Change verbose logging output of apt-ftparchive to go t...
[ntk/apt.git] / apt-pkg / pkgsystem.h
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1// -*- mode: cpp; mode: fold -*-
2// Description /*{{{*/
90f057fd 3// $Id: pkgsystem.h,v 1.5 2002/03/26 07:38:58 jgg Exp $
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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#ifdef __GNUG__
41#pragma interface "apt-pkg/pkgsystem.h"
42#endif
43
44#include <apt-pkg/depcache.h>
90f057fd 45#include <vector>
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46
47class pkgPackageManager;
48class pkgVersioningSystem;
49class Configuration;
50class pkgIndexFile;
51
52class pkgSystem
53{
54 public:
55
56 // Global list of supported systems
57 static pkgSystem **GlobalList;
58 static unsigned long GlobalListLen;
59 static pkgSystem *GetSystem(const char *Label);
60
61 const char *Label;
62 pkgVersioningSystem *VS;
63
64 /* Prevent other programs from touching shared data not covered by
65 other locks (cache or state locks) */
66 virtual bool Lock() = 0;
67 virtual bool UnLock(bool NoErrors = false) = 0;
68
69 /* Various helper classes to interface with specific bits of this
70 environment */
71 virtual pkgPackageManager *CreatePM(pkgDepCache *Cache) const = 0;
72
73 /* Load environment specific configuration and perform any other setup
74 necessary */
db5c1b54 75 virtual bool Initialize(Configuration &/*Cnf*/) {return true;};
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76
77 /* Type is some kind of Globally Unique way of differentiating
78 archive file types.. */
79 virtual bool ArchiveSupported(const char *Type) = 0;
80
81 // Return a list of system index files..
82 virtual bool AddStatusFiles(vector<pkgIndexFile *> &List) = 0;
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83 virtual bool FindIndex(pkgCache::PkgFileIterator File,
84 pkgIndexFile *&Found) const = 0;
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85
86 /* Evauluate how 'right' we are for this system based on the filesystem
87 etc.. */
db5c1b54 88 virtual signed Score(Configuration const &/*Cnf*/) {return 0;};
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89
90 pkgSystem();
91 virtual ~pkgSystem() {};
92};
93
94// The environment we are operating in.
95extern pkgSystem *_system;
96
97#endif