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  16     <p>Next: <a href="pswgen08.html">08 - Building Storage Module</a>, Previous: <a href="pswgen06.html">06 - Storage Module</a></p>
  17
  18         <h1>eVaf Tutorial</h1>
  19
  20         <h2>07 - Storage Module</h2>
  21
  22         <p>Create the <tt>module.cpp</tt> file in the <tt>src/apps/PswGen/Storage</tt> directory:</tt>
  23
  24         <pre class="hl"><span class="hl com">/**</span>
  25 <span class="hl com"> * &#64;file PswGen/Storage/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 <span class="hl ppc">#include &lt;QtCore&gt;</span></pre>
  30
  31         <p>Copy version information files from the <tt>Generator</tt> module:</p>
  32
  33         <pre>evaf/src/apps/PswGen/Storage $ <code>cp ../Generator/version.{h,rc} .</code></pre>
  34
  35         <p>Modify the <tt>version.h</tt> file:</p>
  36
  37         <pre class="hl"><span class="hl com">/**</span>
  38 <span class="hl com"> * &#64;file PswGen/Storage/version.h</span>
  39 <span class="hl com"> */</span>
  40
  41 <span class="hl ppc">#ifndef __PSWGEN_STORAGE_VERSION_H</span>
  42 <span class="hl ppc">#define   __PSWGEN_STORAGE_VERSION_H</span>
  43
  44 <span class="hl ppc">#include &lt;version_rc.h&gt;</span>
  45
  46 <span class="hl com">/**</span>
  47 <span class="hl com"> * Module/library version number in the form major,minor,release,build</span>
  48 <span class="hl com"> */</span>
  49 <span class="hl ppc">#define VER_FILE_VERSION                0,1,1,1</span>
  50
  51 <span class="hl com">/**</span>
  52 <span class="hl com"> * Module/library version number in the string format (shall end with \0)</span>
  53 <span class="hl com"> */</span>
  54 <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>
  55
  56 <span class="hl com">/**</span>
  57 <span class="hl com"> * Module/library name (shall end with \0)</span>
  58 <span class="hl com"> */</span>
  59 <span class="hl ppc">#define VER_MODULE_NAME_STR</span>             <span class="hl pps">&quot;PswStorage\0&quot;</span><span class="hl ppc"></span>
  60
  61 <span class="hl com">/**</span>
  62 <span class="hl com"> * Module type (see version_rc.h for all the types)</span>
  63 <span class="hl com"> */</span>
  64 <span class="hl ppc">#define VER_MODULE_TYPE                 MT_GENERIC</span>
  65
  66 <span class="hl com">/**</span>
  67 <span class="hl com"> * Module type in the string format (see version_rc for all the types)</span>
  68 <span class="hl com"> */</span>
  69 <span class="hl ppc">#define VER_MODULE_TYPE_STR             MT_GENERIC</span>
  70
  71 <span class="hl com">/**</span>
  72 <span class="hl com"> * Original file name for windows (shall end with \0)</span>
  73 <span class="hl com"> */</span>
  74 <span class="hl ppc">#define VER_ORIGINAL_FILE_NAME_STR</span>      <span class="hl pps">&quot;PswStorage.dll\0&quot;</span><span class="hl ppc"></span>
  75
  76 <span class="hl com">/**</span>
  77 <span class="hl com"> * Description of the module/library (shall end with \0)</span>
  78 <span class="hl com"> */</span>
  79 <span class="hl ppc">#define VER_FILE_DESCRIPTION_STR</span>         <span class="hl pps">&quot;Module that stores data for generating strong passwords.\0&quot;</span><span class="hl ppc"></span>
  80
  81 <span class="hl ppc">#endif</span> <span class="hl slc">// version.h</span><span class="hl ppc"></span></pre>
  82
  83         <p>Include the <tt>version.h</tt> header file in <tt>module.cpp</tt> and export version information:</p>
  84
  85         <pre class="hl">
  86 <span class="hl ppc">#include</span> <span class="hl pps">&quot;version.h&quot;</span><span class="hl ppc"></span>
  87
  88 <span class="hl kwd">VER_EXPORT_VERSION_INFO</span><span class="hl opt">()</span></pre>
  89
  90         <p>Make it a proper Qt plugin by using the <tt>Q_EXPORT_PLUGIN2()</tt> macro:</p>
  91
  92         <pre class="hl"><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>Storage<span class="hl opt">::</span>Module<span class="hl opt">)</span></pre>
  93
  94         <p>The <tt>Module</tt> class creates the internal <tt>StorageImpl</tt> object in the constructor, but initializes it in the
  95         <tt>init()</tt> method. This way we can return errors from the module if initialization fails. Similarly, we finalize the
  96         internal <tt>StorageImpl</tt> object in the <tt>done()</tt> method and delete in the destructor.</p>
  97
  98         <p>The module is ready when the internal <tt>StorageImpl</tt> object is initalized and we set the <tt>mReady</tt> flag to
  99         <tt>true</tt> when the initialization is done and back to <tt>false</tt> in the <tt>done()</tt> method.</p>
 100
 101         <p>The rest of the code sets the name of the object and outputs info messages.</p>
 102
 103         <pre class="hl">Module<span class="hl opt">::</span><span class="hl kwd">Module</span><span class="hl opt">()</span>
 104     <span class="hl opt">:</span> Plugins<span class="hl opt">::</span><span class="hl kwd">iPlugin</span><span class="hl opt">()</span>
 105     <span class="hl opt">,</span> <span class="hl kwd">mReady</span><span class="hl opt">(</span><span class="hl kwa">false</span><span class="hl opt">)</span>
 106 <span class="hl opt">{</span>
 107     <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>
 108
 109     mStorage <span class="hl opt">=</span> <span class="hl kwa">new</span> Internal<span class="hl opt">::</span>StorageImpl<span class="hl opt">;</span>
 110
 111     <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>
 112 <span class="hl opt">}</span>
 113
 114 Module<span class="hl opt">::~</span><span class="hl kwd">Module</span><span class="hl opt">()</span>
 115 <span class="hl opt">{</span>
 116     <span class="hl kwa">delete</span> mStorage<span class="hl opt">;</span>
 117
 118     <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>
 119 <span class="hl opt">}</span>
 120
 121 <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>
 122 <span class="hl opt">{</span>
 123     <span class="hl kwd">Q_UNUSED</span><span class="hl opt">(</span>args<span class="hl opt">);</span>
 124
 125     <span class="hl kwa">if</span> <span class="hl opt">(!</span>mStorage<span class="hl opt">-&gt;</span><span class="hl kwd">init</span><span class="hl opt">())</span>
