Project

General

Profile

Algorithms » History » Version 18

Greg Burri, 08/07/2009 01:37 PM

1 1 Greg Burri
h1. Algorithms
2
3
h2. Searching
4 2 Greg Burri
5 3 Greg Burri
For a functional description see here : [[Functional definition#The-search-window]]
6 15 Greg Burri
7 1 Greg Burri
!aybabtu_search.png!
8 18 Greg Burri
_This schema depicts how the results are sorted from one peer. Each peer result are then merged._
9 4 Greg Burri
10 5 Greg Burri
h2. Peer ID
11
12 7 Greg Burri
Each peer owns a peer id which is unique and generated during the first start. This ID is used to identify a peer, it's better than the previous usage of peer IP, considering this situation :
13 5 Greg Burri
14
* _A_ put in queue a file entry _f_ from _B_, _B_ doesn't know the hashes of this file entry.
15
* _B_ change his IP address.
16
* _A_ want to download _f_, it can ask _B_ for the hashes even _B_'s IP changed.
17
18 8 Greg Burri
h2. Core threads
19
20 9 Greg Burri
There are three kind of threads in the core in addition to the main thread :
21
* [[Protocol_core-core#Downloading-thread|Downloading thread]] : @DownloadManager::ChunkDownloader@
22 8 Greg Burri
* Uploading thread : @UploadManager::Uploader@
23 11 Greg Burri
* [[Algorithms#Updating-the-file-cache|Updating file cache thread]] : @FileManager::FileUpdater@
24 5 Greg Burri
25 17 Greg Burri
h2. Updating the file cache (Obsolete, must be rewritten)
26 10 Greg Burri
27
Here is the algorithm for the thread (@FileManager::FileUpdater@) which will periodically update the file cache and persist it.
28
29
<pre>
30
D : The set of shared directories
31
T : Time during the hashes are computed (for example 30s)
32
F : A set of file initialy empty
33
34 13 Greg Burri
- Add a watcher to the shared directories
35
36
// First synchronize (at start)
37
For each d in D (recursively) :
38 14 Greg Burri
   - Synchronize physical folders and files with d content
39 13 Greg Burri
   - Add in F the files which doesn't have computed hashes
40
41
Loop :   
42 10 Greg Burri
   t : Time.now
43 1 Greg Burri
   For each f in F :
44 13 Greg Burri
      - Compute the unknown hash of files f
45 1 Greg Burri
      - Remove f from F
46 10 Greg Burri
      If (Time.now - t) > T : break
47
   - Wait T - (Time.now - t)
48 13 Greg Burri
   - Wait for changes for a period of P
49
      - When a modification occurs synchronise the file/folder
50
      - Add each new file in F
51 12 Greg Burri
   - Persist the entire cache in a file (only every ~30min)
52 10 Greg Burri
</pre>
53
54 5 Greg Burri
55 4 Greg Burri
h2. Downloading
56
57
See here : [[Protocol_core-core#Downloading-threads]]