add the inner/outer paradigm for signed uninstaller

cmake/templates/NSIS.template.in

@@ -31,6 +31,31 @@
 ;--------------------------------
 ;General
 
+  !ifdef INNER
+    !echo "Inner invocation"                  ; just to see what's going on
+    OutFile "$%TEMP%\tempinstaller.exe"       ; not really important where this is
+    SetCompress off                           ; for speed
+  !else
+    !echo "Outer invocation"
+
+    ; Call makensis again, defining INNER.  This writes an installer for us which, when
+    ; it is invoked, will just write the uninstaller to some location, and then exit.
+    ; Be sure to substitute the name of this script here.
+
+    !system "$\"${NSISDIR}\makensis$\" /DINNER <name_of_script>.nsi" = 0
+
+    ; So now run that installer we just created as %TEMP%\tempinstaller.exe.  Since it
+    ; calls quit the return value isn't zero.
+
+    !system "$%TEMP%\tempinstaller.exe" = 2
+
+    ; That will have written an uninstaller binary for us.  Now we sign it with your
+    ; favourite code signing tool.
+
+    !system "signcode <signing options> $%TEMP%\uninstaller.exe" = 0
+
+    ; Good.  Now we can carry on writing the real installer.
+
     ;Name and file
     Name "@CPACK_NSIS_PACKAGE_NAME@"
     OutFile "@CPACK_TOPLEVEL_DIRECTORY@/@CPACK_OUTPUT_FILE_NAME@"
@@ -40,6 +65,7 @@
 
     ;Require administrator access
     RequestExecutionLevel admin
+  !endif
 
 @CPACK_NSIS_DEFINES@
 
@@ -648,8 +674,15 @@ Section "-Core installation"
   ;Store installation folder
   WriteRegStr SHCTX "Software\@CPACK_PACKAGE_VENDOR@\@CPACK_PACKAGE_INSTALL_REGISTRY_KEY@" "" $INSTDIR
 
-  ;Create uninstaller
-  WriteUninstaller "$INSTDIR\Uninstall.exe"
+  ;Package the signed uninstaller produced by the inner loop
+  !ifndef INNER
+    SetOutPath $INSTDIR
+
+    ; this packages the signed uninstaller
+
+    File $%TEMP%\uninstaller.exe
+  !endif
+
   Push "DisplayName"
   Push "@CPACK_NSIS_DISPLAY_NAME@"
   Call ConditionalAddToRegisty
@@ -951,6 +984,10 @@ FunctionEnd
 ;--------------------------------
 ;Uninstaller Section
 
+; the normal uninstaller section is only defined for inner (they're not needed in the "outer"
+; installer and will just cause warnings because there is no WriteInstaller command)
+
+!ifdef INNER
 Section "Uninstall"
   ReadRegStr $START_MENU SHCTX \
    "Software\Microsoft\Windows\CurrentVersion\Uninstall\@CPACK_PACKAGE_INSTALL_REGISTRY_KEY@" "StartMenu"
@@ -1046,6 +1083,7 @@ Section "Uninstall"
     Call un.RemoveFromPath
   doNotRemoveFromPath:
 SectionEnd
+!endif
 
 ;--------------------------------
 ; determine admin versus local install
@@ -1058,6 +1096,18 @@ SectionEnd
 ; "Program Files" for AllUsers, "My Documents" for JustMe...
 
 Function .onInit
+
+  !ifdef INNER
+    ; If INNER is defined, then we aren't supposed to do anything except write out
+    ; the installer.  This is better than processing a command line option as it means
+    ; this entire code path is not present in the final (real) installer.
+
+    WriteUninstaller "$%TEMP%\uninstaller.exe"
+
+    ; just bail out quickly when running the "inner" installer
+    Quit
+  !endif
+
   StrCmp "@CPACK_NSIS_ENABLE_UNINSTALL_BEFORE_INSTALL@" "ON" 0 inst
 
   ReadRegStr $0 HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\@CPACK_PACKAGE_INSTALL_REGISTRY_KEY@" "UninstallString"