Network/parameters.h

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 //
  20 // parameters - dynamic parameter retrieval interface
  21 //
  22 #ifndef _H_PARAMETERS
  23 #define _H_PARAMETERS
  24
  25 #include <Security/typedvalue.h>
  26 #include <Security/debugging.h>
  27 #include <vector>
  28 #include <cstdarg>
  29
  30
  31 namespace Security {
  32 namespace Network {
  33
  34
  35 class ParameterSource {
  36 public:
  37     // Keys are unsigned integers with integrated typing
  38     typedef uint32 Key;
  39     typedef GenericValue Value;
  40
  41     enum {
  42         integerKey = 1,         // int
  43         stringKey = 2,          // string
  44         boolKey = 3,            // bool
  45         dataKey = 4                     // ConstData
  46     };
  47 #       define PARAMKEY(id,type)        ((id) << 8 | (Security::Network::ParameterSource::type##Key))
  48     inline int keyType(Key key) const           { return key & 0xFF; }
  49
  50 public:
  51     virtual ~ParameterSource() { }
  52
  53 public:
  54     // core form: this can be virtually overridden
  55     virtual bool getParams(Key key, Value &value) const = 0;
  56
  57     // convenience form: unwrap to Value base type
  58     template <class T> bool get(Key key, T &result) const
  59     {
  60         TypedValue<T> value;
  61         if (getParams(key, value)) {
  62             result = value;
  63             debug("paramsource", "%p key=0x%lx retrieved", this, key);
  64             return true;
  65         } else {
  66             debug("paramsource", "%p key=0x%lx not found", this, key);
  67             return false;
  68         }
  69     }
  70
  71     // convenience form: return value, use default if not found (no failure indication)
  72     template <class T> T getv(Key key, T value = T()) const
  73     {
  74         get(key, value);                // overwrite value if successful
  75         return value;                   // then return it or remaining default
  76     }
  77 };
  78
  79
  80 //
  81 // A ParameterPointer is a ParameterSource that has an indirection to another
  82 // ParameterSource. The underlying ("base") reference can be changed at will.
  83 // If it is NULL, all lookups fail.
  84 //
  85 class ParameterPointer : public ParameterSource {
  86 public:
  87     ParameterPointer() : mBase(NULL) { }
  88     ParameterPointer(ParameterSource *src) : mBase(src) { }
  89
  90     operator bool () const                              { return mBase; }
  91     ParameterSource *parameters() const { return mBase; }
  92     ParameterSource *parameters(ParameterSource *newBase)
  93     { ParameterSource *old = mBase; mBase = newBase; return old; }
  94
  95     ParameterSource *parameters(ParameterSource &newBase)
  96     { return parameters(&newBase); }
  97
  98     bool getParams(Key key, Value &value) const
  99     { return mBase && mBase->getParams(key, value); }
 100
 101 private:
 102     ParameterSource *mBase;                             // where to get it from...
 103 };
 104
 105
 106 //
 107 // Here's an entire (ordered) "stack" of ParameterSources. Just build a vector
 108 // of pointers to ParameterSources, and have them searched in order.
 109 //
 110 class ParameterStack : public ParameterSource, public vector<ParameterSource *> {
 111 public:
 112     bool getParams(Key key, Value &value) const;
 113 };
 114
 115
 116 }       // end namespace Network
 117 }       // end namespace Security
 118
 119
 120 #endif //_H_PARAMETERS