Difference between revisions of "Policies/Kdepim Coding Style"

Jump to: navigation, search
(Use block)
(The specification rules of coding style for kdepim and akonadi)
 
(117 intermediate revisions by one user not shown)
Line 1: Line 1:
{{Construction}}
 
 
 
== Purpose of this document ==
 
== Purpose of this document ==
  
Line 10: Line 8:
 
[http://techbase.kde.org/Policies/Kdelibs_Coding_Style Kdelibs coding style].
 
[http://techbase.kde.org/Policies/Kdelibs_Coding_Style Kdelibs coding style].
  
== The rules for kdepim and akonadi ==
+
== Why is coding Style useful? ==
  
*don't use any <TAB>s
+
Let us make a comparision with real life.
*Trim the lines
+
To make an addition, one can write:
*Only single empty lines should be used
+
*The first line, the last line(s) may not be empty
+
*Use one space after each keyword, but not after a cast
+
*no "one line" if-statement
+
  
== Migration ==
+
{{Output| 1=123
 +
+      456
 +
  ==========
 +
    =      579
 +
}}
  
As discussed at the KDEPIM meeting, Berlin, 3 March 2013, all the files of KDEPIM will
+
But we have learned in primary school to write:
be reviewed to follow the coding style.  This will be done over a long time,
+
directory after directory, for each of the
+
rules defined above.  For each rule, one can find one or two script(s). 
+
  
== Check the objects ==
+
{{Output| 1=Addition
 +
  123
 +
+456
 +
====
 +
=579
 +
}}
  
As a first approach, not any object may have binary change after applying one of the rules.
+
Which is much more readable, easy to control (or debug).
To check this, one uses the '''Check-the-Objects.sh'''. Download the script: [[Media:Check-the-Objects.sh.gz]]
+
  
The script can be used with one of the commands:
+
This is Coding Style: not mandatory but very useful and pretty to read.
* save
+
* test
+
* clean
+
  
'''An example:'''
+
== What do we need? ==
  
{{Input|1=cd <some_kdepim_directory>
+
'''We need at least:'''
mkdir build
+
*a '''specification''' (a set of rules) for the coding style of the sources
cd build
+
*some tools to '''check the sources''' against the specification
ccmake ../
+
*some tools to '''change the sources'''
make}}
+
{{Output|1=<span style="color:Fuchsia">Scanning dependencies of target gpgmepp</span>
+
[  0%] <span style="color:green">Building CXX object gpgme++/CMakeFiles/gpgmepp.dir/gpgmepp_automoc.cpp.o</span>
+
[  0%] <span style="color:green">Building CXX object gpgme++/CMakeFiles/gpgmepp.dir/exception.cpp.o</span>
+
[  0%] <span style="color:green">Building CXX object gpgme++/CMakeFiles/gpgmepp.dir/context.cpp.o</span>
+
...}}
+
  
{{Input|1=Check-the-Objects.sh save}}
 
The script makes a copy of all the objects and a "time stamp":
 
{{Output|1=save the object ./kholidays/tests/CMakeFiles/testzodiac.dir/testzodiac.cpp.o
 
save the object ./kholidays/tests/CMakeFiles/testzodiac.dir/testzodiac_automoc.cpp.o
 
...
 
all objects are saved}}
 
  
Now, one makes somes change(s) on the source(s) and:
+
[http://astyle.sourceforge.net/ astyle] is a suitable tool to make such changes. But astyle doesn't implement (yet) all the specification rules.
  
{{Input| 1=make}}
+
You can find below some awk-scripts which help us to check all the rules.
  
Depending on the Makefile, some objects will be compiled again:
+
You can find below some awk-scripts which help us to make most of the changes.
 +
The last part must be done manually.
  
{{Output| 1=<span style="color:Fuchsia">Scanning dependencies of target akonadi-kde</span>
+
== The specification rules of coding style for kdepim and akonadi ==
[ 17%] <span style="color:green">Building CXX object akonadi/CMakeFiles/akonadi-kde.dir/entitytreeview.cpp.o</span>
+
[ 17%] <span style="color:green">Building CXX object akonadi/CMakeFiles/akonadi-kde.dir/itemfetchjob.cpp.o</span>
+
[ 17%] <span style="color:green">Building CXX object akonadi/CMakeFiles/akonadi-kde.dir/statisticsproxymodel.cpp.o</span>
+
...
+
<span style="color:Fuchsia">Scanning dependencies of target akonadi-kmime</span>
+
[ 56%] <span style="color:green">Building CXX object akonadi/kmime/CMakeFiles/akonadi-kmime.dir/standardmailactionmanager.cpp.o</span>}}
+
  
