diff options
Diffstat (limited to 'vendor/github.com/authzed/cel-go/interpreter/interpreter.go')
| -rw-r--r-- | vendor/github.com/authzed/cel-go/interpreter/interpreter.go | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/vendor/github.com/authzed/cel-go/interpreter/interpreter.go b/vendor/github.com/authzed/cel-go/interpreter/interpreter.go new file mode 100644 index 0000000..96eea0e --- /dev/null +++ b/vendor/github.com/authzed/cel-go/interpreter/interpreter.go @@ -0,0 +1,185 @@ +// Copyright 2018 Google LLC +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +// Package interpreter provides functions to evaluate parsed expressions with +// the option to augment the evaluation with inputs and functions supplied at +// evaluation time. +package interpreter + +import ( + "github.com/authzed/cel-go/common/ast" + "github.com/authzed/cel-go/common/containers" + "github.com/authzed/cel-go/common/types" + "github.com/authzed/cel-go/common/types/ref" +) + +// Interpreter generates a new Interpretable from a checked or unchecked expression. +type Interpreter interface { + // NewInterpretable creates an Interpretable from a checked expression and an + // optional list of InterpretableDecorator values. + NewInterpretable(exprAST *ast.AST, decorators ...InterpretableDecorator) (Interpretable, error) +} + +// EvalObserver is a functional interface that accepts an expression id and an observed value. +// The id identifies the expression that was evaluated, the programStep is the Interpretable or Qualifier that +// was evaluated and value is the result of the evaluation. +type EvalObserver func(id int64, programStep any, value ref.Val) + +// Observe constructs a decorator that calls all the provided observers in order after evaluating each Interpretable +// or Qualifier during program evaluation. +func Observe(observers ...EvalObserver) InterpretableDecorator { + if len(observers) == 1 { + return decObserveEval(observers[0]) + } + observeFn := func(id int64, programStep any, val ref.Val) { + for _, observer := range observers { + observer(id, programStep, val) + } + } + return decObserveEval(observeFn) +} + +// EvalCancelledError represents a cancelled program evaluation operation. +type EvalCancelledError struct { + Message string + // Type identifies the cause of the cancellation. + Cause CancellationCause +} + +func (e EvalCancelledError) Error() string { + return e.Message +} + +// CancellationCause enumerates the ways a program evaluation operation can be cancelled. +type CancellationCause int + +const ( + // ContextCancelled indicates that the operation was cancelled in response to a Golang context cancellation. + ContextCancelled CancellationCause = iota + + // CostLimitExceeded indicates that the operation was cancelled in response to the actual cost limit being + // exceeded. + CostLimitExceeded +) + +// TODO: Replace all usages of TrackState with EvalStateObserver + +// TrackState decorates each expression node with an observer which records the value +// associated with the given expression id. EvalState must be provided to the decorator. +// This decorator is not thread-safe, and the EvalState must be reset between Eval() +// calls. +// DEPRECATED: Please use EvalStateObserver instead. It composes gracefully with additional observers. +func TrackState(state EvalState) InterpretableDecorator { + return Observe(EvalStateObserver(state)) +} + +// EvalStateObserver provides an observer which records the value +// associated with the given expression id. EvalState must be provided to the observer. +// This decorator is not thread-safe, and the EvalState must be reset between Eval() +// calls. +func EvalStateObserver(state EvalState) EvalObserver { + return func(id int64, programStep any, val ref.Val) { + state.SetValue(id, val) + } +} + +// ExhaustiveEval replaces operations that short-circuit with versions that evaluate +// expressions and couples this behavior with the TrackState() decorator to provide +// insight into the evaluation state of the entire expression. EvalState must be +// provided to the decorator. This decorator is not thread-safe, and the EvalState +// must be reset between Eval() calls. +func ExhaustiveEval() InterpretableDecorator { + ex := decDisableShortcircuits() + return func(i Interpretable) (Interpretable, error) { + return ex(i) + } +} + +// InterruptableEval annotates comprehension loops with information that indicates they +// should check the `#interrupted` state within a custom Activation. +// +// The custom activation is currently managed higher up in the stack within the 'cel' package +// and should not require any custom support on behalf of callers. +func InterruptableEval() InterpretableDecorator { + return decInterruptFolds() +} + +// Optimize will pre-compute operations such as list and map construction and optimize +// call arguments to set membership tests. The set of optimizations will increase over time. +func Optimize() InterpretableDecorator { + return decOptimize() +} + +// RegexOptimization provides a way to replace an InterpretableCall for a regex function when the +// RegexIndex argument is a string constant. Typically, the Factory would compile the regex pattern at +// RegexIndex and report any errors (at program creation time) and then use the compiled regex for +// all regex function invocations. +type RegexOptimization struct { + // Function is the name of the function to optimize. + Function string + // OverloadID is the ID of the overload to optimize. + OverloadID string + // RegexIndex is the index position of the regex pattern argument. Only calls to the function where this argument is + // a string constant will be delegated to this optimizer. + RegexIndex int + // Factory constructs a replacement InterpretableCall node that optimizes the regex function call. Factory is + // provided with the unoptimized regex call and the string constant at the RegexIndex argument. + // The Factory may compile the regex for use across all invocations of the call, return any errors and + // return an interpreter.NewCall with the desired regex optimized function impl. + Factory func(call InterpretableCall, regexPattern string) (InterpretableCall, error) +} + +// CompileRegexConstants compiles regex pattern string constants at program creation time and reports any regex pattern +// compile errors. +func CompileRegexConstants(regexOptimizations ...*RegexOptimization) InterpretableDecorator { + return decRegexOptimizer(regexOptimizations...) +} + +type exprInterpreter struct { + dispatcher Dispatcher + container *containers.Container + provider types.Provider + adapter types.Adapter + attrFactory AttributeFactory +} + +// NewInterpreter builds an Interpreter from a Dispatcher and TypeProvider which will be used +// throughout the Eval of all Interpretable instances generated from it. +func NewInterpreter(dispatcher Dispatcher, + container *containers.Container, + provider types.Provider, + adapter types.Adapter, + attrFactory AttributeFactory) Interpreter { + return &exprInterpreter{ + dispatcher: dispatcher, + container: container, + provider: provider, + adapter: adapter, + attrFactory: attrFactory} +} + +// NewIntepretable implements the Interpreter interface method. +func (i *exprInterpreter) NewInterpretable( + checked *ast.AST, + decorators ...InterpretableDecorator) (Interpretable, error) { + p := newPlanner( + i.dispatcher, + i.provider, + i.adapter, + i.attrFactory, + i.container, + checked, + decorators...) + return p.Plan(checked.Expr()) +} |
