modelchecker

package
v0.3.1 Latest Latest
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 Go to latest Published: Nov 17, 2025 License: Apache-2.0 Imports: 32 Imported by: 0

Documentation

Overview

Package modelchecker implements the model checker for the FizzBuzz program. It is based on the Starlark interpreter for the python part of the code. For the interpreter to implement the model checker, we need to simulate parallel universe. Every time, there is a non-deterministic choice, we need to fork the universe and continue the execution in both the universes with the different choices. Each universe is represented by a process. Each process has a heap and multiple threads. Each thread has a stack of call frames. Each call frame has a program counter and scope (with nesting). The heap is shared across all the threads in the process. Duplicate detection: Two threads are same if they have the same stack of call frames Two processes are same if they have the same heap and same threads.

Index

Constants

View Source 
const (
	ActionsWithMultipleBlocks = `` /* 3732-byte string literal not displayed */

)

Variables

This section is empty.

Functions

func CheckAssertion 

func CheckAssertion(process *Process, invariant *ast.Invariant, index int) bool

func CheckFastLiveness 

func CheckFastLiveness(allNodes []*Node) ([]*Link, *InvariantPosition)

func CheckInvariant 

func CheckInvariant(process *Process, invariant *ast.Invariant) bool

func CheckInvariants 

func CheckInvariants(process *Process) map[int][]int

func CheckLivenessSccAlwaysEventually 

func CheckLivenessSccAlwaysEventually(nodes []*Node, invPos InvariantPosition) (bool, error)

func CheckRefinement added in v0.2.0 

func CheckRefinement(process *Process, refinement *ast.Refinement, joinHashes JoinHashes) bool

func CheckStrictLiveness 

func CheckStrictLiveness(node *Node, nodes []*Node) ([]*Link, *InvariantPosition)

func CheckTransitionAssertion 

func CheckTransitionAssertion(process *Process, invariant *ast.Invariant, index int) bool

func CheckTransitionInvariants 

func CheckTransitionInvariants(process *Process) map[int][]int

func CloneDict 

func CloneDict(oldDict starlark.StringDict, refs map[starlark.Value]starlark.Value, permutations map[lib.SymmetricValue][]lib.SymmetricValue, alt int) starlark.StringDict

func ContainsInt 

func ContainsInt(skipstmts []int, i int) bool

func CopyDict 

func CopyDict(from starlark.StringDict, to starlark.StringDict, refs map[starlark.Value]starlark.Value, permutations map[lib.SymmetricValue][]lib.SymmetricValue, alt int) starlark.StringDict

CopyDict copies values `from` to `to` overriding existing values. If the `to` is nil, creates a new dict.

func DeepCopyBuiltIn 

func DeepCopyBuiltIn(thread *starlark.Thread, fn *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error)

func EndOfBlock 

func EndOfBlock(path string) string

func ExecFunction added in v0.2.0 

func ExecFunction(process *Process, name string) starlark.Value

func GenerateCommunicationGraph 

func GenerateCommunicationGraph(messages []string) string

func GenerateDotFile 

func GenerateDotFile(node *Node, visited map[*Node]bool) string

func GenerateErrorPathProtoOfJson 

func GenerateErrorPathProtoOfJson(errorPath []*Link, pathPrefix string) ([]string, []string, error)

func GenerateFailurePath 

func GenerateFailurePath(nodes []*Link, name string, invariant *InvariantPosition) string

func GenerateFailurePathHtml added in v0.2.0 

func GenerateFailurePathHtml(srcFileName string, failurePath []*Link, invariant *InvariantPosition, outDir string) error

GenerateFailurePathHtml creates an HTML file showing differences between adjacent failurePath Links

func GenerateProtoOfJson 

func GenerateProtoOfJson(nodes []*Node, pathPrefix string) ([]string, []string, error)

func GetAllNodes 

func GetAllNodes(root *Node, maxActions int64) ([]*Node, []string, *Node, int)

func GetFieldByPath 

func GetFieldByPath(msg proto.Message, path string) *reflect.Value

func GetNextFieldPath 

func GetNextFieldPath(msg proto.Message, path string) (string, *reflect.Value)

func GetProtoFieldByPath 

func GetProtoFieldByPath(file *ast.File, location string) proto.Message

func GetStringFieldByPath 

func GetStringFieldByPath(file *ast.File, location string) (string, bool)

func HandleModules 

func HandleModules(path string) map[string]starlark.Value

func LoadModule 

func LoadModule(moduleFile string) starlark.StringDict

func MapRoleValuesInOrder 

func MapRoleValuesInOrder(m map[starlark.Value]starlark.Value, oldList []*lib.Role) []*lib.Role