{{Input|1=Check-the-Objects.sh test}}
+
*Indentation with four spaces, don't use any <TAB>s
 +
*Trim the lines
 +
*Only single empty lines
 +
*The first line and the last line(s) may not be empty
 +
*Only one statement per line
 +
*Variable declaration
 +
*Only one declaration per line
 +
*Use a space after each keyword, but not after a cast
 +
*Use a space after the name of the class
 +
*include directive
 +
*Place '''*''' and '''&''' next to the variable
 +
*Use '''namespace foo {''' in the same line
 +
*Each member initialization of a method in a separate line
 +
*Surround all operators with spaces
 +
*'''switch''' rules
 +
*'''try-catch''' rules
 +
*'''if''', '''for''', '''while''' and similar macros rules
 +
*'''typedef struct''' statement over more lines
 +
*Don't use '''&,''' without a variable
 +
*Don't use untyped '''enum'''
 +
*Don't use '''enum''' with empty member
 +
*No ''';''' after some macros
 +
*No "one line" '''if''' '''for''' '''while''' statement
 +
*No code after '''{'''
 +
*No code before '''}'' (but else)
 +
*No header and body code in the same line, even empty body
 +
*No space between some keywords
 +
*No space around the index of an array
 +
*No space around an expression surrounded with braces
 +
*No space before ''':''' in a case statement
 +
*No space before ''';''' at the end of statement
  
The script finds all the new objects, makes a comparision with the saved version:
+
== Migration ==
{{Output|1=test the object ./akonadi/CMakeFiles/akonadi-kde.dir/statisticsproxymodel.cpp.o
+
test the object ./akonadi/CMakeFiles/akonadi-kde.dir/entitytreeview.cpp.o
+
test the object ./akonadi/CMakeFiles/akonadi-kde.dir/itemfetchjob.cpp.o
+
test the object ./akonadi/kmime/CMakeFiles/akonadi-kmime.dir/standardmailactionmanager.cpp.o
+
all tests are OK
+
}}
+
  
== Check the assembler files ==
+
As discussed at the KDEPIM meeting, Berlin, 3 March 2013, all the files of KDEPIM will
If we add or remove some lines, the debug informations included in the object file will be change also.
+
be reviewed to follow the coding style.  This will be done over a long time,
 +
directory after directory, for each of the
 +
rules defined above.  For each rule, there are one or two script(s).
  
This is the case with the test/change of "''Only single empty lines should be used''", "''First line, last line(s) may not be empty''" and some more test/change below (''adding some blocks'' with { and }).
+
The main part of the changes can be done with astyle:
 +
http://astyle.sourceforge.net/
  
For this reason it is no more possible to compare the objects.
+
The results can be seen [[here]].
We have to compare the assembler files.
+
This works pretty well for the version with '''CMAKE_BUILD_TYPE''' set to ''release''.
+
For the version with '''CMAKE_BUILD_TYPE''' set to ''debug'', we must remove all the debug informations before the comparision could take place.
+
  
=== Generate the assembler files ===
+
== Two scripts '''to check all the rules''' and '''to make the all the changes''' ==
  
To generate the assembler files, we only need to modify the ''build.make'' in every folder.
+
Most of the rules can be checked with the scripts below.
 +
For some of the rules, we don't have a script to change the sources.
 +
It is better first to make a check for such a rule, second to make the modification(s) manually to suscript the rule(s).
  
The script '''Prepare-build_make_files.sh''' works on the all directory, finds the line with the compiler command,
+
There are two scripts that run all the checks and apply all the changes at once:
duplicates the line, add a ''-S option'' and changes the name of the output to ''somename.s''.
+
*All-Check.sh
After a new ''make'' command, we can save all the assembler files with the script '''Check-the-assembler_code.sh'''.
+
*Change-All.sh
Download the script: [[Media:Prepare-build_make_files.sh.gz]]
+
  
=== Remove the debug informations ===
+
Download the scripts: [[Media:ALL-Coding-Style.tar.gz]]
  
The biggest part of the debug informations beginns with the directive line
+
For each specification rule, the name of the scripts to check and apply the changes
*.Ldebug_info0
+
are given at the beginning of the section.
We drop all the next lines.
+
  
We drop also the lines with the directive .loc
+
== The scripts '''to check''' and '''to make the changes''' ==
They contain an information about the source line (here 123) we need later to drop the lines
+
* movl $123, %edx
+
* movl $123, %ecx
+
  
The lines with
+
The first script is '''to check''' a single file or all .h and .cpp files in a directory.
* .string "/home/guy-kde/projects/kdepimlibs/akonadi/agentbase.cpp:454"
+
will be also removed.
+
  
The script to check the assembler files can be used in the same way as the one above (Check-the-Objects.sh).
+
If present, the second script '''applies the changes'''.
To check this, one uses the '''Check-the-assembler_code.sh'''. Download the script: [[Media:Check-the-assembler_code.sh.gz]]
+
For some complicated situations, the script makes no change.
  
