След на паутине

Originally published at Fiberglass flowers. You can comment here or there.

Another problem with MSBuild bootstrappers that can screw all your installation…

If scheduling reboot after installing .NET or other prerequisites, bootstrapper copies itself to run from TEMP on boot. Why not staying where it is - who knows. And definitely, all the other MSIs are not copied, so it won’t find them. Reproduced for me.

Now give up and go write own bootstrapper. I’m setiously considering going for InnoSetup deployment.

For now, I’m trying a crazy ting, to copy MSI to TEMP for Setup.exe to find it after reincarnation… It’s the way to use given tools.

Originally published at Fiberglass flowers. You can comment here or there.

After Microsoft didn’t include .NET 3.5 in any current release of Windows (read “Vista service pack 1″), some of us developers who believed in long-ago C# 3.0 ads, had to roll back to .NET 3.0 and C# 2.0.

Including me.

Not mentioning pain of rolling back all LINQ tasties in code and debugging our replacements (do you know why you can’t implement Where() just with yield-style function?), it means installing .NET 3.0.

It seemed to be not a problem, having a MSBuild code snippet that worked for 3.5 - just replace 3.5 with 3.0:

<ItemGroup>
<BootstrapperFile Include="Microsoft.Net.Framework.3.0">
<ProductName>.NET Framework 3.0</ProductName>
</BootstrapperFile>
<BootstrapperFile Include="Microsoft.Windows.Installer.3.1">
<ProductName>Windows Installer 3.1</ProductName>
</BootstrapperFile>

<Target Name="Bootstrapper">
<GenerateBootstrapper
ApplicationName="blah blah blah blah"
BootstrapperItems="@(BootstrapperFile)"
BootstrapperKeyFile=""
OutputPath="obj"
ComponentsLocation="HomeSite" CopyComponents="false"
SupportUrl="http://www.microsoft.com/downloads/details.aspx?familyid=10CC340B-F857-4A14-83F5-25634C3BF043"
Culture="en" Path="$(BootstrapperPath)"/>
</Target>

Won’t work.

Hell why? Who knows. Logs in temp don’t give proper diagnostics, nor system events do. WPF fails to install at some point onto every XP installations we have, including clean special test XP SP2 VMWare images downloaded from Microsoft.

Update: Here’s the answer.

Now I rolled back to dotnetfx3setup.exe redistributable. It’s 2.8M compared to 300K bootstrapper generated by MSBuild, and it’s a pain to see installer grow…And if .NET 3.0 is already installed it starts to uninstall it… and there is no key to make it just “check or install”, need to trick it via WiX.

But we have to pay it. Oh my.

All over the Web I see no evidence that any man walked this path before. For.NET 2.0 - a lot of mentions and code samples. And completely empty for .NET 3.0.

Originally published at Fiberglass flowers. You can comment here or there.

Till now, I did understand but didn’t remember the very situation, as I wasn’t the one creating thread pools and alike: all the core things were already there.
It’s a blessing to work for start-up.
You can think about

Monitor.Wait(toRetrieve); // will throw SynchronizationLockException

Now, after a look into docs, I see that one needs to hold the monitored object lock to avoid race conditions: a thread wakes up already holding a lock for an object it needs. The thread that did Pulse() acquired that lock and safely passed it to Wait()ing one.
Just watch out for deadlocks: it’s easy to wake up with one object lock, try to acquire another and die then…

lock(toRetrieve)
{
  Monitor.Wait(toRetrieve); // will throw SynchronizationLockException
}

As Doug Lea recommends in his excellent eternal “Concurrent Programming in Java“, just make it impossible. Lock only on a single object. If you really really need two locks, make them ordered: always acquire A then B.

If you do:

lock(a){
  // :
  lock (b)
  {
    //:
  }
  // or:
  b.SomethingThatLocks();
}

//then will you never ever do

lock(b)
{
  //:
  a.SomethingThatMightLock();
}

as calling other objects’ methods while holding a lock badly affects your karma.

For more in-detail look, read “EventWaitHandle and Monitors: how to pick one?” by Joe Duffy. He goes very deep down to system details.
He also did a nice brief overview of missed pulse problem - why do you always check wait condition in a loop:

while (toRetrieve.Count == 0)
{
  lock(toRetrieve)
  {
    Monitor.Wait(toRetrieve);
  }
}

Originally published at Fiberglass flowers. You can comment here or there.

Am I the only one who ran into .NET (or GDI?) bug with Pen (or Matrix) .ScaleTransform()?
When I scale a pen to certain width, and it has an anchor, anchor draws at inverse scale.
I might be missing something, but here’s my test. Pen scales proportionally to form width, for simplicity.

Here’s how it looks:

You see, the thinner the line, the bigger is the cap. Uh-oh.

My workaround should be here after some time.
Source code for interested ones:

private void Form1_Load(object sender, EventArgs e)
        {
            pen.StartCap = LineCap.SquareAnchor;
            //pen.EndCap = LineCap.ArrowAnchor;
            pen.EndCap = LineCap.DiamondAnchor;
        }

        private readonly Pen pen = new Pen(Color.Black, 2);

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            pen.ResetTransform();
            float scale = Width / 300.0F;
            pen.ScaleTransform(scale, scale);
            e.Graphics.DrawLine(pen, 10, 10, ClientRectangle.Width - 10, ClientRectangle.Height - 10);
        }

        private void Form1_Resize(object sender, EventArgs e)
        {
            Invalidate();
        }

Originally published at Fiberglass flowers. You can comment here or there.

Till two years ago, I didn’t know that C# 2.0 had closures (reference to Joe Walnes’ blog). Now declarative programming is slowly coming into fashion.
Reference taken from classicist. The latter has a bunch of short bliki-articles, all worth reading.

Please note variables visibility scope:

public List<Employee> HighPaid(List<Employee> emps) {

int threshold = 150;
return emps.FindAll(delegate(Employee e) {
return e.Salary > threshold;
});

}

interesting quotation about arguments against closures in Java - about memory allocation. Found again by Martin Fowler’s reference, in Guy Steele’s archive:
One of the early design principles of Java was that heap allocation occurs if and only if a construct involving the "new" keyword is executed. Adding full-blown closures violated this design principle. (Dynamic class loading also violated the principle, but users seemed to be comfortable with that, perhaps because they believed that "once the computation got going" no more heap allocation would occur.)
Other features for Java release 1.5 will perform certain kinds of autoboxing, which also violates the design principle. This fact will make it easier to argue for restoring full-blown support for closures in the future.

upd: But .NET doesn’t have an unordered container (set), and these cool Find()/FindAll() don’t exist in IList. Too bad.

Oh yes, and Python always had closures.