vaikene.ee Git - evaf/blob - www/pswgen04.html

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
   2 <html lang="et" xmlns="http://www.w3.org/1999/xhtml" xml:lang="et">
   3
   4     <head>
   5         <meta http-equiv="CONTENT-TYPE" content="text/html; charset=utf-8" />
   6         <title>eVaf Tutorial - 04 - Generator Module</title>
   7         <meta name="Author" content="Enar Väikene" />
   8         <meta name="description" content="eVaf Tutorial" />
   9         <meta name="keywords" content="evaf c++ application development framework tutorial password generator" />
  10         <link rel="StyleSheet" href="evaf.css" type="text/css" media="all" />
  11         <link rel="StyleSheet" href="highlight.css" type="text/css" media="all" />
  12     </head>
  13
  14     <body>
  15
  16         <h1>eVaf Tutorial</h1>
  17
  18         <h2>04 - Generator Module</h2>
  19
  20         <p>Now we are going to implement all the classes declared in the <tt>module.h</tt>. Create the <tt>module.cpp</tt> file
  21         in the <tt>src/apps/PswGen/Generator</tt> directory. We obviously include the <tt>module.h</tt> header file, but also
  22         the <tt>QtCore</tt> header file for any non-GUI Qt classes.</p>
  23
  24 <pre class="hl"><span class="hl com">/**</span>
  25 <span class="hl com"> * &#64;file src/apps/PswGen/Generator/module.cpp</span>
  26 <span class="hl com"> */</span>
  27
  28 <span class="hl ppc">#include</span> <span class="hl pps">&quot;module.h&quot;</span><span class="hl ppc"></span>
  29
  30 <span class="hl ppc">#include &lt;QtCore&gt;</span></pre>
  31
  32         <p>All the eVaf modules need to include version information. This is common for all the modules and we can simply
  33         copy existing version info files from another eVaf module:</p>
  34
  35         <pre>evaf/src/apps/PswGen/Generator $ <code>cp ../../../plugins/SdiWindow/version.{h,rc} .</code></pre>
  36
  37         <p>The <tt>version.h</tt> file contains version information for the module. The <tt>version.rc</tt> is for Windows
  38         builds only and embeds the same version information into the dll or exe file. Modify the copied <tt>version.h</tt>
  39         file for our new module. The <tt>version.rc</tt> file uses the values from the <tt>version.h</tt> and does not
  40         need to be touched.</p>
  41
  42 <pre class="hl"><span class="hl com">/**</span>
  43 <span class="hl com"> * &#64;file src/apps/PswGen/Generator/version.h</span>
  44 <span class="hl com"> */</span>
  45 <span class="hl ppc">#ifndef __PSWGEN_GENERATOR_VERSION_H</span>
  46 <span class="hl ppc">#define __PSWGEN_GENERATOR_VERSION_H</span>
  47
  48 <span class="hl ppc">#include &lt;version_rc.h&gt;</span>
  49
  50 <span class="hl com">/**</span>
  51 <span class="hl com"> * Module/library version number in the form major,minor,release,build</span>
  52 <span class="hl com"> */</span>
  53 <span class="hl ppc">#define VER_FILE_VERSION                0,1,1,1</span>
  54
  55 <span class="hl com">/**</span>
  56 <span class="hl com"> * Module/library version number in the string format (shall end with \0)</span>
  57 <span class="hl com"> */</span>
