/src/lib/storage/low_level/recycling_pool.e

  1-- This file is part of a Liberty Eiffel library.
  2-- See the full copyright at the end.
  3--
  4class RECYCLING_POOL[R_ -> RECYCLABLE]
  5   --
  6   -- RECYCLABLE objects container.
  7   --
  8   -- Useful to implement recycling support in libraries.
  9   --
 10   -- Has no sense for expanded types (it will not even compile).
 11   --
 12   -- This class is designed to work with and without the garbage collector. It takes advantage of the GC if
 13   -- it is used, but it also minimises the memory footprint when the GC is ''not'' used.
 14   --
 15   -- See also STRING_RECYCLING_POOL, especially tuned for STRING usage.
 16   --
 17
 18insert
 19   STACK[R_]
 20      rename
 21         item as collection_item,
 22         recycle as stack_recycle
 23      export
 24         {RECYCLING_POOL} lower, upper, storage, count;
 25         {ANY} is_empty;
 26         {} all
 27      redefine
 28         mark_native_arrays
 29      end
 30   ANY
 31      -- To get reasonable default exports
 32      undefine default_create, out_in_tagged_out_memory, copy, is_equal
 33      end
 34
 35create {ANY}
 36   make
 37
 38create {RECYCLING_POOL}
 39   collection_make
 40
 41feature {ANY}
 42   item: R_
 43         --
 44         -- Returns a recycled object, if there is one to be obtained. Returns Void otherwise.
 45         --
 46         -- See also `recycle'
 47         --
 48      require
 49         not is_empty
 50      do
 51         Result := top
 52         pop
 53      ensure
 54         Result /= Void
 55      end
 56
 57  recycle (an_item: like item)
 58         --
 59         -- Stores the object as being reusable. Automatically calls the "recycle" feature of the object.
 60         --
 61         -- Two notes:
 62         --
 63         -- * You should not directly reuse the object after it is recycled; call `item' instead to obtain a
 64         -- fresh reference. Using it directly will lead to classic problems of double referencing. In a
 65         -- nutshell, '''be sure not to hold any reference to a recycled object'''.
 66         --
 67         -- * If the GC is used it may free some recycled objects so using a RECYCLING_POOL does not interfere
 68         -- with memory conservation.
 69         --
 70         -- See also `item'
 71         --
 72      require
 73         an_item /= Void
 74      do
 75         an_item.recycle
 76         push(an_item)
 77      end
 78
 79feature {}
 80   mark_native_arrays
 81      do
 82         clear_count
 83      end
 84
 85end -- class RECYCLING_POOL
 86--
 87-- Copyright (C) 2009-2017: by all the people cited in the AUTHORS file.
 88--
 89-- Permission is hereby granted, free of charge, to any person obtaining a copy
 90-- of this software and associated documentation files (the "Software"), to deal
 91-- in the Software without restriction, including without limitation the rights
 92-- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 93-- copies of the Software, and to permit persons to whom the Software is
 94-- furnished to do so, subject to the following conditions:
 95--
 96-- The above copyright notice and this permission notice shall be included in
 97-- all copies or substantial portions of the Software.
 98--
 99-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
100-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
101-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
102-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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105-- THE SOFTWARE.