mirror of https://github.com/perkeep/perkeep.git
78 lines
2.2 KiB
Go
78 lines
2.2 KiB
Go
/*
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Copyright 2013 Google Inc.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package blobserver
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import (
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"sync"
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"camlistore.org/pkg/blob"
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"camlistore.org/pkg/context"
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)
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// EnumerateAll runs fn for each blob in src.
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// If fn returns an error, iteration stops and fn isn't called again.
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// EnumerateAll will not return concurrently with fn.
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func EnumerateAll(ctx *context.Context, src BlobEnumerator, fn func(blob.SizedRef) error) error {
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return EnumerateAllFrom(ctx, src, "", fn)
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}
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// EnumerateAllFrom is like EnumerateAll, but takes an after parameter.
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func EnumerateAllFrom(ctx *context.Context, src BlobEnumerator, after string, fn func(blob.SizedRef) error) error {
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const batchSize = 1000
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var mu sync.Mutex // protects returning with an error while fn is still running
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errc := make(chan error, 1)
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for {
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ch := make(chan blob.SizedRef, 16)
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n := 0
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go func() {
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var err error
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for sb := range ch {
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if err != nil {
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continue
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}
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mu.Lock()
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err = fn(sb)
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mu.Unlock()
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after = sb.Ref.String()
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n++
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}
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errc <- err
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}()
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err := src.EnumerateBlobs(ctx, ch, after, batchSize)
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if err != nil {
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mu.Lock() // make sure fn callback finished; no need to unlock
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return err
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}
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if err := <-errc; err != nil {
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return err
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}
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if n == 0 {
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return nil
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}
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}
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}
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// RefTypes returns a list of blobref types appearing on the provided enumerator.
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// A blobref type is a string like "sha1", or whatever is on the left side
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// of the hyphen in a blobref.
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// To get the alphabet valid for the right side of the hyphen, use blob.TypeAlphabet(type).
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func RefTypes(src BlobEnumerator) ([]string, error) {
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// TODO(bradfitz): implement, with various short enumerate
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// reads at the right places.
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return []string{"sha1"}, nil
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}
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