99 lines
2.1 KiB
Go
99 lines
2.1 KiB
Go
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package zerr
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import "iter"
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// Sequence is the implementation of zerr.Sequence.
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//
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// The implementation is reversed linked list.
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//
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// New Sequence value will be added to the start of the list.
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type Sequence struct {
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prev *Sequence
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next *Sequence
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err Error
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index int
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}
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// Set prepends the next Sequence to the current Sequence.
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func (se *Sequence) Set(next *Sequence) {
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next.next = se
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se.prev = next
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se.index = next.index + 1
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if next.next != nil {
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next.next.Set(se)
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}
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}
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// Outer returns the error that wraps this Error.
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// Return nil if this Error is not wrapped
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// or wrapping outer is not a zerr.Error.
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func (se *Sequence) Outer() Error {
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if se.prev != nil {
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return se.prev.err
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}
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return nil
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}
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// Inner returns the inner zerr.Error in the sequence.
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//
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// if there is no inner zerr.Error, it returns nil.
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//
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// if the inner error is not a zerr.Error, this returns nil.
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func (se *Sequence) Inner() Error {
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if se.next != nil {
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return se.next.err
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}
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return nil
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}
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// Index returns the index of this Error in the sequence.
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func (se *Sequence) Index() int {
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return se.index
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}
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// Root returns the outermost Error in the sequence.
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//
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// Returns self if there is no outermost.
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func (se *Sequence) Root() *Sequence {
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root := se
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for root.prev != nil {
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root = root.prev
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}
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return root
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}
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func (se *Sequence) IsRoot() bool {
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return se.prev == nil
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}
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// Iter returns an iterator to traverse the sequence.
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//
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// The iterator will start from outermost zerr.Error (root) to the last zerr.Error
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// in depth-first order.
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//
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// Iterator will skip any nil values in the sequence.
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//
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// Iterator does not guarantee idempotent behavior.
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// Next call to iterator may start from different root
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// because the parent in the tree may be wrapped
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// by another zerr.Error.
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//
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// Example:
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//
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// for _, e := range err.Sequence().Iter() {
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// // e is zerr.Error
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// // do something with e
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// }
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func (se *Sequence) Iter() iter.Seq[Error] {
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root := se.Root()
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return iter.Seq[Error](func(yield func(V Error) bool) {
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for next := root; next != nil; next = next.next {
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if next.err != nil {
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if !yield(next.err) {
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return
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}
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}
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}
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})
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}
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