 126         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 127
 128     mReady <span class="hl opt">=</span> <span class="hl kwa">true</span><span class="hl opt">;</span>
 129
 130     <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>
 131
 132     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 133 <span class="hl opt">}</span>
 134
 135 <span class="hl kwb">void</span> Module<span class="hl opt">::</span><span class="hl kwd">done</span><span class="hl opt">()</span>
 136 <span class="hl opt">{</span>
 137     mReady <span class="hl opt">=</span> <span class="hl kwa">false</span><span class="hl opt">;</span>
 138
 139     mStorage<span class="hl opt">-&gt;</span><span class="hl kwd">done</span><span class="hl opt">();</span>
 140
 141     <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>
 142 <span class="hl opt">}</span></pre>
 143
 144         <p>The <tt>StorageImpl</tt> class does very little in the constructor and in the destructor:</p>
 145
 146         <pre class="hl">StorageImpl<span class="hl opt">::</span><span class="hl kwd">StorageImpl</span><span class="hl opt">()</span>
 147     <span class="hl opt">:</span> <span class="hl kwd">QAbstractListModel</span><span class="hl opt">()</span>
 148 <span class="hl opt">{</span>
 149     <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>
 150
 151     <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>
 152 <span class="hl opt">}</span>
 153
 154 StorageImpl<span class="hl opt">::~</span><span class="hl kwd">StorageImpl</span><span class="hl opt">()</span>
 155 <span class="hl opt">{</span>
 156     <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>
 157 <span class="hl opt">}</span></pre>
 158
 159         <p>Initialization of the <tt>StorageImpl</tt> class happens in the <tt>init()</tt> method, where we open the database connection,
 160         create tables if necessary and load data from the database. We also register the <tt>iStorage</tt> interface in the global
 161         registry of interfaces.</p>
 162
 163         <p>We use the <tt>Common::iApp</tt> interface to find the data root directory where the SQLITE database file is going to be
 164         located.</p>
 165
 166         <pre class="hl"><span class="hl kwb">bool</span> StorageImpl<span class="hl opt">::</span><span class="hl kwd">init</span><span class="hl opt">()</span>
 167 <span class="hl opt">{</span>
 168     <span class="hl slc">// Open the database</span>
 169     <span class="hl kwa">if</span> <span class="hl opt">(!</span>QSqlDatabase<span class="hl opt">::</span><span class="hl kwd">contains</span><span class="hl opt">(</span>DbConnectionName<span class="hl opt">)) {</span>
 170         <span class="hl slc">// No database connection yet</span>
 171         mDb <span class="hl opt">=</span> QSqlDatabase<span class="hl opt">::</span><span class="hl kwd">addDatabase</span><span class="hl opt">(</span><span class="hl str">&quot;QSQLITE&quot;</span><span class="hl opt">,</span> DbConnectionName<span class="hl opt">);</span>
 172         mDb<span class="hl opt">.</span><span class="hl kwd">setDatabaseName</span><span class="hl opt">(</span>Common<span class="hl opt">::</span>iApp<span class="hl opt">::</span><span class="hl kwd">instance</span><span class="hl opt">()-&gt;</span><span class="hl kwd">dataRootDir</span><span class="hl opt">() +</span> DbName<span class="hl opt">);</span>
 173         <span class="hl kwa">if</span> <span class="hl opt">(!</span>mDb<span class="hl opt">.</span><span class="hl kwd">open</span><span class="hl opt">()) {</span>
 174             QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 175             <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to open database : %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 176             <span class="hl kwa">return false</span><span class="hl opt">;</span>
 177         <span class="hl opt">}</span>
 178     <span class="hl opt">}</span>
 179     <span class="hl kwa">else</span> <span class="hl opt">{</span>
 180         <span class="hl slc">// Database connection already exists</span>
 181         mDb <span class="hl opt">=</span> QSqlDatabase<span class="hl opt">::</span><span class="hl kwd">database</span><span class="hl opt">(</span>DbConnectionName<span class="hl opt">);</span>
 182     <span class="hl opt">}</span>
 183
 184     <span class="hl slc">// Create tables if necessary</span>
 185     <span class="hl kwa">if</span> <span class="hl opt">(!</span><span class="hl kwd">createTables</span><span class="hl opt">())</span>
 186         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 187
 188     <span class="hl slc">// Load data</span>
 189     <span class="hl kwa">if</span> <span class="hl opt">(!</span><span class="hl kwd">loadData</span><span class="hl opt">())</span>
 190         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 191
 192     <span class="hl slc">/// Register our interface</span>
 193     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;iStorage&quot;</span><span class="hl opt">,</span> <span class="hl kwa">this</span><span class="hl opt">);</span>
 194
 195     <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>
 196
 197     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 198 <span class="hl opt">}</span></pre>
 199
 200         <p>The finalization of the <tt>StorageImpl</tt> class happens in the <tt>done()</tt> method, where we only need to clear the list
 201         of shared data objects:</p>
 202
 203         <pre class="hl"><span class="hl kwb">void</span> StorageImpl<span class="hl opt">::</span><span class="hl kwd">done</span><span class="hl opt">()</span>
 204 <span class="hl opt">{</span>
 205     mData<span class="hl opt">.</span><span class="hl kwd">clear</span><span class="hl opt">();</span>
 206     <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>
 207 <span class="hl opt">}</span></pre>
 208
 209         <p>The <tt>StorageImpl::save()</tt> method verifies that the shared data object is valid and the name not empty. Then it either
 210         adds a new data record to the database or updates an existing one.</p>
 211
