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1 ???using System; |
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2 using System.Collections.Generic; |
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3 |
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4 namespace UCIS { |
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5 public class Cache<TKey, TValue> { |
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6 private Dictionary<TKey, WeakReference> _items; |
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7 |
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8 public Cache() { |
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9 _items = new Dictionary<TKey, WeakReference>(); |
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10 } |
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11 |
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12 public int Count { get { return _items.Count; } } |
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13 public int getCount(bool checkAlive) { |
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14 Purge(); |
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15 return _items.Count; |
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16 } |
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17 |
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18 private void getItem(TKey key, out TValue value, out bool exists, out bool collected) { |
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19 WeakReference w; |
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20 lock (_items) { |
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21 if (!_items.TryGetValue(key, out w)) { |
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22 value = default(TValue); |
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23 exists = false; |
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24 collected = false; |
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25 return; |
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26 } |
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27 Object r = w.Target; |
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28 if (r == null) { |
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29 _items.Remove(key); |
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30 value = default(TValue); |
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31 exists = false; |
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32 collected = true; |
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33 return; |
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34 } |
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35 value = (TValue)r; |
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36 exists = true; |
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37 collected = false; |
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38 return; |
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39 } |
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40 } |
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41 |
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42 public bool TryGetValue(TKey key, out TValue value) { |
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43 bool exists, collected; |
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44 getItem(key, out value, out exists, out collected); |
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45 return exists; |
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46 } |
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47 |
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48 public void Purge() { |
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49 lock (_items) { |
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50 List<TKey> remove = new List<TKey>(); |
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51 foreach (KeyValuePair<TKey, WeakReference> kvp in _items) { |
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52 if (!kvp.Value.IsAlive) remove.Add(kvp.Key); |
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53 } |
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54 foreach (TKey key in remove) { |
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55 _items.Remove(key); |
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56 } |
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57 } |
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58 } |
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59 |
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60 public void Add(TKey key, TValue value) { |
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61 lock(_items) _items.Add(key, new WeakReference(value)); |
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62 } |
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63 |
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64 public bool Remove(TKey key) { |
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65 lock(_items) return _items.Remove(key); |
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66 } |
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67 |
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68 public void Clear() { |
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69 _items.Clear(); |
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70 } |
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71 } |
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72 } |
