git.saurik.com Git - apt-legacy.git/blame_incremental

... / ...

Commit	Line	Data
	1	// -- mode: cpp; mode: fold --
	2	// Description /{{{/
	3	// $Id: error.h,v 1.8 2001/05/07 05:06:52 jgg Exp $
	4	/* ######################################################################
	5
	6	Global Erorr Class - Global error mechanism
	7
	8	This class has a single global instance. When a function needs to
	9	generate an error condition, such as a read error, it calls a member
	10	in this class to add the error to a stack of errors.
	11
	12	By using a stack the problem with a scheme like errno is removed and
	13	it allows a very detailed account of what went wrong to be transmitted
	14	to the UI for display. (Errno has problems because each function sets
	15	errno to 0 if it didn't have an error thus eraseing erno in the process
	16	of cleanup)
	17
	18	Several predefined error generators are provided to handle common
	19	things like errno. The general idea is that all methods return a bool.
	20	If the bool is true then things are OK, if it is false then things
	21	should start being undone and the stack should unwind under program
	22	control.
	23
	24	A Warning should not force the return of false. Things did not fail, but
	25	they might have had unexpected problems. Errors are stored in a FIFO
	26	so Pop will return the first item..
	27
	28	I have some thoughts about extending this into a more general UI<->
	29	Engine interface, ie allowing the Engine to say 'The disk is full' in
	30	a dialog that says 'Panic' and 'Retry'.. The error generator functions
	31	like errno, Warning and Error return false always so this is normal:
	32	if (open(..))
	33	return _error->Errno(..);
	34
	35	This source is placed in the Public Domain, do with it what you will
	36	It was originally written by Jason Gunthorpe.
	37
	38	##################################################################### */
	39	/}}}/
	40	#ifndef PKGLIB_ERROR_H
	41	#define PKGLIB_ERROR_H
	42
	43	#include <apt-pkg/macros.h>
	44
	45	#include <string>
	46
	47	class GlobalError
	48	{
	49	struct Item
	50	{
	51	std::string Text;
	52	bool Error;
	53	Item *Next;
	54	};
	55
	56	Item *List;
	57	bool PendingFlag;
	58	void Insert(Item *I);
	59
	60	public:
	61
	62	// Call to generate an error from a library call.
	63	bool Errno(const char Function,const char Description,...) __like_printf_2 __cold;
	64	bool WarningE(const char Function,const char Description,...) __like_printf_2 __cold;
	65
	66	/* A warning should be considered less severe than an error, and may be
	67	ignored by the client. */
	68	bool Error(const char *Description,...) __like_printf_1 __cold;
	69	bool Warning(const char *Description,...) __like_printf_1 __cold;
	70
	71	// Simple accessors
	72	inline bool PendingError() {return PendingFlag;};
	73	inline bool empty() {return List == 0;};
	74	bool PopMessage(std::string &Text);
	75	void Discard();
	76
	77	// Usefull routine to dump to cerr
	78	void DumpErrors();
	79
	80	GlobalError();
	81	};
	82
	83	// The 'extra-ansi' syntax is used to help with collisions.
	84	GlobalError *_GetErrorObj();
	85	#define _error _GetErrorObj()
	86
	87	#endif