--- /dev/null
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmp
+
+import (
+ "fmt"
+ "reflect"
+ "regexp"
+ "strings"
+
+ "github.com/google/go-cmp/cmp/internal/function"
+)
+
+// Option configures for specific behavior of Equal and Diff. In particular,
+// the fundamental Option functions (Ignore, Transformer, and Comparer),
+// configure how equality is determined.
+//
+// The fundamental options may be composed with filters (FilterPath and
+// FilterValues) to control the scope over which they are applied.
+//
+// The cmp/cmpopts package provides helper functions for creating options that
+// may be used with Equal and Diff.
+type Option interface {
+ // filter applies all filters and returns the option that remains.
+ // Each option may only read s.curPath and call s.callTTBFunc.
+ //
+ // An Options is returned only if multiple comparers or transformers
+ // can apply simultaneously and will only contain values of those types
+ // or sub-Options containing values of those types.
+ filter(s *state, t reflect.Type, vx, vy reflect.Value) applicableOption
+}
+
+// applicableOption represents the following types:
+// Fundamental: ignore | validator | *comparer | *transformer
+// Grouping: Options
+type applicableOption interface {
+ Option
+
+ // apply executes the option, which may mutate s or panic.
+ apply(s *state, vx, vy reflect.Value)
+}
+
+// coreOption represents the following types:
+// Fundamental: ignore | validator | *comparer | *transformer
+// Filters: *pathFilter | *valuesFilter
+type coreOption interface {
+ Option
+ isCore()
+}
+
+type core struct{}
+
+func (core) isCore() {}
+
+// Options is a list of Option values that also satisfies the Option interface.
+// Helper comparison packages may return an Options value when packing multiple
+// Option values into a single Option. When this package processes an Options,
+// it will be implicitly expanded into a flat list.
+//
+// Applying a filter on an Options is equivalent to applying that same filter
+// on all individual options held within.
+type Options []Option
+
+func (opts Options) filter(s *state, t reflect.Type, vx, vy reflect.Value) (out applicableOption) {
+ for _, opt := range opts {
+ switch opt := opt.filter(s, t, vx, vy); opt.(type) {
+ case ignore:
+ return ignore{} // Only ignore can short-circuit evaluation
+ case validator:
+ out = validator{} // Takes precedence over comparer or transformer
+ case *comparer, *transformer, Options:
+ switch out.(type) {
+ case nil:
+ out = opt
+ case validator:
+ // Keep validator
+ case *comparer, *transformer, Options:
+ out = Options{out, opt} // Conflicting comparers or transformers
+ }
+ }
+ }
+ return out
+}
+
+func (opts Options) apply(s *state, _, _ reflect.Value) {
+ const warning = "ambiguous set of applicable options"
+ const help = "consider using filters to ensure at most one Comparer or Transformer may apply"
+ var ss []string
+ for _, opt := range flattenOptions(nil, opts) {
+ ss = append(ss, fmt.Sprint(opt))
+ }
+ set := strings.Join(ss, "\n\t")
+ panic(fmt.Sprintf("%s at %#v:\n\t%s\n%s", warning, s.curPath, set, help))
+}
+
+func (opts Options) String() string {
+ var ss []string
+ for _, opt := range opts {
+ ss = append(ss, fmt.Sprint(opt))
+ }
+ return fmt.Sprintf("Options{%s}", strings.Join(ss, ", "))
+}
+
+// FilterPath returns a new Option where opt is only evaluated if filter f
+// returns true for the current Path in the value tree.
+//
+// This filter is called even if a slice element or map entry is missing and
+// provides an opportunity to ignore such cases. The filter function must be
+// symmetric such that the filter result is identical regardless of whether the
+// missing value is from x or y.
+//
+// The option passed in may be an Ignore, Transformer, Comparer, Options, or
+// a previously filtered Option.