The script can be used with one of the commands:
+
You can use the scripts for your own work. It is recommended to use them in this order.
* save
+
* test
+
* clean
+
  
== The scripts ==
+
=== Don't test all directories ===
The first script is '''to check''' a single file or a complete directory for all .h and
+
.cpp files.
+
  
If present, the second script '''makes the changes''' for a single file or a complete
+
If a '''.no_coding_style''' file is present on a directory, the test will not be done.
directory for all .h and .cpp files.  For some complicated situations, the
+
script makes no change.
+
  
One can use the scripts for own work.It is recommanded to use them in this order.
+
If a '''.no_recursion''' file is present on a directory, we do not explore the subdirectory(ies)
 +
 
 +
=== Indentation with four spaces, don't use any <TAB>s ===
  
==== don't use any <TAB>s ====
 
 
*coding-style-check-Tabs.sh
 
*coding-style-check-Tabs.sh
*coding-style-change-Tabs.sh
+
*The changes are well done with
 +
{{Output| 1=astyle --indent=spaces
 +
}}
  
 
Download the scripts: [[Media:Tabs.tar.gz]]
 
Download the scripts: [[Media:Tabs.tar.gz]]
  
 
The output of the '''check''' script is:
 
The output of the '''check''' script is:
  {{Output|1=check the file /home/guy-kde/projects/kdepimlibs/ktnef/ktnefparser.cpp
+
  {{Output|1=check the file ktnefparser.cpp
1->308: Tab at 16:  stream_ >> i;              // i <- attribute type & name
+
308: Tab at 16:  stream_ >> i;              // i <- attribute type & name
2->311: Tab at 16:  stream_ >> i;              // i <- data length
+
311: Tab at 16:  stream_ >> i;              // i <- data length
3->326: Tab at 22:  case attATTACHMENT:        // try to get attachment info
+
326: Tab at 22:  case attATTACHMENT:        // try to get attachment info
4->367: Tab at 16:  stream_ >> u;      // u <- checksum
+
367: Tab at 16:  stream_ >> u;      // u <- checksum
a  b    c            d}}
+
}}
 
+
 
 
This shows:
 
This shows:
 
* the name of the file which is under test.
 
* the name of the file which is under test.
* the number of occurence('''a'''), the line number('''b'''), the position found('''c''') and the line itself('''d''').
+
* the line number, the position found and the line itself.
  
The '''change''' script:
+
=== Trim the lines ===
*makes a substitution of any <TAB> with eight spaces,
+
*The change works for the complete source, even within comments and strings,
+
*That might be too much and changes the vertical alignment of the code.
+
 
+
==== Trim the lines ====
+
  
 
*coding-style-check-Trim.sh
 
*coding-style-check-Trim.sh
*coding-style-change-Trim.sh
+
*The changes are well done with:
 +
{{Output| 1=astyle --indent=spaces
 +
}}
  
 
Download the scripts: [[Media:Trim.tar.gz]]
 
Download the scripts: [[Media:Trim.tar.gz]]
  
 
The output of the '''check''' script is:
 
The output of the '''check''' script is:
  {{Output|1=check the file /home/guy-kde/Software/coding-style-check/trim.cpp
+
  {{Output|1=check the file trim.cpp
1->51: Space(s) at end of line (28):  QVariant m_matchData;}}
+
51: Space(s) at end of line (28):  QVariant m_matchData;
 
+
}}
 +
 
 
This shows:
 
This shows:
 
* the name of the file which is under test.
 
* the name of the file which is under test.
* the number of occurence, the line number, the position found and the line itself.
+
* the line number, the position found and the line itself.
 
+
 
+
The '''change''' script:
+
*remove all trailing space(s).
+
  
==== Only single empty lines should be used ====
+
=== Only single empty lines ===
 
Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Whitespace
 
Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Whitespace
  
 
*coding-style-check-Twice.sh
 
*coding-style-check-Twice.sh
 
*coding-style-change-Twice.sh
 
*coding-style-change-Twice.sh
 +
* astyle cannot (yet) do it
  
 
Download the scripts: [[Media:Twice.tar.gz]]
 
Download the scripts: [[Media:Twice.tar.gz]]
  
 
The output of the '''check''' script is:
 
The output of the '''check''' script is:
{{Output|1=check the file /home/guy-kde/projects/kdepimlibs/syndication/rss2/enclosure.cpp
+
{{Output|1=check the file enclosure.cpp
1->25: next empty line found
+
25: multiple empty line found
2->26: next empty line found
+
26: multiple empty line found
3->30: next empty line found}}
+
30: multiple empty line found
   
+
}}
 +
 
 
This shows:
 
This shows:
 
* the name of the file which is under test.
 
* the name of the file which is under test.
* the number of occurrences and the line numbers.
+
* the line numbers.
  
 
The '''change''' script:
 
The '''change''' script:
*removes all the next empty line(s).
+
*removes all the multiple empty line(s).
  
==== First line, last line(s) may not be empty ====
+
=== The first line and the last line(s) may not be empty ===
  
Some of the sources have a first empty lines, some have one or more empty last line(s).
+
Some of the sources have empty lines at the beginning of the file. Some have one or more empty last line(s).
 
