mirror of
https://github.com/ceph/ceph-csi.git
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628 lines
21 KiB
Go
628 lines
21 KiB
Go
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// Copyright 2022 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 checker
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import (
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"math"
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"github.com/google/cel-go/common"
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"github.com/google/cel-go/common/overloads"
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"github.com/google/cel-go/parser"
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exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
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)
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// WARNING: Any changes to cost calculations in this file require a corresponding change in interpreter/runtimecost.go
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// CostEstimator estimates the sizes of variable length input data and the costs of functions.
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type CostEstimator interface {
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// EstimateSize returns a SizeEstimate for the given AstNode, or nil if
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// the estimator has no estimate to provide. The size is equivalent to the result of the CEL `size()` function:
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// length of strings and bytes, number of map entries or number of list items.
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// EstimateSize is only called for AstNodes where
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// CEL does not know the size; EstimateSize is not called for values defined inline in CEL where the size
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// is already obvious to CEL.
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EstimateSize(element AstNode) *SizeEstimate
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// EstimateCallCost returns the estimated cost of an invocation, or nil if
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// the estimator has no estimate to provide.
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EstimateCallCost(function, overloadID string, target *AstNode, args []AstNode) *CallEstimate
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}
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// CallEstimate includes a CostEstimate for the call, and an optional estimate of the result object size.
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// The ResultSize should only be provided if the call results in a map, list, string or bytes.
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type CallEstimate struct {
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CostEstimate
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ResultSize *SizeEstimate
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}
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// AstNode represents an AST node for the purpose of cost estimations.
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type AstNode interface {
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// Path returns a field path through the provided type declarations to the type of the AstNode, or nil if the AstNode does not
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// represent type directly reachable from the provided type declarations.
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// The first path element is a variable. All subsequent path elements are one of: field name, '@items', '@keys', '@values'.
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Path() []string
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// Type returns the deduced type of the AstNode.
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Type() *exprpb.Type
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// Expr returns the expression of the AstNode.
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Expr() *exprpb.Expr
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// ComputedSize returns a size estimate of the AstNode derived from information available in the CEL expression.
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// For constants and inline list and map declarations, the exact size is returned. For concatenated list, strings
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// and bytes, the size is derived from the size estimates of the operands. nil is returned if there is no
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// computed size available.
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ComputedSize() *SizeEstimate
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}
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type astNode struct {
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path []string
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t *exprpb.Type
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expr *exprpb.Expr
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derivedSize *SizeEstimate
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}
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func (e astNode) Path() []string {
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return e.path
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}
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func (e astNode) Type() *exprpb.Type {
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return e.t
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}
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func (e astNode) Expr() *exprpb.Expr {
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return e.expr
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}
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func (e astNode) ComputedSize() *SizeEstimate {
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if e.derivedSize != nil {
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return e.derivedSize
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}
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var v uint64
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switch ek := e.expr.GetExprKind().(type) {
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case *exprpb.Expr_ConstExpr:
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switch ck := ek.ConstExpr.GetConstantKind().(type) {
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case *exprpb.Constant_StringValue:
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v = uint64(len(ck.StringValue))
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case *exprpb.Constant_BytesValue:
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v = uint64(len(ck.BytesValue))
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case *exprpb.Constant_BoolValue, *exprpb.Constant_DoubleValue, *exprpb.Constant_DurationValue,
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*exprpb.Constant_Int64Value, *exprpb.Constant_TimestampValue, *exprpb.Constant_Uint64Value,
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*exprpb.Constant_NullValue:
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v = uint64(1)
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default:
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return nil
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}
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case *exprpb.Expr_ListExpr:
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v = uint64(len(ek.ListExpr.GetElements()))
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case *exprpb.Expr_StructExpr:
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if ek.StructExpr.GetMessageName() == "" {
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v = uint64(len(ek.StructExpr.GetEntries()))
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}
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default:
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return nil
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}
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return &SizeEstimate{Min: v, Max: v}
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}
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// SizeEstimate represents an estimated size of a variable length string, bytes, map or list.
