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  16         <p>Next: <a href="pswgen07.html">07 - Storage Module</a>, Previous: <a href="pswgen05.html">05 - Building Generator Module</a></p>
  17
  18         <h1>eVaf Tutorial</h1>
  19
  20         <h2>06 - Storage Module</h2>
  21
  22         <p>In this section we start implementing the Storage module. The storage module stores non-sensitive data required to re-generate
  23         passwords. We use a simple SQLITE database in this module, but nothing prevents us replacing it with a more complex storage
  24         module in the future.</p>
  25
  26         <h3>iStorage interface</h3>
  27
  28         <p>Once again, we start by defining the interface for the module and create the file <tt>istorage.h</tt> in the
  29         <tt>src/apps/PswGen/Storage</tt> directory:</p>
  30
  31         <pre class="hl"><span class="hl com">/**</span>
  32 <span class="hl com"> * &#64;file PswGen/Storage/istorage.h</span>
  33 <span class="hl com"> */</span>
  34
  35 <span class="hl ppc">#ifndef __PSWGEN_STORAGE_ISTORAGE_H</span>
  36 <span class="hl ppc">#  define __PSWGEN_STORAGE_ISTORAGE_H</span>
  37 <span class="hl ppc">#endif</span> <span class="hl slc">// istorage.h</span></pre>
  38
  39         <p>Include Qt header files for <tt>QObject</tt> and <tt>QString</tt> as they are almost always needed. In additon, we are going to
  40         include headers for <tt>QSharedData</tt> and <tt>QExplicitlySharedDataPointer</tt>. We need a container for the data that
  41         we store and making it shared data object with the benefit of automatic reference counting and memory management makes sense.</p>
  42
  43         <pre class="hl"><span class="hl ppc">#include &lt;QObject&gt;</span>
  44 <span class="hl ppc">#include &lt;QString&gt;</span>
  45 <span class="hl ppc">#include &lt;QSharedData&gt;</span>
  46 <span class="hl ppc">#include &lt;QExplicitlySharedDataPointer&gt;</span></pre>
  47
  48         <p>Use the <tt>eVaf::PswGen</tt> namespace:</p>
  49
  50         <pre class="hl"><span class="hl kwa">namespace</span> eVaf <span class="hl opt">{</span>
  51 <span class="hl kwa">namespace</span> PswGen <span class="hl opt">{</span>
  52
  53 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen</span>
  54 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf</span></pre>
  55
  56         <p>The container class for stored data has the following attributes:</p>
  57         <ul>
  58             <li>Name -- Name of the generated password</li>
  59             <li>Length -- Length of the password</li>
  60             <li>Options -- Additional parameters for the password generator</li>
  61         </ul>
  62
  63         <p>The container class belongs to the Storage module and we use the <tt>eVaf::PswGen::Storage</tt> namespace for it:</p>
  64
  65         <pre class="hl"><span class="hl kwa">namespace</span> Storage <span class="hl opt">{</span>
  66
  67 <span class="hl kwc">class</span> Data <span class="hl opt">:</span> <span class="hl kwc">public</span> QSharedData
  68 <span class="hl opt">{</span>
  69 <span class="hl kwc">private</span><span class="hl opt">:</span>
  70
  71     <span class="hl kwb">bool</span> mModified<span class="hl opt">;</span>
  72     QString mName<span class="hl opt">;</span>
  73     <span class="hl kwb">int</span> mLength<span class="hl opt">;</span>
  74     uint mFlags<span class="hl opt">;</span>
  75
  76 <span class="hl opt">};</span>
  77
  78 <span class="hl opt">}</span> <span class="hl slc">// eVaf::PswGen::Storage</span></pre>
  79
  80         <p>The extra attribute - <tt>mModified</tt> - is used to detect unsaved modifications in the data object.</p>
  81
  82         <p>Add constructors for the shared data class. Creating a data object without name makes no sense and we include the
  83         name attribute in all our constructors:</p>
  84
  85         <pre class="hl"><span class="hl kwc">public</span><span class="hl opt">:</span>
  86
  87     <span class="hl kwd">Data</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>
  88         <span class="hl opt">:</span> <span class="hl kwd">QSharedData</span><span class="hl opt">()</span>
  89         <span class="hl opt">,</span> <span class="hl kwd">mModified</span><span class="hl opt">(</span><span class="hl kwa">false</span><span class="hl opt">)</span>
  90         <span class="hl opt">,</span> <span class="hl kwd">mName</span><span class="hl opt">(</span>name<span class="hl opt">)</span>
  91         <span class="hl opt">,</span> <span class="hl kwd">mLength</span><span class="hl opt">(</span><span class="hl num">0</span><span class="hl opt">)</span>
  92         <span class="hl opt">,</span> <span class="hl kwd">mFlags</span><span class="hl opt">(</span><span class="hl num">0</span><span class="hl opt">)</span>
