unit IDE.FileAssocFunc;

{
  Inno Setup
  Copyright (C) 1997-2024 Jordan Russell
  Portions by Martijn Laan
  For conditions of distribution and use, see LICENSE.TXT.

  Compiler IDE's functions for registering/unregistering the .iss file association
}

interface

function RegisterISSFileAssociation(const AllowInteractive: Boolean; var AllUsers: Boolean): Boolean;
procedure UnregisterISSFileAssociation(const Conditional: Boolean);

implementation

uses
  Windows, SysUtils, PathFunc, ShlObj, Shared.CommonFunc.Vcl, Shared.CommonFunc;
  
function GetRootkey: HKEY;
begin
  if IsAdminLoggedOn then
    Result := HKEY_LOCAL_MACHINE
  else
    Result := HKEY_CURRENT_USER;
end;

procedure UnregisterISSFileAssociationDo(const Rootkey: HKEY;
  const Conditional: Boolean); forward;

function RegisterISSFileAssociation(const AllowInteractive: Boolean; var AllUsers: Boolean): Boolean;

  procedure SetKeyValue(const Rootkey: HKEY; const Subkey, ValueName: PChar; const Data: String);

    procedure Check(const Res: Longint);
    begin
      if Res <> ERROR_SUCCESS then
        raise Exception.CreateFmt('Error creating file association:'#13#10'%d - %s',
          [Res, Win32ErrorString(Res)]);
    end;

  var
    K: HKEY;
    Disp: DWORD;
  begin
    Check(RegCreateKeyExView(rvDefault, Rootkey, Subkey, 0, nil, 0, KEY_SET_VALUE,
      nil, K, @Disp));
    try
      Check(RegSetValueEx(K, ValueName, 0, REG_SZ, PChar(Data), (Length(Data)+1)*SizeOf(Data[1])));
    finally
      RegCloseKey(K);
    end;
  end;

var
  SelfName: String;
  Rootkey: HKEY;
begin
  Rootkey := GetRootkey;
  AllUsers := Rootkey = HKEY_LOCAL_MACHINE;
  
  Result := AllUsers or not AllowInteractive or
            (MsgBox('Unable to associate for all users without administrative privileges. Do you want to associate only for yourself instead?',
              'Associate', mbConfirmation, MB_YESNO) = IDYES);
  if not Result then
    Exit;

  { Remove any cruft left around from an older/newer version }
  UnregisterISSFileAssociationDo(Rootkey, False);

  SelfName := NewParamStr(0);

  SetKeyValue(Rootkey, 'Software\Classes\.iss', nil, 'InnoSetupScriptFile');
  SetKeyValue(Rootkey, 'Software\Classes\.iss', 'Content Type', 'text/plain');
  SetKeyValue(Rootkey, 'Software\Classes\.iss\OpenWithProgids', 'InnoSetupScriptFile', '');

  SetKeyValue(Rootkey, 'Software\Classes\InnoSetupScriptFile', nil, 'Inno Setup Script');
  SetKeyValue(Rootkey, 'Software\Classes\InnoSetupScriptFile\DefaultIcon', nil, SelfName + ',1');
  SetKeyValue(Rootkey, 'Software\Classes\InnoSetupScriptFile\shell\open\command', nil,
    '"' + SelfName + '" "%1"');
  SetKeyValue(Rootkey, 'Software\Classes\InnoSetupScriptFile\shell\Compile', nil, 'Compi&le');
  SetKeyValue(Rootkey, 'Software\Classes\InnoSetupScriptFile\shell\Compile\command', nil,
    '"' + SelfName + '" /cc "%1"');

  { If we just associated for all users, remove our existing association for the current user if it exists. }
  if AllUsers then
    UnregisterISSFileAssociationDo(HKEY_CURRENT_USER, False);

  SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nil, nil);
end;

procedure UnregisterISSFileAssociationDo(const Rootkey: HKEY;
  const Conditional: Boolean);
{ If Conditional is True, no action is taken if the association exists but
  doesn't point to the currently-running EXE file. That can happen when there
  are multiple Inno Setup installations in different paths. When one of them
  is uninstalled, the association shouldn't be unregistered if a different
  installation currently "owns" it. }

  function GetKeyValue(const Rootkey: HKEY; const Subkey: PChar;
    var Data: String): Boolean;
  var
    K: HKEY;
  begin
    Result := False;
    if RegOpenKeyExView(rvDefault, Rootkey, Subkey, 0, KEY_QUERY_VALUE, K) = ERROR_SUCCESS then begin
      if RegQueryStringValue(K, nil, Data) then
        Result := True;
      RegCloseKey(K);
    end;
  end;

  procedure DeleteValue(const Rootkey: HKEY; const Subkey, ValueName: PChar);
  var
    K: HKEY;
  begin
    if RegOpenKeyExView(rvDefault, Rootkey, Subkey, 0, KEY_SET_VALUE, K) = ERROR_SUCCESS then begin
      RegDeleteValue(K, ValueName);
      RegCloseKey(K);
    end;
  end;

begin
  if Conditional then begin
    const ExpectedCommand = '"' + NewParamStr(0) + '" "%1"';
    var CurCommand: String;
    if GetKeyValue(Rootkey, 'Software\Classes\InnoSetupScriptFile\shell\open\command', CurCommand) and
       (PathCompare(CurCommand, ExpectedCommand) <> 0) then
      Exit;
  end;

  { Remove 'InnoSetupScriptFile' entirely. We own it. }
  RegDeleteKeyIncludingSubkeys(rvDefault, Rootkey,
    'Software\Classes\InnoSetupScriptFile');

  { As for '.iss', remove only our OpenWithProgids value, not the whole key.
    Other apps may have added their own OpenWithProgids values there, and
    Microsoft docs recommend against trying to delete the key's default value
    (which points to a ProgID). See:
    https://learn.microsoft.com/en-us/windows/win32/shell/fa-file-types
  }
  DeleteValue(Rootkey, 'Software\Classes\.iss\OpenWithProgids',
    'InnoSetupScriptFile');

  { Remove unnecessary key set by previous versions }
  RegDeleteKeyIncludingSubkeys(rvDefault, Rootkey,
    'Software\Classes\Applications\Compil32.exe');
end;

procedure UnregisterISSFileAssociation(const Conditional: Boolean);
begin
  UnregisterISSFileAssociationDo(HKEY_CURRENT_USER, Conditional);
  if IsAdminLoggedOn then
    UnregisterISSFileAssociationDo(HKEY_LOCAL_MACHINE, Conditional);

  SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nil, nil);
end;

end.