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r168@gandalf: fugalh | 2006-07-11 16:29:22 -0600

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I just had an epiphany. I tried so many ways to make saving function name and
 args work, it never occured to me that you could just as easily save undo
 information as a pair of mementos, even in the Command-based structure we
 agreed on.
 
 Since many (read: almost all) existing undo commands take this form:
 
     begin_reversible_command (_("change fade in length"));
     session->add_undo (arv->region.get_memento());
     arv->region.set_fade_in_length (fade_length);
     session->add_redo_no_execute (arv->region.get_memento());
     commit_reversible_command ();
 
 We are already doing the save a memento before and after work. All we need to
 do is instantiate an appropriate instance of MementoCommand. So the above
 becomes:
 
 
     begin_reversible_command (_("change fade in length"));
     MementoCommand<arv_region_t, arv_region_memento_t>  before, after;
     before = arv->region.get_memento();
     arv->region.set_fade_in_length (fade_length);
     after = arv->region.get_memento();
     session->add_command(arv->region, before, after);
     commit_reversible_command ();
 
 (With apologies for being too lazy to go look up what arv_region_t and
 arv_region_memento_t are)
 
 Note that the true command approach is still possible, and encouraged (both by
 dictate and design). 
 


git-svn-id: svn://localhost/ardour2/branches/undo@680 d708f5d6-7413-0410-9779-e7cbd77b26cf
This commit is contained in:
Hans Fugal 2006-07-11 22:29:39 +00:00
parent ab1b29bcb2
commit 0bd3b0b670
1 changed files with 9 additions and 56 deletions
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65
libs/pbd3/pbd/memento_command.h
View File

@ -24,73 +24,26 @@
#include <pbd/command.h>
#include <sigc++/slot.h>
#define MEMENTO_COMMAND(obj_T, mem_T, obj, meth) \
(MementoCommand<(obj_T),(mem_T)>((obj),sigc::mem_fun((obj),&(meth)),#meth))
#define MEMENTO_COMMAND_1(obj_T, mem_T, obj, meth, arg1) \
(MementoCommand<(obj_T),(mem_T)>((obj),\
sigc::bind(sigc::mem_fun((obj),\
&(meth)),\
arg1),#meth))
#define MEMENTO_COMMAND_2(obj_T, mem_T, obj, meth, arg1, arg2) \
(MementoCommand<(obj_T),(mem_T)>((obj),\
sigc::bind(sigc::mem_fun((obj),\
&(meth)),\
arg1, arg2),#meth))
#define MEMENTO_COMMAND_3(obj_T, mem_T, obj, meth, arg1, arg2, arg3) \
(MementoCommand<(obj_T),(mem_T)>((obj),\
sigc::bind(sigc::mem_fun((obj),\
&(meth)),\
arg1, arg2, arg3),#meth))
template <class obj_T, class mem_T>
class MementoCommand : public Command
{
public:
MementoCommand(obj_T obj,
sigc::slot<void> action,
std::string key
std::list<Serializable *> args
MementoCommand(obj_T &obj,
mem_T before,
mem_T after
)
: obj(obj), action(action), key(key), args(args), memento(obj.get_memento()) {}
MementoCommand(obj_T obj,
sigc::slot<void> action,
std::string key
Serializable *arg1 = 0,
Serializable *arg2 = 0,
Serializable *arg3 = 0
)
: obj(obj), action(action), key(key), memento(obj.get_memento())
{
if (arg1 == 0)
return;
args.push_back(arg1);
if (arg2 == 0)
return;
args.push_back(arg2);
if (arg3 == 0)
return;
args.push_back(arg3);
}
void operator() () { action(); }
void undo() { obj.set_memento(memento); }
: obj(obj), before(before), after(after) {}
void operator() () { obj.set_memento(after); }
void undo() { obj.set_memento(before); }
virtual XMLNode &serialize()
{
// obj.id
// key
// args
// key is "MementoCommand" or something
// before and after mementos
}
protected:
obj_T &obj;
mem_T memento;
sigc::slot<void> action;
std::string key;
std::list<Serializable*> args;
mem_T before, after;
};
#endif // __lib_pbd_memento_h__