+func FilterPath(f func(Path) bool, opt Option) Option {
+ if f == nil {
+ panic("invalid path filter function")
+ }
+ if opt := normalizeOption(opt); opt != nil {
+ return &pathFilter{fnc: f, opt: opt}
+ }
+ return nil
+}
+
+type pathFilter struct {
+ core
+ fnc func(Path) bool
+ opt Option
+}
+
+func (f pathFilter) filter(s *state, t reflect.Type, vx, vy reflect.Value) applicableOption {
+ if f.fnc(s.curPath) {
+ return f.opt.filter(s, t, vx, vy)
+ }
+ return nil
+}
+
+func (f pathFilter) String() string {
+ return fmt.Sprintf("FilterPath(%s, %v)", function.NameOf(reflect.ValueOf(f.fnc)), f.opt)
+}
+
+// FilterValues returns a new Option where opt is only evaluated if filter f,
+// which is a function of the form "func(T, T) bool", returns true for the
+// current pair of values being compared. If either value is invalid or
+// the type of the values is not assignable to T, then this filter implicitly
+// returns false.
+//
+// The filter function must be
+// symmetric (i.e., agnostic to the order of the inputs) and
+// deterministic (i.e., produces the same result when given the same inputs).
+// If T is an interface, it is possible that f is called with two values with
+// different concrete types that both implement T.
+//
+// The option passed in may be an Ignore, Transformer, Comparer, Options, or
+// a previously filtered Option.
+func FilterValues(f interface{}, opt Option) Option {
+ v := reflect.ValueOf(f)
+ if !function.IsType(v.Type(), function.ValueFilter) || v.IsNil() {
+ panic(fmt.Sprintf("invalid values filter function: %T", f))
+ }
+ if opt := normalizeOption(opt); opt != nil {
+ vf := &valuesFilter{fnc: v, opt: opt}
+ if ti := v.Type().In(0); ti.Kind() != reflect.Interface || ti.NumMethod() > 0 {
+ vf.typ = ti
+ }
+ return vf
+ }
+ return nil
+}
+
+type valuesFilter struct {
+ core
+ typ reflect.Type // T
+ fnc reflect.Value // func(T, T) bool
+ opt Option
+}
+
+func (f valuesFilter) filter(s *state, t reflect.Type, vx, vy reflect.Value) applicableOption {
+ if !vx.IsValid() || !vx.CanInterface() || !vy.IsValid() || !vy.CanInterface() {
+ return nil
+ }
+ if (f.typ == nil || t.AssignableTo(f.typ)) && s.callTTBFunc(f.fnc, vx, vy) {
+ return f.opt.filter(s, t, vx, vy)
+ }
+ return nil
+}
+
+func (f valuesFilter) String() string {
+ return fmt.Sprintf("FilterValues(%s, %v)", function.NameOf(f.fnc), f.opt)
+}
+
+// Ignore is an Option that causes all comparisons to be ignored.
+// This value is intended to be combined with FilterPath or FilterValues.
+// It is an error to pass an unfiltered Ignore option to Equal.
+func Ignore() Option { return ignore{} }
+
+type ignore struct{ core }
+
+func (ignore) isFiltered() bool { return false }
+func (ignore) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption { return ignore{} }
+func (ignore) apply(s *state, _, _ reflect.Value) { s.report(true, reportByIgnore) }
+func (ignore) String() string { return "Ignore()" }
+
+// validator is a sentinel Option type to indicate that some options could not
+// be evaluated due to unexported fields, missing slice elements, or
+// missing map entries. Both values are validator only for unexported fields.
+type validator struct{ core }
+
+func (validator) filter(_ *state, _ reflect.Type, vx, vy reflect.Value) applicableOption {
+ if !vx.IsValid() || !vy.IsValid() {
+ return validator{}
+ }
+ if !vx.CanInterface() || !vy.CanInterface() {
+ return validator{}
+ }
+ return nil
+}
+func (validator) apply(s *state, vx, vy reflect.Value) {
+ // Implies missing slice element or map entry.
+ if !vx.IsValid() || !vy.IsValid() {
+ s.report(vx.IsValid() == vy.IsValid(), 0)
+ return
+ }
+
+ // Unable to Interface implies unexported field without visibility access.