 212         <pre class="hl"><span class="hl kwb">bool</span> StorageImpl<span class="hl opt">::</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>
 213 <span class="hl opt">{</span>
 214     <span class="hl kwd">EVAF_TEST_X</span><span class="hl opt">(</span>data<span class="hl opt">,</span> <span class="hl str">&quot;Data cannot be null&quot;</span><span class="hl opt">);</span>
 215     <span class="hl kwd">EVAF_TEST_X</span><span class="hl opt">(!</span>name<span class="hl opt">.</span><span class="hl kwd">isEmpty</span><span class="hl opt">(),</span> <span class="hl str">&quot;Name cannot be empty&quot;</span><span class="hl opt">);</span>
 216
 217     <span class="hl slc">// Is it an update or a new data record?</span>
 218     <span class="hl kwa">if</span> <span class="hl opt">(</span>mData<span class="hl opt">.</span><span class="hl kwd">constFind</span><span class="hl opt">(</span>name<span class="hl opt">) !=</span> mData<span class="hl opt">.</span><span class="hl kwd">constEnd</span><span class="hl opt">()) {</span>
 219         <span class="hl slc">// This is an update</span>
 220         <span class="hl kwa">if</span> <span class="hl opt">(</span>data<span class="hl opt">-&gt;</span><span class="hl kwd">modified</span><span class="hl opt">()) {</span>
 221             QSqlQuery <span class="hl kwd">q</span><span class="hl opt">(</span>mDb<span class="hl opt">);</span>
 222             <span class="hl kwa">if</span> <span class="hl opt">(!</span>q<span class="hl opt">.</span><span class="hl kwd">exec</span><span class="hl opt">(</span><span class="hl kwd">QString</span><span class="hl opt">(</span><span class="hl str">&quot;UPDATE data SET length =</span> <span class="hl esc">\'</span><span class="hl str">%1</span><span class="hl esc">\'</span><span class="hl str">, flags =</span> <span class="hl esc">\'</span><span class="hl str">%2</span><span class="hl esc">\'</span> <span class="hl str">WHERE name =</span> <span class="hl esc">\'</span><span class="hl str">%3</span><span class="hl esc">\'</span><span class="hl str">;&quot;</span><span class="hl opt">)</span>
 223                             <span class="hl opt">.</span><span class="hl kwd">arg</span><span class="hl opt">(</span>data<span class="hl opt">-&gt;</span><span class="hl kwd">length</span><span class="hl opt">()).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>data<span class="hl opt">-&gt;</span><span class="hl kwd">flags</span><span class="hl opt">()).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>name<span class="hl opt">))) {</span>
 224                 QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 225                 <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to update</span> <span class="hl esc">\'</span><span class="hl str">%s</span><span class="hl esc">\'</span> <span class="hl str">: %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>name<span class="hl opt">),</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 226                 <span class="hl kwa">return false</span><span class="hl opt">;</span>
 227             <span class="hl opt">}</span>
 228         <span class="hl opt">}</span>
 229     <span class="hl opt">}</span>
 230     <span class="hl kwa">else</span> <span class="hl opt">{</span>
 231         <span class="hl slc">// Store to the database</span>
 232         QSqlQuery <span class="hl kwd">q</span><span class="hl opt">(</span>mDb<span class="hl opt">);</span>
 233         <span class="hl kwa">if</span> <span class="hl opt">(!</span>q<span class="hl opt">.</span><span class="hl kwd">exec</span><span class="hl opt">(</span><span class="hl kwd">QString</span><span class="hl opt">(</span><span class="hl str">&quot;INSERT INTO data (name, length, flags) VALUES (</span><span class="hl esc">\'</span><span class="hl str">%1</span><span class="hl esc">\'</span><span class="hl str">, %2, %3);&quot;</span><span class="hl opt">)</span>
 234                             <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>data<span class="hl opt">-&gt;</span><span class="hl kwd">length</span><span class="hl opt">())</span>
 235                             <span class="hl opt">.</span><span class="hl kwd">arg</span><span class="hl opt">(</span><span class="hl kwb">int</span><span class="hl opt">(</span>data<span class="hl opt">-&gt;</span><span class="hl kwd">flags</span><span class="hl opt">())))) {</span>
 236             QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 237             <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to insert</span> <span class="hl esc">\'</span><span class="hl str">%s</span><span class="hl esc">\'</span> <span class="hl str">: %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>name<span class="hl opt">),</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 238             <span class="hl kwa">return false</span><span class="hl opt">;</span>
 239         <span class="hl opt">}</span>
 240
 241         <span class="hl slc">// Store also into the local hash</span>
 242         mData<span class="hl opt">.</span><span class="hl kwd">insert</span><span class="hl opt">(</span>name<span class="hl opt">,</span> data<span class="hl opt">);</span>
 243
 244         <span class="hl slc">// Reset the model</span>
 245         <span class="hl kwd">reset</span><span class="hl opt">();</span>
 246     <span class="hl opt">}</span>
 247
 248     data<span class="hl opt">-&gt;</span><span class="hl kwd">reset</span><span class="hl opt">();</span>
 249
 250     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 251 <span class="hl opt">}</span></pre>
 252
 253         <p>Calling the <tt>reset()</tt> method resets the <tt>QAbstractItemModel</tt> data model and assures that the associated widget
 254         updates the <tt>QCompleter</tt> with a fresh list of auto completion words. Resetting the data model in this case is fine as
 255         long as the data model is simple and the list short. The proper way would be finding out the actual insertion point and using
 256         <tt>beginInsertRows()</tt> and <tt>endInsertRows()</tt> methods.</p>
 257
 258         <p>Querying data is much simpler thanks to the internal <tt>QMap</tt> container:</p>
 259
 260         <pre class="hl">QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> StorageImpl<span class="hl opt">::</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>