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type SizeEstimate struct {
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Min, Max uint64
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}
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// Add adds to another SizeEstimate and returns the sum.
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// If add would result in an uint64 overflow, the result is math.MaxUint64.
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func (se SizeEstimate) Add(sizeEstimate SizeEstimate) SizeEstimate {
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return SizeEstimate{
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addUint64NoOverflow(se.Min, sizeEstimate.Min),
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addUint64NoOverflow(se.Max, sizeEstimate.Max),
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}
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}
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// Multiply multiplies by another SizeEstimate and returns the product.
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// If multiply would result in an uint64 overflow, the result is math.MaxUint64.
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func (se SizeEstimate) Multiply(sizeEstimate SizeEstimate) SizeEstimate {
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return SizeEstimate{
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multiplyUint64NoOverflow(se.Min, sizeEstimate.Min),
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multiplyUint64NoOverflow(se.Max, sizeEstimate.Max),
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}
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}
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// MultiplyByCostFactor multiplies a SizeEstimate by a cost factor and returns the CostEstimate with the
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// nearest integer of the result, rounded up.
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func (se SizeEstimate) MultiplyByCostFactor(costPerUnit float64) CostEstimate {
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return CostEstimate{
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multiplyByCostFactor(se.Min, costPerUnit),
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multiplyByCostFactor(se.Max, costPerUnit),
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}
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}
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// MultiplyByCost multiplies by the cost and returns the product.
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// If multiply would result in an uint64 overflow, the result is math.MaxUint64.
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func (se SizeEstimate) MultiplyByCost(cost CostEstimate) CostEstimate {
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return CostEstimate{
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multiplyUint64NoOverflow(se.Min, cost.Min),
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multiplyUint64NoOverflow(se.Max, cost.Max),
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}
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}
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// Union returns a SizeEstimate that encompasses both input the SizeEstimate.
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func (se SizeEstimate) Union(size SizeEstimate) SizeEstimate {
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result := se
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if size.Min < result.Min {
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result.Min = size.Min
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}
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if size.Max > result.Max {
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result.Max = size.Max
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}
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return result
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}
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// CostEstimate represents an estimated cost range and provides add and multiply operations
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// that do not overflow.
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type CostEstimate struct {
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Min, Max uint64
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}
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// Add adds the costs and returns the sum.
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// If add would result in an uint64 overflow for the min or max, the value is set to math.MaxUint64.
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func (ce CostEstimate) Add(cost CostEstimate) CostEstimate {
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return CostEstimate{
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addUint64NoOverflow(ce.Min, cost.Min),
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addUint64NoOverflow(ce.Max, cost.Max),
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}
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}
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// Multiply multiplies by the cost and returns the product.
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// If multiply would result in an uint64 overflow, the result is math.MaxUint64.
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func (ce CostEstimate) Multiply(cost CostEstimate) CostEstimate {
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return CostEstimate{
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multiplyUint64NoOverflow(ce.Min, cost.Min),
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multiplyUint64NoOverflow(ce.Max, cost.Max),
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}
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}
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// MultiplyByCostFactor multiplies a CostEstimate by a cost factor and returns the CostEstimate with the
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// nearest integer of the result, rounded up.
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func (ce CostEstimate) MultiplyByCostFactor(costPerUnit float64) CostEstimate {
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return CostEstimate{
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multiplyByCostFactor(ce.Min, costPerUnit),
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multiplyByCostFactor(ce.Max, costPerUnit),
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}
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}
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// Union returns a CostEstimate that encompasses both input the CostEstimates.
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func (ce CostEstimate) Union(size CostEstimate) CostEstimate {
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result := ce
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if size.Min < result.Min {
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result.Min = size.Min
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}
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if size.Max > result.Max {
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result.Max = size.Max
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}
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return result
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}
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// addUint64NoOverflow adds non-negative ints. If the result is exceeds math.MaxUint64, math.MaxUint64
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// is returned.
