Renderers/HitRenderer.cs

   1 //
   2 // HitRenderer.cs
   3 //
   4 // Copyright (C) 2004 Novell, Inc.
   5 //
   6
   7 //
   8 // Permission is hereby granted, free of charge, to any person obtaining a copy
   9 // of this software and associated documentation files (the "Software"), to deal
  10 // in the Software without restriction, including without limitation the rights
  11 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12 // copies of the Software, and to permit persons to whom the Software is
  13 // furnished to do so, subject to the following conditions:
  14 //
  15 // The above copyright notice and this permission notice shall be included in all
  16 // copies or substantial portions of the Software.
  17 //
  18 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24 // SOFTWARE.
  25 //
  26
  27
  28 using System;
  29 using System.Collections;
  30
  31 namespace Beagle {
  32
  33         public abstract class HitRenderer {
  34
  35                 public delegate void RefreshHandler (HitRenderer hr);
  36                 public event RefreshHandler RefreshEvent;
  37
  38                 protected virtual bool ProcessHit (Hit hit)
  39                 {
  40                         return true;
  41                 }
  42
  43                 protected virtual void ProcessClear ()
  44                 { }
  45
  46                 //
  47                 // Widgety Goodness
  48                 //
  49
  50                 public abstract Gtk.Widget Widget { get; }
  51                 protected abstract void DoRefresh ();
  52
  53                 private uint timeoutId;
  54
  55                 public void Refresh ()
  56                 {
  57                         lock (this) {
  58                                 if (timeoutId != 0) {
  59                                         GLib.Source.Remove (timeoutId);
  60                                         timeoutId = 0;
  61                                 }
  62                                 DoRefresh ();
  63                                 if (RefreshEvent != null)
  64                                         RefreshEvent (this);
  65                         }
  66                 }
  67
  68                 public void Flush ()
  69                 {
  70                         lock (this) {
  71                                 if (timeoutId != 0)
  72                                         Refresh ();
  73                         }
  74                 }
  75
  76                 private bool HandleScheduled ()
  77                 {
  78                         lock (this) {
  79                                 timeoutId = 0;
  80                                 Refresh ();
  81                         }
  82                         return false;
  83                 }
  84
  85                 public void ScheduleRefresh (uint time)
  86                 {
  87                         lock (this) {
  88                                 if (timeoutId != 0)
  89                                         return;
  90
  91                                 if (time == 0) {
  92                                         GLib.IdleHandler handler;
  93                                         handler = new GLib.IdleHandler (HandleScheduled);
  94                                         timeoutId = GLib.Idle.Add (handler);
  95                                 } else {
  96                                         GLib.TimeoutHandler handler;
  97                                         handler = new GLib.TimeoutHandler (HandleScheduled);
  98                                         timeoutId = GLib.Timeout.Add (time, handler);
  99                                 }
 100                         }
 101                 }
 102
 103                 //
 104                 // Collect & Manage Hits
 105                 //
 106
 107                 private ArrayList hits = new ArrayList ();
 108
 109                 private int first = 0;
 110                 private int displayedCount = 10;
 111
 112                 public int FirstDisplayed {
 113                         get { return first; }
 114
 115                         set {
 116                                 int f = (int) value;
 117                                 f = Math.Max (0, Math.Min (f, hits.Count - displayedCount));
 118                                 if (f != first) {
 119                                         first = f;
 120                                         ScheduleRefresh (0);
 121                                 }
 122                         }
 123                 }
 124
 125                 public int LastDisplayed {
 126                         get { return FirstDisplayed + DisplayedCount - 1; }
 127                 }
 128
 129                 public int DisplayedCount {
 130                         get {
 131                                 int n = hits.Count - first;
 132                                 if (n < 0)
 133                                         return 0;
 134                                 if (n > displayedCount)
 135                                         n = displayedCount;
 136                                 return n;
 137                         }
 138
 139                         set {
 140                                 int dc = (int) value;
 141                                 if (dc != displayedCount) {
 142                                         displayedCount = dc;
 143                                         ScheduleRefresh (0);
 144                                 }
 145                         }
 146
 147                 }
 148
 149                 public void DisplayFirst ()
 150                 {
 151                         FirstDisplayed = 0;
 152                 }
 153
 154                 public void DisplayPrev ()
 155                 {
 156                         FirstDisplayed -= displayedCount;
 157                 }
 158
 159                 public void DisplayNext ()
 160                 {
 161                         FirstDisplayed += displayedCount;
 162                 }
 163
 164                 public void DisplayLast ()
 165                 {
 166                         FirstDisplayed = hits.Count;
 167                 }
 168
 169                 /////////////////////////////////////
 170
 171
 172                 public IList Hits {
 173                         get { return hits; }
 174                 }
 175
 176                 public int TotalCount {
 177                         get { return hits.Count; }
 178                 }
 179
 180                 public float MaxScore {
 181                         get {
 182                                 if (hits.Count > 0)
 183                                         return ((Hit) hits [0]).Score;
 184                                 return 0;
 185                         }
 186                 }
 187
 188                 public void Clear ()
 189                 {
 190                         lock (this) {
 191                                 ProcessClear ();
 192                                 hits.Clear ();
 193                         }
 194                         ScheduleRefresh (0);
 195                 }
 196
 197                 // Return true if we need a refresh after this add.
 198                 private bool AddInRightPlace (Hit hit)
 199                 {
 200                         if (hits.Count == 0) {
 201                                 hits.Add (hit);
 202                                 if (first == 0)
 203                                         return true;
 204                         } else {
 205                                 int i = hits.BinarySearch (hit);
 206                                 hits.Insert (i < 0 ? ~i : i, hit);
 207                                 if (hits.Count >= first && i < first + displayedCount)
 208                                         return true;
 209                         }
 210
 211                         return false;
 212                 }
 213
 214                 public void Add (Hit hit)
 215                 {
 216                         bool needRefresh = false;
 217                         lock (this) {
 218                                 if (ProcessHit (hit))
 219                                         needRefresh = AddInRightPlace (hit);
 220                         }
 221
 222                         // ScheduleRefresh needs to acquire a lock,
 223                         // so we wait until hits is unlocked before
 224                         // calling it.
 225                         if (needRefresh)
 226                                 ScheduleRefresh (100);
 227                 }
 228
 229                 public void Add (ICollection _hits)
 230                 {
 231                         bool needRefresh = false;
 232                         lock (this) {
 233                                 foreach (Hit hit in _hits)
 234                                         if (ProcessHit (hit))
 235                                                 if (AddInRightPlace (hit))
 236                                                         needRefresh = true;
 237                         }
 238
 239                         // Again, we do this here to avoid a potential
 240                         // deadlock.
 241                         if (needRefresh)
 242                                 ScheduleRefresh (50);
 243                 }
 244         }
 245 }