1	/*
     2	Copyright 2013 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 stats contains an in-memory StatReceiver that only stores sizes
    18	// of received blobs but not their contents.
    19	package stats // import "perkeep.org/pkg/blobserver/stats"
    20	
    21	import (
    22		"context"
    23		"io"
    24		"sort"
    25		"sync"
    26	
    27		"perkeep.org/pkg/blob"
    28	)
    29	
    30	// Receiver is a dummy blobserver.StatReceiver that doesn't
    31	// store anything; it just collects statistics.
    32	//
    33	// TODO: we have another copy of this same type in
    34	// pk-put/files.go. move them to a common place?  well, the pk-put one
    35	// is probably going away at some point.
    36	type Receiver struct {
    37		sync.Mutex // guards Have
    38		Have       map[blob.Ref]int64
    39	}
    40	
    41	func (sr *Receiver) NumBlobs() int {
    42		sr.Lock()
    43		defer sr.Unlock()
    44		return len(sr.Have)
    45	}
    46	
    47	// Sizes returns the sorted blob sizes.
    48	func (sr *Receiver) Sizes() []int {
    49		sr.Lock()
    50		defer sr.Unlock()
    51		sizes := make([]int, 0, len(sr.Have))
    52		for _, size := range sr.Have {
    53			sizes = append(sizes, int(size))
    54		}
    55		sort.Ints(sizes)
    56		return sizes
    57	}
    58	
    59	func (sr *Receiver) SumBlobSize() int64 {
    60		sr.Lock()
    61		defer sr.Unlock()
    62		var sum int64
    63		for _, v := range sr.Have {
    64			sum += v
    65		}
    66		return sum
    67	}
    68	
    69	func (sr *Receiver) ReceiveBlob(ctx context.Context, br blob.Ref, source io.Reader) (sb blob.SizedRef, err error) {
    70		n, err := io.Copy(io.Discard, source)
    71		if err != nil {
    72			return
    73		}
    74		return sr.ReceiveRef(br, n)
    75	}
    76	
    77	func (sr *Receiver) ReceiveRef(br blob.Ref, size int64) (sb blob.SizedRef, err error) {
    78		sr.Lock()
    79		defer sr.Unlock()
    80		if sr.Have == nil {
    81			sr.Have = make(map[blob.Ref]int64)
    82		}
    83		sr.Have[br] = size
    84		return blob.SizedRef{Ref: br, Size: uint32(size)}, nil
    85	}
    86	
    87	func (sr *Receiver) StatBlobs(ctx context.Context, blobs []blob.Ref, fn func(blob.SizedRef) error) error {
    88		var sized []blob.SizedRef
    89		sr.Lock()
    90		for _, br := range blobs {
    91			if size, ok := sr.Have[br]; ok {
    92				sized = append(sized, blob.SizedRef{Ref: br, Size: uint32(size)})
    93			}
    94		}
    95		sr.Unlock()
    96	
    97		// Call fn with no locks held:
    98		for _, sb := range sized {
    99			if err := fn(sb); err != nil {
   100				return err
   101			}
   102		}
   103		return nil
   104	}
   105	
   106	func (sr *Receiver) RemoveBlobs(ctx context.Context, blobs []blob.Ref) error {
   107		sr.Lock()
   108		defer sr.Unlock()
   109		for _, br := range blobs {
   110			delete(sr.Have, br)
   111		}
   112	
   113		return nil
   114	}
   115	
   116	func (sr *Receiver) EnumerateBlobs(ctx context.Context, dest chan<- blob.SizedRef, after string, limit int) error {
   117		sr.Lock()
   118		defer sr.Unlock()
   119		defer close(dest)
   120	
   121		refs := blob.SizedByRef{}
   122		for ref, size := range sr.Have {
   123			if after != "" && ref.String() <= after {
   124				continue
   125			}
   126			refs = append(refs, blob.SizedRef{Ref: ref, Size: uint32(size)})
   127		}
   128		sort.Sort(refs)
   129	
   130		if len(refs) == 0 {
   131			return nil
   132		}
   133	
   134		if len(refs) <= limit {
   135			limit = len(refs)
   136		}
   137	
   138		for _, sb := range refs[:limit] {
   139			dest <- sb
   140		}
   141	
   142		return nil
   143	}