127 lines
2.7 KiB
Go
Vendored
127 lines
2.7 KiB
Go
Vendored
package analysis
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import (
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"fmt"
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"reflect"
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"strings"
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"unicode"
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)
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// Validate reports an error if any of the analyzers are misconfigured.
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// Checks include:
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// that the name is a valid identifier;
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// that the Requires graph is acyclic;
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// that analyzer fact types are unique;
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// that each fact type is a pointer.
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func Validate(analyzers []*Analyzer) error {
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// Map each fact type to its sole generating analyzer.
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factTypes := make(map[reflect.Type]*Analyzer)
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// Traverse the Requires graph, depth first.
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const (
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white = iota
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grey
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black
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finished
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)
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color := make(map[*Analyzer]uint8)
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var visit func(a *Analyzer) error
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visit = func(a *Analyzer) error {
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if a == nil {
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return fmt.Errorf("nil *Analyzer")
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}
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if color[a] == white {
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color[a] = grey
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// names
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if !validIdent(a.Name) {
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return fmt.Errorf("invalid analyzer name %q", a)
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}
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if a.Doc == "" {
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return fmt.Errorf("analyzer %q is undocumented", a)
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}
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// fact types
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for _, f := range a.FactTypes {
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if f == nil {
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return fmt.Errorf("analyzer %s has nil FactType", a)
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}
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t := reflect.TypeOf(f)
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if prev := factTypes[t]; prev != nil {
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return fmt.Errorf("fact type %s registered by two analyzers: %v, %v",
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t, a, prev)
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}
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if t.Kind() != reflect.Ptr {
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return fmt.Errorf("%s: fact type %s is not a pointer", a, t)
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}
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factTypes[t] = a
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}
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// recursion
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for _, req := range a.Requires {
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if err := visit(req); err != nil {
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return err
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}
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}
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color[a] = black
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}
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if color[a] == grey {
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stack := []*Analyzer{a}
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inCycle := map[string]bool{}
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for len(stack) > 0 {
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current := stack[len(stack)-1]
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stack = stack[:len(stack)-1]
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if color[current] == grey && !inCycle[current.Name] {
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inCycle[current.Name] = true
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stack = append(stack, current.Requires...)
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}
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}
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return &CycleInRequiresGraphError{AnalyzerNames: inCycle}
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}
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return nil
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}
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for _, a := range analyzers {
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if err := visit(a); err != nil {
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return err
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}
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}
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// Reject duplicates among analyzers.
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// Precondition: color[a] == black.
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// Postcondition: color[a] == finished.
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for _, a := range analyzers {
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if color[a] == finished {
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return fmt.Errorf("duplicate analyzer: %s", a.Name)
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}
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color[a] = finished
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}
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return nil
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}
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func validIdent(name string) bool {
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for i, r := range name {
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if !(r == '_' || unicode.IsLetter(r) || i > 0 && unicode.IsDigit(r)) {
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return false
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}
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}
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return name != ""
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}
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type CycleInRequiresGraphError struct {
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AnalyzerNames map[string]bool
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}
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func (e *CycleInRequiresGraphError) Error() string {
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var b strings.Builder
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b.WriteString("cycle detected involving the following analyzers:")
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for n := range e.AnalyzerNames {
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b.WriteByte(' ')
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b.WriteString(n)
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}
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return b.String()
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}
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