I just discovered that almost 2 weeks ago, the FastMM code repository added support for these defines in Mac OS X in Commit [r67].:
FullDebugMode
LogErrorsToFile
LogMemoryLeakDetailToFile
This is great news!
Note: this is not a full FastMM release, but since the original change by Sebastian Zierer has been done about half a year ago, the code is pretty stable.
And from the comments PlantUML which generates UML diagrams from text, of which the sequence diagrams can also be generated as ASCII (the others only as images).
Finally there is ditaa which goes from ASCII diagrams to images. The complete circle is done (:
It is a very nice article with annotations on the (very old, but still very prevalent Big Ball of Mud design pattern of which a lot of software projects suffer).
I didn’t know about the design pattern yet, but have seen it in so many places, and even helped quite a few of them to become less big, and contain less mud. If the article and paper are tool long, you can read a WikiPedia BBM abstract.
I’m glad that the .NET/Delphi based suite of projects I landed on recently – though containing quite a bit of legacy – is different. Still a lot of improvements to be made, but it is very manageable.
In other words: any language that merges null behaviour in the underlying storage will have a problem somwehere.
So if you want to have true nullable types, your null flag should be stored outside the underlying storage.
The .NET framework 2 and up, most database management systems and many other environment support that.
But most languages don’t support it for pointer types. So there will be portions of address spaces either inaccessible, or only accessible when skipping the null pointer checks.
Note that the thread above contains some very interesting bits, for instance this one:
Matt 28 Mar 2013 5:58 PM #
@MarkY “Dereferencing null is undefined? Cool! I thought it was guaranteed to crash, just like a false assertion or something. So crashing is the OS guarantee, not the language guarantee apparently.”
Nope. It’s not an OS guarantee either. The OS won’t ever normally allocate memory at address zero, but there’s nothing to stop you telling it to. Try doing “VirtualAlloc(1, 4096, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE)” on your pre-Windows8 machine.
In fact, this is the reason why null-dereferences in kernel mode are often exploitable as elevation of privilege attacks. The null-page is mappable and within the user-addressable region of memory, so if the kernel dereferences a null pointer, it reads attacker controllable data.
And btw, this is the reason why on Linux and Windows8+ you can’t map the null-page.
Recently I pushed two sets ofchanges for Spring4D with packages and test projects that support Appmethod. The test projects are configured to use Firemonkey (conditional define FMX) as that is what Appmethod is centered around.
This weekend I filed Appmethod issue AP-64 that prevents Spring4D and other open source projects to automatically build the underlying projects. Since the new Quality site does not (yet?) make reports on public reports visible to the public, the full report is at the end of this post.
The issue comes down to that Embarcadero has intentionally made the command-line compilers dysfunctional. They are there, but – as you see when running this small batch file – they all will display “This version of the product does not support command line compiling.“. It makes it impossible for open source projects to just distribute the sources, and ship a small build tool that builds and installs the compiled binaries into the available products. So this issue doesn’t only affect Spring4D. The large JCL open source project also requires the command-line compilers.
In the past, only some free or trial products came without the command-line compilers, and I personally am anxious why the command-line compilers were crippled. On the other hand – even though the compiler DLLs list themselves as version 19.50, the functionality in Appmethod basically is the same as in RAD Studio XE5.
The Spring4D team regrets the lack of command-line compiler support in Appmethod. We really hope this restriction is removed soon, preferably in this version, but – since the docteam is prepping for XE6, Delphi XE6 is around the corner (the first XE6 webinar is in slightly more than a week from now) and Appmethod is based on the most recent Delphi version – in a future version.
We could go the long path of encapsulating the DLL versions of the compilers, but those do not have a public API. Reverse engineering that would cost a lot of effort, which we’d rather put into enhancing Spring4D.
If Another thing we could do – if we’d get the compilers, or Embarcadero would build the Spring4D sources with them – is provide precompiled packages for every Appmethod version. We’d rather not do that either because of the exact same reason: extra effort that we’d rather spend on other Spring4D things.
So for now, the Spring4D team keeps the Appmethod support as is. If there are people interested, they can manually compile and install the packages and test projects from within the IDE.
–jeroen
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The Wiert Corner - irregular stream of stuff 