121 lines
4.2 KiB
Go
121 lines
4.2 KiB
Go
package commandkit
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import (
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"errors"
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"fmt"
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"sort"
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)
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// ErrFlagInput identifies a missing required captured flag selected for an input.
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var ErrFlagInput = errors.New("required flag input is missing")
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// ErrFlagWiring identifies an invalid captured binding or destination.
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var ErrFlagWiring = errors.New("flag wiring is invalid")
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// FlagValues stores invocation-local converted values and presence for captured
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// flags. It does not retain an input instance; values can be applied to
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// independently initialized destinations. Captured occurrence flags retain
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// their relative command-line order across the selected bindings.
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type FlagValues[I any] struct {
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values map[*bindingIdentity]preparedValue[I]
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}
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// CaptureFlags adapts flags declared for I into flags on Outer. During parsing,
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// each adapted flag stores its prepared value in target, associated with the
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// original inner binding identity. Copies of an original handle remain
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// selectable; an independently constructed lookalike does not.
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func CaptureFlags[Outer, I any](flags []Flag[I], target func(*Outer) *FlagValues[I]) []Flag[Outer] {
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captured := make([]Flag[Outer], len(flags))
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for index, original := range flags {
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inner := original
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identity := newBindingIdentity()
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binding := flagBinding[Outer]{
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identity: identity,
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meta: inner.binding.meta,
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deferredRequired: inner.binding.meta.Required,
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defaultText: inner.binding.defaultText,
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repeated: inner.binding.repeated,
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boolean: inner.binding.boolean,
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}
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if target != nil && inner.binding.identity != nil && inner.binding.valid && inner.binding.prepare != nil {
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binding.valid = true
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binding.prepare = func(raw []string) (preparedValue[Outer], error) {
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prepared, err := inner.binding.prepare(raw)
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if err != nil {
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return preparedValue[Outer]{}, err
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}
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result := preparedValue[Outer]{
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identity: identity,
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supplied: prepared.supplied,
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apply: func(outer *Outer) {
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store := target(outer)
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if store == nil {
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return
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}
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if store.values == nil {
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store.values = make(map[*bindingIdentity]preparedValue[I])
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}
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store.values[inner.binding.identity] = prepared
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},
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}
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for _, occurrence := range prepared.ordered {
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result.ordered = append(result.ordered, preparedOccurrence[Outer]{ordinal: occurrence.ordinal})
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}
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return result, nil
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}
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}
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captured[index] = Flag[Outer]{binding: binding}
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}
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return captured
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}
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// ApplyTo applies selected original captured flags to an initialized
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// destination. A missing captured binding or nil destination matches
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// ErrFlagWiring. A required selected value that was not supplied matches
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// ErrFlagInput. Ordinary selected values are applied first, followed by selected
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// occurrence values in command-line order. Repeated core-owned values are copied
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// for each application.
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func (values FlagValues[I]) ApplyTo(target *I, selected ...Flag[I]) error {
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if target == nil {
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return fmt.Errorf("%w: destination is nil", ErrFlagWiring)
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}
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preparedValues := make([]preparedValue[I], 0, len(selected))
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for _, flag := range selected {
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binding := flag.binding
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if binding.identity == nil {
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return fmt.Errorf("%w: selected flag has no identity", ErrFlagWiring)
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}
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prepared, exists := values.values[binding.identity]
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if !exists {
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return fmt.Errorf("%w: flag --%s was not captured", ErrFlagWiring, binding.meta.Name)
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}
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if binding.meta.Required && !prepared.supplied {
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return fmt.Errorf("flag --%s: %w", binding.meta.Name, ErrFlagInput)
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}
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preparedValues = append(preparedValues, prepared)
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}
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var ordered []preparedOccurrence[I]
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for _, prepared := range preparedValues {
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if prepared.apply != nil {
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prepared.apply(target)
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}
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for _, occurrence := range prepared.ordered {
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if occurrence.apply != nil {
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ordered = append(ordered, occurrence)
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}
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}
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}
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sort.SliceStable(ordered, func(i, j int) bool { return *ordered[i].ordinal < *ordered[j].ordinal })
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for _, occurrence := range ordered {
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occurrence.apply(target)
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}
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return nil
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}
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func classifyInputError(err error) Outcome {
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if errors.Is(err, ErrFlagWiring) {
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return Failure(err.Error()).WithCause(err)
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}
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return Usage(err.Error()).WithCause(err)
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}
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