  58 <span class="hl ppc">#define VER_FILE_VERSION_STR</span>            <span class="hl pps">&quot;0.1.1.1\0&quot;</span><span class="hl ppc"></span>
  59
  60 <span class="hl com">/**</span>
  61 <span class="hl com"> * Module/library name (shall end with \0)</span>
  62 <span class="hl com"> */</span>
  63 <span class="hl ppc">#define VER_MODULE_NAME_STR</span>             <span class="hl pps">&quot;PswGen\0&quot;</span><span class="hl ppc"></span>
  64
  65 <span class="hl com">/**</span>
  66 <span class="hl com"> * Module type (see version_rc.h for all the types)</span>
  67 <span class="hl com"> */</span>
  68 <span class="hl ppc">#define VER_MODULE_TYPE                 MT_GENERIC</span>
  69
  70 <span class="hl com">/**</span>
  71 <span class="hl com"> * Module type in the string format (see version_rc for all the types)</span>
  72 <span class="hl com"> */</span>
  73 <span class="hl ppc">#define VER_MODULE_TYPE_STR             MT_GENERIC</span>
  74
  75 <span class="hl com">/**</span>
  76 <span class="hl com"> * Original file name for windows (shall end with \0)</span>
  77 <span class="hl com"> */</span>
  78 <span class="hl ppc">#define VER_ORIGINAL_FILE_NAME_STR</span>      <span class="hl pps">&quot;PswGen.dll\0&quot;</span><span class="hl ppc"></span>
  79
  80 <span class="hl com">/**</span>
  81 <span class="hl com"> * Description of the module/library (shall end with \0)</span>
  82 <span class="hl com"> */</span>
  83 <span class="hl ppc">#define VER_FILE_DESCRIPTION_STR</span>         <span class="hl pps">&quot;Module that generates strong passwords using MD5 hashes.\0&quot;</span><span class="hl ppc"></span>
  84
  85 <span class="hl ppc">#endif</span> <span class="hl slc">// version.h</span><span class="hl ppc"></span></pre>
  86
  87         <p>Then include the version info file in the <tt>module.cpp</tt> file and use the <tt>VER_EXPORT_VERSION_INFO()</tt> macro
  88         to export version information from the module. This macro defines a public function that all the eVaf modules export and
  89         is used to collect version information from them. In your modules you only need to modify the <tt>version.h</tt> file and then
  90         use the <tt>VER_EXPORT_VERSION_INFO()</tt> macro once somewhere in your code.</p>
  91
  92 <pre class="hl"><span class="hl ppc">#include</span> <span class="hl pps">&quot;version.h&quot;</span><span class="hl ppc"></span>
  93
  94 <span class="hl kwd">VER_EXPORT_VERSION_INFO</span><span class="hl opt">()</span></pre>
  95
  96         <p>We make our life easier with several <tt>using namespace</tt> keywords:</p>
  97
  98 <pre class="hl"><span class="hl kwa">using namespace</span> eVaf<span class="hl opt">;</span>
  99 <span class="hl kwa">using namespace</span> eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">;</span>
 100 <span class="hl kwa">using namespace</span> eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>Generator<span class="hl opt">;</span></pre>
 101
 102         <p>The Module class needs to instantiate the <tt>iGenerator</tt> interface in the constructor. We also need to set
 103         the QObject's name property to the name of the plugin by combining the name of the module with the name of the class.
