Fetch the Blender install from MSI registry

Somewhere around Blender 2.75, the SCONS build system was removed and
CMake reigned supreme. The installer was of course changed to a Windows
Installer generated by CPack. Unfortunately for us, the registry keys
changed. Windows Installer's registry stuff sucks, but this is the
easiest way for us to get at it.

installer/Installer.nsi

@@ -4,10 +4,7 @@
 !include MUI2.nsh
 !include WinVer.nsh
 !include x64.nsh
-!include StrFunc.nsh
+!include RegGuid.nsh
-
-; Enable StrStr
-${StrStr}
 
 ;;;;;;;;;;;;;;;;;;;;;;
 ; Installer Settings ;
@@ -43,7 +40,12 @@ VIProductVersion    "0.0.0.0"
 ;;;;;;;;;;;;;
 ; Variables ;
 ;;;;;;;;;;;;;
+!define BlenderUpgradeCode "B767E4FD-7DE7-4094-B051-3AE62E13A17A"
+!define UninstallRegKey "SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall"
+!define UpgradeRegKey "SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UpgradeCodes"
+
 Var BlenderDir
+Var BlenderDirScanned
 Var BlenderVer
 
 ;;;;;;;;;;;;;;;;;
@@ -98,41 +100,52 @@ FunctionEnd
 ; Tries to find the Blender directory in the registry.
 Function FindBlenderDir
     ; To prevent overwriting user data, we will only do this once
-    StrCmp     $BlenderDir "" 0 done
+    StrCmp $BlenderDirScanned "" 0 done
-
+    StrCpy $BlenderDirScanned "true"
-    ; Try to grab the Blender directory from the default registry...
+
-    ReadRegStr  $BlenderDir HKLM "Software\BlenderFoundation" "Install_Dir"
+    StrCpy $1 ""
-    ReadRegStr  $BlenderVer HKLM "Software\BlenderFoundation" "ShortVersion"
+    find_product_code:
-
+    ; Blender's CPack-generated MSI package has spewed mess into hidden registry keys.
-    ; Bad news, old chap, certain x86 Blender versions will write their registry keys to the
+    ; We know what the upgrade guid is, so we will use that to find the install directory
-    ; x64 registry. Dang! It looks like we will have to try to hack around that. But only if
+    ; and the Blender version.
-    ; we got nothing...
+    ${MangleGuidForRegistry} ${BlenderUpgradeCode} $0
+    EnumRegValue $0 HKLM "${UpgradeRegKey}\$0" 0
+
+    ; If we are on a 64-bit system, we might not have found the product code guid in the 32-bit registry
+    ; ergo, we will need to change over to that registry
     ${If} ${RunningX64}
-        StrCmp  $BlenderDir "" try_again winning
+        IfErrors 0 find_uninstall_info
+        StrCmp $1 "" 0 done
+        StrCpy $1 "DEADBEEF"
 
-        try_again:
+        ClearErrors
         SetRegView 64
-        ReadRegStr  $BlenderDir HKLM "Software\BlenderFoundation" "Install_Dir"
+        Goto find_product_code
-        ReadRegStr  $BlenderVer HKLM "Software\BlenderFoundation" "ShortVersion"
+    ${Else}
-        SetRegView  32
-
-        StrCmp  $BlenderDir "" total_phailure
-
-        ; Before we suggest this, let's make sure it's not Program Files (x64) version unleashed(TM)
-        StrCpy  $0 "$PROGRAMFILES64\" ; Otherwise, it would match ALL Program Files directories...
-        ${StrStr}  $1 $BlenderDir $0
-        StrCmp  $1 "" winning total_phailure
-    ${EndIf}
-
-    winning:
-    StrCpy  $INSTDIR "$BlenderDir\$BlenderVer"
         Goto done
+    ${EndIf}
 
-    total_phailure:
+    find_uninstall_info:
-    StrCpy  $INSTDIR ""
+    ; Read the Blender directory and the versions from the uninstall record
-    Goto done
+    ${UnmangleGuidFromRegistry} $0 $1
+    StrCpy $0 "${UninstallRegKey}\{$1}"
+    ReadRegStr $BlenderDir HKLM $0 "InstallLocation"
+    IfErrors done
+    ReadRegDWORD $1 HKLM $0 "VersionMajor"
+    ReadRegDWORD $2 HKLM $0 "VersionMinor"
+    StrCpy $BlenderVer "$1.$2"
+
+    ; Test our detected schtuff for validity
+    ; NOTE: Windows Installer puts a trailing slash on the end of directories!
+    StrCpy $3 "$BlenderDir$BlenderVer"
+    IfFileExists "$3\*.*" 0 done
+    StrCpy $INSTDIR $3
 
     done:
+    ClearErrors
+    ${If} ${RunningX64}
+        SetRegView 32
+    ${EndIf}
 FunctionEnd
 
