How can you list all available function names in a given dll using JNA?
JNA lets you invoke those functions at runtime. To see what is available, use a tool appropriate for the job. On windows, you have "dumpbin /exports". On linux, you have objdump. On MacOSX you have otool.
If you want to dynamically look up function names in a DLL from a running Java program using JNA, then you'd need to duplicate at least some of the functionality of those programs to parse the object file looking for exported symbols. If you're only interested in windows, then this question provides a relatively concise parsing of the DLL data.
Related
is there any tool like Borland "coff2omf.exe"for converting Borland OMF LIB format to
MS VC++ COFF LIB format ?
actually i want to create .obj file in delphi and use that in MSVC++ .
Yes, there is such a tool.
See this tool.
This utility can be used for converting object files between COFF/PE, OMF, ELF and Mach-O formats for all 32-bit and 64-bit x86 platforms. Can modify symbol names in object files. Can build, modify and convert function libraries across platforms. Can dump object files and executable files. Also includes a very good disassembler supporting the SSE4, AVX, AVX2, FMA and XOP instruction sets. Source code included (GPL). Manual.
Note that this http://www.agner.org web site is the best resource I know about low-level optimization. All the linked information is worth reading, if you want to deal with performance.
But for using the Delphi-generated .obj with VC++, it won't be easily feasible, but for very small part of code. You will need the Delphi RTL used in your code. An external .dll is much better. Note also that some types (like strings or dynamic arrays) won't be easily modifiable in VC++.
To the best of my knowledge there is no such tool. Using Agner Fog's object file converter, the tool that Arnaud refers to, I've never succeeded in converting a Delphi unit into a COFF .obj that can be linked to an MSVC program.
I do believe that it's not realistic to take Delphi source code, compile it, and then use the generated object in MSVC. The other direction is quite possible. You can compile C code to an object, and link that object to your Delphi executable. When you do this you need to resolve any dependencies that the compiled object has.
But to link a Delphi object into a C/C++ program is going to require whatever part of the Delphi RTL that you use. And that's going to be tricky unless you happen not to use any part of the Delphi RTL, which seems unlikely.
In your situation I think your options are:
Port the code to C or C++.
Compile the Delphi code into a dynamic library and link to that from your C++ program.
Is there a way within FSI that I can reference and use registered COM components?
In a normal .fs compiled program I can simply reference the component in question and then open the relevant generated namespace(s). In a .fsx file, however, I can't seem to replicate this behaviour. I have tried using #r to reference the .dll directly, and I have tried using #I to point to the directory followed #r both with the library's "friendly" name and the file name, but nothing seems to work.
Are you only able to reference .NET assemblies from a .fsx? I don't really want to have to write/gen a wrapper assembly. I am hoping there might be a way to force FSI to take whatever steps the normal executable takes in order to provide the interop layer.
When you add a reference to a COM component in Visual Studio, it invokes a tool to generate a wrapper (standard .NET assembly) and then references the wrapper.
If you want to reference COM from fsx, you'll need to generate the wrapper yourself (or find the one generated by Visual Studio?) The tool that generates the wrapper that is called TlbImp.exe (see Type Library Importer on MSDN).
We are reversing Delphi internal structures, does anyone know of any good resource or other details about how Delphi executables are compiled and linked together and what is the layout of the various parts inside the final exe.
I am not looking for high level details like it has n sections.
I am looking for something (the following is 'made up') like section '.text' has 3 parts:
data (a)
pointers table (b)
code interleaved with data which can be identified by using mechanism (c)
etc,etc.
Ok, I am looking for references or knowledge about the structures. I already have the tools mentioned below, and a ton more to aid in reverse engineering this from scratch.
I should have mentioned that I know the resource layout as that is well documented. It's the internal compiled structures embedded in code and data sections I am after. (e.g. how RTTI info is compiled in, where is the mapping between event handlers and form resources, etc).
Start with using existing tools like IDR (Interactive Delphi Reconstructor) and IDA (the Interactive Disassembler) and the already mentioned PE Explorer.
I would also suggest compiling some simple executables and studying the disassembly of that.
The most identifiable parts of a Delphi or C++ Builder executable are the resources.
They will contain a resource section named RCDATA. This section contains the following:
A section named DVCLAL, which identifies the compiler's SKU, such as Personal, Professional or Enterprise.
A section named PACKAGEINFO, which contains a list of contained units and a flag for Delphi or C++ Builder
Individual resources for each DFM.
On some settings, compressors like UPX may hide these resources, so you won't be able to see them unless you decompress the executable.
It could be worthwhile to have a look at Jedi JCL. IIRC their traceback tools (jcldebug unit?) open binaries to recover debug info. It would at least teach the global structure of the file.
Some bits might be delphi version specific btw.
Downloading the evaluation version of PE-Explorer might be a good start too.
