Custom action library, initial version

installer/src/custom-action/abp_ca.cpp

+/**
+ * \file abp_ca.cpp Top-level source for custom actions. Includes DLL initialization.
+ */
+#include "DLL.h"
+#include <stdexcept>
+
+/**
+ * DllMain is the standard entry point call when the DLL is loaded or unloaded.
+ *
+ * \param[in] module_handle 
+ *    Handle for this instance of the DLL; same as the module handle.
+ *    This handle allows us to get the DLL file name for logging.
+ * \param[in] reason 
+ *    The point in the DLL life cycle at which this call is made. Called "reason code" by Microsoft.
+ * \param[in] reserved 
+ *    No longer reserved, since it contains a point in the thread life cycle.
+ *    We aren't using it, though.
+
+ * \sa { http://msdn.microsoft.com/en-us/library/windows/desktop/ms682583%28v=vs.85%29.aspx }
+ * Documentation on DLL entry points in Windows.
+ */
+extern "C" BOOL WINAPI DllMain(
+  IN HINSTANCE module_handle,
+  IN ULONG reason,
+  IN LPVOID reserved )
+{
+  /*
+   * Because this is an external API, we must ensure that there is a catch-all block for each execution path. There are two of these below.
+   */
+  switch ( reason )
+  {
+  case DLL_PROCESS_ATTACH:
+    try
+    {
+      DLL_Module::attach( module_handle );
+      return TRUE;
+    }
+    catch(...)
+    {
+      // We can't log to the installation log yet, and this couldn't shouldn't be executed except in rare cases such as out-of-memory.
+      // Since it's a lot of code to do something useful (such as logging to the Windows system event log), we don't do anything but return a failure.
+      return FALSE;
+    }
+    break;
+
+  case DLL_PROCESS_DETACH:
+    try
+    {
+      DLL_Module::detach();
+      return TRUE;
+    }
+    catch(...)
+    {
+      // See comment above in parallel catch-block.
+      return FALSE;
+    }
+    break;
+
+  /*
+   * This entry point is called for each thread after the first in a process with this DLL loaded. Note "after the first".
+   * The process life cycle is always called, and we do our global initialization there.  So even though this DLL
+   * doesn't support asynchronous operation, this entry point gets called anyway. We need to ignore these calls.
+   */
+  case DLL_THREAD_ATTACH:
+  case DLL_THREAD_DETACH:
+    return TRUE;
+
+  default:
+    return FALSE;
+  }
+}