+ if !vx.CanInterface() || !vy.CanInterface() {
+ const help = "consider using a custom Comparer; if you control the implementation of type, you can also consider using an Exporter, AllowUnexported, or cmpopts.IgnoreUnexported"
+ var name string
+ if t := s.curPath.Index(-2).Type(); t.Name() != "" {
+ // Named type with unexported fields.
+ name = fmt.Sprintf("%q.%v", t.PkgPath(), t.Name()) // e.g., "path/to/package".MyType
+ } else {
+ // Unnamed type with unexported fields. Derive PkgPath from field.
+ var pkgPath string
+ for i := 0; i < t.NumField() && pkgPath == ""; i++ {
+ pkgPath = t.Field(i).PkgPath
+ }
+ name = fmt.Sprintf("%q.(%v)", pkgPath, t.String()) // e.g., "path/to/package".(struct { a int })
+ }
+ panic(fmt.Sprintf("cannot handle unexported field at %#v:\n\t%v\n%s", s.curPath, name, help))
+ }
+
+ panic("not reachable")
+}
+
+// identRx represents a valid identifier according to the Go specification.
+const identRx = `[_\p{L}][_\p{L}\p{N}]*`
+
+var identsRx = regexp.MustCompile(`^` + identRx + `(\.` + identRx + `)*$`)
+
+// Transformer returns an Option that applies a transformation function that
+// converts values of a certain type into that of another.
+//
+// The transformer f must be a function "func(T) R" that converts values of
+// type T to those of type R and is implicitly filtered to input values
+// assignable to T. The transformer must not mutate T in any way.
+//
+// To help prevent some cases of infinite recursive cycles applying the
+// same transform to the output of itself (e.g., in the case where the
+// input and output types are the same), an implicit filter is added such that
+// a transformer is applicable only if that exact transformer is not already
+// in the tail of the Path since the last non-Transform step.
+// For situations where the implicit filter is still insufficient,
+// consider using cmpopts.AcyclicTransformer, which adds a filter
+// to prevent the transformer from being recursively applied upon itself.
+//
+// The name is a user provided label that is used as the Transform.Name in the
+// transformation PathStep (and eventually shown in the Diff output).
+// The name must be a valid identifier or qualified identifier in Go syntax.
+// If empty, an arbitrary name is used.
+func Transformer(name string, f interface{}) Option {
+ v := reflect.ValueOf(f)
+ if !function.IsType(v.Type(), function.Transformer) || v.IsNil() {
+ panic(fmt.Sprintf("invalid transformer function: %T", f))
+ }
+ if name == "" {
+ name = function.NameOf(v)
+ if !identsRx.MatchString(name) {
+ name = "λ" // Lambda-symbol as placeholder name
+ }
+ } else if !identsRx.MatchString(name) {
+ panic(fmt.Sprintf("invalid name: %q", name))
+ }
+ tr := &transformer{name: name, fnc: reflect.ValueOf(f)}
+ if ti := v.Type().In(0); ti.Kind() != reflect.Interface || ti.NumMethod() > 0 {
+ tr.typ = ti
+ }
+ return tr
+}
+
+type transformer struct {
+ core
+ name string
+ typ reflect.Type // T
+ fnc reflect.Value // func(T) R
+}
+
+func (tr *transformer) isFiltered() bool { return tr.typ != nil }
+
+func (tr *transformer) filter(s *state, t reflect.Type, _, _ reflect.Value) applicableOption {
+ for i := len(s.curPath) - 1; i >= 0; i-- {
+ if t, ok := s.curPath[i].(Transform); !ok {
+ break // Hit most recent non-Transform step
+ } else if tr == t.trans {
+ return nil // Cannot directly use same Transform
+ }
+ }
+ if tr.typ == nil || t.AssignableTo(tr.typ) {
+ return tr
+ }
+ return nil
+}
+
+func (tr *transformer) apply(s *state, vx, vy reflect.Value) {
+ step := Transform{&transform{pathStep{typ: tr.fnc.Type().Out(0)}, tr}}
+ vvx := s.callTRFunc(tr.fnc, vx, step)
+ vvy := s.callTRFunc(tr.fnc, vy, step)
+ step.vx, step.vy = vvx, vvy
+ s.compareAny(step)
+}
+
+func (tr transformer) String() string {
+ return fmt.Sprintf("Transformer(%s, %s)", tr.name, function.NameOf(tr.fnc))
+}
+
+// Comparer returns an Option that determines whether two values are equal
+// to each other.
