summaryrefslogtreecommitdiff
path: root/src/corelib/fpg_msgqueue.inc
blob: 386178d9d3a09a6e8860317909033148ae0e3fc4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
{%mainunit fpg_main.pas}

// fpGUI internal message queue implementation

type
  // a simlpe linked list implementation
  TMessageListElement = class(TObject)
  protected
    Next: TMessageListElement;
    Prev: TMessageListElement;
  public
    msg: TfpgMessageRec;
  end;

var
  // to make things easier we have a few global variable that will get set
  UsedFirstMessage: TMessageListElement;
  UsedLastMessage: TMessageListElement;
  FreeFirstMessage: TMessageListElement;
  FreeLastMessage: TMessageListElement;

procedure MsgListInsertElement(Elem: TMessageListElement; var First: TMessageListElement; var Last: TMessageListElement);
begin
  Elem.Prev := nil;
  Elem.Next := nil;

  if First = nil then
  begin
    First := Elem;
    Last  := Elem;
  end
  else
  begin
    Last.Next := Elem;
    Elem.Prev := Last;
    Last      := Elem;
  end;
end;

procedure MsgListRemoveElement(Elem: TMessageListElement; var First: TMessageListElement; var Last: TMessageListElement);
begin
  if Elem = First then
    First := Elem.Next;

  if Elem = Last  then
    Last  := Elem.Prev;

  if Elem.Next <> nil then
    Elem.Next.Prev := Elem.Prev;

  if Elem.Prev <> nil then
    Elem.Prev.Next := Elem.Next;
end;

function fpgAllocateMessage: PfpgMessageRec;
var
  e: TMessageListElement;
begin
  e := FreeFirstMessage;
  if e <> nil then
  begin
    MsgListRemoveElement(e, FreeFirstMessage, FreeLastMessage);
    MsgListInsertElement(e, UsedFirstMessage, UsedLastMessage);
    result := @(e.msg);
  end
  else
    result := nil;
end;

procedure fpgDeleteFirstMessage;
var
  e: TMessageListElement;
begin
  fpgApplication.Lock;
  try
    e := UsedFirstMessage;
    if e <> nil then
    begin
      MsgListRemoveElement(e, UsedFirstMessage, UsedLastMessage);
      MsgListInsertElement(e, FreeFirstMessage, FreeLastMessage);
    end;
  finally
    fpgApplication.Unlock;
  end;
end;

function fpgGetFirstMessage: PfpgMessageRec;
begin
  if UsedFirstMessage <> nil then
    Result := @(UsedFirstMessage.msg)
  else
    Result := nil;
end;

procedure fpgInitMsgQueue;
var
  n: integer;
  e: TMessageListElement;
begin
  UsedFirstMessage := nil;
  UsedLastMessage  := nil;
  FreeFirstMessage := nil;
  FreeLastMessage  := nil;
  
  uMsgQueueList := TList.Create;

  for n := 1 to cMessageQueueSize do
  begin
    e := TMessageListElement.Create;
    uMsgQueueList.Add(e); // so we can free it off later
    MsgListInsertElement(e,FreeFirstMessage,FreeLastMessage);
  end;
end;

procedure fpgPostMessage(Sender, Dest: TObject; MsgCode: integer; var aparams: TfpgMessageParams); overload;
var
  p: PfpgMessageRec;
begin
  if Dest = nil then
    Exit; //==>
  fpgApplication.Lock;
  try
    p := fpgAllocateMessage;
    if p <> nil then
    begin
      p^.MsgCode := MsgCode;
      p^.Sender  := Sender;
      p^.Dest    := Dest;
      p^.Params  := aparams;
    end
    else
      raise Exception.Create('THE fpGUI MESSAGE QUEUE IS FULL.');
  finally
    fpgApplication.Unlock;
  end;
end;

procedure fpgPostMessage(Sender, Dest: TObject; MsgCode: integer); overload;
var
  p: PfpgMessageRec;
begin
  if Dest = nil then
    Exit; //==>

  fpgApplication.Lock;
  try
    p := fpgAllocateMessage;
    if p <> nil then
    begin
      p^.MsgCode := MsgCode;
      p^.Sender  := Sender;
      p^.Dest    := Dest;
      p^.Stop    := False;
    end
    else
      raise Exception.Create('THE fpGUI MESSAGE QUEUE IS FULL.');
  finally
    fpgApplication.Unlock;
  end;
end;

procedure fpgSendMessage(Sender, Dest: TObject; MsgCode: integer; var aparams: TfpgMessageParams); overload;
var
  m: TfpgMessageRec;
begin
  if Dest = nil then
    Exit; //==>

  m.MsgCode := MsgCode;
  m.Sender  := Sender;
  m.Dest    := Dest;
  m.Params  := aparams;

  fpgDeliverMessage(m);
end;

procedure fpgSendMessage(Sender, Dest: TObject; MsgCode: integer); overload;
var
  m: TfpgMessageRec;
begin
  if Dest = nil then
    Exit; //==>

  m.MsgCode := MsgCode;
  m.Sender  := Sender;
  m.Dest    := Dest;

  fpgDeliverMessage(m);
end;

procedure fpgDeliverMessage(var msg: TfpgMessageRec);
var
  oItem: TMsgHookItem;
  i: integer;
begin
  if msg.MsgCode = FPGM_KILLME then
    msg.Dest.Free
  else
  begin
    msg.Dest.Dispatch(msg);
    if fpgApplication.FMessageHookList.Count > 0 then
    begin
      for i := 0 to fpgApplication.FMessageHookList.Count - 1 do
      begin
        oItem := TMsgHookItem(fpgApplication.FMessageHookList.Items[i]);
        if (msg.Dest = oItem.Dest) and (msg.MsgCode = oItem.MsgCode) then
          oItem.Listener.Dispatch(msg);
      end;
    end;
  end;
end;

procedure fpgDeliverMessages;
var
  mp: PfpgMessageRec;
  m: TfpgMessageRec;
begin
  repeat
    mp := fpgGetFirstMessage;
    if mp <> nil then
    begin
      m := mp^;
      fpgDeleteFirstMessage;
      fpgDeliverMessage(m);
    end;
  until mp = nil;
end;