 261 <span class="hl opt">{</span>
 262     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>const_iterator it <span class="hl opt">=</span> mData<span class="hl opt">.</span><span class="hl kwd">constFind</span><span class="hl opt">(</span>name<span class="hl opt">);</span>
 263     <span class="hl kwa">if</span> <span class="hl opt">(</span>it <span class="hl opt">!=</span> mData<span class="hl opt">.</span><span class="hl kwd">constEnd</span><span class="hl opt">())</span>
 264         <span class="hl kwa">return</span> it<span class="hl opt">.</span><span class="hl kwd">value</span><span class="hl opt">();</span>
 265     <span class="hl kwa">else</span>
 266         <span class="hl kwa">return</span> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;();</span>
 267 <span class="hl opt">}</span></pre>
 268
 269         <p>We return an empty <tt>QExplicitlySharedDataPointer</tt> object if no data objects with the given name exists.</p>
 270
 271         <p>The <tt>data()</tt> method returns names of data objects for the <tt>QCompleter</tt> auto completion list of words:</p>
 272
 273         <pre class="hl">QVariant StorageImpl<span class="hl opt">::</span><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> <span class="hl kwb">const</span>
 274 <span class="hl opt">{</span>
 275     <span class="hl kwa">if</span> <span class="hl opt">(!</span>index<span class="hl opt">.</span><span class="hl kwd">isValid</span><span class="hl opt">() ||</span> index<span class="hl opt">.</span><span class="hl kwd">row</span><span class="hl opt">() &lt;</span> <span class="hl num">0</span> <span class="hl opt">||</span> index<span class="hl opt">.</span><span class="hl kwd">row</span><span class="hl opt">() &gt;=</span> mData<span class="hl opt">.</span><span class="hl kwd">size</span><span class="hl opt">() ||</span> index<span class="hl opt">.</span><span class="hl kwd">column</span><span class="hl opt">() !=</span> <span class="hl num">0</span><span class="hl opt">)</span>
 276         <span class="hl kwa">return</span> <span class="hl kwd">QVariant</span><span class="hl opt">();</span>
 277
 278     <span class="hl kwa">if</span> <span class="hl opt">(</span>role <span class="hl opt">==</span> Qt<span class="hl opt">::</span>EditRole <span class="hl opt">||</span> role <span class="hl opt">==</span> Qt<span class="hl opt">::</span>DisplayRole<span class="hl opt">)</span>
 279         <span class="hl kwa">return</span> mData<span class="hl opt">.</span><span class="hl kwd">keys</span><span class="hl opt">().</span><span class="hl kwd">at</span><span class="hl opt">(</span>index<span class="hl opt">.</span><span class="hl kwd">row</span><span class="hl opt">());</span>
 280
 281     <span class="hl kwa">return</span> <span class="hl kwd">QVariant</span><span class="hl opt">();</span>
 282 <span class="hl opt">}</span></pre>
 283
 284         <p>The <tt>createTabled()</tt> method creates the <tt>data</tt> table if it does not exist. This function could be improved to
 285         alter the <tt>data</tt> table if it exists, but is from an older version. Right now we assume that if the table exists, it
 286         is good for our application:</p>
 287
 288         <pre class="hl"><span class="hl kwb">bool</span> StorageImpl<span class="hl opt">::</span><span class="hl kwd">createTables</span><span class="hl opt">()</span>
 289 <span class="hl opt">{</span>
 290     QSqlQuery <span class="hl kwd">q</span><span class="hl opt">(</span>mDb<span class="hl opt">);</span>
 291     <span class="hl kwa">if</span> <span class="hl opt">(!</span>q<span class="hl opt">.</span><span class="hl kwd">exec</span><span class="hl opt">(</span><span class="hl str">&quot;SELECT name FROM sqlite_master WHERE type=</span><span class="hl esc">\'</span><span class="hl str">table</span><span class="hl esc">\'</span> <span class="hl str">AND name=</span><span class="hl esc">\'</span><span class="hl str">data</span><span class="hl esc">\'</span><span class="hl str">;&quot;</span><span class="hl opt">)) {</span>
 292         QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 293         <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to query database : %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 294         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 295     <span class="hl opt">}</span>
 296
 297     <span class="hl kwa">if</span> <span class="hl opt">(</span>q<span class="hl opt">.</span><span class="hl kwd">isActive</span><span class="hl opt">() &amp;&amp;</span> q<span class="hl opt">.</span><span class="hl kwd">isSelect</span><span class="hl opt">() &amp;&amp;</span> q<span class="hl opt">.</span><span class="hl kwd">first</span><span class="hl opt">())</span>
 298         <span class="hl kwa">return true</span><span class="hl opt">;</span> <span class="hl slc">// We already have a table called 'data'</span>
 299
 300     <span class="hl slc">// Create the 'data' table</span>
 301     <span class="hl kwa">if</span> <span class="hl opt">(!</span>q<span class="hl opt">.</span><span class="hl kwd">exec</span><span class="hl opt">(</span><span class="hl str">&quot;CREATE TABLE data (name text primary key not null, length integer, flags integer);&quot;</span><span class="hl opt">)) {</span>
 302         QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 303         <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to create table</span> <span class="hl esc">\'</span><span class="hl str">data</span><span class="hl esc">\'</span> <span class="hl str">: %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 304         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 305     <span class="hl opt">}</span>
 306
 307     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 308 <span class="hl opt">}</span></pre>
 309
 310         <p>Finally, the <tt>loadData()</tt> method loads all the data records from the database to the memory:</p>
 311
 312         <pre class="hl"><span class="hl kwb">bool</span> StorageImpl<span class="hl opt">::</span><span class="hl kwd">loadData</span><span class="hl opt">()</span>
 313 <span class="hl opt">{</span>
 314     QSqlQuery <span class="hl kwd">q</span><span class="hl opt">(</span>mDb<span class="hl opt">);</span>