 104         While the application would work without the name property, it makes our life much easier if the name property is set.</p>
 105
 106         <p>Finally, we output an info message telling that the object was created. Every eVaf module and class is expected to
 107         output info messages when they are created, destroyed, initialized or destroyed.</p>
 108
 109 <pre class="hl">Module<span class="hl opt">::</span><span class="hl kwd">Module</span><span class="hl opt">()</span>
 110     <span class="hl opt">:</span> Plugins<span class="hl opt">::</span><span class="hl kwd">iPlugin</span><span class="hl opt">()</span>
 111 <span class="hl opt">{</span>
 112     <span class="hl kwd">setObjectName</span><span class="hl opt">(</span><span class="hl kwd">QString</span><span class="hl opt">(</span><span class="hl str">&quot;%1.%2&quot;</span><span class="hl opt">).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>VER_MODULE_NAME_STR<span class="hl opt">).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>__FUNCTION__<span class="hl opt">));</span>
 113
 114     mGenerator <span class="hl opt">=</span> <span class="hl kwa">new</span> Internal<span class="hl opt">::</span>GeneratorImpl<span class="hl opt">;</span>
 115
 116     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s created&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 117 <span class="hl opt">}</span></pre>
 118
 119         <p>The <tt>EVAF_INFO</tt> macro comes from the <tt>Common/iLogger</tt> header file ane we need to include it:</p>
 120
 121 <pre class="hl"><span class="hl ppc">#include &lt;Common/iLogger&gt;</span></pre>
 122
 123         <p>The destructor should delete the <tt>iGenerator</tt> interface object, which we created in the constructor. The common
 124         rule is that any resources allocated in the constructor shall be released in the destructor, preferrably in the opposite
 125         order, ie. the first resource allocated in the constructor is released last in the destructor.</tt>
 126
 127 <pre class="hl">Module<span class="hl opt">::~</span><span class="hl kwd">Module</span><span class="hl opt">()</span>
 128 <span class="hl opt">{</span>
 129     <span class="hl kwa">delete</span> mGenerator<span class="hl opt">;</span>
 130
 131     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s destroyed&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 132 <span class="hl opt">}</span></pre>
 133
 134         <p>We also need to implement <tt>init()</tt> and <tt>done()</tt> functions, which are used to initialize and finalize modules.
 135         They are similar to the constructor and destructor with two major differences:</p>
 136         <ol>
 137             <li>The <tt>init()</tt> function can fail and return <tt>false</tt> to indicate a failure. eVaf does not use exceptions and
 138             this is the only way for a module to fail without terminating the whole application. A failed module will be disabled
 139             and the rest of the application can still run if it can.</li>
 140             <li>eVaf modules are loaded in two steps. At first, all the modules are created, which means that all the objects
 141             are constructed. Only then will eVaf call <tt>init()</tt> functions meaning that when the <tt>init()</tt> function is
 142             called, all the modules are already loaded and instantiated. Interfaces and resources from other modules that might be not
 143             available when the object is created, are available when the <tt>init()</tt> function is called.</li>
 144         </ol>
 145
 146         <p>The rule for <tt>init()</tt> and <tt>done()</tt> functions is the same than for constructors and destructors -- any resource
 147         allocated in the <tt>init()</tt> function shall be released in the <tt>done()</tt> function and preferrably in the opposite
 148         order.</p>
 149
 150         <p>This simple module needs no extra resources to be allocated and our <tt>init()</tt> and <tt>done()</tt> functions can be
 151         the following:</p>
 152
 153 <pre class="hl"><span class="hl kwb">bool</span> Module<span class="hl opt">::</span><span class="hl kwd">init</span><span class="hl opt">(</span>QString <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> args<span class="hl opt">)</span>
 154 <span class="hl opt">{</span>
 155     <span class="hl kwd">Q_UNUSED</span><span class="hl opt">(</span>args<span class="hl opt">);</span>
 156
 157     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s initialized&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 158
