]
|
||
|
location, _ := e.parserHelper.source.OffsetLocation(offset)
|
||
|
return location
|
||
|
}
|
||
|
|
||
|
var (
|
||
|
// Thread-safe pool of ExprHelper values to minimize alloc overhead of ExprHelper creations.
|
||
|
exprHelperPool = &sync.Pool{
|
||
|
New: func() interface{} {
|
||
|
return &exprHelper{}
|
||
|
},
|
||
|
}
|
||
|
)
|