  93     <span class="hl opt">{}</span>
  94
  95     <span class="hl kwd">Data</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> <span class="hl kwb">int</span> l<span class="hl opt">,</span> uint f <span class="hl opt">=</span> <span class="hl num">0</span><span class="hl opt">)</span>
  96         <span class="hl opt">:</span> <span class="hl kwd">QSharedData</span><span class="hl opt">()</span>
  97         <span class="hl opt">,</span> <span class="hl kwd">mModified</span><span class="hl opt">(</span><span class="hl kwa">false</span><span class="hl opt">)</span>
  98         <span class="hl opt">,</span> <span class="hl kwd">mName</span><span class="hl opt">(</span>name<span class="hl opt">)</span>
  99         <span class="hl opt">,</span> <span class="hl kwd">mLength</span><span class="hl opt">(</span>l<span class="hl opt">)</span>
 100         <span class="hl opt">,</span> <span class="hl kwd">mFlags</span><span class="hl opt">(</span>f<span class="hl opt">)</span>
 101     <span class="hl opt">{}</span></pre>
 102
 103     <p>Fianlly, we add getter and setter methods:</p>
 104
 105     <pre class="hl">
 106     QString <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> <span class="hl kwd">name</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mName<span class="hl opt">; }</span>
 107
 108     <span class="hl kwb">int</span> <span class="hl kwd">length</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mLength<span class="hl opt">; }</span>
 109     <span class="hl kwb">void</span> <span class="hl kwd">setLength</span><span class="hl opt">(</span><span class="hl kwb">int</span> value<span class="hl opt">)</span>
 110     <span class="hl opt">{</span>
 111         <span class="hl kwa">if</span> <span class="hl opt">(</span>mLength <span class="hl opt">!=</span> value<span class="hl opt">) {</span>
 112             mLength <span class="hl opt">=</span> value<span class="hl opt">;</span>
 113             mModified <span class="hl opt">=</span> <span class="hl kwa">true</span><span class="hl opt">;</span>
 114         <span class="hl opt">}</span>
 115     <span class="hl opt">}</span>
 116
 117     uint <span class="hl kwd">flags</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mFlags<span class="hl opt">; }</span>
 118     <span class="hl kwb">void</span> <span class="hl kwd">setFlags</span><span class="hl opt">(</span>uint value<span class="hl opt">)</span>
 119     <span class="hl opt">{</span>
 120         <span class="hl kwa">if</span> <span class="hl opt">(</span>mFlags <span class="hl opt">!=</span> value<span class="hl opt">) {</span>
 121             mFlags <span class="hl opt">=</span> value<span class="hl opt">;</span>
 122             mModified <span class="hl opt">=</span> <span class="hl kwa">true</span><span class="hl opt">;</span>
 123         <span class="hl opt">}</span>
 124     <span class="hl opt">}</span>
 125
 126     <span class="hl kwb">bool</span> <span class="hl kwd">modified</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mModified<span class="hl opt">; }</span>
 127
 128     <span class="hl kwb">void</span> <span class="hl kwd">reset</span><span class="hl opt">() {</span> mModified <span class="hl opt">=</span> <span class="hl kwa">false</span><span class="hl opt">; }</span></pre>
 129
 130     <p>The <tt>reset()</tt> method resets the <tt>modified</tt> attribute.</p>
 131
 132     <p>Continue with the <tt>iStorage</tt> interface:</tt>
 133
 134     <pre class="hl"><span class="hl kwb">struct</span> iStorage
 135 <span class="hl opt">{</span>
 136
 137 <span class="hl opt">};</span></pre>
 138
 139     <p>According to the specification, we need functions to store and query data:</p>
 140
 141     <pre class="hl">
 142     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</span> <span class="hl kwd">save</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> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> data<span class="hl opt">) =</span> <span class="hl num">0</span><span class="hl opt">;</span>
 143
 144     <span class="hl kwc">virtual</span> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> <span class="hl kwd">query</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> <span class="hl kwb">const</span> <span class="hl opt">=</span> <span class="hl num">0</span><span class="hl opt">;</span></pre>
 145
 146     <p>The <tt>query()</tt> method returns an explicitly shared shared data pointer, which has the following advantages:</p>
 147     <ul>
 148         <li>The same data object is shared between multiple modules and if a module changes attributes in the data object, these
 149         changes are immediately seen by any other modules;</li>
 150         <li>No need to worry about ownership -- the shared data object is deleted when the last module stops using it;</li>