MapRoleValuesInOrder returns the values of the map m. The values will be in an indeterminate order.

func NewDictFromStringDict 

func NewDictFromStringDict(vals starlark.StringDict) *starlark.Dict

func PanicIfFalse 

func PanicIfFalse(ok bool, msg string)

func PanicOnError 

func PanicOnError(err error)

func ParentBlockPath 

func ParentBlockPath(path string) string

func ReadOptionsFromYaml 

func ReadOptionsFromYaml(filename string) (*proto.StateSpaceOptions, error)

func ReadOptionsFromYamlString 

func ReadOptionsFromYamlString(contents string) (*proto.StateSpaceOptions, error)

func RemoveLastBlock 

func RemoveLastBlock(path string) string

func RemoveLastForStmt 

func RemoveLastForStmt(path string) string

func RemoveLastLoop 

func RemoveLastLoop(path string) string

func RemoveLastLoopBlock 

func RemoveLastLoopBlock(path string) string

func RemoveLastSegment 

func RemoveLastSegment(path string, substr string) string

func RemoveLastWhileStmt 

func RemoveLastWhileStmt(path string) string

func RemoveMergeNodes 

func RemoveMergeNodes(root *Node)

func StringDictToJson 

func StringDictToJson(stringDict starlark.StringDict) ([]byte, error)

func StringDictToJsonRetainType 

func StringDictToJsonRetainType(strDict starlark.StringDict) ([]byte, error)

func StringDictToJsonString 

func StringDictToJsonString(stringDict starlark.StringDict) string

func StringDictToMap 

func StringDictToMap(stringDict starlark.StringDict) map[string]string

Types

type CallFrame 

type CallFrame struct {
	// FileIndex is the ast.FileIndex that this frame is executing.
	FileIndex int

	// Name is the full path of the function/action being executed.
	Name string
	// contains filtered or unexported fields
}

func (*CallFrame) Clone 

func (c *CallFrame) Clone(refs map[starlark.Value]starlark.Value, permutations map[lib.SymmetricValue][]lib.SymmetricValue, alt int) (*CallFrame, error)

func (*CallFrame) HashCode 

func (c *CallFrame) HashCode() string

func (*CallFrame) MarshalJSON 

func (c *CallFrame) MarshalJSON() ([]byte, error)

type CallStack 

type CallStack struct {
	*lib.Stack[*CallFrame]
}

func NewCallStack 

func NewCallStack() *CallStack

func (*CallStack) Clone 

func (s *CallStack) Clone(map[lib.SymmetricValue][]lib.SymmetricValue, int) *CallStack

func (*CallStack) HashCode 

func (s *CallStack) HashCode() string

type ChannelMessage 

type ChannelMessage struct {
	// contains filtered or unexported fields
}

func (*ChannelMessage) Clone 

func (cm *ChannelMessage) Clone(refs map[starlark.Value]starlark.Value, permutations map[lib.SymmetricValue][]lib.SymmetricValue, alt int) *ChannelMessage

func (*ChannelMessage) Frame 

func (cm *ChannelMessage) Frame() *CallFrame

func (*ChannelMessage) Function 

func (cm *ChannelMessage) Function() string

func (*ChannelMessage) HashCode 

func (cm *ChannelMessage) HashCode() string

func (*ChannelMessage) MarshalJSON 

func (cm *ChannelMessage) MarshalJSON() ([]byte, error)

func (*ChannelMessage) Params 

func (cm *ChannelMessage) Params() starlark.StringDict

func (*ChannelMessage) Receiver 

func (cm *ChannelMessage) Receiver() string

func (*ChannelMessage) String 

func (cm *ChannelMessage) String() string

type CodeSnippet 

type CodeSnippet interface {
	GetSourceInfo() *ast.SourceInfo
}

type CycleCallback 

type CycleCallback func(path []*Link, cycles int) (bool, *CycleCallbackResult)