*coding-style-check-First-Last.sh
 
*coding-style-check-First-Last.sh
 
*coding-style-change-First-Last.sh
 
*coding-style-change-First-Last.sh
 +
*astyle cannot (yet) do it
  
 
Download the scripts: [[Media:First.tar.gz]]
 
Download the scripts: [[Media:First.tar.gz]]
  
 
The output of the '''check''' script is:
 
The output of the '''check''' script is:
  {{Output|1=check the file /home/guy-kde/Software/coding-style-check/trim.cpp
+
  {{Output|1=check the file trim.cpp
 
The first line is empty
 
The first line is empty
 
The last line is empty}}
 
The last line is empty}}
   
+
 
 
The '''change''' script:
 
The '''change''' script:
 
*removes the first line if empty, all the last empty line(s).
 
*removes the first line if empty, all the last empty line(s).
  
====put the comments away====
+
=== Only one statement per line ===
  
The comments might contain some keyword. It is very difficult to avoid the confusion with the very simple awk-scripts. We prefer to change all the comments with the same number of empty lines.
+
We don't provide (yet) any check for this rule.
  
*Comments.awk
+
=== Variable declaration ===
  
Download the scripts: [[Media:Comments.tar.gz]]
+
We follow the kdelibs rule: [[http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Variable_declaration]]
 +
We don't provide (yet) any check for this rule.
  
====change the strings====
+
=== Only one declaration per line ===
  
It is very difficult to parse the strings correctly, so we prefer to change them to an empty string.
+
We follow the kdelibs rule: [[http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Variable_declaration]]
 +
We don't provide (yet) any check for this rule.
  
*Strings.awk
+
=== Use one space after each keyword, but not after a cast ===
  
Download the scripts: [[Media:Strings.tar.gz]]
+
Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Whitespace
  
 +
For most of the keywords, it is not necessary to make a test. Because the sources have been already compiled. For example this code never appear in a compiled source:
 +
{{Output|1=intmyVariableAa;
 +
floatmyVariableBb;}}
  
After the use of the last two awk-scripts (Comments.awk and Strings.awk), we go on with the next check.
+
In this case, the missing space leads to a syntax error which is detected by the compiler. We don't need to check this manually.
  
====no "one line" if-statement====
+
Some of the keywords are alone in the statement, such as '''break''' and '''continue'''. No test is necessary.
  
Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Braces
+
The only tests we have to do are the ones where a keyword is (or can be) followed
 +
by a sign '''( { [ :'''
  
The following code:
+
These are:
{{Output|1=if ( a > b ) c = 123;}}
+
'''alignas decltype alignof noexcept typeid asm static_assert switch if catch while for sizeof new Q_FOREACH do try enum union Q_FOREVER bool char char16_t char32_t double float int long wchar_t signed unsigned short'''
is correct, but we prefer the block:
+
{{Output|1=if ( a > b ) {
+
  c = 123;
+
} }}
+
which is easier to read, to modify.
+
  
It is also possible to put a breakpoint at the line in the block.
+
For only '''one''' keyword:
 +
*coding-style-check-SpaceAfterKeyword.sh
 +
*coding-style-change-SpaceAfterKeyword.sh
  
As the awk-script is too simple to recognize all the if-statements, we get some false alarm and
 
we can't make the changes automatically.
 
  
*coding-style-check-One-Line-If.sh
+
For '''all''' keywords above:
 +
*coding-style-check-SpaceAfter.sh
 +
*coding-style-change-SpaceAfter.sh
  
Download the scripts: [[Media:One-Line-If.tar.gz]]
+
Download the scripts: [[Media:SpaceAfter.tar.gz]]
  
The output of the '''check''' script is:
+
=== Use a space after the name of the class ===
{{Output|1=check the file /home/guy-kde/Software/coding-style-check/if-example.cpp
+
1->25: one-line-if found}}
+
 
+
====Pedantic====
+
 
+
Looking over the git-history, one can find some "pedantic" changes.
+
These are changes to make a better code. The most of them are at the use of macro, where it is not necessary to have a ''';''' at the end ofthe command.
+
The script make a check over all these:
+
'''AKTEST_MAIN;MAKE_CMD_ROW;Q_DECLARE_FLAGS;Q_PRIVATE_SLOT;Q_DECLARE_METATYPE;Q_DECLARE_OPERATORS_FOR_FLAGS;Q_DE
+
CLARE_PRIVATE;Q_DECLARE_PUBLIC;Q_DISABLE_COPY;K_GLOBAL_STATIC;Q_IMPORT_PLUGIN;Q_PROPERTY;Q_UNUSED;QTEST_KDEMAIN;QTEST_MAIN'''
+
 
+
*coding-style-check-Pedantic.sh
+
 
+
Download the scripts: [[Media:Pedantic.tar.gz]]
+
 
+
====Public====
+
  
 
We prefer having a space before the keyword public at the definition of a new class:
 
We prefer having a space before the keyword public at the definition of a new class:
Line 277: Line 255:
 
*coding-style-check-Public.sh
 
*coding-style-check-Public.sh
 
*coding-style-change-Public.sh
 
*coding-style-change-Public.sh
 +
*astyle cannot (yet) do it
  
 
Download the scripts: [[Media:Public.tar.gz]]
 
Download the scripts: [[Media:Public.tar.gz]]
  
====#include directive====
+
The output of the '''check''' script is:
 +
{{Output|1=check the file contactstreemodel.cpp
 +
98:  if( at 10:          if(contact.realName().isEmpty()) {
 +
99:  if( at 12:            if(contact.preferredEmail().isEmpty()) {
 +
}}
 +
 
 +
The '''change''' script:
 +
*puts a space after the keyword.
 +
 
 +
=== #include directive ===
  
 
Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Qt_Includes
 
Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Qt_Includes
Line 289: Line 277:
 
# include <A/b>
 
# include <A/b>
  
// we prefer, to unify the coding style
+
// we prefer to unify the coding style
 
#include <A/b>}}
 
#include <A/b>}}
  
Line 296: Line 284:
 
Download the scripts: [[Media:Space-Include.tar.gz]]
 
Download the scripts: [[Media:Space-Include.tar.gz]]
  
====enum without any type====
+
=== Place '''*''' and '''&''' next to the variable ===
 +
 
 +
The declaration S *D; declares D as a pointer to the type determined by decl-specifier-seq S.
 +
 
 +
For most compilers, the three declarations below are semantically the same:
 +
 
 +
{{Output|1=int *a;
 +
int* b;
 +
int * c
 +
}}
 +
 
 +
We prefer the first one, without a space beetwen the star and the name of the variable:
 +
 
 +
{{Output|1=int *a;
 +
}}
 +
 
 +
The same rule may be use for:
 +
 
 +
{{Output|1=myFunction(int &a, int& b, int & c)
 +
{
 +
    // some lines
 +
}
 +
}}
 +
 
 +
We prefer:
 +
{{Output|1=myFunction(int &a, int &b, int &c)
 +
}}
 +
 
 +
The awk-script checks also the occurences of:
 +
* '''&,'''
 +
* '''& >'''
 +
* '''* >'''
 +
* '''( )''' and '''(  )''' ''empty function call''
 +
 
 +
* '''enum {''' ''untyped enum''
 +
 
 +
Not all the ouputs are real errors. Some codings might be correct.
 +
 
 +
*coding-style-check-NO-Space.sh
 +
*using astyle to make the changes:
 +
{{Output| 1=astyle --reference=name --align-pointer=name
 +
}}
 +
 
 +
 
 +
Some lines with "type & name..." must be manually corrected.
 +
 
 +
Download the scripts: [[Media:NO-Space.tar.gz]]
 +
 
 +
The script gives information about the found line(s).
 +
 
 +
=== Use '''namespace foo {''' in the same line ===
 +
 
 +
We prefer having all in one line:
 +
{{Output|1=namespace foo {
 +
  ...
 +
}
 +
}}
 +
 
 +
*coding-style-check-Namespace.sh
 +
 
 +
Download the scripts: [[Media:Namespace.tar.gz]]
 +
 
 +
=== Each member initialization of a method in separate line ===
 +
 
 +
This example shows the indentation we prefer:
 +
 
 +
{{Output|1=class myClass {
 +
    // some lines
 +
public:
 +
    myClass(int r, int b, int i, int j)
 +
        : r(0)
 +
        , b(i)
 +
        , i(5)
 +
        , j(13)
 +
{
 +
    // more lines
 +
}
 +
}}
 +
 
 +
*coding-style-check-Default-1.sh
 +
*coding-style-check-Default-2.sh
 +
*coding-style-change-Default-1.sh
 +
*coding-style-change-Default-2.sh
 +
*astyle cannot (yet) do it
 +
 
 +
Download the scripts: [[Media:Default-1.tar.gz]]
 +
Download the scripts: [[Media:Default-2.tar.gz]]
 +
 
 +
=== Surround all operators with spaces ===
 +
 
 +
This is well done with astyle:
 +
{{Output| 1=astyle --pad-oper
 +
}}
 +
 
 +
=== '''switch''' rules ===
 +
 
 +
This example shows the indentation we prefer:
 +
 
 +
{{Output|1=switch (a) {
 +
case ''one'':
 +
    // some lines
 +
    break;
 +
case ''two'': {
 +
    // some lines
 +
    break;
 +
}
 +
default:
 +
    // some lines
 +
    break;
 +
}
 +
}}
 +
 