 315     <span class="hl kwa">if</span> <span class="hl opt">(!</span>q<span class="hl opt">.</span><span class="hl kwd">exec</span><span class="hl opt">(</span><span class="hl str">&quot;SELECT name, length, flags FROM data;&quot;</span><span class="hl opt">)) {</span>
 316         QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 317         <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to query database : %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 318         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 319     <span class="hl opt">}</span>
 320
 321     <span class="hl kwa">while</span> <span class="hl opt">(</span>q<span class="hl opt">.</span><span class="hl kwd">next</span><span class="hl opt">()) {</span>
 322         QString name <span class="hl opt">=</span> q<span class="hl opt">.</span><span class="hl kwd">value</span><span class="hl opt">(</span><span class="hl num">0</span><span class="hl opt">).</span><span class="hl kwd">toString</span><span class="hl opt">();</span>
 323         QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> <span class="hl kwd">data</span><span class="hl opt">(</span><span class="hl kwa">new</span> Storage<span class="hl opt">::</span><span class="hl kwd">Data</span><span class="hl opt">(</span>name<span class="hl opt">,</span> q<span class="hl opt">.</span><span class="hl kwd">value</span><span class="hl opt">(</span><span class="hl num">1</span><span class="hl opt">).</span><span class="hl kwd">toInt</span><span class="hl opt">(),</span> <span class="hl kwd">uint</span><span class="hl opt">(</span>q<span class="hl opt">.</span><span class="hl kwd">value</span><span class="hl opt">(</span><span class="hl num">2</span><span class="hl opt">).</span><span class="hl kwd">toInt</span><span class="hl opt">())));</span>
 324         mData<span class="hl opt">.</span><span class="hl kwd">insert</span><span class="hl opt">(</span>name<span class="hl opt">,</span> data<span class="hl opt">);</span>
 325     <span class="hl opt">}</span>
 326
 327     <span class="hl kwd">reset</span><span class="hl opt">();</span>
 328
 329     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 330 <span class="hl opt">}</span></pre>
 331
 332         <p>Resetting the <tt>QAbstractItemModel</tt> data model here is ok, becase before loading any data the model is supposed to be
 333         empty.</p>
 334
 335         <p>Here is the complete <tt>module.cpp</tt> file:
 336
 337         <pre class="hl"><span class="hl com">/**</span>
 338 <span class="hl com"> * &#64;file PswGen/Storage/module.cpp</span>
 339 <span class="hl com"> */</span>
 340
 341 <span class="hl ppc">#include</span> <span class="hl pps">&quot;module.h&quot;</span><span class="hl ppc"></span>
 342 <span class="hl ppc">#include</span> <span class="hl pps">&quot;version.h&quot;</span><span class="hl ppc"></span>
 343
 344 <span class="hl ppc">#include &lt;Common/Globals&gt;</span>
 345 <span class="hl ppc">#include &lt;Common/iLogger&gt;</span>
 346 <span class="hl ppc">#include &lt;Common/iRegistry&gt;</span>
 347 <span class="hl ppc">#include &lt;Common/iApp&gt;</span>
 348
 349 <span class="hl ppc">#include &lt;QtCore&gt;</span>
 350 <span class="hl ppc">#include &lt;QtSql/QtSql&gt;</span>
 351
 352 <span class="hl kwd">VER_EXPORT_VERSION_INFO</span><span class="hl opt">()</span>
 353 <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>Storage<span class="hl opt">::</span>Module<span class="hl opt">)</span>
 354
 355 <span class="hl kwa">using namespace</span> eVaf<span class="hl opt">;</span>
 356 <span class="hl kwa">using namespace</span> eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">;</span>
 357 <span class="hl kwa">using namespace</span> eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>Storage<span class="hl opt">;</span>
 358
 359 Module<span class="hl opt">::</span><span class="hl kwd">Module</span><span class="hl opt">()</span>
 360     <span class="hl opt">:</span> Plugins<span class="hl opt">::</span><span class="hl kwd">iPlugin</span><span class="hl opt">()</span>
 361     <span class="hl opt">,</span> <span class="hl kwd">mReady</span><span class="hl opt">(</span><span class="hl kwa">false</span><span class="hl opt">)</span>
 362 <span class="hl opt">{</span>
 363     <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>
 364
 365     mStorage <span class="hl opt">=</span> <span class="hl kwa">new</span> Internal<span class="hl opt">::</span>StorageImpl<span class="hl opt">;</span>
 366
 367     <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>
 368 <span class="hl opt">}</span>
 369
 370 Module<span class="hl opt">::~</span><span class="hl kwd">Module</span><span class="hl opt">()</span>
 371 <span class="hl opt">{</span>
 372     <span class="hl kwa">delete</span> mStorage<span class="hl opt">;</span>
 373
 374     <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>
 375 <span class="hl opt">}</span>
 376
 377 <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>
 378 <span class="hl opt">{</span>
 379     <span class="hl kwd">Q_UNUSED</span><span class="hl opt">(</span>args<span class="hl opt">);</span>
 380
 381     <span class="hl kwa">if</span> <span class="hl opt">(!</span>mStorage<span class="hl opt">-&gt;</span><span class="hl kwd">init</span><span class="hl opt">())</span>
 382         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 383
 384     mReady <span class="hl opt">=</span> <span class="hl kwa">true</span><span class="hl opt">;</span>
 385
 386     <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>
 387
 388     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 389 <span class="hl opt">}</span>
 390
 391 <span class="hl kwb">void</span> Module<span class="hl opt">::</span><span class="hl kwd">done</span><span class="hl opt">()</span>
 392 <span class="hl opt">{</span>
 393     mReady <span class="hl opt">=</span> <span class="hl kwa">false</span><span class="hl opt">;</span>
 394
 395     mStorage<span class="hl opt">-&gt;</span><span class="hl kwd">done</span><span class="hl opt">();</span>
 396
 397     <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>
 398 <span class="hl opt">}</span>
 399
