cinelerra/garbage.h

   1 #ifndef GARBAGE_H
   2 #define GARBAGE_H
   3
   4
   5 #include "arraylist.h"
   6 #include "garbage.inc"
   7 #include "mutex.inc"
   8
   9 // Garbage collection
  10 // The objects inherit from GarbageObject.
  11 // The constructor sets users to 0 so the caller must call add_user if it
  12 // wants to use it.  If it doesn't intend to use it after calling the constructor,
  13 // it should not call add_user.
  14 // Other users of the object must call add_user to increment the user count
  15 // and remove_user to decriment the user count.
  16 // The object is only deleted if a call to Garbage::delete_object is made and
  17 // the user count is 0.
  18 // A user who is using it and wants to delete it must first call
  19 // remove_user and then call Garbage::delete_object.
  20
  21
  22 // They are deleted by calling delete_object.  They get deleted at a
  23 // random point later on.  The objects must not change anything in their
  24 // destructors.
  25
  26 // Can't make graphics elements inherit because they must be deleted
  27 // when the window is locked and they change their parent pointers.
  28
  29 // Elements of link lists must first be unlinked with remove_pointer and then
  30 // passed to delete_object.
  31
  32 // ArrayList objects must be deleted one at a time with delete_object.
  33 // Then the pointers must be deleted with remove_all.
  34 class GarbageObject
  35 {
  36 public:
  37         GarbageObject(char *title);
  38         virtual ~GarbageObject();
  39
  40 // Called when user begins to use the object.
  41         void add_user();
  42 // Called when user is done with the object.
  43         void remove_user();
  44
  45         int users;
  46         int deleted;
  47         char *title;
  48 };
  49
  50
  51
  52 class Garbage
  53 {
  54 public:
  55         Garbage();
  56         ~Garbage();
  57
  58 // Called by GarbageObject constructor
  59         void add_object(GarbageObject *ptr);
  60
  61 // Called by user to delete the object.
  62 // Flags the object for deletion as soon as it has no users.
  63         static void delete_object(GarbageObject *ptr);
  64
  65
  66 // Called by remove_user and delete_object
  67         static void remove_expired();
  68         Mutex *lock;
  69         ArrayList<GarbageObject*> objects;
  70
  71 // Global garbage collector
  72         static Garbage *garbage;
  73 };
  74
  75
  76
  77 #endif