GITPackStore Class Reference
#import <GITPackStore.h>
Inherits GITObjectStore.
Protected Attributes | |
| NSArray * | packFiles |
| GITPackFile * | lastReadPack |
Properties | |
| NSString * | packsDir |
Path to .git/objects/pack directory. | |
Detailed Description
Packed objects storage. Accesses objects stored as in PACK files in.git/objects/pack directory. For internal use only.
PACK files are do not independently represent the objects of a repository. Instead each PACK holds only the objects which were not already stored within a PACK. For this reason the GITPackStore must to keep a reference to each PACK file within the packsDir so that it may correctly find the objects which are requested. To improve the speed of retrieval some kind of caching should probably be done. The two main options I can see are an NSDictionary of SHA1 -> PACK mappings and a reference to the last PACK which successfully returned an object. The first method is primarily useful for repetitive accesses of the same SHA, while possible it would probably be a better idea to leave this option for now and see how often a SHA is accessed. The other method is useful for accessing objects which are likely to be nearby to each other. This would be the most useful as typical operation would involve reading a Commit, accessing its Tree and the Tree contents. These objects are all reasonably likely to be contained within the same PACK file.
Houston we have a problem PACK files do not store the object data in a similar way to loose files. Loose files include a type/size meta header at the top of the loose file. The data for an object in a PACK file is just the contents. The type/size meta header information is not present within the object data. Instead this information is separate within the PACK file just before the object data. This poses a problem for the current method of extracting the object data from a store and creating an instance of the correct class from that data. This could require a fundamental re-engineering of the way in which objects are retrieved from stores & the way in which objects are instanciated from the data retrieved from the stores.
The main question is, how do we change it and into what form?
Member Data Documentation
- (GITPackFile*) lastReadPack [protected] |
- (NSArray*) packFiles [protected] |
Property Documentation
- (NSString *) packsDir [read, copy] |
Path to .git/objects/pack directory.
The documentation for this class was generated from the following file:
