• Refreshed the Update Repositories to contain latest patches
• Applied latest Updates to the Appliance

Following up on KDE’s announcement of the latest stable release, we have now packages available for 12.3 and 13.1 (a 13.2 repository will be made available after it is out). You will find them in the KDE:Current repository. Current users of this repository will get the new release automatically once they update.

Why you should upgrade? You can take a look at the list of changes to get an idea. These fixes touch many important KDE applications, including KMail, Okular and Dolphin.

Packages are also on their way to openSUSE Factory.

As usual, bugs with the packaging should be reported to openSUSE and upstream bugs should be reported to KDE.

Also, if you like what KDE is doing and you feel you can not contribute directly, you may want to support this end of year fundraiser.

Geckos are taking over China, at the openSUSE Asia Summit to be held this coming weekend in Beijing. It is the first time that an openSUSE event of this scale is being held so far east of the Geeko Meridian. The organizing committee has worked their socks off for the event, and things are shaping up well. The schedule is ready and their are some great talks lined up. Overall, it promises to be a great event. As for me, I am going to speak about the Google Summer of Code, openSUSE Activities in India and a workshop on the Qt Framework.So, see you in Beijing

http://summit.opensuse.org

For this task we need newest version of libgreattao and tao-manager application. You can download tao-manager from my home page. You can download newest version of libgreattao from svn of SourceForge,.

Our configuration window

Firstly, we take care about configuration window. In this example we looks on ready class of configuration dialog belonged to “modern” design.

This window contains buttons on the left side, labels and edits. In standard design are placed tabs instead of buttons. In modern design clicking on the button will switch view.

The code are below:

<root>

<variable name="displayed_path" action="change" value="" />

<hbox>

<vbox>

<template path="/category/*">

  <variable name="blank_path" action="change" value="" />

  <if type="equal" variable1="blank_path" variable2="displayed_path">

     <variable name="displayed_path" action="change" function="path" />

     <variable name="active" action="change" function="path" />

     <variable name="active_directory" action="change" value="/" />

      <variable name="active" action="append" variable="active_directory" />

  </if>

  <button dir-for="label">

    <handler>

       <hide variable="active"  />

       <variable name="active" action="change" function="path" />

       <variable name="active_directory" action="change" value="/" />

       <variable name="active" action="append" variable="active_directory" />

       <show variable="active" />

    </handler>

  </button>

</template>

</vbox>

<vbox>

<template path="/category/*/*/text">

<variable name="current_path" action="change" function="path" />

<hide />

<if type="is_children" variable1="displayed_path" variable2="current_path">

  <show />

</if>

<hbox>

<label dir-for="label" />

<edit dir-for="event,input,output" />

<label dir-for="description" />

</hbox>

</template>

</vbox>

</hbox>

<hbox>

<button label="Ok" dir-for="label,event" path="/actions/ok" />

<button label="Cancel" dir-for="label,event" path="/actions/cancel" />

<button label="Save" dir-for="label,event" path="/actions/save" />

</hbox>

</root>

We can see one handler, few variables, conditions and show/hide elements. Show/hide elements are changing visibility:

1. For parent element,, if there’s no “name” and “variable” attribute
2. For elements with given path, if there’s “variable” attribute
3. For elements with given name, if there’s “name” attribute

What we can do to show/hide elements once button is clicked? After all we must select method(using path or name). We select path and controling elements using children path “/category/*/, because buttons are present in “/category/*” and elemetns to control are in path “/catrgory/*/*”. In first step we hide all elements using “hide” element without attributes for template:

<template path="/category/*/*/text">

This way will hide all elements without category buttons. We must also show firstly created category. This code will complete this task:

<if type="is_children" variable1="displayed_path" variable2="current_path">

   <show />

 </if>

Condition typw “is_children” checks that path are child of other path. In case we need it touches only children of matched element(without parent), we must end value with slash. Jn this case we check if “current_path” are child of “displayed_path”. “current_path” is set above and the value of it is cuirrent path. We set also “active variable”, which points to children fof active element(we add slash at the end, using”append”). Before setting value of variable “displayed_path” we checks if that variable are not s,lash(this variable will contains slash near after view is loaded).

In next step we take care about showing/hidding elements on button’s click event. Our handler will complete this task. In first step, we hide active element using “active” variable. We must remember that firstly created element will be active. In next step we set “active” variable using clicked button’s action path. We also append slash to it. In  next step we show elements belonged to clicked button. “active” variable will contain path of clicked element, so after clicked another button displayed elements(without buttons) will be hide.

This is the end of describing configuration window. There’s only one matter. Once application delete active elements, there’s no elements visible(buttons are only visible). Other situation is with tabs. There’s framework will display another tab automatically.

---

Custom file management window for tao-manager

Next example are about adding file information dialog for my file manager. We will change view of file manager windolw, but only for this one application. Firstly, we need to create directory “$HOME/.tao”. In this directory we need to create directory “$HOME/.tao/tao-manager” and “$HOME/.tao/tao-manager/mWidgets” and “$HOME/.tao/tao-manager/mWidgets/app”. In next step we need to create file with UI paths definitions(“$HOME/.tao/app”). In this directory we will create UI defintion directory for my file manager:

tao-manger = tao-manger

We must now copy configuration file for mWidgets design:

cp /usr/share/tao-design/mWidgets/config ~/.tao/tao-manager/mWidgets

We must now create file called “file manager” in “$HOME/.tao/tao-manager/mWidgets/app” directory. This file should looks like below:

<root>

<menu>

<template path="/actions/*">

<submenu dir-for="label">

<attr-connect name="label" function="last-dir" />

<template path="*">

<item dir-for="label,event">

<icon dir-for="icon" width="8" height="8" />

<attr-connect name="label" function="last-dir" />

</item>

</template>

</submenu>

</template>

</menu>

<hbox>

<vbox>

<template path="/fileviews/*/list/items/*">

<variable name="name" action="change" function="path" />

<variable name="name" action="append" value="/name" />

<attr-connect name="widget-name" variable="name" />

<template path="data/*">

<hbox>

  <label>

   <attr-connect name="label" function="last-dir" />'

  </label>

  <label dir-for="label" />

</hbox>

</template>

<hide />

</template>

</vbox>

<template path="/fileviews/*">

<vbox>

<template path="path_edit">

<edit dir-for="input,output,event" />

</template>

<list>

<template path="list/columns/*">

  <column>

    <attr-connect name="name" function="last-dir" />

    <attr-connect name="label" function="last-dir" />

  </column>

</template>

<template path="list/items/*">

  <selection>

    <template path="selected">

       <handler>

          <hide name="path" />

          <variable name="path" action="change" function="remove_last_dir" />

          <variable name="path" action="append" value="/name" />

          <variable name="call-path" action="change" function="path" />

          <show name="path" />

          <call var="call-path" />

       </handler>

    </template>

    <template path="data/*">

       <data dir-for="label">

         <attr-connect name="column-name" function="last-dir" />

         <attr-connect name="label" function="last-dir" />

       </data>

    </template>

  </selection>

</template>

</list>

</vbox>

</template>

</hbox>

</root>

Our information panel are definied in template with path pattern “/fileviews/*/list/items/*. In this step I must mentoin about widgets names. Many widgets can have the same name and one widget can have many names. Name are used to control visibility of widget, but in future it will be used in other tasks. We can define widget’s name usaing “attr-connect” tag with “name” attribute equal to “widget-name” and giving variable name. Our name is actions’s path with appented string “/name”. Why we don’t use action’s paths? We are using the same path for elements in lists, so using name could causing list’s elements to show/hide. I must mentoin, that displaying/hidding elements of lists are not implemented, but maybe it will be implemented in future.

Described tempalte contains template with relative path pattern “data/*”. In this pattern exist label with text equal to last directory of path to this action. There’s also label connected to value of current attribute of active file. All attributes of file are hidden by default.

Take also look at only one handler in this file. It exist in template with relative path “selected”, “selected” is event invoked, when a file is selected. “path” variable point to active file. It is empty by default, so nothink will be hidden.  This handler first will hide element(vbox for file attribute). In next step it will get path without last element(“/selected”) and next append value “/name” for it. This is way of generation path of element to show. “call-path” variable contains path pointed to “selected” action. This variable is used to call event connected with this action,.

There’s only one problem. Names of file attributes in left panel are not set by application.

 We use names obtained from path of template(last directory). It can be solved in very simplem way. You must only replace first code bellow with second code below:

1)

<hbox>
<label>
<attr-connect name=”label” function=”last-dir” />
</label>
<label dir-for=”label” />
</hbox>

2)

<hbox>
<variable name=”column-path” action=”change” value=”/fileviews/” />
<variable name=”column-path” action=”append” function=”nth-dir” param=”2″ />
<variable name=”column-path” action=”append” value=”/list/columns/” />
<variable name=”column-path” action=”append” function=”last-dir” />
<label>
<attr-connect name=”label” function=”last-dir” />
<attr-connect name=”label” function=”label” param=”column-path” />’
</label>
<label dir-for=”label” />
</hbox>

Hi,
My motivation for writing this blog post is to have one simple place where I can point everybody using += in a loop. I will describe here why it can kill the performance of any application or library and will also show some measurement to demonstrate it.

Let’s start with practical measurement. I created a simple measurement script which looks like this:

require "benchmark"

N = 100000
Benchmark.bm(15) do |x|
  x.report("Array#+=") do
    arr = []
    N.times { arr += [1] }
  end

  x.report("Array#concat") do
    arr = []
    N.times { arr.concat [1] }
  end

  x.report("String#+=") do
    s = ""
    N.times { s += "1" }
  end

  x.report("String#<<") do
    s = ""
    N.times { s << "1"  }
  end
end

And result for N = 10 000 looks like this:

                      user     system      total        real
Array#+=          0.280000   0.020000   0.300000 (  0.302993)
Array#concat      0.000000   0.000000   0.000000 (  0.002291)
String#+=         0.040000   0.000000   0.040000 (  0.041442)
String#<<         0.000000   0.000000   0.000000 (  0.002437)

and for N = 100 000 looks like this:

                      user     system      total        real
Array#+=         31.410000   6.940000  38.350000 ( 38.635201)
Array#concat      0.030000   0.000000   0.030000 (  0.028933)
String#+=         3.590000   0.020000   3.610000 (  3.635690)
String#<<         0.030000   0.000000   0.030000 (  0.029524)

As can be seen, it does not raise in a linear way and now it is time for some theory to explain why.

When you push elements to the same object, the complexity class of the loop is O(n), since it grows in a linear way. For += it needs to create a copy of the array or string first and then append the new part. The copy complexity class is also O(n) as it depends on array size (the approximation would be O(n/2), which means an O(n) complexity class because half is constant). Copy optimization mechanisms can help, but the complexity class will remain the same. The result is that you need to perform n times the copy operation, which is O(n). So += complexity class is O(n^2). That explains why the times do not raise linearly but quadratically.

Therefore, += should never, ever, be used in loops. If you need to have a new object, then create an empty Array or String before the loop and push new elements into it. It is more efficient. Sure Ruby is not your tool if you are looking for a way to reduce every millisecond, but there is no excuse to use the worse algorithm as it can make application unusable performance-wise.

# dumpe2fs 
dumpe2fs 1.42.12 (29-Aug-2014)
Segmentation fault

# echo $?
139

# dumpe2fs -h
dumpe2fs 1.42.12 (29-Aug-2014)
Segmentation fault

> rpm -qf `which dumpe2fs`
e2fsprogs-1.42.12-1.2.x86_64

> cat /etc/SuSE-release 
openSUSE 20140909 (x86_64)
VERSION = 20140909
CODENAME = Harlequin
# /etc/SuSE-release is deprecated and will be removed in the future,
use /etc/os-release instead

# ltrace dumpe2fs
__libc_start_main([ "dumpe2fs" ] 
setlocale(LC_MESSAGES, "")                        = "en_US.UTF-8"
setlocale(LC_CTYPE,"")                            = "en_US.UTF-8"
bindtextdomain("e2fsprogs", "/usr/share/locale")  = "/usr/share/locale"
textdomain("e2fsprogs")                           = "e2fsprogs"
set_com_err_gettext(0x401a00, 1, 1, 0x73676f72707366)                              = 0
add_error_table(0x605260, 1, 1, 0x73676f72707366)                                  = 0
__fprintf_chk(0x7f4fcb90f060, 1, 0x403b42, 0x403b3adumpe2fs 1.42.12 (29-Aug-2014)) = 31
getopt(1, 0x7fff9f754798, "bfhixVo:")                                              = -1
ext2fs_open(0, 0x29000, 0, 0 < no return ...>
--- SIGSEGV (Segmentation fault) ---
+++ killed by SIGSEGV +++