 151         <li>The <tt>query()</tt> method can return an empty shared data pointer to indicate that no data objects with the
 152         given name exist.</tt>
 153     </ul>
 154
 155     <p>The drawback is that if a module needs a local copy of the data object, it has to use the <tt>QExplicitlySharedDataPointer::detach()</tt> method to create a deep copy of the data object.</p>
 156
 157     <p>The specification also mentions partial matches where entering "fa" would offer "facebook.com" if it exists. This could be done by
 158     using the <tt>QCompleter</tt> class that provides auto completion in Qt widgets like <tt>QLineEdit</tt> and <tt>QComboBox</tt>. The
 159     <tt>QCompleter<tt> class needs a <tt>QAbstractItemModel</tt> for the auto completion word list and we can provide it
 160     from our <tt>Storage</tt> module:</tt>
 161
 162     <pre class="hl">
 163     <span class="hl kwc">virtual</span> QAbstractItemModel <span class="hl opt">*</span> <span class="hl kwd">autoCompletionModel</span><span class="hl opt">() =</span> <span class="hl num">0</span><span class="hl opt">;</span></pre>
 164
 165     <p><tt>QAbstractItemModel</tt> is not known at this moment and we need to add a forward class declaration to the beginning of the
 166     <tt>istorage.h</tt> file:</p>
 167
 168     <pre class="hl">
 169     <span class="hl kwc">class</span> QAbstractItemModel<span class="hl opt">;</span></pre>
 170
 171     <p>At the the end of the <tt>istorage.h</tt> file, we declare the <tt>iStorage</tt> interface:</p>
 172
 173     <pre class="hl"><span class="hl kwd">Q_DECLARE_INTERFACE</span><span class="hl opt">(</span>eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>iStorage<span class="hl opt">,</span> <span class="hl str">&quot;eVaf.PswGen.iStorage/1.0&quot;</span><span class="hl opt">)</span></pre>
 174
 175     <p>This is the complete <tt>istorage.h</tt> file:</p>
 176
 177     <pre class="hl"><span class="hl com">/**</span>
 178 <span class="hl com"> * &#64;file PswGen/Storage/istorage.h</span>
 179 <span class="hl com"> */</span>
 180
 181 <span class="hl ppc">#ifndef __PSWGEN_STORAGE_ISTORAGE_H</span>
 182 <span class="hl ppc">#  define __PSWGEN_STORAGE_ISTORAGE_H</span>
 183
 184 <span class="hl ppc">#include &lt;QObject&gt;</span>
 185 <span class="hl ppc">#include &lt;QString&gt;</span>
 186 <span class="hl ppc">#include &lt;QSharedData&gt;</span>
 187 <span class="hl ppc">#include &lt;QExplicitlySharedDataPointer&gt;</span>
 188
 189 <span class="hl kwc">class</span> QAbstractItemModel<span class="hl opt">;</span>
 190
 191 <span class="hl kwa">namespace</span> eVaf <span class="hl opt">{</span>
 192 <span class="hl kwa">namespace</span> PswGen <span class="hl opt">{</span>
 193
 194 <span class="hl kwa">namespace</span> Storage <span class="hl opt">{</span>
 195
 196 <span class="hl com">/// Data stored for every password.</span>
 197 <span class="hl kwc">class</span> Data <span class="hl opt">:</span> <span class="hl kwc">public</span> QSharedData
 198 <span class="hl opt">{</span>
 199 <span class="hl kwc">public</span><span class="hl opt">:</span>
 200
 201     <span class="hl kwd">Data</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>
 202         <span class="hl opt">:</span> <span class="hl kwd">QSharedData</span><span class="hl opt">()</span>
 203         <span class="hl opt">,</span> <span class="hl kwd">mModified</span><span class="hl opt">(</span><span class="hl kwa">false</span><span class="hl opt">)</span>
 204         <span class="hl opt">,</span> <span class="hl kwd">mName</span><span class="hl opt">(</span>name<span class="hl opt">)</span>
 205         <span class="hl opt">,</span> <span class="hl kwd">mLength</span><span class="hl opt">(</span><span class="hl num">0</span><span class="hl opt">)</span>
 206         <span class="hl opt">,</span> <span class="hl kwd">mFlags</span><span class="hl opt">(</span><span class="hl num">0</span><span class="hl opt">)</span>
 207     <span class="hl opt">{}</span>
 208
 209     <span class="hl kwd">Data</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> <span class="hl kwb">int</span> l<span class="hl opt">,</span> uint f <span class="hl opt">=</span> <span class="hl num">0</span><span class="hl opt">)</span>
 210         <span class="hl opt">:</span> <span class="hl kwd">QSharedData</span><span class="hl opt">()</span>
 211         <span class="hl opt">,</span> <span class="hl kwd">mModified</span><span class="hl opt">(</span><span class="hl kwa">false</span><span class="hl opt">)</span>
 212         <span class="hl opt">,</span> <span class="hl kwd">mName</span><span class="hl opt">(</span>name<span class="hl opt">)</span>
 213         <span class="hl opt">,</span> <span class="hl kwd">mLength</span><span class="hl opt">(</span>l<span class="hl opt">)</span>