type CycleCallbackResult 

type CycleCallbackResult struct {
	// contains filtered or unexported fields
}

type DefType 

type DefType string

DefType is a custom enum-like type 

const (
	Function DefType = "function"
)

type Definition 

type Definition struct {
	DefType DefType
	// contains filtered or unexported fields
}

type DurabilitySpec 

type DurabilitySpec struct {
	RoleDurabilitySpec map[string]RoleDurabilitySpec
}

func (*DurabilitySpec) AddDurabilitySpec 

func (d *DurabilitySpec) AddDurabilitySpec(evaluator *Evaluator, role *ast.Role)

func (*DurabilitySpec) HasDurabilitySpec 

func (d *DurabilitySpec) HasDurabilitySpec(role string) bool

HasDurabilitySpec returns true if the role has a durability spec.

func (*DurabilitySpec) IsFieldDurable 

func (d *DurabilitySpec) IsFieldDurable(role string, field string) bool

IsFieldDurable returns true if the field is durable for the role.

type Evaluator 

type Evaluator struct {
	// contains filtered or unexported fields
}

func NewEvaluator 

func NewEvaluator(options *syntax.FileOptions, thread *starlark.Thread) *Evaluator

func NewModelChecker 

func NewModelChecker(name string) *Evaluator

func (*Evaluator) EvalExpr 

func (e *Evaluator) EvalExpr(filename string, expr *ast.Expr, prevState starlark.StringDict) (starlark.Value, error)

func (*Evaluator) EvalPyExpr 

func (e *Evaluator) EvalPyExpr(filename string, src interface{}, prevState starlark.StringDict) (starlark.Value, error)

func (*Evaluator) ExecAction 

func (e *Evaluator) ExecAction(filename string, action *ast.Action, prevState starlark.StringDict) (bool, error)

func (*Evaluator) ExecAnyStmt 

func (e *Evaluator) ExecAnyStmt(filename string, anyStmt *ast.AnyStmt, prevState starlark.StringDict) (bool, error)

func (*Evaluator) ExecBlock 

func (e *Evaluator) ExecBlock(filename string, block *ast.Block, prevState starlark.StringDict) (bool, error)

func (*Evaluator) ExecForStmt 

func (e *Evaluator) ExecForStmt(filename string, forStmt *ast.ForStmt, prevState starlark.StringDict) bool

func (*Evaluator) ExecIfStmt 

func (e *Evaluator) ExecIfStmt(filename string, ifStmt *ast.IfStmt, prevState starlark.StringDict) bool

func (*Evaluator) ExecInit 

func (e *Evaluator) ExecInit(variables *ast.StateVars) (starlark.StringDict, error)

func (*Evaluator) ExecInitOld 

func (e *Evaluator) ExecInitOld(variables *ast.StateVars) (starlark.StringDict, error)

func (*Evaluator) ExecPyStmt 

func (e *Evaluator) ExecPyStmt(filename string, stmt *ast.PyStmt, prevState starlark.StringDict) (bool, error)

type HashKey added in v0.2.0 

type HashKey string

type Heap 

type Heap struct {
	CachedHashCode string
	// contains filtered or unexported fields
}

func NewComposedHeap added in v0.2.0 

func NewComposedHeap(composed map[string]*Heap) *Heap

func (*Heap) Clone 

func (h *Heap) Clone(refs map[starlark.Value]starlark.Value, permutations map[lib.SymmetricValue][]lib.SymmetricValue, alt int) *Heap

func (*Heap) GetSymmetryDefs 

func (h *Heap) GetSymmetryDefs() []*lib.SymmetricValues

func (*Heap) HashCode 

func (h *Heap) HashCode() string

HashCode returns a string hash of the global state.

