1	/*
     2	Copyright 2011 The Perkeep Authors
     3	
     4	Licensed under the Apache License, Version 2.0 (the "License");
     5	you may not use this file except in compliance with the License.
     6	You may obtain a copy of the License at
     7	
     8	     http://www.apache.org/licenses/LICENSE-2.0
     9	
    10	Unless required by applicable law or agreed to in writing, software
    11	distributed under the License is distributed on an "AS IS" BASIS,
    12	WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13	See the License for the specific language governing permissions and
    14	limitations under the License.
    15	*/
    16	
    17	package index
    18	
    19	import (
    20		"context"
    21		"errors"
    22		"fmt"
    23		"strconv"
    24		"strings"
    25	
    26		"perkeep.org/pkg/blob"
    27		"perkeep.org/pkg/sorted"
    28	)
    29	
    30	func (ix *Index) EnumerateBlobs(ctx context.Context, dest chan<- blob.SizedRef, after string, limit int) (err error) {
    31		defer close(dest)
    32		it := ix.s.Find("have:"+after, "have~")
    33		defer func() {
    34			closeErr := it.Close()
    35			if err == nil {
    36				err = closeErr
    37			}
    38		}()
    39	
    40		afterKey := "have:" + after
    41		n := int(0)
    42		for n < limit && it.Next() {
    43			k := it.Key()
    44			if k <= afterKey {
    45				continue
    46			}
    47			if !strings.HasPrefix(k, "have:") {
    48				break
    49			}
    50			n++
    51			br, ok := blob.Parse(k[len("have:"):])
    52			if !ok {
    53				continue
    54			}
    55			size, err := parseHaveVal(it.Value())
    56			if err == nil {
    57				select {
    58				case dest <- blob.SizedRef{Ref: br, Size: uint32(size)}:
    59				case <-ctx.Done():
    60					return ctx.Err()
    61				}
    62			}
    63		}
    64		return nil
    65	}
    66	
    67	func (ix *Index) StatBlobs(ctx context.Context, blobs []blob.Ref, fn func(blob.SizedRef) error) error {
    68		for _, br := range blobs {
    69			key := "have:" + br.String()
    70			v, err := ix.s.Get(key)
    71			if errors.Is(err, sorted.ErrNotFound) {
    72				continue
    73			}
    74			if err != nil {
    75				return fmt.Errorf("error looking up key %q: %w", key, err)
    76			}
    77			size, err := parseHaveVal(v)
    78			if err != nil {
    79				return fmt.Errorf("invalid size for key %q = %q", key, v)
    80			}
    81			if err := fn(blob.SizedRef{Ref: br, Size: uint32(size)}); err != nil {
    82				return err
    83			}
    84		}
    85		return nil
    86	}
    87	
    88	// parseHaveVal takes the value part of an "have" index row and returns
    89	// the blob size found in that value. Examples:
    90	// parseHaveVal("324|indexed") == 324
    91	// parseHaveVal("654") == 654
    92	func parseHaveVal(val string) (size uint64, err error) {
    93		pipei := strings.Index(val, "|")
    94		if pipei >= 0 {
    95			// filter out the "indexed" suffix
    96			val = val[:pipei]
    97		}
    98		return strconv.ParseUint(val, 10, 32)
    99	}