# strace dumpe2fs
execve("/sbin/dumpe2fs", ["dumpe2fs"], [/* 94 vars */]) = 0
brk(0)                                  = 0x15c1000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc391daf000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=153158, ...}) = 0
mmap(NULL, 153158, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fc391d89000
close(3)                                = 0
open("/lib64/libext2fs.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3>\1 \360"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=285064, ...}) = 0
mmap(NULL, 2380840, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fc39194a000
mprotect(0x7fc39198d000, 2097152, PROT_NONE) = 0
mmap(0x7fc391b8d000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3,
0x43000) = 0x7fc391b8d000
close(3)                                = 0
open("/lib64/libcom_err.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3>\1 \27"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=14712, ...}) = 0
mmap(NULL, 2109960, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fc391746000
mprotect(0x7fc391749000, 2093056, PROT_NONE) = 0
mmap(0x7fc391948000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3,
0x2000) = 0x7fc391948000
close(3)                                = 0
open("/lib64/libe2p.so.2", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3>\1`\""..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=32528, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc391d88000
mmap(NULL, 2128304, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fc39153e000
mprotect(0x7fc391545000, 2093056, PROT_NONE) = 0
mmap(0x7fc391744000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3,
0x6000) = 0x7fc391744000
close(3)                                = 0
open("/usr/lib64/libuuid.so.1", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3>\1\340\26"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=19048, ...}) = 0
mmap(NULL, 2113928, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fc391339000
mprotect(0x7fc39133c000, 2097152, PROT_NONE) = 0
mmap(0x7fc39153c000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3,
0x3000) = 0x7fc39153c000
close(3)                                = 0
open("/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3>\1\20\34\2"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1978611, ...}) = 0
mmap(NULL, 3832352, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fc390f91000
mprotect(0x7fc39112f000, 2097152, PROT_NONE) = 0
mmap(0x7fc39132f000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3,
0x19e000) = 0x7fc39132f000
mmap(0x7fc391335000, 14880, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1,
0) = 0x7fc391335000
close(3)                                = 0
open("/lib64/libpthread.so.0", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3>\1\20o"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=137435, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc391d87000
mmap(NULL, 2213008, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fc390d74000
mprotect(0x7fc390d8c000, 2093056, PROT_NONE) = 0
mmap(0x7fc390f8b000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3,
0x17000) = 0x7fc390f8b000
mmap(0x7fc390f8d000, 13456, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1,
0) = 0x7fc390f8d000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc391d86000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc391d84000
arch_prctl(ARCH_SET_FS, 0x7fc391d84780) = 0
mprotect(0x7fc39132f000, 16384, PROT_READ) = 0
mprotect(0x7fc390f8b000, 4096, PROT_READ) = 0
mprotect(0x7fc39153c000, 4096, PROT_READ) = 0
mprotect(0x7fc391744000, 4096, PROT_READ) = 0
mprotect(0x7fc391948000, 4096, PROT_READ) = 0
mprotect(0x7fc391b8d000, 4096, PROT_READ) = 0
mprotect(0x604000, 4096, PROT_READ)     = 0
mprotect(0x7fc391db0000, 4096, PROT_READ) = 0
munmap(0x7fc391d89000, 153158)          = 0
set_tid_address(0x7fc391d84a50)         = 4002
set_robust_list(0x7fc391d84a60, 24)     = 0
rt_sigaction(SIGRTMIN, {0x7fc390d7a9f0, [], SA_RESTORER|SA_SIGINFO, 0x7fc390d83890},
NULL, 8) = 0
rt_sigaction(SIGRT_1, {0x7fc390d7aa80, [], SA_RESTORER|SA_RESTART|SA_SIGINFO,
0x7fc390d83890}, NULL, 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN RT_1], NULL, 8) = 0
getrlimit(RLIMIT_STACK, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0
brk(0)                                  = 0x15c1000
brk(0x15e2000)                          = 0x15e2000
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = -1 ENOENT
(No such file or directory)
open("/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=2434, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fc391dae000
read(3, "# Locale name alias data base.\n#"..., 4096) = 2434
read(3, "", 4096)                       = 0
close(3)                                = 0
munmap(0x7fc391dae000, 4096)            = 0
open("/usr/lib/locale/en_US.UTF-8/LC_MESSAGES", O_RDONLY|O_CLOEXEC) = -1 ENOENT
(No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_MESSAGES", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
close(3)                                = 0
open("/usr/lib/locale/en_US.utf8/LC_MESSAGES/SYS_LC_MESSAGES", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=57, ...}) = 0
mmap(NULL, 57, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fc391dae000
close(3)                                = 0
open("/usr/lib64/gconv/gconv-modules.cache", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=26244, ...}) = 0
mmap(NULL, 26244, PROT_READ, MAP_SHARED, 3, 0) = 0x7fc391da7000
close(3)                                = 0
futex(0x7fc3913348f8, FUTEX_WAKE_PRIVATE, 2147483647) = 0
open("/usr/lib/locale/en_US.UTF-8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT
(No such file or directory)
open("/usr/lib/locale/en_US.utf8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=256420, ...}) = 0
mmap(NULL, 256420, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fc391d45000
close(3)                                = 0
write(2, "dumpe2fs 1.42.12 (29-Aug-2014)\n", 31dumpe2fs 1.42.12 (29-Aug-2014)
) = 31
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0x8} ---
+++ killed by SIGSEGV +++
Segmentation fault