You can find all types in a Delphi module (exe or dll) because they are always prepended with a pointer to the structure itself. You can create a small app and scan the exe to see for yourself how to get that information. With type information comes good information where units are / where methods are etc etc.
Combine that information with the resources available (a good resource viewer can decode the binary resources in text for all forms /frames / datamodule ).
Now if you disassemble the application you can use the information from the resources / typeinfo to make sense of the assembly code found.
I have a Delphi application that I have written a fairly simple wrapper .exe for.
Basically, there was a dll that had a bunch of functions, one of which I would call iteratively once my wrapper did what it needed to. I am not in control of this dll file, and will never be.
Well, now this DLL is a BPL, and I'm not sure how to call functions within that file. Thanks in advance.
The easy way to use functions from a package is to "use" the unit that contains the function, call it as usual, and put the package on the list of your project's runtime packages. For that to work, there are a few requirements:
Your project must use the same Delphi version as was used to compile the package.
You must have access to the DCU file for the unit, or at least the DCP file for the package.
The package must exist in the operating system's search path when your program starts.
If you can't satisfy the third requirement, or if you don't want to have the package loaded all the time, then you can call LoadPackage for it instead. The way to make that work is to have another package that is loaded all the time. It will be used by both your project and the package you wish to load. The intermediate package will expose an interface (such as some registration functions, a variable, or a class) that the main package can use to tell the application what its functions are. You won't be able to "use" the main package's unit in your application directly.
If you can't satisfy the first two requirements, then there is the much harder way, which is also what you'd need to do if your application isn't written in Delphi or C++ Builder. Treat the package like an ordinary DLL. Load it with LoadLibrary. Use GetProcAddress to load its Initialize function, and then call it. (Remember that the calling convention is register, not stdcall.) Then load the address of the function you wish to call, keeping in mind that the name of the function has been mangled to include some unit and type information. Call the Finalize function before you call FreeLibrary. Check the source for LoadPackage and UnloadPackage; whether you need to call CheckForDuplicateUnits probably depends on whether you can satisfy requirement number 1.
A BPL is just a DLL with a few specific additions to it. You should have no trouble calling functions from it just like you did with the DLL, with one specific caveat: The BPL has to be built in the same version of Delphi as you're using. This can be a major drawback if you don't have the source code. If this is a problem for you, you should probably talk with whoever created it and ask them to make it back into a DLL.
A BPL can eliminate a lot of DLL problems. If you can statically link it, the border becomes all but transparent. If you have to load it dynamically, you need one DLL-style access function (usually one that returns an object or an interface) and some common type (interface) definitions. All that should be supplied by the maker of the BPL.
I am looking to add the capability for users to write plugins to the program I have developed in Delphi. The program is a single executable with no DLLs used.
This would allow the user community to write extensions to my program to access the internal data and add capabilities that they may find useful.
I've seen the post at: Suggestions for Adding Plugin Capability? but its answers don't seem transferrable to a Delphi program.
I would like, if possible, to add this capability and keep my application as a single executable without any DLLs or additional modules required.
Do you know of any resources, components or articles that would suggest how to best do this in Delphi, or do you have your own recommendation?
The first question I would ask is, do you need the plugins to access the UI of your host application, or add any UI elements of their own? Or will the plugins be limited to querying and/or supplying data to your host app?
The latter is much easier and opens up two possibilities. Others have already mentioned DLLs, which is the first way to go. Certain caveats apply - in general you should be interfacing with a dll using only the data types that are used in Windows API. THat way you can be sure that the plugin DLLs will understand your data types, no matter what language/compiler they were created in. (So for example, use PChars, not strings. Do not as a rule pass Delphi classes such as TStream to a DLL. This will appear to work in some cases, but is unsafe in general, because even if the DLL was compiled in Delphi, it may have been a different version of the compiler, with a slightly different idea of what TStream is). Google for using DLLs in Delphi, and you'll find plenty more tips.
Another way that hasn't been mentioned yet is to enable scripting in your application itself. There are several very capable 3rd-party scripting engines, both commercial and free, and most of them allow you to exchange Delphi objects with the script. Some of these libraries support only Pascal as the scripting language, others will let you use Basic (perhaps better for beginner users) or other languages. See for example RemObjects Pascal Script (free) at http://www.remobjects.com/free.aspx .
My favorite scripting solution at the moment is Python for Delphi (P4D, also free) from http://mmm-experts.com/Products.aspx?ProductID=3 It can interface beautifully with your classes via RTTI, and allows you to execute Python code in your Delphi app, as well as use Delphi classes in Python scripts. Given the popularity of Python, this may be a viable solution if you want to attract developers to your project. However, every user will need to have a Python distribution installed.
It seems to me that the barrier to entry, from the point of view of potential plugin writers, is lower if you use scripting than if you choose DLLs.
