Updated installer with custom action

installer/src/installer-lib/database.h

 /**
  * \file database.h MSI database
  */
 
 #ifndef DATABASE_H
 #define DATABASE_H
 
 #include <string>
-#include "windows.h"
-#include "msi.h"
+#include <memory>
 
+#include <Windows.h>
+#include <Msi.h>
+#include <MsiQuery.h>
+
+#include "handle.h"
 #include "session.h"
 
+// Forward declarations
+class View ;
+
+//-------------------------------------------------------
+// Database
+//-------------------------------------------------------
 /**
  * A Windows Installer database as contained in an MSI file.
  *
  * The API for MSI databases is shared between installation and non-installation contexts.
  * Roughly speaking, outside an installation the database supports both read and write,
  *   but inside an installation the database is read-only.
  * The life cycle functions are not shared, in addition.
  * Outside of these restrictions, however, the API is mostly common.
  * This class is the base class for the common API.
  * Subclasses provide public constructors and provide access to API calls not in common.
  */
 class Database
 {
 protected:
-  /**
-   * Protected constructor. Life cycle depends strongly on context.
-   */
-  Database( MSIHANDLE handle );
+  typedef handle< MSIHANDLE, Disallow_Null, MSI_Generic_Destruction > handle_type ;
 
   /**
-   * Destructor.
+   * Protected constructor. 
+   *
+   * An MSI database handle is an overloaded type, used both for installation databases and one opened outside an installation.
+   * These database handles, while both databases, have different capabilities and are thus defined in subclasses.
+   * Each subclass has the responsibility for obtaining a database handle appropriate to its circumstance.
+   * 
+   * \sa MSDN "Obtaining a Database Handle"
+   *    http://msdn.microsoft.com/en-us/library/windows/desktop/aa370541(v=vs.85).aspx
    */
-  ~Database();
+  Database( MSIHANDLE handle )
+    : handle( handle )
+  {}
 
-protected:
   /**
    */
-  MSIHANDLE handle;
+  handle_type handle ;
 
 private:
   /**
    * Private copy constructor is declared but not defined.
    */
-  Database( const Database & );
+  Database( const Database & ) ;
 
   /**
    * Private assignment operator is declared but not defined.
    */
   Database & operator=( const Database & ) ;
-};
+
+  /**
+   * Open a new view for this database.
+   *
+   * \param query
+   *    An SQL query using the restricted MSI syntax
+   *
+   * \sa
+   *   - MSDN [MsiDatabaseOpenView function](http://msdn.microsoft.com/en-us/library/aa370082%28v=vs.85%29.aspx)
+   */
+  msi_handle open_view( const wchar_t * query ) ;
+
+  friend class View ;
+} ;
 
 /**
  * A Windows Installer database in an installation context.
  */
 class Installation_Database : public Database
 {
 public:
   /**
    * The constructor of a database in an installation context has no arguments because the database is a part of that context.
    */
-  Installation_Database( Immediate_Session & session );
-};
+  Installation_Database( Immediate_Session & session ) ;
+} ;
 
+//-------------------------------------------------------
+//
+//-------------------------------------------------------
 /**
- * A Windows Installer database in a non-installation context.
+ * A Windows Installer database outside of an installation context, opened as a file from the file system.
+ *
+ * This is a read-only version of a file-system database.
+ * Refactor the class to obtain other open-modes.
+ *
  */
-class Non_Installation_Database : public Database
+class File_System_Database : public Database
 {
-};
+  /**
+   * Open function is separate to enable initializing base class before constructor body.
+   *
+   * \sa
+   *   - MSDN [MsiOpenDatabase function](http://msdn.microsoft.com/en-us/library/aa370338%28v=vs.85%29.aspx)
+   */
+  msi_handle handle_from_pathname( const wchar_t * pathname )
+  {
+    MSIHANDLE handle ;
+    UINT x = MsiOpenDatabaseW( pathname, MSIDBOPEN_READONLY, & handle ) ;
+    if ( x != ERROR_SUCCESS )
+    {
+      throw std::runtime_error( "Open database from file system failed" ) ;
+    }
+    return msi_handle( handle ) ;
+  }
+
+public:
+  File_System_Database( const wchar_t * pathname )
+    : Database( handle_from_pathname( pathname ) )
+  {}
+} ;
+
+//-------------------------------------------------------
+// View
+//-------------------------------------------------------
+/*
+ * The MSI database is accessible through a cut-down version of SQL.
+ * There's no distinction between view and query in this dialect.
+ *
+ * \sa
+ *   - MSDN [Working with Queries](http://msdn.microsoft.com/en-us/library/aa372879%28v=vs.85%29.aspx)
+ */
+class View
+{
+  /**
+   * Policy class to close a view handle.
+   * View handles don't get closed with the generic close function for other MSI handles.
+   */
+  template< class T >
+  struct View_Destruction
+  {
+    /**
+     * \sa MSDN [MsiViewClose function](http://msdn.microsoft.com/en-us/library/aa370510%28v=vs.85%29.aspx)
+     */
+    inline static void close( T handle )
+    {
+      ::MsiViewClose( handle ) ;
+    }
+  } ;
+
+  typedef handle< MSIHANDLE, Disallow_Null, View_Destruction > handle_type ;
+
+  /**
+   * Handle for the MSI view object
+   */
+  handle_type _handle;
+
+public:
+  /**
+   * Ordinary constructor
+   */
+  View( Database & db, wchar_t * query )
+    : _handle( db.open_view( query ) )
+  {}
+
+  /**
+   * Execute the query and return the first record in its results.
+   * 
+   * \param arguments
+   *    List of parameters to supply as the query arguments (question marks).
+   */
+  Record first( Record & arguments ) ;
+
+  /**
+   * Execute the query and return the first record in its results.
+   * 
+   * With no arguments, this version of the function may only be used with a query that takes no arguments.
+   */
+  Record first() ;
+
+  /**
+   * Retrieve the next record.
+   */
+  Record next() ;
+
+  /**
+   * End marker
+   */
+  inline Record end()
+  {
+    return Record( Record::null_t() ) ;
+  }
+} ;
+
 
 #endif