source: cpp/frams/param/multiparamload.h @ 277

Last change on this file since 277 was 277, checked in by Maciej Komosinski, 10 years ago

ParamInterface::load() can be aborted (used to avoid incorrect warnings about unknown fields when switching expdefs)

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File size: 6.6 KB
1// This file is a part of the Framsticks GDK.
2// Copyright (C) 1999-2014  Maciej Komosinski and Szymon Ulatowski.  See LICENSE.txt for details.
3// Refer to for further information.
8#include <stdio.h>
9#include "param.h"
10#include <frams/virtfile/virtfile.h>
11#include <frams/util/extvalue.h>
13/** This is the general "framsticks-format" file parser for loading multiple objects.
15        The loader can be configured to recognize multiple object types from object headers
16    and automatically call ParamInterface::load for the matching class.
18    Your code should repeatedly call MultiParamLoader::go() method and check the status after each call, until the end of file.
19    The loader pauses before and/or after each object giving you a chance to perform your application-specific actions (see MultiParamLoader::breakOn()).
20    If your application does not require any special actions, then the simple MultiParamLoader:run() can be used.
21    The word "record" (and "record type") used in this description refer to the textual form of a serialized object - this is to avoid confusion with 'live' objects passed to the loader methods. "Record type" can be the same as the class name, but it does not have to be the same. For example, the most common record type for storing the Genotype object is called "org" (think: organism) instead of "Genotype".
23    Typical usage scenarios:
24    1. Loading a file that contains at most one object of any given class:
25    - declare the object class(es) - MultiParamLoader::addClass()
26    - call MultiParamLoader::run()
27    - and that's all, the records from the file will be loaded into the corresponding objects
29    2. Loading multiple objects and adding them to a list (see loadtest.cpp for a sample code that demonstrates this scenario)
30    - declare the object class giving the empty "template" object - MultiParamLoader::addClass()
31    - set breakOn(AfterObject)
32    - call MultiParamLoader::go() in a loop
33    - the returned status will be equal to AfterObject each time an object is loaded. One can detect this condition and create the real object from our template object
34    (alternatively, one could breakOn(BeforeObject) and use MultiParamLoader::loadObjectNow(ParamInterface*) to load the incoming object into a newly created object).   
35 */
36class MultiParamLoader
38VirtFILE *file;
39SListTempl<VirtFILE*> filestack;
40char ownfile;
41PtrListTempl<ExtObject*> objects;
42int status;
43SString lasterror, lastcomment, lastunknown;
44ExtObject lastobject;
45int breakcond;
46Param emptyparam;
47bool aborting;
49void init();
51int maybeBreak(int cond)
52{ status=cond; return breakcond & cond; }
54VirtFILE* popstack();
55void clearstack();
57  public:
58MultiParamLoader() {init();}
59MultiParamLoader(VirtFILE *f) {init(); load(f);}
60MultiParamLoader(const char* filename) {init(); load(filename);}
62~MultiParamLoader() {abort();clearObjects();}
64void reset();
66void load(); //< use previously opened file
67void load(VirtFILE *f);
68void load(const char* filename);
70/** Register the object class. Class names will be matched with object headers ("xxx:" in the input file).
71    Used with breakOn(BeforeObject) and/or breakOn(AfterObject).
72    Note that registered classes will only work when the record name matches the class name, otherwise breakOn(BeforeUnknown) must be used and then getClassName() to check for the expected record.
73 */
74void addObject(ParamInterface *pi) {objects+=new ExtObject(pi);}
75void removeObject(ParamInterface *pi) {removeObject(ExtObject(pi));}
76void addObject(const ExtObject &o) {objects+=new ExtObject(o);}
77void removeObject(const ExtObject &o);
78int findObject(const ExtObject &o);
79void clearObjects();
81/** To be used in the main loop: while(event=loader.go()) { ... }
82    loader.go() will return on specified events (@see breakOn(), noBreakOn()),
83    then you can handle the event and resume loading.
84 */
85virtual int go();
86/** same value as 'go()' */
87int getStatus() {return status;}
88int finished() {return (status==Finished);}
90VirtFILE *getFile() {return file;}
92/** Abort immediately and close the file if needed */
93void abort();
94/** @param conditions can be combined bitwise, eg. MultiParamLoader::BeforeObject |  MultiParamLoader::OnComment
95    @see BreakConfitions
97void breakOn(int conditions) {breakcond|=conditions;}
98void noBreakOn(int conditions) {breakcond&=~conditions;}
100   These constants are used as arguments in breakOn(), and as status values from go() and getStatus().
101   The user code can define some classes for automatic recognition (using addClass()); such records can be read without performing any additional actions.
103   - BeforeObject: found an object with recognized classname (addClass()). Application code can choose to skip the incoming record (skipObject()), redirect the incoming data into a different object (loadObjectNow(ParamInterface*)), or do nothing for default behavior (loading into previously registered object).
105   - AfterObject: the object was loaded into the registered class interface (addClass()). This is to allow for additional actions after loading the object (e.g. data validation).
107   - BeforeUnknown: unknown (not registered) object header detected. Like in BeforeObject, the application can skipObject() or loadObjectNow().
109@see getClass(), GetClassName()
110 */
111enum BreakConditions { Finished=0, BeforeObject=1, AfterObject=2,
112                       BeforeUnknown=4, OnComment=8, OnError=16, Loading=32 };
114/** Can be used BeforeObject and AfterObject */
115ExtObject &getObject() {return lastobject;}
116/** Can be used BeforeUnknown, BeforeObject, AfterObject */
117const SString& getObjectName() {return lastunknown;}
118void setObjectName(SString n) {lastunknown=n;}
119/** Unknown object will be loaded if you set its class BeforeUnknown */
120void setObject(ParamInterface *pi) {lastobject=ExtObject(pi);}
121void setObject(const ExtObject& o) {lastobject=o;}
122/** Can be used OnComment */
123const SString& getComment() {return lastcomment;}
124/** Can be used OnError */
125const SString& getError() {return lasterror;}
126/** Can be used BeforeObject and BeforeUnknown */
127int loadObjectNow(ParamInterface *pi,bool warn_unknown_fields=true) {return loadObjectNow(ExtObject(pi),warn_unknown_fields);}
128int loadObjectNow(const ExtObject &o,bool warn_unknown_fields=true);
129/** Can be used BeforeObject */
130int loadObjectNow() {return loadObjectNow(getObject());}
131/** Can be used BeforeObject and BeforeUnknown.
132    Object data will not be loaded. */
133int skipObject() {return loadObjectNow(&emptyparam,false);}
134/** @return 1 if no errors */
135int run();
137void includeFile(SString& filename);
138bool returnFromIncluded();
139bool alreadyIncluded(const char* filename);
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