Cleaned up CA exceptions. Integrated free-standing handle class.

installer/src/installer-lib/installer-lib.h

Index: installer/src/installer-lib/installer-lib.h
===================================================================
new file mode 100644
--- /dev/null
+++ b/installer/src/installer-lib/installer-lib.h
@@ -0,0 +1,114 @@
+/**
+ * \file handle.h The "install session" is the context for all custom installation behavior.
+ */
+
+#ifndef INSTALLER_LIB_H
+#define INSTALLER_LIB_H
+
+#include <stdexcept>
+#include <sstream>
+
+/**
+ * Standard runtime error for failure of Windows API calls.
+ *
+ * The design purpose of this class is to consistently report the details of a failed API call, with an eye toward logging.
+ * All the arguments passed to the constructor appear in what().
+ * In addition the return value of GetLastError() appears.
+ *
+ * All the types for the constructors are generic.
+ * Any type that works with the output operator '<<' of a stream will work.
+ *
+ * \par Example
+ *   For a simple error, where there's not much to add over the API call and the error code itself, just omit the second argument.
+ *   \code
+ *     throw windows_api_error( "MsiDatabaseOpenView", "ERROR_BAD_QUERY_SYNTAX" )
+ *   \endcode
+ *
+ * \par
+ *   Sometimes you don't have a symbolic error code.
+ *   This example uses a numeric error and a clarifying message.
+ *   \code
+ *     throw windows_api_error( "MsiOpenDatabaseW", x, "MSI database is on file system" )
+ *   \endcode
+ */
+class windows_api_error
+  : public std::runtime_error
+{
+  template< class T1, class T2, class T3 >
+  static std::string make_message( T1 api_function, T2 error_code, T3 message )
+  {
+    std::ostringstream r, t ;
+    std::string s ;
+
+    t << api_function ;
+    s = t.str() ;
+    if ( s.empty() )
+    {
+      s = "<unspecified>" ;
+    }
+    r << s <<  " returned " ;
+
+    t = std::ostringstream() ;
+    t << error_code ;
+    s = t.str() ;
+    if ( s.empty() )
+    {
+      s = "<unknown>" ;
+    }
+    r << s << " with last error code " << ::GetLastError() ;
+
+    t = std::ostringstream() ;
+    t << message ;
+    s = t.str() ;
+    if ( ! s.empty() )
+    {
+      r << ": " << s ;
+    }
+
+    return r.str() ;
+  }
+
+public:
+  /**
+   * Constructor with additional message.
+   *
+   * \param api_function
+   *	The name of the API function that returned an error code or a null handle.
+   * \param error_code
+   *    The error code that the function returned, either symbolic or numeric.
+   *    Will be zero when the function returned a null handle.
+   * \param message
+   *    Extra message to clarify the error
+   */
+  template< class T1, class T2, class T3 >
+  windows_api_error( T1 api_function, T2 error_code, T3 message  )
+    : std::runtime_error( make_message( api_function, error_code, message ) )
+  {}
+
+  /**
+   * Constructor without anything extra.
+   *
+   * \param api_function
+   *	The name of the API function that returned an error code or a null handle.
+   * \param error_code
+   *    The error code that the function returned, either symbolic or numeric.
+   *    Will be zero when the function returned a null handle.
+   */
+  template< class T1, class T2 >
+  windows_api_error( T1 api_function, T2 error_code )
+    : std::runtime_error( make_message( api_function, error_code, "" ) )
+  {}
+} ;
+
+/**
+ */
+class not_yet_supported
+  : public std::runtime_error
+{
+public:
+  not_yet_supported( std::string message )
+    : std::runtime_error( "Not yet supported: " + message )
+  {}
+} ;
+
+#endif