 159     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 160 <span class="hl opt">}</span>
 161
 162 <span class="hl kwb">void</span> Module<span class="hl opt">::</span><span class="hl kwd">done</span><span class="hl opt">()</span>
 163 <span class="hl opt">{</span>
 164     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s finalized&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 165 <span class="hl opt">}</span></pre>
 166
 167         <p>We continue by implementing the <tt>iGenerator</tt> interface. There are no resources to be allocated in the constructor
 168         and we just set the QObject's name property and output the info message.</p>
 169
 170         <p>We also register the <tt>iGenerator</tt> interface in the global registry so that other modules can query for it and
 171         use our interface. This is done by using the <tt>Common::iRegistry</tt> interface, which we need to include:</p>
 172
 173 <pre class="hl"><span class="hl ppc">#include &lt;Common/iRegistry&gt;</span></pre>
 174
 175         <p>The <tt>GeneratorImpl</tt> class was declared in the <tt>eVaf::PswGen::Generator::Internal</tt> namespace, so we need
 176         another <tt>using namespace</tt> keyword before the implementation of the class:</p>
 177
 178 <pre class="hl"><span class="hl kwa">using namespace</span> eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>Generator<span class="hl opt">::</span>Internal<span class="hl opt">;</span>
 179
 180 GeneratorImpl<span class="hl opt">::</span><span class="hl kwd">GeneratorImpl</span><span class="hl opt">()</span>
 181     <span class="hl opt">:</span> <span class="hl kwd">iGenerator</span><span class="hl opt">()</span>
 182 <span class="hl opt">{</span>
 183     <span class="hl kwd">setObjectName</span><span class="hl opt">(</span><span class="hl kwd">QString</span><span class="hl opt">(</span><span class="hl str">&quot;%1.iGenerator&quot;</span><span class="hl opt">).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>VER_MODULE_NAME_STR<span class="hl opt">));</span>
 184
 185     Common<span class="hl opt">::</span>iRegistry<span class="hl opt">::</span><span class="hl kwd">instance</span><span class="hl opt">()-&gt;</span><span class="hl kwd">registerInterface</span><span class="hl opt">(</span><span class="hl str">&quot;iGenerator&quot;</span><span class="hl opt">,</span> <span class="hl kwa">this</span><span class="hl opt">);</span>
 186
 187     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s created&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 188 <span class="hl opt">}</span>
 189
 190 GeneratorImpl<span class="hl opt">::~</span><span class="hl kwd">GeneratorImpl</span><span class="hl opt">()</span>
 191 <span class="hl opt">{</span>
 192     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s destroyed&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 193 <span class="hl opt">}</span></pre>
 194
 195     <p>Finally, we write the <tt>generatePassword</tt> function that does the actual job of the module.</p>
 196
 197     <p>We use the MD5 cryptographic hash function to calculate a hash value over the <tt>name</tt> and <tt>masterPassword</tt> values.
 198     The result, which is a binary blob, needs to be convert into something that can be used as a password and we use base 64 encoding
 199     for this and cut the result to the requested length:</p>
 200
 201 <pre class="hl">QString GeneratorImpl<span class="hl opt">::</span><span class="hl kwd">generatePassword</span><span class="hl opt">(</span>QString <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> name<span class="hl opt">,</span> QString <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> masterPassword<span class="hl opt">,</span> <span class="hl kwb">int</span> length<span class="hl opt">,</span> uint flags<span class="hl opt">)</span> <span class="hl kwb">const</span>
 202 <span class="hl opt">{</span>
 203     <span class="hl kwd">Q_UNUSED</span><span class="hl opt">(</span>flags<span class="hl opt">);</span>
 204
 205     QByteArray inputString <span class="hl opt">=</span> <span class="hl kwd">QString</span><span class="hl opt">(</span><span class="hl str">&quot;%1%2&quot;</span><span class="hl opt">).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>name<span class="hl opt">).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>masterPassword<span class="hl opt">).</span><span class="hl kwd">toLatin1</span><span class="hl opt">();</span>
 206     QCryptographicHash <span class="hl kwd">hash</span><span class="hl opt">(</span>QCryptographicHash<span class="hl opt">::</span>Md5<span class="hl opt">);</span>