 214         <span class="hl opt">,</span> <span class="hl kwd">mFlags</span><span class="hl opt">(</span>f<span class="hl opt">)</span>
 215     <span class="hl opt">{}</span>
 216
 217     <span class="hl slc">/// Name of the password</span>
 218     QString <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> <span class="hl kwd">name</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mName<span class="hl opt">; }</span>
 219
 220     <span class="hl slc">/// Length of the generated password</span>
 221     <span class="hl kwb">int</span> <span class="hl kwd">length</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mLength<span class="hl opt">; }</span>
 222     <span class="hl kwb">void</span> <span class="hl kwd">setLength</span><span class="hl opt">(</span><span class="hl kwb">int</span> value<span class="hl opt">)</span>
 223     <span class="hl opt">{</span>
 224         <span class="hl kwa">if</span> <span class="hl opt">(</span>mLength <span class="hl opt">!=</span> value<span class="hl opt">) {</span>
 225             mLength <span class="hl opt">=</span> value<span class="hl opt">;</span>
 226             mModified <span class="hl opt">=</span> <span class="hl kwa">true</span><span class="hl opt">;</span>
 227         <span class="hl opt">}</span>
 228     <span class="hl opt">}</span>
 229
 230     <span class="hl slc">/// Optional flags for the password generator</span>
 231     uint <span class="hl kwd">flags</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mFlags<span class="hl opt">; }</span>
 232     <span class="hl kwb">void</span> <span class="hl kwd">setFlags</span><span class="hl opt">(</span>uint value<span class="hl opt">)</span>
 233     <span class="hl opt">{</span>
 234         <span class="hl kwa">if</span> <span class="hl opt">(</span>mFlags <span class="hl opt">!=</span> value<span class="hl opt">) {</span>
 235             mFlags <span class="hl opt">=</span> value<span class="hl opt">;</span>
 236             mModified <span class="hl opt">=</span> <span class="hl kwa">true</span><span class="hl opt">;</span>
 237         <span class="hl opt">}</span>
 238     <span class="hl opt">}</span>
 239
 240     <span class="hl slc">/// Flag indicating that some fields are modified</span>
 241     <span class="hl kwb">bool</span> <span class="hl kwd">modified</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mModified<span class="hl opt">; }</span>
 242
 243     <span class="hl slc">/// Resets the modified flag</span>
 244     <span class="hl kwb">void</span> <span class="hl kwd">reset</span><span class="hl opt">() {</span> mModified <span class="hl opt">=</span> <span class="hl kwa">false</span><span class="hl opt">; }</span>
 245
 246 <span class="hl kwc">private</span><span class="hl opt">:</span>
 247
 248     <span class="hl kwb">bool</span> mModified<span class="hl opt">;</span>
 249     QString mName<span class="hl opt">;</span>
 250     <span class="hl kwb">int</span> mLength<span class="hl opt">;</span>
 251     uint mFlags<span class="hl opt">;</span>
 252
 253 <span class="hl opt">};</span>
 254
 255 <span class="hl opt">}</span> <span class="hl slc">// eVaf::PswGen::Storage</span>
 256
 257 <span class="hl com">/// Password storage interface.</span>
 258 <span class="hl kwb">struct</span> iStorage
 259 <span class="hl opt">{</span>
 260
 261     <span class="hl com">/// Saves the data record</span>
 262     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</span> <span class="hl kwd">save</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> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> data<span class="hl opt">) =</span> <span class="hl num">0</span><span class="hl opt">;</span>
 263
 264     <span class="hl com">/// Returns a data record by the name</span>
 265     <span class="hl kwc">virtual</span> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> <span class="hl kwd">query</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> <span class="hl kwb">const</span> <span class="hl opt">=</span> <span class="hl num">0</span><span class="hl opt">;</span>
 266
 267     <span class="hl com">/// Returns an item model with the names of all the stored passwords</span>
 268     <span class="hl kwc">virtual</span> QAbstractItemModel <span class="hl opt">*</span> <span class="hl kwd">autoCompletionModel</span><span class="hl opt">() =</span> <span class="hl num">0</span><span class="hl opt">;</span>
 269
 270 <span class="hl opt">};</span>
 271
 272 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen</span>
 273 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf</span>
 274
 275 <span class="hl kwd">Q_DECLARE_INTERFACE</span><span class="hl opt">(</span>eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>iStorage<span class="hl opt">,</span> <span class="hl str">&quot;eVaf.PswGen.iStorage/1.0&quot;</span><span class="hl opt">)</span>