+//
+// The comparer f must be a function "func(T, T) bool" and is implicitly
+// filtered to input values assignable to T. If T is an interface, it is
+// possible that f is called with two values of different concrete types that
+// both implement T.
+//
+// The equality function must be:
+// • Symmetric: equal(x, y) == equal(y, x)
+// • Deterministic: equal(x, y) == equal(x, y)
+// • Pure: equal(x, y) does not modify x or y
+func Comparer(f interface{}) Option {
+ v := reflect.ValueOf(f)
+ if !function.IsType(v.Type(), function.Equal) || v.IsNil() {
+ panic(fmt.Sprintf("invalid comparer function: %T", f))
+ }
+ cm := &comparer{fnc: v}
+ if ti := v.Type().In(0); ti.Kind() != reflect.Interface || ti.NumMethod() > 0 {
+ cm.typ = ti
+ }
+ return cm
+}
+
+type comparer struct {
+ core
+ typ reflect.Type // T
+ fnc reflect.Value // func(T, T) bool
+}
+
+func (cm *comparer) isFiltered() bool { return cm.typ != nil }
+
+func (cm *comparer) filter(_ *state, t reflect.Type, _, _ reflect.Value) applicableOption {
+ if cm.typ == nil || t.AssignableTo(cm.typ) {
+ return cm
+ }
+ return nil
+}
+
+func (cm *comparer) apply(s *state, vx, vy reflect.Value) {
+ eq := s.callTTBFunc(cm.fnc, vx, vy)
+ s.report(eq, reportByFunc)
+}
+
+func (cm comparer) String() string {
+ return fmt.Sprintf("Comparer(%s)", function.NameOf(cm.fnc))
+}
+
+// Exporter returns an Option that specifies whether Equal is allowed to
+// introspect into the unexported fields of certain struct types.
+//
+// Users of this option must understand that comparing on unexported fields
+// from external packages is not safe since changes in the internal
+// implementation of some external package may cause the result of Equal
+// to unexpectedly change. However, it may be valid to use this option on types
+// defined in an internal package where the semantic meaning of an unexported
+// field is in the control of the user.
+//
+// In many cases, a custom Comparer should be used instead that defines
+// equality as a function of the public API of a type rather than the underlying
+// unexported implementation.
+//
+// For example, the reflect.Type documentation defines equality to be determined
+// by the == operator on the interface (essentially performing a shallow pointer
+// comparison) and most attempts to compare *regexp.Regexp types are interested
+// in only checking that the regular expression strings are equal.
+// Both of these are accomplished using Comparers:
+//
+// Comparer(func(x, y reflect.Type) bool { return x == y })
+// Comparer(func(x, y *regexp.Regexp) bool { return x.String() == y.String() })
+//
+// In other cases, the cmpopts.IgnoreUnexported option can be used to ignore
+// all unexported fields on specified struct types.
+func Exporter(f func(reflect.Type) bool) Option {
+ if !supportExporters {
+ panic("Exporter is not supported on purego builds")
+ }
+ return exporter(f)
+}
+
+type exporter func(reflect.Type) bool
+
+func (exporter) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption {
+ panic("not implemented")
+}
+
+// AllowUnexported returns an Options that allows Equal to forcibly introspect
+// unexported fields of the specified struct types.
+//
+// See Exporter for the proper use of this option.
