From 952ae50d80b5d0002a1d7715e35fd2fffcc0c2e1 Mon Sep 17 00:00:00 2001
From: Sebastian Schuberth <sschuberth@gmail.com>
Date: Mon, 7 Jun 2010 17:04:05 +0200
Subject: [PATCH] Installer: Move the code to replace in-use files to a
 separate function

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
---
 share/WinGit/install.iss     | 35 ++--------------------
 share/WinGit/modules.inc.iss | 69 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 33 deletions(-)

diff --git a/share/WinGit/install.iss b/share/WinGit/install.iss
index 476c4c93..86e03c47 100644
--- a/share/WinGit/install.iss
+++ b/share/WinGit/install.iss
@@ -992,39 +992,8 @@ begin
         DeleteContextMenuEntries;
 
         FileName:=AppDir+'\git-cheetah\git_shell_ext.dll';
-        TempName:=GenerateUniqueName(ExtractFilePath(FileName),'.git_shell_ext');
-
-        // Try to delete any previously renamed old shell extension files.
-        DelTree(ExtractFilePath(FileName)+'\*.git_shell_ext',False,True,False);
-
-        if FileExists(FileName) then begin
-            if not UnregisterServer(Is64BitInstallMode,FileName,False) then begin
-                Msg:='Line {#emit __LINE__}: Unable to unregister "'+FileName+'".';
-                MsgBox(Msg,mbError,MB_OK);
-                Log(Msg);
-                // This is not a critical error, the user can probably fix it manually,
-                // so we continue.
-            end;
-
-            if (not DeleteFile(FileName)) and (not RenameFile(FileName,TempName)) then begin
-                Msg:='Line {#emit __LINE__}: Unable to delete or rename "'+FileName+'".';
-                MsgBox(Msg,mbError,MB_OK);
-                Log(Msg);
-                // This is pretty much critical, but will be catched below when
-                // renaming the new shell extension file fails.
-            end;
-        end;
-
-        if not RenameFile(FileName+'.new',FileName) then begin
-            Msg:='Line {#emit __LINE__}: Unable to install git-cheetah. Please do it manually by renaming' + #13 + #13 +
-                 '"'+FileName+'.new" to "'+FileName+'"' + #13 + #13 +
-                 'and registering the shell extension by typing' + #13 + #13 +
-                 '"regsvr32 '+ExtractFileName(FileName)+'"' + #13 + #13 +
-                 'at the command prompt in the git-cheetah directory.';
-            MsgBox(Msg,mbError,MB_OK);
-            Log(Msg);
-        end else begin
-            RegisterServer(Is64BitInstallMode,FileName,False);
+        if not ReplaceInUseFile(FileName,FileName+'.new',True) then begin
+            Log('Line {#emit __LINE__}: Replacing file "'+FileName+'" failed.');
         end;
     end;
 end;
diff --git a/share/WinGit/modules.inc.iss b/share/WinGit/modules.inc.iss
index 6dc90cbd..5033db74 100644
--- a/share/WinGit/modules.inc.iss
+++ b/share/WinGit/modules.inc.iss
@@ -539,3 +539,72 @@ begin
         Result:=FindProcessesUsingModule_WinVista(Module,Processes);
     end;
 end;
+
+{
+    Helper code
+}
+
+// Tries to replace an in-use file, e.g. a registered shell extension, by
+// renaming it and then renaming the new file to the original name. Optionally,
+// performs (un-)registering via regsvr32.
+function ReplaceInUseFile(CurFile,NewFile:String;Register:Boolean):Boolean;
+var
+    CurFilePath,CurFileName,NewFileName:String;
+    CurFileStem,CurFileTemp:String;
+    UnregisterFailed,RenameFailed:Boolean;
+    Msg:String;
+begin
+    Result:=False;
+
+    // Note that CurFile may not exist, in which case NewFile is just renamed.
+    if not FileExists(NewFile) then begin
+        Exit;
+    end;
+
+    CurFilePath:=ExtractFilePath(CurFile);
+    CurFileName:=ExtractFileName(CurFile);
+    NewFileName:=ExtractFileName(NewFile);
+
+    // Get the file name without extension or period and use that as a suffix
+    // for the temporary file.
+    CurFileStem:=ChangeFileExt(CurFileName,'');
+    CurFileTemp:=GenerateUniqueName(CurFilePath,'.'+CurFileStem);
+
+    // Clean-up by trying to delete any previously renamed temporary files.
+    DelTree(CurFilePath+'\*.'+CurFileStem,False,True,False);
+
+    UnregisterFailed:=False;
+    RenameFailed:=False;
+
+    if FileExists(CurFile) then begin
+        if Register and (not UnregisterServer(Is64BitInstallMode,CurFile,False)) then begin
+            UnregisterFailed:=True;
+        end;
+
+        if (not DeleteFile(CurFile)) and (not RenameFile(CurFile,CurFileTemp)) then begin
+            RenameFailed:=True;
+        end;
+    end;
+
+    if not RenameFile(NewFile,CurFile) then begin
+        Msg:='Unable to install a new version of "'+CurFileName+'". ' +
+             'Please finish the installation manually by following theses steps on the command line:' + #13 + #13;
+        if FileExists(CurFile) then begin
+            if UnregisterFailed then begin
+                Msg := Msg + '- run "regsvr32 /u ' + CurFileName + '",' + #13;
+            end;
+            if RenameFailed then begin
+                Msg := Msg + '- rename "' + CurFileName + '" to something else,' + #13;
+            end;
+        end;
+        Msg         := Msg + '- rename "' + NewFileName + '" to "' + CurFileName + '",' + #13;
+        Msg         := Msg + '- run "regsvr32 ' + CurFileName + '".';
+
+        MsgBox(Msg,mbError,MB_OK);
+    end else begin
+        if Register then begin
+            RegisterServer(Is64BitInstallMode,CurFile,False);
+        end;
+        Result:=True;
+    end;
+end;
-- 
2.11.4.GIT