apt: apt-pkg/pkgsystem.h Source File

apt 3.1.16 commandline package manager

pkgsystem.h
1// -*- mode: cpp; mode: fold -*-
2// Description /*{{{*/
3/* ######################################################################
4
5 System - Abstraction for running on different systems.
6
7 Instances of this class can be thought of as factories or meta-classes
8 for a variety of more specialized classes. Together this class and
9 it's specialized offspring completely define the environment and how
10 to access resources for a specific system. There are several sub
11 areas that are all orthogonal - each system has a unique combination of
12 these sub areas:
13 - Versioning. Different systems have different ideas on versions.
14 Within a system all sub classes must follow the same versioning
15 rules.
16 - Local tool locking to prevent multiple tools from accessing the
17 same database.
18 - Candidate Version selection policy - this is probably almost always
19 managed using a standard APT class
20 - Actual Package installation
21 * Indication of what kind of binary formats are supported
22 - Selection of local 'status' indexes that make up the pkgCache.
23
24 It is important to note that the handling of index files is not a
25 function of the system. Index files are handled through a separate
26 abstraction - the only requirement is that the index files have the
27 same idea of versioning as the target system.
28
29 Upon startup each supported system instantiates an instance of the
30 pkgSystem class (using a global constructor) which will make itself
31 available to the main APT init routine. That routine will select the
32 proper system and make it the global default.
33
34 ##################################################################### */
35 /*}}}*/
36#ifndef PKGLIB_PKGSYSTEM_H
37#define PKGLIB_PKGSYSTEM_H
38
39#include <apt-pkg/pkgcache.h>
40
41#include <vector>
42
43
44class pkgDepCache;
45class pkgPackageManager;
46class pkgVersioningSystem;
47class Configuration;
48class pkgIndexFile;
49class OpProgress;
50
51class pkgSystemPrivate;
52 class APT_PUBLIC 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 * const Label;
62 pkgVersioningSystem * const VS;
63
64 /* Prevent other programs from touching shared data not covered by
65 other locks (cache or state locks) */
66 virtual bool Lock(OpProgress *const Progress = nullptr) = 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 */
75 virtual bool Initialize(Configuration &/*Cnf*/) {return true;};
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(std::vector<pkgIndexFile *> &List) = 0;
83
84 virtual bool FindIndex(pkgCache::PkgFileIterator File,
85 pkgIndexFile *&Found) const = 0;
86
87 /* Evaluate how 'right' we are for this system based on the filesystem
88 etc.. */
89 virtual signed Score(Configuration const &/*Cnf*/) {
90 return 0;
91 };
92
93 //FIXME: these methods should be virtual
104 virtual bool MultiArchSupported() const = 0;
113 virtual std::vector<std::string> ArchitecturesSupported() const = 0;
114
115 APT_HIDDEN void SetVersionMapping(map_id_t const in, map_id_t const out);
116 APT_HIDDEN map_id_t GetVersionMapping(map_id_t const in) const;
117
118 pkgSystem(char const * const Label, pkgVersioningSystem * const VS);
119 virtual ~pkgSystem();
120
121
122 /* companions to Lock()/UnLock
123 *
124 * These functions can be called prior to calling dpkg to release an inner
125 * lock without releasing the overall outer lock, so that dpkg can run
126 * correctly but no other APT instance can acquire the system lock.
127 */
128 virtual bool LockInner(OpProgress *const Progress = 0, int timeOutSec = 0) = 0;
129 virtual bool UnLockInner(bool NoErrors = false) = 0;
131 virtual bool IsLocked() = 0;
132 private:
133 pkgSystemPrivate * const d;
134};
135
136// The environment we are operating in.
137APT_PUBLIC extern pkgSystem *_system;
138
139#endif
Configuration
Definition configuration.h:41
OpProgress
Definition progress.h:30
pkgCache::PkgFileIterator
Definition cacheiterators.h:496
pkgDepCache
Definition depcache.h:63
pkgIndexFile
Definition indexfile.h:103
pkgPackageManager
Definition packagemanager.h:49
pkgSystemPrivate
Definition pkgsystem.cc:30
pkgSystem
Definition pkgsystem.h:53
pkgSystem::IsLocked
virtual bool IsLocked()=0
checks if the system is currently locked
pkgSystem::MultiArchSupported
virtual bool MultiArchSupported() const =0
pkgSystem::ArchitecturesSupported
virtual std::vector< std::string > ArchitecturesSupported() const =0
pkgVersioningSystem
Definition version.h:27
pkgcache.h
pkgCache - Structure definitions for the cache file