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func addUint64NoOverflow(x, y uint64) uint64 {
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if y > 0 && x > math.MaxUint64-y {
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return math.MaxUint64
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}
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return x + y
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}
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// multiplyUint64NoOverflow multiplies non-negative ints. If the result is exceeds math.MaxUint64, math.MaxUint64
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// is returned.
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func multiplyUint64NoOverflow(x, y uint64) uint64 {
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if x > 0 && y > 0 && x > math.MaxUint64/y {
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return math.MaxUint64
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}
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return x * y
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}
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// multiplyByFactor multiplies an integer by a cost factor float and returns the nearest integer value, rounded up.
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func multiplyByCostFactor(x uint64, y float64) uint64 {
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xFloat := float64(x)
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if xFloat > 0 && y > 0 && xFloat > math.MaxUint64/y {
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return math.MaxUint64
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}
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return uint64(math.Ceil(xFloat * y))
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}
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var (
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selectAndIdentCost = CostEstimate{Min: common.SelectAndIdentCost, Max: common.SelectAndIdentCost}
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constCost = CostEstimate{Min: common.ConstCost, Max: common.ConstCost}
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createListBaseCost = CostEstimate{Min: common.ListCreateBaseCost, Max: common.ListCreateBaseCost}
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createMapBaseCost = CostEstimate{Min: common.MapCreateBaseCost, Max: common.MapCreateBaseCost}
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createMessageBaseCost = CostEstimate{Min: common.StructCreateBaseCost, Max: common.StructCreateBaseCost}
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)
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type coster struct {
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// exprPath maps from Expr Id to field path.
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exprPath map[int64][]string
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// iterRanges tracks the iterRange of each iterVar.
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iterRanges iterRangeScopes
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// computedSizes tracks the computed sizes of call results.
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computedSizes map[int64]SizeEstimate
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checkedExpr *exprpb.CheckedExpr
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estimator CostEstimator
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}
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// Use a stack of iterVar -> iterRange Expr Ids to handle shadowed variable names.
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type iterRangeScopes map[string][]int64
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func (vs iterRangeScopes) push(varName string, expr *exprpb.Expr) {
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vs[varName] = append(vs[varName], expr.GetId())
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}
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func (vs iterRangeScopes) pop(varName string) {
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varStack := vs[varName]
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vs[varName] = varStack[:len(varStack)-1]
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}
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func (vs iterRangeScopes) peek(varName string) (int64, bool) {
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varStack := vs[varName]
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if len(varStack) > 0 {
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return varStack[len(varStack)-1], true
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}
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return 0, false
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}
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// Cost estimates the cost of the parsed and type checked CEL expression.
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func Cost(checker *exprpb.CheckedExpr, estimator CostEstimator) CostEstimate {
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c := coster{
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checkedExpr: checker,
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estimator: estimator,
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exprPath: map[int64][]string{},