 207     hash<span class="hl opt">.</span><span class="hl kwd">addData</span><span class="hl opt">(</span>inputString<span class="hl opt">);</span>
 208     QByteArray result <span class="hl opt">=</span> hash<span class="hl opt">.</span><span class="hl kwd">result</span><span class="hl opt">().</span><span class="hl kwd">toBase64</span><span class="hl opt">();</span>
 209     <span class="hl kwa">if</span> <span class="hl opt">(</span>length <span class="hl opt">&gt;</span> <span class="hl num">0</span><span class="hl opt">)</span>
 210         <span class="hl kwa">return</span> result<span class="hl opt">.</span><span class="hl kwd">left</span><span class="hl opt">(</span>length<span class="hl opt">);</span>
 211     <span class="hl kwa">else</span>
 212         <span class="hl kwa">return</span> result<span class="hl opt">;</span>
 213 <span class="hl opt">}</span></pre>
 214
 215     <p>We also know now the maximum length of the generated password, which is 24. Go back to the <tt>module.h</tt> header file and
 216     modify the <tt>GeneratorImpl::maxLength()</tt> function:</p>
 217
 218 <pre class="hl"><span class="hl kwc">virtual</span> <span class="hl kwb">int</span> <span class="hl kwd">maxLength</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> <span class="hl num">24</span><span class="hl opt">; }</span></pre>
 219
 220     <p>Here is the final <tt>module.cpp</tt> file:</p>
 221
 222 <pre class="hl"><span class="hl com">/**</span>
 223 <span class="hl com"> * &#64;file src/apps/PswGen/Generator/module.cpp</span>
 224 <span class="hl com"> */</span>
 225
 226 <span class="hl ppc">#include</span> <span class="hl pps">&quot;module.h&quot;</span><span class="hl ppc"></span>
 227 <span class="hl ppc">#include</span> <span class="hl pps">&quot;version.h&quot;</span><span class="hl ppc"></span>
 228
 229 <span class="hl ppc">#include &lt;Common/iLogger&gt;</span>
 230 <span class="hl ppc">#include &lt;Common/iRegistry&gt;</span>
 231
 232 <span class="hl ppc">#include &lt;QtCore&gt;</span>
 233
 234 <span class="hl kwd">VER_EXPORT_VERSION_INFO</span><span class="hl opt">()</span>
 235 <span class="hl kwd">Q_EXPORT_PLUGIN2</span><span class="hl opt">(</span>VER_MODULE_NAME_STR<span class="hl opt">,</span> eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>Generator<span class="hl opt">::</span>Module<span class="hl opt">)</span>
 236
 237 <span class="hl kwa">using namespace</span> eVaf<span class="hl opt">;</span>
 238 <span class="hl kwa">using namespace</span> eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">;</span>
 239 <span class="hl kwa">using namespace</span> eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>Generator<span class="hl opt">;</span>
 240
 241 Module<span class="hl opt">::</span><span class="hl kwd">Module</span><span class="hl opt">()</span>
 242     <span class="hl opt">:</span> Plugins<span class="hl opt">::</span><span class="hl kwd">iPlugin</span><span class="hl opt">()</span>
 243 <span class="hl opt">{</span>
 244     <span class="hl kwd">setObjectName</span><span class="hl opt">(</span><span class="hl kwd">QString</span><span class="hl opt">(</span><span class="hl str">&quot;%1.%2&quot;</span><span class="hl opt">).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>VER_MODULE_NAME_STR<span class="hl opt">).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>__FUNCTION__<span class="hl opt">));</span>
 245
 246     mGenerator <span class="hl opt">=</span> <span class="hl kwa">new</span> Internal<span class="hl opt">::</span>GeneratorImpl<span class="hl opt">;</span>
 247
 248     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s created&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 249 <span class="hl opt">}</span>
 250
 251 Module<span class="hl opt">::~</span><span class="hl kwd">Module</span><span class="hl opt">()</span>
 252 <span class="hl opt">{</span>
 253     <span class="hl kwa">delete</span> mGenerator<span class="hl opt">;</span>
 254
 255     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s destroyed&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 256 <span class="hl opt">}</span>
 257
 258 <span class="hl kwb">bool</span> Module<span class="hl opt">::</span><span class="hl kwd">init</span><span class="hl opt">(</span>QString <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> args<span class="hl opt">)</span>
 259 <span class="hl opt">{</span>
 260     <span class="hl kwd">Q_UNUSED</span><span class="hl opt">(</span>args<span class="hl opt">);</span>