func (*Heap) MarshalJSON 

func (h *Heap) MarshalJSON() ([]byte, error)

func (*Heap) String 

func (h *Heap) String() string

func (*Heap) ToJson 

func (h *Heap) ToJson() string

type Histogram 

type Histogram struct {
	// contains filtered or unexported fields
}

func FindAbsorptionCosts 

func FindAbsorptionCosts(root *Node, perfModel *proto.PerformanceModel, fileId int, invariantId int) ([]float64, *Histogram)

func (*Histogram) GetAllHistogram 

func (h *Histogram) GetAllHistogram() []HistogramEntry

func (*Histogram) GetMean 

func (h *Histogram) GetMean(counter string) float64

func (*Histogram) GetMeanCounts 

func (h *Histogram) GetMeanCounts() map[string]float64

type HistogramEntry 

type HistogramEntry struct {
	// contains filtered or unexported fields
}

type InvariantPosition 

type InvariantPosition struct {
	FileIndex      int
	InvariantIndex int
}

func CheckSimpleExistsWitness 

func CheckSimpleExistsWitness(nodes []*Node) []*InvariantPosition

func NewInvariantPosition 

func NewInvariantPosition(fileIndex, invariantIndex int) *InvariantPosition

type JoinHashes added in v0.2.0 

type JoinHashes map[HashKey][]TransitionSet
type Link struct {
	Node             *Node
	Type             string
	Name             string
	Labels           []string
	Fairness         ast.FairnessLevel
	ChoiceFairness   ast.FairnessLevel
	Messages         []*ast.Message
	ReqId            int
	ThreadsMap       map[int]int
	FailedInvariants map[int][]int
}

func AlwaysEventuallyFast 

func AlwaysEventuallyFast(nodes []*Node, predicate Predicate) ([]*Link, bool)

func AlwaysEventuallyFinal 

func AlwaysEventuallyFinal(nodes []*Node, root *Node, predicate Predicate) ([]*Link, bool)

func CycleFinderFinal 

func CycleFinderFinal(nodes []*Node, root *Node, callback CycleCallback) ([]*Link, bool)

func CycleFinderFinalBfs 

func CycleFinderFinalBfs(node *Node, callback CycleCallback) ([]*Link, bool)

func EventuallyAlwaysFast 

func EventuallyAlwaysFast(nodes []*Node, predicate Predicate) ([]*Link, bool)

func EventuallyAlwaysFinal 

func EventuallyAlwaysFinal(nodes []*Node, root *Node, predicate Predicate) ([]*Link, bool)

func ExtractFailurePath added in v0.2.0 

func ExtractFailurePath(node *Node, rootNode *Node) []*Link
func InitNodeToLink(node *Node) *Link
func ReverseLink(node *Node, link *Link) *Link

func (*Link) HasFailedInvariants 

func (l *Link) HasFailedInvariants() bool
func (l *Link) IsCrashLink() bool

type ModelError 

type ModelError struct {
	SourceInfo  *proto.SourceInfo
	Msg         string
	Process     *Process
	NestedError error
}

func NewModelError 

func NewModelError(sourceInfo *proto.SourceInfo, msg string, process *Process, nestedError error) *ModelError

func (*ModelError) Error 

func (e *ModelError) Error() string

func (*ModelError) SprintStackTrace 

func (e *ModelError) SprintStackTrace() string

type Node 

type Node struct {
	*Process `json:"process"`

	Inbound  []*Link `json:"-"`
	Outbound []*Link `json:"-"`

	DuplicateOf *Node
	// contains filtered or unexported fields
}

func NewNode 

func NewNode(process *Process) *Node

func (*Node) Attach 

func (n *Node) Attach()

func (*Node) CreateNewToOldThreadIndexMap 

func (n *Node) CreateNewToOldThreadIndexMap(other *Node) map[int]int

func (*Node) Duplicate 

func (n *Node) Duplicate(other *Node, yield bool)

func (*Node) ForkForAction 

func (n *Node) ForkForAction(process *Process, role *lib.Role, action *ast.Action) *Node

func (*Node) ForkForAlternatePaths 

func (n *Node) ForkForAlternatePaths(process *Process, name string) *Node

func (*Node) GetJsonString 

func (n *Node) GetJsonString() string

func (*Node) GetName 

func (n *Node) GetName() string

GetName returns the name

func (*Node) GetStateString 

func (n *Node) GetStateString() string

func (*Node) MarshalJSON 

func (n *Node) MarshalJSON() ([]byte, error)

func (*Node) String 

func (n *Node) String() string

String method for Process

type Predicate 

type Predicate func(n *Node) (bool, bool)