Now, back to my initial question: things get much more complicated if you need the plugins to interact with your user interface, e.g. by placing controls on it. In general, DLLs cannot be used to do this. The Borland/CodeGear-sanctioned way is to use packages (BPLs). With BPLs, you can access and instantiate classes offered by a plugin as if they were declared in your host application. The catch is, all BPLs must be compiled with the same exact version and build of Delphi that your main application is. In my opinion this makes packages completely impractical, since it's hard to expect that all the potential plugin writers around the world will be using the same version of Delphi you are. A major pitfall.
To get around this, I have experimented with a different approach: keep using DLLs, and develop a syntax for the plugin to describe the UI it needs, then create the UI yourself in the host app. (XML is a convenient way to express the UI, since you get the concept of parenting / nesting for free.) The UI description syntax can include callbacks to the DLL triggered when the contents or state of the control changes. This method will restrict plugins to the set of VCL controls your application already uses or has registered, though. And it's not a one-nighter job, while BPLs certainly are.
Google for "Delphi plugin framework", too. There are some ready-made solutions, but as far as I know they usually use BPLs, with their limited usefulness.
Actually, the accepted answer to the question you cite is quite appropriate for Delphi as well. Your plug-ins will be DLLs, and you can dictate that they should export a function with a certain name and signature. Then, your program will load the DLL (with LoadLibrary) and get the address of the function (with GetProcAddress). If the DLL doesn't load, or the function isn't there, then the DLL is not a plug-in for your application.
After you have the address for the DLL, you can call it. You can pass the function an interface to something that represents the parts of your application that you wish to expose. You can also require that the function return an interface with methods that your application will call at various times.
When testing your plug-in system, it will be wise to write a plug-in yourself with a language other than Delphi. That way, you can be more confident that you haven't inadvertently required everyone to use Delphi.
At first I went for BPL and DLL base plugins. And found them hard to mantain.
If you use BPL system, then you need to match BPL version with EXE version. This includes Delphi updates which can break something. I found out (the hard way) that if I need to include all my plugins with every release, there is no point in having plugins at all.
Then I switched to plain DLL plugins. But that system just complicated code base. And that's not a good thing.
While crusing the net I found out Lua embedded script language, and delivered with it. Lua is 150K DLL, embedding bytecode compiler, interpreter and very simple and smart dynamic programing language.
My plugins are simple lua scripts. Easily mantaind and made. There are premade Delphi examples, so you can export any class or procedure as Lua table or function. GUI or not. For example I had TurboPower Abbrevia in my app for zipping. I exported my zipping class to lua, and all plugins now can call zip('.', 'dir.zip') and unzip(). Then I switched to 7zip and only implemented old class to use 7zip. All plugins work as they did, with support for new zip('.', 'dir.7z').
I made TLuaAction which calls Execute(), Update(), Hint() procedure from its script.
Lua allso have it's own plugin system that makes it easy to add funcionality to it. Eg luacom make is easy to use COM automation, luainterface allows calling .net from lua.
See luaforge for more. There is Lua IDE made in Delphi, with source.
I tried to make an overview of all such options some time ago. Together with my readers/commenters we built this list:
DLL/BPL loaded from the program.
DLL/BPL loaded from a sandbox (which could be another copy of the program or a specialized "server" application and which communicates with the main program via messages/sockets/msmq/named pipes/mailslots/memory mapped files).
COM (in any of its variants).
DDE (please not).
External program that communicates via stanard input/output.
External program that communicates via files (file name is a parameter to the program).
External program that works via drop folder (useful for batch processing).
External program that communicates with windows messages/windows sockets/msmq/named pipes/mailslots/memory mapped files/database publish-subscribe.
The most universal method of adding plug-in capability is to use COM. A good book to get you started on the road is Delphi Com Programming by Eric Harmon. While it was originally written for Delphi versions 3 through 5, the books contents are still valid with the latest versions of Delphi.
Personally, I have used this technique along with active scripting to allow end user customization.
I'm using plug-ins to implement most of the functionality in the game engine I'm building. The main EXE is made up of a script engine, a plug-in manager, some basic graphics routines and not much else. I'm using TJvPluginManager from the JEDI VCL library. It's a very good manager, and it can add just about anything you want to your program. Check out the demos included with the package to see how it works. The only downside is that it adds a lot of JCL/JVCL code to your program, but that's not really an issue if you're already using other JVCL components.
If plugins will be developed in Delphi or C++ builder, use packages + interfaces. Delphi OTA is a good example for that.
If plugins will be language independent, COM is a good way to go.
Addition: If you won't use COM, u may need to provide SDKs for each language. And datatype handling between different languages can be pain(for example delphi string type). Delphi COM support is excellent, u don't need to worry about kind of details. Those are mostly impilicit with Delphi COM support. Don't try to invent the wheel again. I'm surprised why people doesn't tend to mention about it.
I found an article by Tim Sullivan:
Implementing Plug-Ins for Your Delphi Applications
You could have a look at Hydra from Remobjects. Not only will this allow you to add plugins, but also to mix win32 and .net.