 276
 277 <span class="hl ppc">#endif</span> <span class="hl slc">// istorage.h</span><span class="hl ppc"></span></pre>
 278
 279     <p>We also create the <tt>iStorage</tt> file so that we can use <tt>#include &lt;Storage/iStorage&gt;</tt> in our other modules:</tt>
 280
 281     <pre class="hl"><span class="hl ppc">#include </span><span class="hl pps">&quot;istorage.h&quot;</span></pre>
 282
 283     <h3>Storage module</h3>
 284
 285     <p>The <tt>Storage<tt> module is simple enough to be derived directly from the <tt>Plugins::iPlugin</tt> interface and needs only one
 286     header/source file. In general, I personally prefer short source files and follow the <i>one-class-per-file</i> rule. Only when classes
 287     are very simple and closely related I put the into the same source file.</p>
 288
 289     <p>Create the <tt>module.h</tt> header file in the <tt>src/apps/PswGen/Storage</tt> directory. Include <tt>istorage.h</tt> and
 290     <tt>Plugins/iPlugin</tt> header files. We use the <tt>eVaf::PswGen::Storage</tt> namespace for public classes and
 291     <tt>eVaf::PswGen::Storage::Internal<tt> namespace for private classes.</p>
 292
 293     <pre class="hl"><span class="hl ppc">#ifndef __PSWGEN_STORAGE_MODULE_H</span>
 294 <span class="hl ppc">#  define __PSWGEN_STORAGE_MODULE_H</span>
 295
 296 <span class="hl ppc">#include</span> <span class="hl pps">&quot;istorage.h&quot;</span><span class="hl ppc"></span>
 297 <span class="hl ppc">#include &lt;Plugins/iPlugin&gt;</span>
 298
 299 <span class="hl kwa">namespace</span> eVaf <span class="hl opt">{</span>
 300 <span class="hl kwa">namespace</span> PswGen <span class="hl opt">{</span>
 301
 302 <span class="hl slc">/// Module that stores options for strong passwords</span>
 303 <span class="hl kwa">namespace</span> Storage <span class="hl opt">{</span>
 304
 305 <span class="hl slc">/// Internal implementation of the Storage module</span>
 306 <span class="hl kwa">namespace</span> Internal <span class="hl opt">{</span>
 307
 308 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen::Storage::Internal</span>
 309 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen::Storage</span>
 310 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen</span>
 311 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf</span>
 312 <span class="hl ppc">#endif</span> <span class="hl slc">// module.h</span><span class="hl ppc"></span></pre>
 313
 314     <p>We use the same name <tt>Module</tt> for the class that implements the module. This class is public and goes to the
 315     <tt>eVaf::PswGen::Storage</tt> namespace:</p>
 316
 317     <pre class="hl"><span class="hl kwc">class</span> Module <span class="hl opt">:</span> <span class="hl kwc">public</span> Plugins<span class="hl opt">::</span>iPlugin
 318 <span class="hl opt">{</span>
 319     Q_OBJECT
 320
 321 <span class="hl kwc">public</span><span class="hl opt">:</span>
 322
 323     <span class="hl kwd">Module</span><span class="hl opt">();</span>
 324
 325     <span class="hl kwc">virtual</span> <span class="hl opt">~</span><span class="hl kwd">Module</span><span class="hl opt">();</span>
 326
 327 <span class="hl opt">};</span></pre>
 328
 329     <p>Implement pure virtual methods in the <tt>iPlugin</tt> interface:</p>
 330
 331     <pre class="hl">
 332     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</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>
 333
 334     <span class="hl kwc">virtual</span> <span class="hl kwb">void</span> <span class="hl kwd">done</span><span class="hl opt">();</span>
 335
 336     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</span> <span class="hl kwd">isReady</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mReady<span class="hl opt">; }</span></pre>
 337
 338     <p>This module needs more complex initialization that the <tt>Generator</tt> module and we use the <tt>mReady</tt> flag to
 339     indicate that the module is fully initialized:</p>
 340
 341     <pre class="hl">
 342 <span class="hl kwc">private</span><span class="hl opt">:</span>
 343
 344     <span class="hl kwb">bool</span> mReady<span class="hl opt">;</span></pre>
 345
 346     <p>The <tt>StorageImpl</tt> class is the internal implementation of the <tt>iStorage</tt> interface:</p>
 347
 348     <pre class="hl">
 349     Internal<span class="hl opt">::</span>StorageImpl <span class="hl opt">*</span> mStorage<span class="hl opt">;</span></pre>
 350
 351     <p>We could declare the <tt>Internal::StorageImpl</tt> class before the <tt>Module</tt> class, but as I like starting with more
 352     generic (public) classes and then go into the details, we add a forward declaration to the beginning of the file:</p>
 353
 354     <pre class="hl">
 355 <span class="hl kwa">namespace</span> Internal <span class="hl opt">{</span>