 400 <span class="hl kwa">using namespace</span> eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>Storage<span class="hl opt">::</span>Internal<span class="hl opt">;</span>
 401
 402 <span class="hl kwb">char const</span> <span class="hl opt">*</span> <span class="hl kwb">const</span> StorageImpl<span class="hl opt">::</span>DbConnectionName <span class="hl opt">=</span> <span class="hl str">&quot;PswGenDB&quot;</span><span class="hl opt">;</span>
 403
 404 <span class="hl kwb">char const</span> <span class="hl opt">*</span> <span class="hl kwb">const</span> StorageImpl<span class="hl opt">::</span>DbName <span class="hl opt">=</span> <span class="hl str">&quot;PswGen.sqlite&quot;</span><span class="hl opt">;</span>
 405
 406 StorageImpl<span class="hl opt">::</span><span class="hl kwd">StorageImpl</span><span class="hl opt">()</span>
 407     <span class="hl opt">:</span> <span class="hl kwd">QAbstractListModel</span><span class="hl opt">()</span>
 408 <span class="hl opt">{</span>
 409     <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>
 410
 411     <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>
 412 <span class="hl opt">}</span>
 413
 414 StorageImpl<span class="hl opt">::~</span><span class="hl kwd">StorageImpl</span><span class="hl opt">()</span>
 415 <span class="hl opt">{</span>
 416     <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>
 417 <span class="hl opt">}</span>
 418
 419 <span class="hl kwb">bool</span> StorageImpl<span class="hl opt">::</span><span class="hl kwd">init</span><span class="hl opt">()</span>
 420 <span class="hl opt">{</span>
 421     <span class="hl slc">// Open the database</span>
 422     <span class="hl kwa">if</span> <span class="hl opt">(!</span>QSqlDatabase<span class="hl opt">::</span><span class="hl kwd">contains</span><span class="hl opt">(</span>DbConnectionName<span class="hl opt">)) {</span>
 423         <span class="hl slc">// No database connection yet</span>
 424         mDb <span class="hl opt">=</span> QSqlDatabase<span class="hl opt">::</span><span class="hl kwd">addDatabase</span><span class="hl opt">(</span><span class="hl str">&quot;QSQLITE&quot;</span><span class="hl opt">,</span> DbConnectionName<span class="hl opt">);</span>
 425         mDb<span class="hl opt">.</span><span class="hl kwd">setDatabaseName</span><span class="hl opt">(</span>Common<span class="hl opt">::</span>iApp<span class="hl opt">::</span><span class="hl kwd">instance</span><span class="hl opt">()-&gt;</span><span class="hl kwd">dataRootDir</span><span class="hl opt">() +</span> DbName<span class="hl opt">);</span>
 426         <span class="hl kwa">if</span> <span class="hl opt">(!</span>mDb<span class="hl opt">.</span><span class="hl kwd">open</span><span class="hl opt">()) {</span>
 427             QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 428             <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to open database : %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 429             <span class="hl kwa">return false</span><span class="hl opt">;</span>
 430         <span class="hl opt">}</span>
 431     <span class="hl opt">}</span>
 432     <span class="hl kwa">else</span> <span class="hl opt">{</span>
 433         <span class="hl slc">// Database connection already exists</span>
 434         mDb <span class="hl opt">=</span> QSqlDatabase<span class="hl opt">::</span><span class="hl kwd">database</span><span class="hl opt">(</span>DbConnectionName<span class="hl opt">);</span>
 435     <span class="hl opt">}</span>
 436
 437     <span class="hl slc">// Create tables if necessary</span>
 438     <span class="hl kwa">if</span> <span class="hl opt">(!</span><span class="hl kwd">createTables</span><span class="hl opt">())</span>
 439         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 440
 441     <span class="hl slc">// Load data</span>
 442     <span class="hl kwa">if</span> <span class="hl opt">(!</span><span class="hl kwd">loadData</span><span class="hl opt">())</span>
 443         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 444
 445     <span class="hl slc">/// Register our interface</span>
 446     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;iStorage&quot;</span><span class="hl opt">,</span> <span class="hl kwa">this</span><span class="hl opt">);</span>
 447
 448     <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>
 449
 450     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 451 <span class="hl opt">}</span>
 452
 453 <span class="hl kwb">void</span> StorageImpl<span class="hl opt">::</span><span class="hl kwd">done</span><span class="hl opt">()</span>
 454 <span class="hl opt">{</span>
 455     mData<span class="hl opt">.</span><span class="hl kwd">clear</span><span class="hl opt">();</span>
 456     <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>
 457 <span class="hl opt">}</span>
 458
 459 <span class="hl kwb">bool</span> StorageImpl<span class="hl opt">::</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>
 460 <span class="hl opt">{</span>
 461     <span class="hl kwd">EVAF_TEST_X</span><span class="hl opt">(</span>data<span class="hl opt">,</span> <span class="hl str">&quot;Data cannot be null&quot;</span><span class="hl opt">);</span>
 462     <span class="hl kwd">EVAF_TEST_X</span><span class="hl opt">(!</span>name<span class="hl opt">.</span><span class="hl kwd">isEmpty</span><span class="hl opt">(),</span> <span class="hl str">&quot;Name cannot be empty&quot;</span><span class="hl opt">);</span>
 463
 464     <span class="hl slc">// Is it an update or a new data record?</span>
 465     <span class="hl kwa">if</span> <span class="hl opt">(</span>mData<span class="hl opt">.</span><span class="hl kwd">constFind</span><span class="hl opt">(</span>name<span class="hl opt">) !=</span> mData<span class="hl opt">.</span><span class="hl kwd">constEnd</span><span class="hl opt">()) {</span>
 466         <span class="hl slc">// This is an update</span>
 467         <span class="hl kwa">if</span> <span class="hl opt">(</span>data<span class="hl opt">-&gt;</span><span class="hl kwd">modified</span><span class="hl opt">()) {</span>
 468             QSqlQuery <span class="hl kwd">q</span><span class="hl opt">(</span>mDb<span class="hl opt">);</span>
