Persistent data¶

Files cache¶

This file contains all the shared files and theirs SHA-1 hashes. This file is saved in user space after an update of the file list, it is completely loaded at the start of Aybabtu. If some paths of some files doesn't match the shared directory they are discarded.

This file is saved as a binary file serialized by protocol buffer.

You can see the proto file here : source:/application/Protos/files_cache.proto

Size¶

Here is a size approximation for 50'000 files stored in 1 TB. The overhead of the file format is not taken in account.

Nb of files : 50'0000
Total size : 1 TB
Chunk Size : 32 MB
Average file per directory : 50
Average filename and dirname length : 50 char
Size of a hash : 20B

AverageFileSize = 1*1024^4 / 50'000 = 21MB
Sha1Size = floor(AverageFileSize / 32MB) * 20 * 50'000 = 1 * 20 * 50'000 = 977kB
FilenameSize = 50'000 * 50 * 2 = 4.8MB (2 bytes per char)
DirnameSize = (50'000 / 50) * 50 * 2 = 97kB

TotalSize = 977kB + 4.8MB + 97kB = 5.9MB

Queued files and directories¶

A file containing the queued files and directories is saved in user space. An item from the list may contains a remote peer id and/or the hashes which identify a file.

As the file cache file (see above), this file is saved as a binary file serialized by protocol buffer.

For more details see the file : source:/application/Protos/queue.proto

Configuration file¶

Core side¶

here are the persisted data :

• The nick
• The peer ID

As the other data described above these data are saved as a file serialized by Protocol Buffer but in a human readable form.

For more details see the message Settings in file : source:/application/Protos/common.proto

Client Side¶

here are the persisted data :

• Core address
• Password for remote core

These data are save using QSettings : http://doc.trolltech.com/4.5/qsettings.html.