 356     <span class="hl kwc">class</span> StorageImpl<span class="hl opt">;</span>
 357 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen::Storage::Internal</span></pre>
 358
 359     <p>The declaration of the <tt>StorageImpl</tt> class goes into the <tt>eVaf::PswGen::Storage::Internal</tt> namespace and the class
 360     shall be derived both from <tt>QObject</tt> and <tt>iStorage</tt>. However, since we also need to implement the
 361     <tt>QAbstractItemModel</tt> data model for the <tt>iStorage::autoCompletionModel()</tt> method, we derive it from the
 362     <tt>QAbstractListModel</tt> class instead. We use the <tt>QAbstractListModel</tt> class because it meets our requirements
 363     to return a list of auto completion words.</p>
 364
 365     <pre class="hl">
 366 <span class="hl kwa">namespace</span> Internal <span class="hl opt">{</span>
 367
 368 <span class="hl kwc">class</span> StorageImpl <span class="hl opt">:</span> <span class="hl kwc">public</span> QAbstractListModel<span class="hl opt">,</span> <span class="hl kwc">public</span> iStorage
 369 <span class="hl opt">{</span>
 370     Q_OBJECT
 371     <span class="hl kwd">Q_INTERFACES</span><span class="hl opt">(</span>eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>iStorage<span class="hl opt">)</span>
 372
 373 <span class="hl kwc">public</span><span class="hl opt">:</span>
 374
 375     <span class="hl kwd">StorageImpl</span><span class="hl opt">();</span>
 376
 377     <span class="hl kwc">virtual</span> <span class="hl opt">~</span><span class="hl kwd">StorageImpl</span><span class="hl opt">();</span>
 378
 379 <span class="hl opt">};</span>
 380
 381 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen::Storage::Internal</span></pre>
 382
 383     <p>First, we implement pure virtual methods found in the <tt>iStorage</tt> interface:</p>
 384
 385     <pre class="hl">
 386     <span class="hl com">/*</span>
 387         <span class="hl com">iStorage interface</span>
 388     <span class="hl com">*/</span>
 389
 390     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</span> <span class="hl kwd">save</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> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> data<span class="hl opt">);</span>
 391
 392     <span class="hl kwc">virtual</span> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> <span class="hl kwd">query</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> <span class="hl kwb">const</span><span class="hl opt">;</span>
 393
 394     <span class="hl kwc">virtual</span> QAbstractItemModel <span class="hl opt">*</span> <span class="hl kwd">autoCompletionModel</span><span class="hl opt">() {</span> <span class="hl kwa">return this</span><span class="hl opt">; }</span></pre>
 395
 396     <p>Since the <tt>QAbstractItemModel</tt> data model is implemented by the same class, we can simply return <tt>this</tt> in the
 397     <tt>autoCompletionModel()</tt> model.</p>
 398
 399     <p>The <tt>QAbstractListModel</tt> class also has pure virtual methods that need to be implemented:</p>
 400
 401     <pre class="hl">
 402     <span class="hl com">/*</span>
 403         <span class="hl com">QAbstractListModel methods</span>
 404     <span class="hl com">*/</span>
 405
 406     <span class="hl kwc">virtual</span> <span class="hl kwb">int</span> <span class="hl kwd">rowCount</span><span class="hl opt">(</span>QModelIndex <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> parent<span class="hl opt">)</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mData<span class="hl opt">.</span><span class="hl kwd">count</span><span class="hl opt">(); }</span>
 407
 408     <span class="hl kwc">virtual</span> QVariant <span class="hl kwd">data</span><span class="hl opt">(</span>QModelIndex <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> index<span class="hl opt">,</span> <span class="hl kwb">int</span> role <span class="hl opt">=</span> Qt<span class="hl opt">::</span>DisplayRole<span class="hl opt">)</span> <span class="hl kwb">const</span><span class="hl opt">;</span></pre>
 409
 410     <p><tt>mData</tt> here is a container with all the stored data objects, which we add to the <tt>private</tt> section. We use
 411     a <tt>QMap&lt;QString, QExplicitlySharedDataPointer&lt;Storage::Data&gt; &gt;</tt> for this purpose as it allows fast lookups
 412     by the name string.</p>
 413
 414     <pre class="hl">
 415 <span class="hl kwc">private</span><span class="hl opt">:</span>
 416
 417     QMap<span class="hl opt">&lt;</span>QString<span class="hl opt">,</span> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt; &gt;</span> mData<span class="hl opt">;</span></pre>
 418
 419     <p>Permanent data storage is done using a SQLITE database. We add the database object and a methods to load data from the database. We
