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Commit	Line	Data
	1	// -- mode: cpp; mode: fold --
	2	// Description /{{{/
	3	// $Id: pkgsystem.h,v 1.6 2002/11/11 06:55:50 doogie Exp $
	4	/* ######################################################################
	5
	6	System - Abstraction for running on different systems.
	7
	8	Instances of this class can be thought of as factories or meta-classes
	9	for a variety of more specialized classes. Together this class and
	10	it's speciallized offspring completely define the environment and how
	11	to access resources for a specific system. There are several sub
	12	areas that are all orthogonal - each system has a unique combination of
	13	these sub areas:
	14	- Versioning. Different systems have different ideas on versions.
	15	Within a system all sub classes must follow the same versioning
	16	rules.
	17	- Local tool locking to prevent multiple tools from accessing the
	18	same database.
	19	- Candidate Version selection policy - this is probably almost always
	20	managed using a standard APT class
	21	- Actual Package installation
	22	* Indication of what kind of binary formats are supported
	23	- Selection of local 'status' indexes that make up the pkgCache.
	24
	25	It is important to note that the handling of index files is not a
	26	function of the system. Index files are handled through a seperate
	27	abstraction - the only requirement is that the index files have the
	28	same idea of versioning as the target system.
	29
	30	Upon startup each supported system instantiates an instance of the
	31	pkgSystem class (using a global constructor) which will make itself
	32	available to the main APT init routine. That routine will select the
	33	proper system and make it the global default.
	34
	35	##################################################################### */
	36	/}}}/
	37	#ifndef PKGLIB_PKGSYSTEM_H
	38	#define PKGLIB_PKGSYSTEM_H
	39
	40
	41	#include <apt-pkg/depcache.h>
	42	#include <vector>
	43
	44	class pkgPackageManager;
	45	class pkgVersioningSystem;
	46	class Configuration;
	47	class pkgIndexFile;
	48
	49	class pkgSystem
	50	{
	51	public:
	52
	53	// Global list of supported systems
	54	static pkgSystem **GlobalList;
	55	static unsigned long GlobalListLen;
	56	static pkgSystem GetSystem(const char Label);
	57
	58	const char *Label;
	59	pkgVersioningSystem *VS;
	60
	61	/* Prevent other programs from touching shared data not covered by
	62	other locks (cache or state locks) */
	63	virtual bool Lock() = 0;
	64	virtual bool UnLock(bool NoErrors = false) = 0;
	65
	66	/* Various helper classes to interface with specific bits of this
	67	environment */
	68	virtual pkgPackageManager CreatePM(pkgDepCache Cache) const = 0;
	69
	70	/* Load environment specific configuration and perform any other setup
	71	necessary */
	72	virtual bool Initialize(Configuration &/Cnf/) {return true;};
	73
	74	/* Type is some kind of Globally Unique way of differentiating
	75	archive file types.. */
	76	virtual bool ArchiveSupported(const char *Type) = 0;
	77
	78	// Return a list of system index files..
	79	virtual bool AddStatusFiles(std::vector<pkgIndexFile *> &List) = 0;
	80	virtual bool FindIndex(pkgCache::PkgFileIterator File,
	81	pkgIndexFile *&Found) const = 0;
	82
	83	/* Evauluate how 'right' we are for this system based on the filesystem
	84	etc.. */
	85	virtual signed Score(Configuration const &/Cnf/) {return 0;};
	86
	87	pkgSystem();
	88	virtual ~pkgSystem() {};
	89	};
	90
	91	// The environment we are operating in.
	92	extern pkgSystem *_system;
	93
	94	#endif