type Process 

type Process struct {
	Heap             *Heap         `json:"state"`
	Threads          []*Thread     `json:"threads"`
	Current          int           `json:"current"`
	Name             string        `json:"name"`
	Files            []*ast.File   `json:"-"`
	Parent           *Process      `json:"-"`
	Evaluator        *Evaluator    `json:"-"`
	Children         []*Process    `json:"-"`
	FailedInvariants map[int][]int `json:"failedInvariants"`
	Stats            *Stats        `json:"stats"`
	// Witness indicates the successful liveness checks
	// For liveness checks, not all nodes will pass the condition, witness indicates
	// which invariants this node passed.
	Witness     [][]bool               `json:"witness"`
	Returns     starlark.StringDict    `json:"returns"`
	SymbolTable map[string]*Definition `json:"-"`
	Labels      []string               `json:"-"`
	Messages    []*ast.Message         `json:"-"`

	// Fairness is actually a property of the transition/link. But to determine whether
	// the link is fair, we need to know if the process stepped through at least one
	// fair statement. To determine that, each thread maintains the fairness level
	// of the action that started. If that thread executed a statement, that process becomes fair,
	// that in-turn makes the link fair.
	Fairness ast.FairnessLevel `json:"-"`

	Enabled        bool `json:"-"`
	ThreadProgress bool `json:"-"`

	Roles    []*lib.Role          `json:"roles"`
	Channels map[int]*lib.Channel `json:"channels"`

	ChannelMessages map[int][]*ChannelMessage `json:"channel_messages"`

	CachedHashCode     string   `json:"-"`
	CachedThreadHashes []string `json:"-"`

	Modules          map[string]starlark.Value `json:"-"`
	EnableCheckpoint bool                      `json:"-"`
	ChoiceFairness   ast.FairnessLevel         `json:"-"`
	// contains filtered or unexported fields
}

func NewProcess 

func NewProcess(name string, files []*ast.File, parent *Process) *Process

func (*Process) CloneForAssert 

func (p *Process) CloneForAssert(permutations map[lib.SymmetricValue][]lib.SymmetricValue, alt int) *Process

func (*Process) Enable 

func (p *Process) Enable()

func (*Process) Fork 

func (p *Process) Fork() *Process

func (*Process) GetAllVariables 

func (p *Process) GetAllVariables() starlark.StringDict

GetAllVariables returns all variables visible in the Current thread. This includes state variables and variables from the Current thread's variables in the top call frame

func (*Process) GetAllVariablesNocopy 

func (p *Process) GetAllVariablesNocopy() starlark.StringDict

GetAllVariablesNocopy returns all variables visible in the Current thread, without deep copying. This includes state variables and variables from the Current thread's variables in the top call frame

func (*Process) GetSymmetryRoles 

func (p *Process) GetSymmetryRoles() []*lib.SymmetricValues

func (*Process) GetThreads 

func (p *Process) GetThreads() []*Thread

GetThreads returns the active threads

func (*Process) GetThreadsCount 

func (p *Process) GetThreadsCount() int

func (*Process) HasFailedInvariants 

func (p *Process) HasFailedInvariants() bool

func (*Process) HashCode 

func (p *Process) HashCode() string

func (*Process) IsYieldNode added in v0.2.0 

func (p *Process) IsYieldNode() bool

func (*Process) MarshalJSON 

func (p *Process) MarshalJSON() ([]byte, error)

func (*Process) NewModelError 

func (p *Process) NewModelError(sourceInfo *ast.SourceInfo, msg string, nestedError error) *ModelError

func (*Process) NewThread 

func (p *Process) NewThread() *Thread

func (*Process) PanicIfFalse 

func (p *Process) PanicIfFalse(ok bool, sourceInfo *ast.SourceInfo, msg string)

func (*Process) PanicOnError 

func (p *Process) PanicOnError(sourceInfo *ast.SourceInfo, msg string, nestedError error)

func (*Process) RecordCall 

func (p *Process) RecordCall(callerFrame *CallFrame, receiverFrame *CallFrame, flow ast.Flow)

func (*Process) RecordReturn 

func (p *Process) RecordReturn(callerFrame *CallFrame, receiverFrame *CallFrame, val starlark.Value, flow ast.Flow)