 469             <span class="hl kwa">if</span> <span class="hl opt">(!</span>q<span class="hl opt">.</span><span class="hl kwd">exec</span><span class="hl opt">(</span><span class="hl kwd">QString</span><span class="hl opt">(</span><span class="hl str">&quot;UPDATE data SET length =</span> <span class="hl esc">\'</span><span class="hl str">%1</span><span class="hl esc">\'</span><span class="hl str">, flags =</span> <span class="hl esc">\'</span><span class="hl str">%2</span><span class="hl esc">\'</span> <span class="hl str">WHERE name =</span> <span class="hl esc">\'</span><span class="hl str">%3</span><span class="hl esc">\'</span><span class="hl str">;&quot;</span><span class="hl opt">)</span>
 470                             <span class="hl opt">.</span><span class="hl kwd">arg</span><span class="hl opt">(</span>data<span class="hl opt">-&gt;</span><span class="hl kwd">length</span><span class="hl opt">()).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>data<span class="hl opt">-&gt;</span><span class="hl kwd">flags</span><span class="hl opt">()).</span><span class="hl kwd">arg</span><span class="hl opt">(</span>name<span class="hl opt">))) {</span>
 471                 QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 472                 <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to update</span> <span class="hl esc">\'</span><span class="hl str">%s</span><span class="hl esc">\'</span> <span class="hl str">: %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>name<span class="hl opt">),</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 473                 <span class="hl kwa">return false</span><span class="hl opt">;</span>
 474             <span class="hl opt">}</span>
 475         <span class="hl opt">}</span>
 476     <span class="hl opt">}</span>
 477     <span class="hl kwa">else</span> <span class="hl opt">{</span>
 478         <span class="hl slc">// Store to the database</span>
 479         QSqlQuery <span class="hl kwd">q</span><span class="hl opt">(</span>mDb<span class="hl opt">);</span>
 480         <span class="hl kwa">if</span> <span class="hl opt">(!</span>q<span class="hl opt">.</span><span class="hl kwd">exec</span><span class="hl opt">(</span><span class="hl kwd">QString</span><span class="hl opt">(</span><span class="hl str">&quot;INSERT INTO data (name, length, flags) VALUES (</span><span class="hl esc">\'</span><span class="hl str">%1</span><span class="hl esc">\'</span><span class="hl str">, %2, %3);&quot;</span><span class="hl opt">)</span>
 481                             <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>data<span class="hl opt">-&gt;</span><span class="hl kwd">length</span><span class="hl opt">())</span>
 482                             <span class="hl opt">.</span><span class="hl kwd">arg</span><span class="hl opt">(</span><span class="hl kwb">int</span><span class="hl opt">(</span>data<span class="hl opt">-&gt;</span><span class="hl kwd">flags</span><span class="hl opt">())))) {</span>
 483             QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 484             <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to insert</span> <span class="hl esc">\'</span><span class="hl str">%s</span><span class="hl esc">\'</span> <span class="hl str">: %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>name<span class="hl opt">),</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 485             <span class="hl kwa">return false</span><span class="hl opt">;</span>
 486         <span class="hl opt">}</span>
 487
 488         <span class="hl slc">// Store also into the local hash</span>
 489         mData<span class="hl opt">.</span><span class="hl kwd">insert</span><span class="hl opt">(</span>name<span class="hl opt">,</span> data<span class="hl opt">);</span>
 490
 491         <span class="hl slc">// Reset the model</span>
 492         <span class="hl kwd">reset</span><span class="hl opt">();</span>
 493     <span class="hl opt">}</span>
 494
 495     data<span class="hl opt">-&gt;</span><span class="hl kwd">reset</span><span class="hl opt">();</span>
 496
 497     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 498 <span class="hl opt">}</span>
 499
 500 QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> StorageImpl<span class="hl opt">::</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>
 501 <span class="hl opt">{</span>
 502     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>const_iterator it <span class="hl opt">=</span> mData<span class="hl opt">.</span><span class="hl kwd">constFind</span><span class="hl opt">(</span>name<span class="hl opt">);</span>
 503     <span class="hl kwa">if</span> <span class="hl opt">(</span>it <span class="hl opt">!=</span> mData<span class="hl opt">.</span><span class="hl kwd">constEnd</span><span class="hl opt">())</span>
 504         <span class="hl kwa">return</span> it<span class="hl opt">.</span><span class="hl kwd">value</span><span class="hl opt">();</span>
 505     <span class="hl kwa">else</span>
 506         <span class="hl kwa">return</span> QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;();</span>
 507 <span class="hl opt">}</span>
 508
 509 QVariant StorageImpl<span class="hl opt">::</span><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> <span class="hl kwb">const</span>
 510 <span class="hl opt">{</span>
 511     <span class="hl kwa">if</span> <span class="hl opt">(!</span>index<span class="hl opt">.</span><span class="hl kwd">isValid</span><span class="hl opt">() ||</span> index<span class="hl opt">.</span><span class="hl kwd">row</span><span class="hl opt">() &lt;</span> <span class="hl num">0</span> <span class="hl opt">||</span> index<span class="hl opt">.</span><span class="hl kwd">row</span><span class="hl opt">() &gt;=</span> mData<span class="hl opt">.</span><span class="hl kwd">size</span><span class="hl opt">() ||</span> index<span class="hl opt">.</span><span class="hl kwd">column</span><span class="hl opt">() !=</span> <span class="hl num">0</span><span class="hl opt">)</span>
 512         <span class="hl kwa">return</span> <span class="hl kwd">QVariant</span><span class="hl opt">();</span>
 513