 ;;;;;;;;;

installer/RegGuid.nsh

@@ -0,0 +1,91 @@
+!macro StrAppendChar src_str src_idx dst_str
+    Push      $R0
+    StrCpy    $R0 ${src_str} 1 ${src_idx}
+    StrCpy    ${dst_str} ${dst_str}$R0
+    Pop       $R0
+!macroend
+!define StrAppendChar `!insertmacro StrAppendChar`
+
+; Takes a Guid string and returns the mangled form found in Windows Installer registry values
+; Input MUST contain dashes but no brackets enclosing the guid
+!macro MangleGuidForRegistry src dst
+    StrCpy               ${dst}  ""
+    ${StrAppendChar}     ${src}  7 ${dst}
+    ${StrAppendChar}     ${src}  6 ${dst}
+    ${StrAppendChar}     ${src}  5 ${dst}
+    ${StrAppendChar}     ${src}  4 ${dst}
+    ${StrAppendChar}     ${src}  3 ${dst}
+    ${StrAppendChar}     ${src}  2 ${dst}
+    ${StrAppendChar}     ${src}  1 ${dst}
+    ${StrAppendChar}     ${src}  0 ${dst}
+    ; Dash
+    ${StrAppendChar}     ${src} 12 ${dst}
+    ${StrAppendChar}     ${src} 11 ${dst}
+    ${StrAppendChar}     ${src} 10 ${dst}
+    ${StrAppendChar}     ${src}  9 ${dst}
+    ; Dash
+    ${StrAppendChar}     ${src} 17 ${dst}
+    ${StrAppendChar}     ${src} 16 ${dst}
+    ${StrAppendChar}     ${src} 15 ${dst}
+    ${StrAppendChar}     ${src} 14 ${dst}
+    ; Dash
+    ${StrAppendChar}     ${src} 20 ${dst}
+    ${StrAppendChar}     ${src} 19 ${dst}
+    ${StrAppendChar}     ${src} 22 ${dst}
+    ${StrAppendChar}     ${src} 21 ${dst}
+    ; Dash
+    ${StrAppendChar}     ${src} 25 ${dst}
+    ${StrAppendChar}     ${src} 24 ${dst}
+    ${StrAppendChar}     ${src} 27 ${dst}
+    ${StrAppendChar}     ${src} 26 ${dst}
+    ${StrAppendChar}     ${src} 29 ${dst}
+    ${StrAppendChar}     ${src} 28 ${dst}
+    ${StrAppendChar}     ${src} 31 ${dst}
+    ${StrAppendChar}     ${src} 30 ${dst}
+    ${StrAppendChar}     ${src} 33 ${dst}
+    ${StrAppendChar}     ${src} 32 ${dst}
+    ${StrAppendChar}     ${src} 35 ${dst}
+    ${StrAppendChar}     ${src} 34 ${dst}
+!macroend
+!define MangleGuidForRegistry `!insertmacro MangleGuidForRegistry`
+
+!macro UnmangleGuidFromRegistry src dst
+    StrCpy               ${dst}  ""
+    ${StrAppendChar}     ${src}  7 ${dst}
+    ${StrAppendChar}     ${src}  6 ${dst}
+    ${StrAppendChar}     ${src}  5 ${dst}
+    ${StrAppendChar}     ${src}  4 ${dst}
+    ${StrAppendChar}     ${src}  3 ${dst}
+    ${StrAppendChar}     ${src}  2 ${dst}
+    ${StrAppendChar}     ${src}  1 ${dst}
+    ${StrAppendChar}     ${src}  0 ${dst}
+    ${StrAppendChar}     "-"     0 ${dst}
+    ${StrAppendChar}     ${src} 11 ${dst}
+    ${StrAppendChar}     ${src} 10 ${dst}
+    ${StrAppendChar}     ${src}  9 ${dst}
+    ${StrAppendChar}     ${src}  8 ${dst}
+    ${StrAppendChar}     "-"     0 ${dst}
+    ${StrAppendChar}     ${src} 15 ${dst}
+    ${StrAppendChar}     ${src} 14 ${dst}
+    ${StrAppendChar}     ${src} 13 ${dst}
+    ${StrAppendChar}     ${src} 12 ${dst}
+    ${StrAppendChar}     "-"     0 ${dst}
+    ${StrAppendChar}     ${src} 17 ${dst}
+    ${StrAppendChar}     ${src} 16 ${dst}
+    ${StrAppendChar}     ${src} 19 ${dst}
+    ${StrAppendChar}     ${src} 18 ${dst}
+    ${StrAppendChar}     "-"     0 ${dst}
+    ${StrAppendChar}     ${src} 21 ${dst}
+    ${StrAppendChar}     ${src} 20 ${dst}
+    ${StrAppendChar}     ${src} 23 ${dst}
+    ${StrAppendChar}     ${src} 22 ${dst}
+    ${StrAppendChar}     ${src} 25 ${dst}
+    ${StrAppendChar}     ${src} 24 ${dst}
+    ${StrAppendChar}     ${src} 27 ${dst}
+    ${StrAppendChar}     ${src} 26 ${dst}
+    ${StrAppendChar}     ${src} 29 ${dst}
+    ${StrAppendChar}     ${src} 28 ${dst}
+    ${StrAppendChar}     ${src} 31 ${dst}
+    ${StrAppendChar}     ${src} 30 ${dst}
+!macroend
+!define UnmangleGuidFromRegistry `!insertmacro UnmangleGuidFromRegistry`