How to get a list of all packages required by another package

Question

My application uses runtime packages and I would like to get a list of all packages that are required by one of these.

Example:

PackA.bpl requires PackB.bpl and PackC.bpl.

How can I get packages required from PackA.bpl at runtime? (In this example, they would be PackB.bpl and PackC.bpl)

Answer 1

You can use GetPackageInfo from SysUtils. Here is an example of using it to enumerate list of units compiled in a package (in your case, in your callback check for ntRequiresPackage instead). For example:

procedure GetRequiredPackageName(const Name: string; NameType: TNameType; Flags: Byte; Param: Pointer);
var
  Names: TStrings absolute Param;
begin
  case NameType of
    ntRequiresPackage:
      Names.Add(Name);
  end;
end;

procedure GetRequiredPackageNames(Module: HMODULE; Names: TStrings);
var
  Flags: Integer;
begin
  Names.BeginUpdate;
  try
    GetPackageInfo(Module, Names, Flags, GetRequiredPackageName);
  finally
    Names.EndUpdate;
  end;
end;

function ListRequiredPackages(HInstance: NativeInt; Data: Pointer): Boolean;
var
  Names: TStrings absolute Data;
  I: Integer;
begin
  Result := True;
  Names.Clear;
  GetRequiredPackageNames(HInstance, Data);
  Writeln(Format('%s requires: %d packages', [ExtractFileName(GetModuleName(HInstance)), Names.Count]));
  if Names.Count > 0 then
    for I := 0 to Names.Count - 1 do
      Writeln(Names[I]);
end;

procedure Main;
var
  Names: TStringList;
  I: Integer;
begin
  Names := TStringList.Create;
  try
    EnumModules(ListRequiredPackages, Names);
    Readln;
  finally
    Names.Free;
  end;
end;

To get the handle of a package by name, you can use GetModuleHandle:

ListRequiredPackages(GetModuleHandle('PackA.bpl'), Names);