 420     also need a method to create database tables if they do not exist yet:</p>
 421
 422     <pre class="hl">
 423     QSqlDatabase mDb<span class="hl opt">;</span>
 424
 425     <span class="hl kwb">bool</span> <span class="hl kwd">createTables</span><span class="hl opt">();</span>
 426
 427     <span class="hl kwb">bool</span> <span class="hl kwd">loadData</span><span class="hl opt">();</span></pre>
 428
 429     <p>The database object needs names for the connection and for the database, which we can add as constants to the class:</p>
 430
 431     <pre class="hl">
 432     <span class="hl kwb">static char const</span> <span class="hl opt">*</span> <span class="hl kwb">const</span> DbConnectionName<span class="hl opt">;</span>
 433
 434     <span class="hl kwb">static char const</span> <span class="hl opt">*</span> <span class="hl kwb">const</span> DbName<span class="hl opt">;</span></pre>
 435
 436     <p>The database needs to be opened and closed, and the list of data objects populated with data from the database. For this purpose
 437     we add <tt>init()</tt> and <tt>done()</tt> methods to the public section of the class. The <tt>init()</tt> method can return
 438     <tt>false</tt> if the initialization fails.</p>
 439
 440     <pre class="hl">
 441     <span class="hl kwb">bool</span> <span class="hl kwd">init</span><span class="hl opt">();</span>
 442
 443     <span class="hl kwb">void</span> <span class="hl kwd">done</span><span class="hl opt">();</span></pre>
 444
 445     <p>This is the final <tt>module.h</tt> file:</p>
 446
 447 <pre class="hl"><span class="hl com">/**</span>
 448 <span class="hl com"> * &#64;file PswGen/Storage/module.h</span>
 449 <span class="hl com"> */</span>
 450
 451 <span class="hl ppc">#ifndef __PSWGEN_STORAGE_MODULE_H</span>
 452 <span class="hl ppc">#  define __PSWGEN_STORAGE_MODULE_H</span>
 453
 454 <span class="hl ppc">#include</span> <span class="hl pps">&quot;istorage.h&quot;</span><span class="hl ppc"></span>
 455
 456 <span class="hl ppc">#include &lt;Plugins/iPlugin&gt;</span>
 457
 458 <span class="hl ppc">#include &lt;QObject&gt;</span>
 459 <span class="hl ppc">#include &lt;QString&gt;</span>
 460 <span class="hl ppc">#include &lt;QAbstractListModel&gt;</span>
 461 <span class="hl ppc">#include &lt;QMap&gt;</span>
 462 <span class="hl ppc">#include &lt;QtSql/QSqlDatabase&gt;</span>
 463
 464
 465 <span class="hl kwa">namespace</span> eVaf <span class="hl opt">{</span>
 466 <span class="hl kwa">namespace</span> PswGen <span class="hl opt">{</span>
 467
 468 <span class="hl slc">/// Module that stores options for strong passwords</span>
 469 <span class="hl kwa">namespace</span> Storage <span class="hl opt">{</span>
 470
 471 <span class="hl slc">/// Internal implementation of the Storage module</span>
 472 <span class="hl kwa">namespace</span> Internal <span class="hl opt">{</span>
 473     <span class="hl kwc">class</span> StorageImpl<span class="hl opt">;</span>
 474 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen::Storage::Internal</span>
 475
 476 <span class="hl com">/// Module implementing the iStorage interface.</span>
 477 <span class="hl kwc">class</span> Module <span class="hl opt">:</span> <span class="hl kwc">public</span> Plugins<span class="hl opt">::</span>iPlugin
 478 <span class="hl opt">{</span>
 479     Q_OBJECT
 480
 481 <span class="hl kwc">public</span><span class="hl opt">:</span>
 482
 483     <span class="hl kwd">Module</span><span class="hl opt">();</span>
 484
 485     <span class="hl kwc">virtual</span> <span class="hl opt">~</span><span class="hl kwd">Module</span><span class="hl opt">();</span>
 486
 487     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</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>
 488
 489     <span class="hl kwc">virtual</span> <span class="hl kwb">void</span> <span class="hl kwd">done</span><span class="hl opt">();</span>
 490
 491     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</span> <span class="hl kwd">isReady</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mReady<span class="hl opt">; }</span>
 492
 493
 494 <span class="hl kwc">private</span><span class="hl opt">:</span> <span class="hl slc">// Members</span>
 495
 496     <span class="hl slc">/// Flag indicating that the module is ready</span>
 497     <span class="hl kwb">bool</span> mReady<span class="hl opt">;</span>
 498
 499     <span class="hl slc">/// iStorage interface instance</span>
 500     Internal<span class="hl opt">::</span>StorageImpl <span class="hl opt">*</span> mStorage<span class="hl opt">;</span>
 501
 502 <span class="hl opt">};</span>
 503
 504 <span class="hl kwa">namespace</span> Internal <span class="hl opt">{</span>
 505
 506 <span class="hl com">/// iStorage interface implementation.</span>