 +
*coding-style-check-Switch.sh
 +
*astyle
 +
 
 +
Download the scripts: [[Media:Switch.tar.gz]]
 +
 
 +
=== '''try-catch''' rules ===
 +
 
 +
This example shows the indentation we prefer:
 +
 
 +
{{Output|1=try {
 +
    // some lines
 +
} catch (...) {
 +
}
 +
}}
 +
 
 +
*coding-style-check-Try.sh
 +
 
 +
Download the scripts: [[Media:Try-Catch.tar.gz]]
 +
 
 +
=== '''if''', '''for''', '''while''' (and similar macros) rules ===
 +
 
 +
Even for blocks with only one statement, we prefer to use braces such as:
 +
 
 +
{{Output|1=if (''condition'') {
 +
    ''statement;''
 +
}
 +
}}
 +
 
 +
This should be used with the keywords '''if''', '''for''', '''while''' and similar macros.
 +
The output of the '''check''' script is:
 +
 
 +
{{Output|1=check the file test-if.cpp
 +
62: if without { at end of line:    if ( collection.cachePolicyLocalParts() )
 +
}}
 +
 
 +
*coding-style-check-If.sh
 +
*coding-style-check-Else.sh
 +
*coding-style-check-For.sh
 +
*coding-style-check-While.sh
 +
*astyle
 +
 
 +
Download the scripts: [[Media:If.tar.gz]]
 +
Download the scripts: [[Media:Else.tar.gz]]
 +
Download the scripts: [[Media:For.tar.gz]]
 +
Download the scripts: [[Media:While.tar.gz]]
 +
 
 +
But we get some false alarm with statements that extend over more than one line:
 +
 
 +
{{Output|1=if (''condition_1''
 +
    && ''condition_2'') {
 +
    ''statement;''
 +
}
 +
}}
 +
 
 +
=== '''typedef struct''' statement over more lines ===
 +
 
 +
This example shows the indentation we prefer:
 +
 
 +
{{Output|1=typedef struct foo {
 +
    // some lines
 +
}
 +
}}
 +
 
 +
*coding-style-check-TypedefStruct.sh
 +
 
 +
Download the scripts: [[Media:TypedefStruct.tar.gz]]
 +
 
 +
=== Don't use '''&''' without a variable ===
 +
 
 +
=== Don't use untyped '''enum''' ===
  
 
Instead of having an untyped enum such as:
 
Instead of having an untyped enum such as:
Line 309: Line 478:
 
Download the scripts: [[Media:Enum.tar.gz]]
 
Download the scripts: [[Media:Enum.tar.gz]]
  
====enum without empty element====
+
=== Don't use '''enum''' with empty member ===
  
 
The most compilers do not complain such a code:
 
The most compilers do not complain such a code:
Line 319: Line 488:
 
}}
 
}}
  
The last element is empty.  
+
The last element is empty.
 
We prefer a "pedantic" code such as:
 
We prefer a "pedantic" code such as:
  
Line 331: Line 500:
  
 
The output of the '''check''' script is:
 
The output of the '''check''' script is:
  {{Output|1=check the file /home/guy-kde/Software/coding-style-check/enum-example.cpp
+
  {{Output|1=check the file enum-example.cpp
 
enum with ,} found at
 
enum with ,} found at
 
3->    bElement,
 
3->    bElement,
Line 339: Line 508:
 
Download the scripts: [[Media:Enum-Pedantic.tar.gz]]
 
Download the scripts: [[Media:Enum-Pedantic.tar.gz]]
  
==== Some more space(s)  ====
+
=== No ''';''' after some macros ===
  
The declaration S *D; declares D as a pointer to the type determined by decl-specifier-seq S.
+
Looking over the git-history, one can find some "pedantic" changes.
 +
These are changes to make a better code. The most of them are at the use of macro, where it is not necessary to have a ''';''' at the end ofthe command.
 +
The script make a check over all these:
 +
'''AKTEST_MAIN;MAKE_CMD_ROW;Q_DECLARE_FLAGS;Q_PRIVATE_SLOT;Q_DECLARE_METATYPE;Q_DECLARE_OPERATORS_FOR_FLAGS;Q_DE
 +
CLARE_PRIVATE;Q_DECLARE_PUBLIC;Q_DISABLE_COPY;K_GLOBAL_STATIC;Q_IMPORT_PLUGIN;Q_PROPERTY;QTEST_KDEMAIN;QTEST_MAIN'''
  
The most compilers do not make any difference for such lines of code:
+
*coding-style-check-Pedantic.sh
 +
*astyle cannot (yet) do it
  
{{Output|1=int *a;
+
Download the scripts: [[Media:Pedantic.tar.gz]]
int* b;
+
int * c}}
+
  
We prefer the first one, without a space beetwen the star and the name of the variable:
+
=== No "one line" '''if''' '''for''' '''while''' statement ===
  
{{Output|1=int *a;}}
+
Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Braces
  
The same rule may be use for:
+
The following code:
 
+
{{Output|1=if (a > b) c = 123;}}
{{Output|1=myFunction( int &a, int& b, int & c)
+
is correct, but we prefer the block:
  { // some lines
+
{{Output|1=if (a > b) {
  }
+
  c = 123;
 +
}
 
}}
 
}}
 +
which is easier to debug, to read and to modify.
  
