mirror of
https://github.com/dolthub/dolt.git
synced 2026-04-21 11:29:51 -05:00
Aaron Son
115 lines
3.2 KiB
Go
115 lines
3.2 KiB
Go
// Copyright 2021 Dolthub, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package datas
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import (
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"context"
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"github.com/dolthub/dolt/go/store/hash"
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"github.com/dolthub/dolt/go/store/types"
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)
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// CommitClosure is a transitive closure of commit parents.
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type CommitClosure interface {
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// Contains returns true if |commit| is contained in the closure.
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Contains(ctx context.Context, commit *Commit) (bool, error)
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}
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// NewSetCommitClosure computes the entire transitive closure of |commit|.
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func NewSetCommitClosure(ctx context.Context, vr types.ValueReader, commit *Commit) (CommitClosure, error) {
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s, err := transitiveClosure(ctx, vr, commit)
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if err != nil {
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return setCommitClosure{}, err
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}
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return setCommitClosure{HashSet: s}, nil
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}
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type setCommitClosure struct {
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hash.HashSet
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}
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var _ CommitClosure = setCommitClosure{}
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// Contains returns true if |commit| is contained in the closure.
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func (s setCommitClosure) Contains(ctx context.Context, commit *Commit) (ok bool, err error) {
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ok = s.HashSet.Has(commit.Addr())
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return
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}
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func transitiveClosure(ctx context.Context, vr types.ValueReader, commit *Commit) (s hash.HashSet, err error) {
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h := &CommitByHeightHeap{commit}
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s = hash.NewHashSet()
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var curr []*Commit
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for !h.Empty() {
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curr = h.PopCommitsOfHeight(h.MaxHeight())
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for _, c := range curr {
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s.Insert(c.Addr())
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}
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err = parentsToQueue(ctx, curr, h, vr)
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if err != nil {
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return nil, err
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}
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}
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return s, nil
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}
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// NewLazyCommitClosure makes a lazy CommitClosure, which computes the
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// transitive closure of |commit| on demand to answer Contains() queries.
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func NewLazyCommitClosure(commit *Commit, vr types.ValueReader) CommitClosure {
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return lazyCommitClosure{
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seen: hash.NewHashSet(commit.Addr()),
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heap: &CommitByHeightHeap{commit},
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vr: vr,
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}
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}
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type lazyCommitClosure struct {
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seen hash.HashSet
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heap *CommitByHeightHeap
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vr types.ValueReader
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}
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var _ CommitClosure = lazyCommitClosure{}
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// Contains returns true if |commit| is contained in the closure.
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func (l lazyCommitClosure) Contains(ctx context.Context, commit *Commit) (ok bool, err error) {
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err = l.traverseBelowDepth(ctx, commit.Height())
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if err != nil {
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return false, err
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}
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return l.seen.Has(commit.Addr()), nil
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}
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// traverseBelowDepth traverses through all of the refs of height |depth| or higher,
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// adding them to the set |l.seen|.
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func (l lazyCommitClosure) traverseBelowDepth(ctx context.Context, depth uint64) (err error) {
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var curr []*Commit
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for !l.heap.Empty() && depth <= l.heap.MaxHeight() {
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curr = l.heap.PopCommitsOfHeight(l.heap.MaxHeight())
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for _, r := range curr {
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l.seen.Insert(r.Addr())
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}
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err = parentsToQueue(ctx, curr, l.heap, l.vr)
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if err != nil {
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return err
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}
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}
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return nil
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}
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