Accessing COM Objects

[Incognito via Digitalmars-d-learn]

On Monday, 13 June 2016 at 07:40:09 UTC, John wrote:
> On Monday, 13 June 2016 at 01:22:33 UTC, Incognito wrote:
>> I've been reading over D's com and can't find anything useful. 
>> It seems there are different ways:
>>
>> http://www.lunesu.com/uploads/ModernCOMProgramminginD.pdf
>>
>> which is of no help and requires an idl file, which I don't 
>> have.
>>
>> Then theres this
>>
>> http://wiki.dlang.org/COM_Programming
>>
>> which is also of no help:
>>
>> import std.stdio;
>>
>> import std.stdio, core.sys.windows.com, 
>> core.sys.windows.windows, std.exception, std.meta, std.traits;
>> import std.utf, core.stdc.stdlib, core.sys.windows.objidl, 
>> core.sys.windows.ole2;
>> pragma(lib, "ole32.lib");
>>
>>
>> GUID Guid(string str)()
>> {
>>     static assert(str.length==36, "Guid string must be 36 
>> chars long");
>>     enum GUIDstring = "GUID(0x" ~ str[0..8] ~ ", 0x" ~ 
>> str[9..13] ~ ", 0x" ~ str[14..18] ~
>>         ", [0x" ~ str[19..21] ~ ", 0x" ~ str[21..23] ~ ", 0x" 
>> ~ str[24..26] ~ ", 0x" ~ str[26..28]
>>         ~ ", 0x" ~ str[28..30] ~ ", 0x" ~ str[30..32] ~ ", 0x" 
>> ~ str[32..34] ~ ", 0x" ~ str[34..36] ~ "])";
>>     return mixin(GUIDstring);
>> }
>>
>> int main(string[] argv)
>> {
>>
>> 	// Adobe Photoshop App 9.0 CLSID 
>> {c09f153e-dff7-4eff-a570-af82c1a5a2a8}
>> 	// Adobe Photoshop App 9.1 CLSID 
>> {6DECC242-87EF-11cf-86B4-444553540000}
>>
>> 	auto CLSID_DOMDocument60 = 
>> Guid!("6DECC242-87EF-11cf-86B4-444553540000");
>> 	auto iid = IID_IUnknown;
>>
>> 	void* pUnk;
>> 	auto hr = CoCreateInstance(&CLSID_DOMDocument60, null, 
>> CLSCTX_ALL, &iid, &pUnk);
>> 	if (FAILED(hr))
>> 		throw new Exception("Error!");
>>
>>     writeln("Hello D-World!");
>>     return 0;
>> }
>>
>> Maybe my CLSID's are wrong. Got them from the registry. The 
>> exception triggers each time. Even if it worked, I wouldn't 
>> know how to use it.
>>
>> I can do this stuff in C# by simply dragging and dropping a 
>> dll into the references and it works fine but is a bit slow. I 
>> was hoping I could speed things up using D but it seems like 
>> COM isn't really supported, despite what several references 
>> say.
>
> COM is supported in D. The difference is that C# hides all the 
> plumbing behind nice classes.
>
> You're going to need Photoshop's COM interface to do anything 
> with it. If you don't have a C header that you can translate 
> into D, you could use a tool included in the Windows SDK called 
> OleView. It will peek inside COM  libraries and give you the 
> interface definitions.
>
> As to why CoCreateInstance isn't working, make sure you're 
> calling CoInitialize or CoInitializeEx beforehand. If it's 
> still failing, use std.windows.syserror.sysErrorString(hr) to 
> see if it gives you a reason. Otherwise, CLSCTX_ALL might be 
> the culprit - try using CLSCTX_SERVER instead.


Cool. Oleview gives me the idl files. How to convert the idl 
files to d or possibly c?

Would I just use them in place of IUnknown once I have the 
interface?