type Processor 

type Processor struct {
	Init  *Node
	Files []*ast.File

	Seed int64
	// contains filtered or unexported fields
}

func NewProcessor 

func NewProcessor(files []*ast.File, options *ast.StateSpaceOptions, simulation bool, seed int64, dirPath string, strategy string, test bool, hashes JoinHashes) *Processor

func (*Processor) ExceedsActionCountLimits 

func (p *Processor) ExceedsActionCountLimits(action *ast.Action, statProcess *Process, role *lib.Role) bool

func (*Processor) GetVisitedNodesCount 

func (p *Processor) GetVisitedNodesCount() int

func (*Processor) InitializeNode 

func (p *Processor) InitializeNode() (*Node, *Node, error)

func (*Processor) ResetEphemeralVariables 

func (p *Processor) ResetEphemeralVariables(node *Node, oldRole *lib.Role)

func (*Processor) Start 

func (p *Processor) Start() (init *Node, failedNode *Node, err error)

Start the model checker

func (*Processor) StartSimulation 

func (p *Processor) StartSimulation() (init *Node, failedNode *Node, err error)

func (*Processor) Stop 

func (p *Processor) Stop()

func (*Processor) Stopped 

func (p *Processor) Stopped() bool

func (*Processor) YieldFork 

func (p *Processor) YieldFork(node *Node, process *Process)

func (*Processor) YieldNode 

func (p *Processor) YieldNode(node *Node)

type ProtoPath 

type ProtoPath struct {
	// contains filtered or unexported fields
}

type RoleDurabilitySpec 

type RoleDurabilitySpec struct {
	// contains filtered or unexported fields
}

type Scope 

type Scope struct {
	// contains filtered or unexported fields
}

func (*Scope) GetAllVisibleVariables 

func (s *Scope) GetAllVisibleVariables(roleRefs map[starlark.Value]starlark.Value) starlark.StringDict

GetAllVisibleVariables returns all variables visible in this scope.

func (*Scope) Hash 

func (s *Scope) Hash() hash.Hash

func (*Scope) Lookup 

func (s *Scope) Lookup(name string) (starlark.Value, bool)

func (*Scope) MarshalJSON 

func (s *Scope) MarshalJSON() ([]byte, error)

func (*Scope) SetFlow 

func (s *Scope) SetFlow(flow ast.Flow)

type Stats 

type Stats struct {
	TotalActions int            `json:"totalActions"`
	Counts       map[string]int `json:"counts"`
}

func NewStats 

func NewStats() *Stats

NewStats returns a new Stats object

func (*Stats) Clone 

func (s *Stats) Clone() *Stats

func (*Stats) Increment 

func (s *Stats) Increment(action string)

type Thread 

type Thread struct {
	Id      int         `json:"id"`
	Process *Process    `json:"-"`
	Files   []*ast.File `json:"-"`
	Stack   *CallStack  `json:"stack"`

	Fairness ast.FairnessLevel `json:"fairness"`
	Aborted  bool              `json:"-"`
}

Thread represents a thread of execution.

func NewThread 

func NewThread(Process *Process, files []*ast.File, fileIndex int, action string) *Thread

func (*Thread) Clone 

func (t *Thread) Clone(permutations map[lib.SymmetricValue][]lib.SymmetricValue, alt int) *Thread

func (*Thread) CopyInitValuesForEphemeralFields 

func (t *Thread) CopyInitValuesForEphemeralFields(oldFrame *CallFrame)

func (*Thread) CurrentPcSourceInfo 

func (t *Thread) CurrentPcSourceInfo() *ast.SourceInfo

func (*Thread) Execute 

func (t *Thread) Execute() ([]*Process, bool)

func (*Thread) ExitScope 

func (t *Thread) ExitScope() *Scope

ExitScope removes the Current scope and returns the removed scope or nil if no scope was present.

func (*Thread) FindNextProgramCounter 

func (t *Thread) FindNextProgramCounter() string

func (*Thread) HashCode 

func (t *Thread) HashCode() string

func (*Thread) InsertNewScope 

func (t *Thread) InsertNewScope() *Scope

InsertNewScope adds a new scope to the Current stack frame and returns the newly created scope.

type Transition added in v0.2.0 

type Transition = lib.Pair[*Node, *Node]

type TransitionSet added in v0.2.0 

type TransitionSet map[Transition]bool

type NodeSet map[*modelchecker.Node]bool

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