contrib/include/wx/applet/echovar.h

   1 /****************************************************************************
   2 *
   3 *                       wxWindows HTML Applet Package
   4 *
   5 *               Copyright (C) 1991-2001 SciTech Software, Inc.
   6 *                            All rights reserved.
   7 *
   8 *  ========================================================================
   9 *
  10 *    The contents of this file are subject to the wxWindows License
  11 *    Version 3.0 (the "License"); you may not use this file except in
  12 *    compliance with the License. You may obtain a copy of the License at
  13 *    http://www.wxwindows.org/licence3.txt
  14 *
  15 *    Software distributed under the License is distributed on an
  16 *    "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  17 *    implied. See the License for the specific language governing
  18 *    rights and limitations under the License.
  19 *
  20 *  ========================================================================
  21 *
  22 * Language:             ANSI C++
  23 * Environment:  Any
  24 *
  25 * Description:  Header file for wxEchoVariable Class, Dynamically constructed
  26 * objects representing variables in SSI #echo directive
  27 *
  28 ****************************************************************************/
  29
  30 #ifndef __WX_ECHOVAR_H
  31 #define __WX_ECHOVAR_H
  32
  33 #include "wx/object.h"
  34 #include "wx/hash.h"
  35
  36 /*--------------------------- Class Definitions ---------------------------*/
  37
  38 /****************************************************************************
  39 RETURNS:
  40 The string value of the variable
  41
  42 PARAMETERS:
  43 parms   - Optional parameter string passed from parm= field in HTML
  44
  45 REMARKS:
  46 To create new variables for the #echo HTML preprocessing directives
  47 you need to derive classes from wxEchoVariable and override the
  48 pure virtual GetValue function. However this should not be done directly
  49 but by using the BEGIN_ECHO_VARIABLE and END_ECHO_VARIABLE macros
  50
  51 SEE ALSO:
  52 wxEchoPrep, BEGIN_ECHO_VARIABLE, END_ECHO_VARIABLE
  53 ****************************************************************************/
  54 typedef wxString (*wxEchoVariableGetValueFn)(const char *parms);
  55
  56 /****************************************************************************
  57 REMARKS:
  58 wxEchoVariable class Definition
  59 ****************************************************************************/
  60 class wxEchoVariable : public wxObject {
  61 protected:
  62     const wxChar                *m_varName;
  63     wxEchoVariableGetValueFn    m_getValueFn;
  64     static wxEchoVariable       *sm_first;
  65     wxEchoVariable              *m_next;
  66     static wxHashTable          *sm_varTable;
  67
  68     static inline wxEchoVariable *wxEchoVariable::FindVariable(const wxChar *varName);
  69
  70 public:
  71     // Constructor to create the echo variable and register the class
  72     wxEchoVariable(
  73         const char *varName,
  74         wxEchoVariableGetValueFn getValueFn);
  75
  76     // Member variable access functions
  77     const wxChar *GetClassName() const          { return m_varName; }
  78     wxEchoVariableGetValueFn GetValueFn() const { return m_getValueFn; }
  79     static const wxEchoVariable* GetFirst()     { return sm_first; }
  80     const wxEchoVariable* GetNext() const       { return m_next; }
  81
  82     // Static functions to retrieve any variable avaliable
  83     static wxString GetValue(const wxChar *varName,const wxChar *parms = NULL);
  84     static bool Exists(const wxChar *varName);
  85
  86     // Initializes parent pointers and hash table for fast searching.
  87     static void Initialize();
  88
  89     // Cleans up hash table used for fast searching.
  90     static void CleanUp();
  91     };
  92
  93 /****************************************************************************
  94 PARAMETERS:
  95 class   - Name of class for echo variable to find
  96
  97 RETURNS:
  98 Pointer to the echo variable class
  99
 100 REMARKS:
 101 Inline helper function to find the echo variable from it's class name.
 102 ****************************************************************************/
 103 inline wxEchoVariable *wxEchoVariable::FindVariable(
 104     const wxChar *varName)
 105 {
 106     if (sm_varTable)
 107         return (wxEchoVariable*)sm_varTable->Get(varName);
 108     else {
 109         wxEchoVariable *info = sm_first;
 110         while (info) {
 111             if (info->m_varName && wxStrcmp(info->m_varName, varName) == 0)
 112                 return info;
 113             info = info->m_next;
 114             }
 115         return NULL;
 116         }
 117 }
 118
 119 /*--------------------------------- MACROS --------------------------------*/
 120
 121 #define BEGIN_ECHO_VARIABLE(name)                                           \
 122 wxString wxEchoVariableFn##name(const char *parms);                         \
 123 wxEchoVariable wxEchoVariable##name(#name,wxEchoVariableFn##name);          \
 124 wxString wxEchoVariableFn##name(const char *parms) {                        \
 125     wxString _BEV_parm = wxString(parms);
 126
 127 #define END_ECHO_VARIABLE(returnval)                                        \
 128     return returnval;                                                       \
 129     }
 130
 131 #define STRING_ECHO_VARIABLE(name, string)                                  \
 132     BEGIN_ECHO_VARIABLE(##name##);                                          \
 133     END_ECHO_VARIABLE(wxString(##string##))
 134
 135 #endif // __WX_ECHOVAR_H
 136