 507 <span class="hl kwc">class</span> StorageImpl <span class="hl opt">:</span> <span class="hl kwc">public</span> QAbstractListModel<span class="hl opt">,</span> <span class="hl kwc">public</span> iStorage
 508 <span class="hl opt">{</span>
 509     Q_OBJECT
 510     <span class="hl kwd">Q_INTERFACES</span><span class="hl opt">(</span>eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>iStorage<span class="hl opt">)</span>
 511
 512 <span class="hl kwc">public</span><span class="hl opt">:</span>
 513
 514     <span class="hl kwd">StorageImpl</span><span class="hl opt">();</span>
 515
 516     <span class="hl kwc">virtual</span> <span class="hl opt">~</span><span class="hl kwd">StorageImpl</span><span class="hl opt">();</span>
 517
 518     <span class="hl kwb">bool</span> <span class="hl kwd">init</span><span class="hl opt">();</span>
 519
 520     <span class="hl kwb">void</span> <span class="hl kwd">done</span><span class="hl opt">();</span>
 521
 522     <span class="hl com">/*</span>
 523         <span class="hl com">iStorage interface</span>
 524     <span class="hl com">*/</span>
 525
 526     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</span> <span class="hl kwd">save</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> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> data<span class="hl opt">);</span>
 527
 528     <span class="hl kwc">virtual</span> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> <span class="hl kwd">query</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> <span class="hl kwb">const</span><span class="hl opt">;</span>
 529
 530     <span class="hl kwc">virtual</span> QAbstractItemModel <span class="hl opt">*</span> <span class="hl kwd">autoCompletionModel</span><span class="hl opt">() {</span> <span class="hl kwa">return this</span><span class="hl opt">; }</span>
 531
 532     <span class="hl com">/*</span>
 533         <span class="hl com">QAbstractListModel methods</span>
 534     <span class="hl com">*/</span>
 535
 536     <span class="hl kwc">virtual</span> <span class="hl kwb">int</span> <span class="hl kwd">rowCount</span><span class="hl opt">(</span>QModelIndex <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> parent<span class="hl opt">)</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mData<span class="hl opt">.</span><span class="hl kwd">count</span><span class="hl opt">(); }</span>
 537
 538     <span class="hl kwc">virtual</span> QVariant <span class="hl kwd">data</span><span class="hl opt">(</span>QModelIndex <span class="hl kwb">const</span> <span class="hl opt">&amp;</span> index<span class="hl opt">,</span> <span class="hl kwb">int</span> role <span class="hl opt">=</span> Qt<span class="hl opt">::</span>DisplayRole<span class="hl opt">)</span> <span class="hl kwb">const</span><span class="hl opt">;</span>
 539
 540 <span class="hl kwc">private</span><span class="hl opt">:</span> <span class="hl slc">// Members</span>
 541
 542     <span class="hl slc">/// Name of the database connection</span>
 543     <span class="hl kwb">static char const</span> <span class="hl opt">*</span> <span class="hl kwb">const</span> DbConnectionName<span class="hl opt">;</span>
 544
 545     <span class="hl slc">/// Name of the database file without path</span>
 546     <span class="hl kwb">static char const</span> <span class="hl opt">*</span> <span class="hl kwb">const</span> DbName<span class="hl opt">;</span>
 547
 548     <span class="hl slc">/// Database connection</span>
 549     QSqlDatabase mDb<span class="hl opt">;</span>
 550
 551     <span class="hl slc">/// List of name/data pairs</span>
 552     QMap<span class="hl opt">&lt;</span>QString<span class="hl opt">,</span> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt; &gt;</span> mData<span class="hl opt">;</span>
 553
 554
 555 <span class="hl kwc">private</span><span class="hl opt">:</span> <span class="hl slc">// Methods</span>
 556
 557     <span class="hl com">/// Creates database tables if necessary</span>
 558     <span class="hl kwb">bool</span> <span class="hl kwd">createTables</span><span class="hl opt">();</span>
 559
 560     <span class="hl com">/// Loads data from the database</span>
 561     <span class="hl kwb">bool</span> <span class="hl kwd">loadData</span><span class="hl opt">();</span>
 562
 563 <span class="hl opt">};</span>
 564
 565 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen::Storage::Internal</span>
 566 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen::Storage</span>
 567 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen</span>
 568 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf</span>
 569
 570 <span class="hl ppc">#endif</span> <span class="hl slc">// module.h</span><span class="hl ppc"></span></pre>
 571
 572     <p>Continue implementing the <a href="pswgen07.html">Storage Module</a>.</p>
 573
 574     </body>
 575 </html>