+func AllowUnexported(types ...interface{}) Option {
+ m := make(map[reflect.Type]bool)
+ for _, typ := range types {
+ t := reflect.TypeOf(typ)
+ if t.Kind() != reflect.Struct {
+ panic(fmt.Sprintf("invalid struct type: %T", typ))
+ }
+ m[t] = true
+ }
+ return exporter(func(t reflect.Type) bool { return m[t] })
+}
+
+// Result represents the comparison result for a single node and
+// is provided by cmp when calling Result (see Reporter).
+type Result struct {
+ _ [0]func() // Make Result incomparable
+ flags resultFlags
+}
+
+// Equal reports whether the node was determined to be equal or not.
+// As a special case, ignored nodes are considered equal.
+func (r Result) Equal() bool {
+ return r.flags&(reportEqual|reportByIgnore) != 0
+}
+
+// ByIgnore reports whether the node is equal because it was ignored.
+// This never reports true if Equal reports false.
+func (r Result) ByIgnore() bool {
+ return r.flags&reportByIgnore != 0
+}
+
+// ByMethod reports whether the Equal method determined equality.
+func (r Result) ByMethod() bool {
+ return r.flags&reportByMethod != 0
+}
+
+// ByFunc reports whether a Comparer function determined equality.
+func (r Result) ByFunc() bool {
+ return r.flags&reportByFunc != 0
+}
+
+// ByCycle reports whether a reference cycle was detected.
+func (r Result) ByCycle() bool {
+ return r.flags&reportByCycle != 0
+}
+
+type resultFlags uint
+
+const (
+ _ resultFlags = (1 << iota) / 2
+
+ reportEqual
+ reportUnequal
+ reportByIgnore
+ reportByMethod
+ reportByFunc
+ reportByCycle
+)
+
+// Reporter is an Option that can be passed to Equal. When Equal traverses
+// the value trees, it calls PushStep as it descends into each node in the
+// tree and PopStep as it ascend out of the node. The leaves of the tree are
+// either compared (determined to be equal or not equal) or ignored and reported
+// as such by calling the Report method.
+func Reporter(r interface {
+ // PushStep is called when a tree-traversal operation is performed.
+ // The PathStep itself is only valid until the step is popped.
+ // The PathStep.Values are valid for the duration of the entire traversal
+ // and must not be mutated.
+ //
+ // Equal always calls PushStep at the start to provide an operation-less
+ // PathStep used to report the root values.
+ //
+ // Within a slice, the exact set of inserted, removed, or modified elements
+ // is unspecified and may change in future implementations.
+ // The entries of a map are iterated through in an unspecified order.
+ PushStep(PathStep)
+
+ // Report is called exactly once on leaf nodes to report whether the
+ // comparison identified the node as equal, unequal, or ignored.
+ // A leaf node is one that is immediately preceded by and followed by
+ // a pair of PushStep and PopStep calls.
+ Report(Result)
+
+ // PopStep ascends back up the value tree.
+ // There is always a matching pop call for every push call.
+ PopStep()
+}) Option {
+ return reporter{r}
+}
+
+type reporter struct{ reporterIface }
+type reporterIface interface {
+ PushStep(PathStep)
+ Report(Result)
+ PopStep()
+}
+
+func (reporter) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption {
+ panic("not implemented")
+}
+
+// normalizeOption normalizes the input options such that all Options groups
+// are flattened and groups with a single element are reduced to that element.
+// Only coreOptions and Options containing coreOptions are allowed.
+func normalizeOption(src Option) Option {
+ switch opts := flattenOptions(nil, Options{src}); len(opts) {
+ case 0:
+ return nil
+ case 1:
+ return opts[0]
+ default:
+ return opts
+ }
+}
+
+// flattenOptions copies all options in src to dst as a flat list.
+// Only coreOptions and Options containing coreOptions are allowed.
+func flattenOptions(dst, src Options) Options {
+ for _, opt := range src {
+ switch opt := opt.(type) {
+ case nil:
+ continue
+ case Options:
+ dst = flattenOptions(dst, opt)
+ case coreOption:
+ dst = append(dst, opt)
+ default:
+ panic(fmt.Sprintf("invalid option type: %T", opt))
+ }
+ }
+ return dst
+}
projects / dotfiles / .git / blobdiff