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iterRanges: map[string][]int64{},
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computedSizes: map[int64]SizeEstimate{},
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}
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return c.cost(checker.GetExpr())
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}
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func (c *coster) cost(e *exprpb.Expr) CostEstimate {
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if e == nil {
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return CostEstimate{}
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}
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var cost CostEstimate
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switch e.GetExprKind().(type) {
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case *exprpb.Expr_ConstExpr:
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cost = constCost
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case *exprpb.Expr_IdentExpr:
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cost = c.costIdent(e)
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case *exprpb.Expr_SelectExpr:
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cost = c.costSelect(e)
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case *exprpb.Expr_CallExpr:
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cost = c.costCall(e)
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case *exprpb.Expr_ListExpr:
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cost = c.costCreateList(e)
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case *exprpb.Expr_StructExpr:
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cost = c.costCreateStruct(e)
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case *exprpb.Expr_ComprehensionExpr:
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cost = c.costComprehension(e)
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default:
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return CostEstimate{}
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}
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return cost
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}
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func (c *coster) costIdent(e *exprpb.Expr) CostEstimate {
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identExpr := e.GetIdentExpr()
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// build and track the field path
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if iterRange, ok := c.iterRanges.peek(identExpr.GetName()); ok {
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switch c.checkedExpr.TypeMap[iterRange].GetTypeKind().(type) {
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case *exprpb.Type_ListType_:
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c.addPath(e, append(c.exprPath[iterRange], "@items"))
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case *exprpb.Type_MapType_:
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c.addPath(e, append(c.exprPath[iterRange], "@keys"))
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}
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} else {
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c.addPath(e, []string{identExpr.GetName()})
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}
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return selectAndIdentCost
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}
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func (c *coster) costSelect(e *exprpb.Expr) CostEstimate {
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sel := e.GetSelectExpr()
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var sum CostEstimate
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if sel.GetTestOnly() {
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return sum
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}
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sum = sum.Add(c.cost(sel.GetOperand()))
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targetType := c.getType(sel.GetOperand())
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switch kindOf(targetType) {
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case kindMap, kindObject, kindTypeParam:
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sum = sum.Add(selectAndIdentCost)
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}
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// build and track the field path
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c.addPath(e, append(c.getPath(sel.GetOperand()), sel.GetField()))
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return sum
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}
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func (c *coster) costCall(e *exprpb.Expr) CostEstimate {
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call := e.GetCallExpr()
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|
target := call.GetTarget()
|
||
|
|
args := call.GetArgs()
|
||
|
|
|
||
|
|
var sum CostEstimate
|
||
|
|
|
||
|
|
argTypes := make([]AstNode, len(args))
|
||
|
|
argCosts := make([]CostEstimate, len(args))
|
||
|
|
for i, arg := range args {
|
||
|
|
argCosts[i] = c.cost(arg)
|
||
|
|
argTypes[i] = c.newAstNode(arg)
|
||
|
|
}
|
||
|
|
|
||
|
|
ref := c.checkedExpr.ReferenceMap[e.GetId()]
|
||