 514     <span class="hl kwa">if</span> <span class="hl opt">(</span>role <span class="hl opt">==</span> Qt<span class="hl opt">::</span>EditRole <span class="hl opt">||</span> role <span class="hl opt">==</span> Qt<span class="hl opt">::</span>DisplayRole<span class="hl opt">)</span>
 515         <span class="hl kwa">return</span> mData<span class="hl opt">.</span><span class="hl kwd">keys</span><span class="hl opt">().</span><span class="hl kwd">at</span><span class="hl opt">(</span>index<span class="hl opt">.</span><span class="hl kwd">row</span><span class="hl opt">());</span>
 516
 517     <span class="hl kwa">return</span> <span class="hl kwd">QVariant</span><span class="hl opt">();</span>
 518 <span class="hl opt">}</span>
 519
 520 <span class="hl kwb">bool</span> StorageImpl<span class="hl opt">::</span><span class="hl kwd">createTables</span><span class="hl opt">()</span>
 521 <span class="hl opt">{</span>
 522     QSqlQuery <span class="hl kwd">q</span><span class="hl opt">(</span>mDb<span class="hl opt">);</span>
 523     <span class="hl kwa">if</span> <span class="hl opt">(!</span>q<span class="hl opt">.</span><span class="hl kwd">exec</span><span class="hl opt">(</span><span class="hl str">&quot;SELECT name FROM sqlite_master WHERE type=</span><span class="hl esc">\'</span><span class="hl str">table</span><span class="hl esc">\'</span> <span class="hl str">AND name=</span><span class="hl esc">\'</span><span class="hl str">data</span><span class="hl esc">\'</span><span class="hl str">;&quot;</span><span class="hl opt">)) {</span>
 524         QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 525         <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to query database : %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 526         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 527     <span class="hl opt">}</span>
 528
 529     <span class="hl kwa">if</span> <span class="hl opt">(</span>q<span class="hl opt">.</span><span class="hl kwd">isActive</span><span class="hl opt">() &amp;&amp;</span> q<span class="hl opt">.</span><span class="hl kwd">isSelect</span><span class="hl opt">() &amp;&amp;</span> q<span class="hl opt">.</span><span class="hl kwd">first</span><span class="hl opt">())</span>
 530         <span class="hl kwa">return true</span><span class="hl opt">;</span> <span class="hl slc">// We already have a table called 'data'</span>
 531
 532     <span class="hl slc">// Create the 'data' table</span>
 533     <span class="hl kwa">if</span> <span class="hl opt">(!</span>q<span class="hl opt">.</span><span class="hl kwd">exec</span><span class="hl opt">(</span><span class="hl str">&quot;CREATE TABLE data (name text primary key not null, length integer, flags integer);&quot;</span><span class="hl opt">)) {</span>
 534         QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 535         <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to create table</span> <span class="hl esc">\'</span><span class="hl str">data</span><span class="hl esc">\'</span> <span class="hl str">: %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 536         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 537     <span class="hl opt">}</span>
 538
 539     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 540 <span class="hl opt">}</span>
 541
 542 <span class="hl kwb">bool</span> StorageImpl<span class="hl opt">::</span><span class="hl kwd">loadData</span><span class="hl opt">()</span>
 543 <span class="hl opt">{</span>
 544     QSqlQuery <span class="hl kwd">q</span><span class="hl opt">(</span>mDb<span class="hl opt">);</span>
 545     <span class="hl kwa">if</span> <span class="hl opt">(!</span>q<span class="hl opt">.</span><span class="hl kwd">exec</span><span class="hl opt">(</span><span class="hl str">&quot;SELECT name, length, flags FROM data;&quot;</span><span class="hl opt">)) {</span>
 546         QSqlError err <span class="hl opt">=</span> mDb<span class="hl opt">.</span><span class="hl kwd">lastError</span><span class="hl opt">();</span>
 547         <span class="hl kwd">EVAF_ERROR</span><span class="hl opt">(</span><span class="hl str">&quot;Failed to query database : %s&quot;</span><span class="hl opt">,</span> <span class="hl kwd">qPrintable</span><span class="hl opt">(</span>err<span class="hl opt">.</span><span class="hl kwd">text</span><span class="hl opt">()));</span>
 548         <span class="hl kwa">return false</span><span class="hl opt">;</span>
 549     <span class="hl opt">}</span>
 550
 551     <span class="hl kwa">while</span> <span class="hl opt">(</span>q<span class="hl opt">.</span><span class="hl kwd">next</span><span class="hl opt">()) {</span>
 552         QString name <span class="hl opt">=</span> q<span class="hl opt">.</span><span class="hl kwd">value</span><span class="hl opt">(</span><span class="hl num">0</span><span class="hl opt">).</span><span class="hl kwd">toString</span><span class="hl opt">();</span>
 553         QExplicitlySharedDataPointer<span class="hl opt">&lt;</span>Storage<span class="hl opt">::</span>Data<span class="hl opt">&gt;</span> <span class="hl kwd">data</span><span class="hl opt">(</span><span class="hl kwa">new</span> Storage<span class="hl opt">::</span><span class="hl kwd">Data</span><span class="hl opt">(</span>name<span class="hl opt">,</span> q<span class="hl opt">.</span><span class="hl kwd">value</span><span class="hl opt">(</span><span class="hl num">1</span><span class="hl opt">).</span><span class="hl kwd">toInt</span><span class="hl opt">(),</span> <span class="hl kwd">uint</span><span class="hl opt">(</span>q<span class="hl opt">.</span><span class="hl kwd">value</span><span class="hl opt">(</span><span class="hl num">2</span><span class="hl opt">).</span><span class="hl kwd">toInt</span><span class="hl opt">())));</span>
 554         mData<span class="hl opt">.</span><span class="hl kwd">insert</span><span class="hl opt">(</span>name<span class="hl opt">,</span> data<span class="hl opt">);</span>
 555     <span class="hl opt">}</span>
 556
 557     <span class="hl kwd">reset</span><span class="hl opt">();</span>
 558
 559     <span class="hl kwa">return true</span><span class="hl opt">;</span>
 560 <span class="hl opt">}</span></pre>
 561
 562         <p>Next -- <a href="pswgen08.html">Building Storage Module</a>.</p>
 563
 564     </body>
 565 </html>