[haiku-appserver] deadlock
- From: Adi Oanca <adioanca@xxxxxxxxxxxxxx>
- To: AppServer <haiku-appserver@xxxxxxxxxxxxx>
- Date: Wed, 06 Apr 2005 11:49:01 +0300
Hi guys,
While playing yesterday I found a "pretty nice" situation.
You can reproduce it by adding a single line:
MoveBy(10,10);
in Stephan's "Windows" app.
----------------
// main.cpp
#include <stdio.h>
#include "Application.h"
#include "TextControl.h"
#include "View.h"
#include "Window.h"
class HelloView : public BView {
public:
HelloView(BRect frame, const char* name,
uint32 resizeFlags,
uint32 flags)
: BView(frame, name,
resizeFlags, flags)
{ }
virtual void Draw(BRect updateRect)
{
// printf("HelloView::Draw()\n");
// updateRect.PrintToStream();
//
SetHighColor(ui_color(B_PANEL_BACKGROUND_COLOR));
// FillRect(updateRect);
BRect r(Bounds());
// r.PrintToStream();
const char* message = "Hello
World!";
float width =
StringWidth(message);
BPoint p(r.left + r.Width() /
2.0 - width / 2.0,
r.top +
r.Height() / 2.0);
SetHighColor(255, 0, 0, 128);
DrawString(message, p);
}
};
// show_window
void
show_window(BRect frame, const char* name)
{
BWindow* window = new BWindow(frame, name,
B_TITLED_WINDOW,
B_ASYNCHRONOUS_CONTROLS | B_QUIT_ON_WINDOW_CLOSE);
BView* view = new HelloView(window->Bounds(), "test", B_FOLLOW_ALL,
B_WILL_DRAW/* |
B_FULL_UPDATE_ON_RESIZE*/);
view->SetViewColor(ui_color(B_PANEL_BACKGROUND_COLOR));
window->AddChild(view);
/* BRect b(view->Bounds());
b.InsetBy(10.0, 20.0);
BTextControl* control = new BTextControl(b, "tc", "Text", "Enter Text
Here", NULL);
view->AddChild(control);*/
window->Show();
----------
++++ window->MoveBy(10,10);
---------
}
// main
int
main(int argc, char** argv)
{
BApplication* app = new
BApplication("application/x.vnd-Haiku.windows_test");
BRect frame(50.0, 50.0, 200.0, 150.0);
show_window(frame, "Window #1");
frame.Set(80.0, 100.0, 250.0, 200.0);
show_window(frame, "Window #2");
app->Run();
delete app;
return 0;
}
----------------------------
Looks to me StringWidth() is not implemented well. I tested this on R5
and it works.
The reason: when you create a BApplication object its looper is locked
until you call ::Run(). StringWidth() uses
BApplication's server connection and for that it must acquire BApplication's
lock. Because StringWidth() is called from
BWindow's thread we get a deadlock.
Don't know how this should be solved... I guess we should use BWindow
for getting font data. Just a thought.
bye,
Adi.
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