|
|
if ref == nil || len(ref.GetOverloadId()) == 0 {
|
||
|
|
return CostEstimate{}
|
||
|
|
}
|
||
|
|
var targetType AstNode
|
||
|
|
if target != nil {
|
||
|
|
if call.Target != nil {
|
||
|
|
sum = sum.Add(c.cost(call.GetTarget()))
|
||
|
|
targetType = c.newAstNode(call.GetTarget())
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// Pick a cost estimate range that covers all the overload cost estimation ranges
|
||
|
|
fnCost := CostEstimate{Min: uint64(math.MaxUint64), Max: 0}
|
||
|
|
var resultSize *SizeEstimate
|
||
|
|
for _, overload := range ref.GetOverloadId() {
|
||
|
|
overloadCost := c.functionCost(call.GetFunction(), overload, &targetType, argTypes, argCosts)
|
||
|
|
fnCost = fnCost.Union(overloadCost.CostEstimate)
|
||
|
|
if overloadCost.ResultSize != nil {
|
||
|
|
if resultSize == nil {
|
||
|
|
resultSize = overloadCost.ResultSize
|
||
|
|
} else {
|
||
|
|
size := resultSize.Union(*overloadCost.ResultSize)
|
||
|
|
resultSize = &size
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// build and track the field path for index operations
|
||
|
|
switch overload {
|
||
|
|
case overloads.IndexList:
|
||
|
|
if len(args) > 0 {
|
||
|
|
c.addPath(e, append(c.getPath(args[0]), "@items"))
|
||
|
|
}
|
||
|
|
case overloads.IndexMap:
|
||
|
|
if len(args) > 0 {
|
||
|
|
c.addPath(e, append(c.getPath(args[0]), "@values"))
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if resultSize != nil {
|
||
|
|
c.computedSizes[e.GetId()] = *resultSize
|
||
|
|
}
|
||
|
|
return sum.Add(fnCost)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) costCreateList(e *exprpb.Expr) CostEstimate {
|
||
|
|
create := e.GetListExpr()
|
||
|
|
var sum CostEstimate
|
||
|
|
for _, e := range create.GetElements() {
|
||
|
|
sum = sum.Add(c.cost(e))
|
||
|
|
}
|
||
|
|
return sum.Add(createListBaseCost)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) costCreateStruct(e *exprpb.Expr) CostEstimate {
|
||
|
|
str := e.GetStructExpr()
|
||
|
|
if str.MessageName != "" {
|
||
|
|
return c.costCreateMessage(e)
|
||
|
|
}
|
||
|
|
return c.costCreateMap(e)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) costCreateMap(e *exprpb.Expr) CostEstimate {
|
||
|
|
mapVal := e.GetStructExpr()
|
||
|
|
var sum CostEstimate
|
||
|
|
for _, ent := range mapVal.GetEntries() {
|
||
|
|
key := ent.GetMapKey()
|
||
|
|
sum = sum.Add(c.cost(key))
|
||
|
|
|
||
|
|
sum = sum.Add(c.cost(ent.GetValue()))
|
||
|
|
}
|
||
|
|
return sum.Add(createMapBaseCost)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) costCreateMessage(e *exprpb.Expr) CostEstimate {
|
||
|
|
msgVal := e.GetStructExpr()
|
||
|
|
var sum CostEstimate
|
||
|
|
for _, ent := range msgVal.GetEntries() {
|
||
|
|
sum = sum.Add(c.cost(ent.GetValue()))
|
||
|
|
}
|
||
|
|
return sum.Add(createMessageBaseCost)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) costComprehension(e *exprpb.Expr) CostEstimate {
|
||
|
|
comp := e.GetComprehensionExpr()
|
||
|
|
var sum CostEstimate
|
||
|
|
sum = sum.Add(c.cost(comp.GetIterRange()))
|
||
|
|
sum = sum.Add(c.cost(comp.GetAccuInit()))
|
||
|
|
|
||
|
|
// Track the iterRange of each IterVar for field path construction
|
||
|
|
c.iterRanges.push(comp.GetIterVar(), comp.GetIterRange())
|
||
|
|
loopCost := c.cost(comp.GetLoopCondition())
|
||
|
|
stepCost := c.cost(comp.GetLoopStep())
|
||
|
|
c.iterRanges.pop(comp.GetIterVar())
|
||
|
|
sum = sum.Add(c.cost(comp.Result))
|
||
|
|
rangeCnt := c.sizeEstimate(c.newAstNode(comp.GetIterRange()))
|
||
|
|
rangeCost := rangeCnt.MultiplyByCost(stepCost.Add(loopCost))
|
||
|
|
sum = sum.Add(rangeCost)
|
||
|
|
|
||
|
|
return sum
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) sizeEstimate(t AstNode) SizeEstimate {
|
||
|
|
if l := t.ComputedSize(); l != nil {
|
||
|
|
return *l
|
||
|
|
}
|
||
|
|
if l := c.estimator.EstimateSize(t); l != nil {
|
||
|
|
return *l
|
||
|
|
}
|
||
|
|
// return an estimate of 1 for return types of set
|
||
|
|
// lengths, since strings/bytes/more complex objects could be of
|
||
|
|
// variable length
|
||
|
|
if isScalar(t.Type()) {
|
||
|
|
// TODO: since the logic for size estimation is split between
|
||
|
|
// ComputedSize and isScalar, changing one will likely require changing
|
||
|
|
// the other, so they should be merged in the future if possible
|
||
|
|
return SizeEstimate{Min: 1, Max: 1}
|
||
|
|
}
|
||
|
|
return SizeEstimate{Min: 0, Max: math.MaxUint64}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) functionCost(function, overloadID string, target *AstNode, args []AstNode, argCosts []CostEstimate) CallEstimate {
|
||
|
|
argCostSum := func() CostEstimate {
|
||
|
|
var sum CostEstimate
|
||
|
|
for _, a := range argCosts {
|
||
|
|
sum = sum.Add(a)
|
||
|
|
}
|
||
|
|
return sum
|
||
|
|
}
|
||
|
|
|
||
|
|
if est := c.estimator.EstimateCallCost(function, overloadID, target, args); est != nil {
|
||
|
|
callEst := *est
|
||
|
|
return CallEstimate{CostEstimate: callEst.Add(argCostSum())}
|
||
|
|
}
|
||
|
|
switch overloadID {
|
||
|
|
// O(n) functions
|
||
|
|
case overloads.StartsWithString, overloads.EndsWithString, overloads.StringToBytes, overloads.BytesToString:
|
||
|
|
if len(args) == 1 {
|
||
|
|
return CallEstimate{CostEstimate: c.sizeEstimate(args[0]).MultiplyByCostFactor(common.StringTraversalCostFactor).Add(argCostSum())}
|
||
|
|
}
|
||
|
|
case overloads.InList:
|
||
|
|
// If a list is composed entirely of constant values this is O(1), but we don't account for that here.