 261
 262     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s initialized&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 263
 264     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 265 <span class="hl opt">}</span>
 266
 267 <span class="hl kwb">void</span> Module<span class="hl opt">::</span><span class="hl kwd">done</span><span class="hl opt">()</span>
 268 <span class="hl opt">{</span>
 269     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s finalized&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 270 <span class="hl opt">}</span>
 271
 272 <span class="hl kwa">using namespace</span> eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>Generator<span class="hl opt">::</span>Internal<span class="hl opt">;</span>
 273
 274 GeneratorImpl<span class="hl opt">::</span><span class="hl kwd">GeneratorImpl</span><span class="hl opt">()</span>
 275     <span class="hl opt">:</span> <span class="hl kwd">iGenerator</span><span class="hl opt">()</span>
 276 <span class="hl opt">{</span>
 277     <span class="hl kwd">setObjectName</span><span class="hl opt">(</span><span class="hl kwd">QString</span><span class="hl opt">(</span><span class="hl str">&quot;%1.iGenerator&quot;</span><span class="hl opt">).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>VER_MODULE_NAME_STR<span class="hl opt">));</span>
 278
 279     Common<span class="hl opt">::</span>iRegistry<span class="hl opt">::</span><span class="hl kwd">instance</span><span class="hl opt">()-&gt;</span><span class="hl kwd">registerInterface</span><span class="hl opt">(</span><span class="hl str">&quot;iGenerator&quot;</span><span class="hl opt">,</span> <span class="hl kwa">this</span><span class="hl opt">);</span>
 280
 281     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s created&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 282 <span class="hl opt">}</span>
 283
 284 GeneratorImpl<span class="hl opt">::~</span><span class="hl kwd">GeneratorImpl</span><span class="hl opt">()</span>
 285 <span class="hl opt">{</span>
 286     <span class="hl kwd">EVAF_INFO</span><span class="hl opt">(</span><span class="hl str">&quot;%s destroyed&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span><span class="hl kwd">objectName</span><span class="hl opt">()));</span>
 287 <span class="hl opt">}</span>
 288
 289 QString GeneratorImpl<span class="hl opt">::</span><span class="hl kwd">generatePassword</span><span class="hl opt">(</span>QString <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> name<span class="hl opt">,</span> QString <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> masterPassword<span class="hl opt">,</span> <span class="hl kwb">int</span> length<span class="hl opt">,</span> uint flags<span class="hl opt">)</span> <span class="hl kwb">const</span>
 290 <span class="hl opt">{</span>
 291     <span class="hl kwd">Q_UNUSED</span><span class="hl opt">(</span>flags<span class="hl opt">);</span>
 292
 293     QByteArray inputString <span class="hl opt">=</span> <span class="hl kwd">QString</span><span class="hl opt">(</span><span class="hl str">&quot;%1%2&quot;</span><span class="hl opt">).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>name<span class="hl opt">).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>masterPassword<span class="hl opt">).</span><span class="hl kwd">toLatin1</span><span class="hl opt">();</span>
 294     QCryptographicHash <span class="hl kwd">hash</span><span class="hl opt">(</span>QCryptographicHash<span class="hl opt">::</span>Md5<span class="hl opt">);</span>
 295     hash<span class="hl opt">.</span><span class="hl kwd">addData</span><span class="hl opt">(</span>inputString<span class="hl opt">);</span>
 296     QByteArray result <span class="hl opt">=</span> hash<span class="hl opt">.</span><span class="hl kwd">result</span><span class="hl opt">().</span><span class="hl kwd">toBase64</span><span class="hl opt">();</span>
 297     <span class="hl kwa">if</span> <span class="hl opt">(</span>length <span class="hl opt">&gt;</span> <span class="hl num">0</span><span class="hl opt">)</span>
 298         <span class="hl kwa">return</span> result<span class="hl opt">.</span><span class="hl kwd">left</span><span class="hl opt">(</span>length<span class="hl opt">);</span>
 299     <span class="hl kwa">else</span>
 300         <span class="hl kwa">return</span> result<span class="hl opt">;</span>
 301 <span class="hl opt">}</span></pre>
 302
 303         <p>Next -- <a href="pswgen05.html">05 - Building Generator Module</a>.</p>
 304
 305     </body>
 306 </html>