We prefer:
+
It is also possible to put a breakpoint at the line in the block.
{{Output|1=myFunction( int &a, int &b, int &c) }}
+
  
The awk-script checks also the occurences of:
+
As the awk-script is too simple to recognize all the if-statements, we get some false alarm and
* '''&,'''
+
we can't make the changes automatically.
* '''& >'''
+
* '''* >'''
+
* '''( )''' and '''(  )''' ''empty function call''
+
* '''[ ''' and ''' ]''' ''index of an array''
+
* '''enum {''' ''untyped enum''
+
  
Not all the ouputs are real errors. Some codings might be correct.
+
*coding-style-check-OneLine-If.sh
  
*coding-style-check-NO-Space.sh
+
Download the scripts: [[Media:One-Line-If.tar.gz]]
  
Download the scripts: [[Media:NO-Space.tar.gz]]
+
The output of the '''check''' script is:
 +
{{Output|1=check the file if-example.cpp
 +
25: one-line-if found
 +
}}
  
The script gives informations about the found line(s).
+
=== No space between some keywords ===
  
==== Member initialization in a class  ====
+
We don't want to have a space:
 +
*after a '''*''' (star), but at the multiplication
 +
*between '''&''' and '''>'''
 +
*between '''*''' and '''>'''
 +
*between '''(''' and ''')''', an empty parameter list.
  
This example shows the indentation we prefer:
+
*coding-style-check-No-Space.sh
  
{{Output|1=class myClass {
+
The output of the '''check''' script is:
  // some lines
+
{{Output|1=check the file NO-space-example.cpp
public:
+
15: Star<Space> found. Check it.   int * myA;
   myClass( int i )
+
28: AND<Space> found. Check it.  abc( & myA);
    : r( a )
+
    , b( i )
+
    , i( i )
+
    , j( this->i )
+
  {
+
  }
+
 
}}
 
}}
  
*coding-style-check-Default.sh
+
Download the scripts: [[Media:NO-Space.tar.gz]]
  
Download the scripts: [[Media:Default.tar.gz]]
+
=== No space around the index of an array ===
  
But the script produces a false alarm with the code:
+
We don't want to have spaces around the index of an array element.
{{Output| 1=if ( ''<expression>'' ) ? a : b;
+
 
 +
*coding-style-check-No-Space.sh
 +
 
 +
The output of the '''check''' script is:
 +
{{Output|1=check the file NO-space-example.cpp
 +
15: [<Space> found. Check it.  a = b[ i ];
 +
15: <Space>] found. Check it.  a = b[ i ];
 
}}
 
}}
  
==== Parenthesis ====
+
Download the scripts: [[Media:NO-Space.tar.gz]]
  
We prefer function definition and function call with a space after the opening brace and before the closing brace.
+
=== No space around an expression surrounded with braces ===
The same is expected beetwen the braces of a '''if''', '''for''', '''do''', '''while''', '''foreach''' statements.
+
 
But not for the '''SLOT''' and '''SIGNAL''' macros.
+
We prefer function definition and function call with no space after the opening brace and before the closing brace.
The use of two braces '''((''' and '''))''' will be also signaled as a missing space.
+
  
 
*coding-style-check-Parenthesis.sh
 
*coding-style-check-Parenthesis.sh
 +
*This is well done with astyle:
 +
{{Output| 1=astyle --unpad-paren
 +
}}
 +
Note that astyle makes also changes within the macros SIGNAL and SLOT, which aren't desired.
 +
This can be corrected with a Qt-utility qt5/qtrepotools/util/normalize/normalize:
 +
{{Output| 1=normalize --modify ''filename''
 +
}}
  
Download the scripts: [[Media:Parenthesis.tar.gz]]
+
=== No space before ''':''' in a case statement ===
  
The changes must bedone manually.
+
We don't provide (yet) any check for this rule.
  
==== Switch statement ====
+
=== No space before ''';''' at the end of statement ===
  
This example shows the indentation we prefer:
+
We don't provide (yet) any check for this rule.
  
{{Output|1=switch ( a ) {
+
== Use all the scripts ==
case ''one'':
+
  // some lines
+
  break;
+
case ''two'':
+
  // some lines
+
  break;
+
default:
+
  // some lines
+
  break;
+
}
+
}}
+
  
*coding-style-check-Switch.sh
+
All the scripts can be used with one only script.
  
Download the scripts: [[Media:Switch.tar.gz]]
+
Download the scripts: [[Media:CodingStyle.tar.gz]]
  
==== Use block  braces ====
+
== Check the objects and the libs ==
  
Even for block with only one statement, we prefer to use braces such as:
+
Since the changes described above are only coding style changes, they are ignored by the compiler.
 +
Therefore, the result of the compilation is expected to be exactly the same after applying any of the rules.
  