|
||
|
|
// We just assume all list containment checks are O(n).
|
||
|
|
if len(args) == 2 {
|
||
|
|
return CallEstimate{CostEstimate: c.sizeEstimate(args[1]).MultiplyByCostFactor(1).Add(argCostSum())}
|
||
|
|
}
|
||
|
|
// O(nm) functions
|
||
|
|
case overloads.MatchesString:
|
||
|
|
// https://swtch.com/~rsc/regexp/regexp1.html applies to RE2 implementation supported by CEL
|
||
|
|
if target != nil && len(args) == 1 {
|
||
|
|
// Add one to string length for purposes of cost calculation to prevent product of string and regex to be 0
|
||
|
|
// in case where string is empty but regex is still expensive.
|
||
|
|
strCost := c.sizeEstimate(*target).Add(SizeEstimate{Min: 1, Max: 1}).MultiplyByCostFactor(common.StringTraversalCostFactor)
|
||
|
|
// We don't know how many expressions are in the regex, just the string length (a huge
|
||
|
|
// improvement here would be to somehow get a count the number of expressions in the regex or
|
||
|
|
// how many states are in the regex state machine and use that to measure regex cost).
|
||
|
|
// For now, we're making a guess that each expression in a regex is typically at least 4 chars
|
||
|
|
// in length.
|
||
|
|
regexCost := c.sizeEstimate(args[0]).MultiplyByCostFactor(common.RegexStringLengthCostFactor)
|
||
|
|
return CallEstimate{CostEstimate: strCost.Multiply(regexCost).Add(argCostSum())}
|
||
|
|
}
|
||
|
|
case overloads.ContainsString:
|
||
|
|
if target != nil && len(args) == 1 {
|
||
|
|
strCost := c.sizeEstimate(*target).MultiplyByCostFactor(common.StringTraversalCostFactor)
|
||
|
|
substrCost := c.sizeEstimate(args[0]).MultiplyByCostFactor(common.StringTraversalCostFactor)
|
||
|
|
return CallEstimate{CostEstimate: strCost.Multiply(substrCost).Add(argCostSum())}
|
||
|
|
}
|
||
|
|
case overloads.LogicalOr, overloads.LogicalAnd:
|
||
|
|
lhs := argCosts[0]
|
||
|
|
rhs := argCosts[1]
|
||
|
|
// min cost is min of LHS for short circuited && or ||
|
||
|
|
argCost := CostEstimate{Min: lhs.Min, Max: lhs.Add(rhs).Max}
|
||
|
|
return CallEstimate{CostEstimate: argCost}
|
||
|
|
case overloads.Conditional:
|
||
|
|
size := c.sizeEstimate(args[1]).Union(c.sizeEstimate(args[2]))
|
||
|
|
conditionalCost := argCosts[0]
|
||
|
|
ifTrueCost := argCosts[1]
|
||
|
|
ifFalseCost := argCosts[2]
|
||
|
|
argCost := conditionalCost.Add(ifTrueCost.Union(ifFalseCost))
|
||
|
|
return CallEstimate{CostEstimate: argCost, ResultSize: &size}
|
||
|
|
case overloads.AddString, overloads.AddBytes, overloads.AddList:
|
||
|
|
if len(args) == 2 {
|
||
|
|
lhsSize := c.sizeEstimate(args[0])
|
||
|
|
rhsSize := c.sizeEstimate(args[1])
|
||
|
|
resultSize := lhsSize.Add(rhsSize)
|
||
|
|
switch overloadID {
|
||
|
|
case overloads.AddList:
|
||
|
|
// list concatenation is O(1), but we handle it here to track size
|
||
|
|
return CallEstimate{CostEstimate: CostEstimate{Min: 1, Max: 1}.Add(argCostSum()), ResultSize: &resultSize}
|
||
|
|
default:
|
||
|
|
return CallEstimate{CostEstimate: resultSize.MultiplyByCostFactor(common.StringTraversalCostFactor).Add(argCostSum()), ResultSize: &resultSize}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
case overloads.LessString, overloads.GreaterString, overloads.LessEqualsString, overloads.GreaterEqualsString,
|
||
|
|
overloads.LessBytes, overloads.GreaterBytes, overloads.LessEqualsBytes, overloads.GreaterEqualsBytes,
|
||
|
|
overloads.Equals, overloads.NotEquals:
|
||
|
|
lhsCost := c.sizeEstimate(args[0])
|
||
|
|
rhsCost := c.sizeEstimate(args[1])
|
||
|
|
min := uint64(0)
|
||
|
|
smallestMax := lhsCost.Max
|
||
|
|
if rhsCost.Max < smallestMax {
|
||
|
|
smallestMax = rhsCost.Max
|
||
|
|
}
|
||
|
|
if smallestMax > 0 {
|
||
|
|
min = 1
|
||
|
|
}
|
||
|
|
// equality of 2 scalar values results in a cost of 1
|
||
|
|
return CallEstimate{CostEstimate: CostEstimate{Min: min, Max: smallestMax}.MultiplyByCostFactor(common.StringTraversalCostFactor).Add(argCostSum())}
|
||
|
|
}
|
||
|
|
// O(1) functions
|
||
|
|
// See CostTracker.costCall for more details about O(1) cost calculations
|
||
|
|
|
||
|
|
// Benchmarks suggest that most of the other operations take +/- 50% of a base cost unit
|
||
|
|
// which on an Intel xeon 2.20GHz CPU is 50ns.
|
||
|
|
return CallEstimate{CostEstimate: CostEstimate{Min: 1, Max: 1}.Add(argCostSum())}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) getType(e *exprpb.Expr) *exprpb.Type {
|
||
|
|
return c.checkedExpr.TypeMap[e.GetId()]
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) getPath(e *exprpb.Expr) []string {
|
||
|
|
return c.exprPath[e.GetId()]
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) addPath(e *exprpb.Expr, path []string) {
|
||
|
|
c.exprPath[e.GetId()] = path
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c *coster) newAstNode(e *exprpb.Expr) *astNode {
|
||
|
|
path := c.getPath(e)
|
||
|
|
if len(path) > 0 && path[0] == parser.AccumulatorName {
|
||
|
|
// only provide paths to root vars; omit accumulator vars
|
||
|
|
path = nil
|
||
|
|
}
|
||
|
|
var derivedSize *SizeEstimate
|
||
|
|
if size, ok := c.computedSizes[e.GetId()]; ok {
|
||
|
|
derivedSize = &size
|
||
|
|
}
|
||
|
|
return &astNode{path: path, t: c.getType(e), expr: e, derivedSize: derivedSize}
|
||
|
|
}
|
||
|
|
|
||
|
|
// isScalar returns true if the given type is known to be of a constant size at
|
||
|
|
// compile time. isScalar will return false for strings (they are variable-width)
|
||
|
|
// in addition to protobuf.Any and protobuf.Value (their size is not knowable at compile time).
|
||
|
|
func isScalar(t *exprpb.Type) bool {
|
||
|
|
switch kindOf(t) {
|
||
|
|
case kindPrimitive:
|
||
|
|
if t.GetPrimitive() != exprpb.Type_STRING && t.GetPrimitive() != exprpb.Type_BYTES {
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
case kindWellKnown:
|
||
|
|
if t.GetWellKnown() == exprpb.Type_DURATION || t.GetWellKnown() == exprpb.Type_TIMESTAMP {
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return false
|
||
|
|
}
|