==== Use one space after each keyword, but not after a cast ====
+
To check this, one uses the '''Md5sum-the-Objects.sh'''. Download the script: [[Media:Md5sum-the-Objects.tar.gz]]
 +
Same for the libs. Use the '''Md5sum-the-Libs.sh'''. Download the script: [[Media:Md5sum-the-Libs.tar.gz]]
  
Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Whitespace
+
The script can be used with one of the commands:
 +
* save
 +
* test
 +
* clean
  
For most of the keywords, it is not necessary to make a test. Because  the sources have been already compiled. For example this code never appear in a source:
+
'''An example:'''
{{Output|1=inta;
+
floatb;}}
+
  
Some of the keywords are alone in the statement, such as '''break''' and '''continue'''. No test is necessary.
+
{{Input|1=cd <some_kdepim_directory>
 +
mkdir build
 +
cd build
 +
ccmake ../
 +
make}}
 +
{{Output|1=<span style="color:Fuchsia">Scanning dependencies of target gpgmepp</span>
 +
[  0%] <span style="color:green">Building CXX object gpgme++/CMakeFiles/gpgmepp.dir/gpgmepp_automoc.cpp.o</span>
 +
[  0%] <span style="color:green">Building CXX object gpgme++/CMakeFiles/gpgmepp.dir/exception.cpp.o</span>
 +
[  0%] <span style="color:green">Building CXX object gpgme++/CMakeFiles/gpgmepp.dir/context.cpp.o</span>
 +
...}}
  
The only tests we have to do are the ones where a keyword is (or can be) followed
+
{{Input|1=Check-the-Objects.sh save}}
by a sign '''( { [ :'''
+
The script makes a copy of all the objects and a "time stamp":
 +
{{Output|1=save the object ./kholidays/tests/CMakeFiles/testzodiac.dir/testzodiac.cpp.o
 +
save the object ./kholidays/tests/CMakeFiles/testzodiac.dir/testzodiac_automoc.cpp.o
 +
...
 +
all objects are saved}}
  
These are:
+
Now, one makes somes change(s) on the source(s) and:
'''alignas decltype alignof noexcept typeid asm static_assert switch if catch while for sizeof new Q_FOREACH do try enum union Q_FOREVER bool char char16_t char32_t double float int long wchar_t signed unsigned short'''
+
  
For only '''one''' keyword:
+
{{Input| 1=make}}
*coding-style-check-SpaceAfterKeyword.sh
+
*coding-style-change-SpaceAfterKeyword.sh
+
  
For '''all''' keywords above:
+
Depending on the Makefile, some objects will be compiled again:
*coding-style-check-SpaceAfter.sh
+
*coding-style-change-SpaceAfter.sh
+
  
Download the scripts: [[Media:SpaceAfter.tar.gz]]
+
{{Output| 1=<span style="color:Fuchsia">Scanning dependencies of target akonadi-kde</span>
 +
[ 17%] <span style="color:green">Building CXX object akonadi/CMakeFiles/akonadi-kde.dir/entitytreeview.cpp.o</span>
 +
[ 17%] <span style="color:green">Building CXX object akonadi/CMakeFiles/akonadi-kde.dir/itemfetchjob.cpp.o</span>
 +
[ 17%] <span style="color:green">Building CXX object akonadi/CMakeFiles/akonadi-kde.dir/statisticsproxymodel.cpp.o</span>
 +
...
 +
<span style="color:Fuchsia">Scanning dependencies of target akonadi-kmime</span>
 +
[ 56%] <span style="color:green">Building CXX object akonadi/kmime/CMakeFiles/akonadi-kmime.dir/standardmailactionmanager.cpp.o</span>}}
  
The output of the '''check''' script is:
+
{{Input|1=Check-the-Objects.sh test}}
{{Output|1=check the file /home/guy-kde/projects/kdepimlibs/akonadi/contact/contactstreemodel.cpp
+
 
1->98:  if( at 10:          if( contact.realName().isEmpty() ) {
+
The script finds all the new objects, makes a comparision with the saved version:
2->99:  if( at 12:            if( contact.preferredEmail().isEmpty() ) {
+
{{Output|1=test the object ./akonadi/CMakeFiles/akonadi-kde.dir/statisticsproxymodel.cpp.o
 +
test the object ./akonadi/CMakeFiles/akonadi-kde.dir/entitytreeview.cpp.o
 +
test the object ./akonadi/CMakeFiles/akonadi-kde.dir/itemfetchjob.cpp.o
 +
test the object ./akonadi/kmime/CMakeFiles/akonadi-kmime.dir/standardmailactionmanager.cpp.o
 +
all tests are OK
 
}}
 
}}
  
The '''change''' script:
+
== Check the assembler files ==
*puts a space after the keyword.
+
If we add or remove some lines, the debug information included in the object file will change also.
 +
 
 +
This is the case with the test/change of "''Only single empty lines should be used''", "''First line, last line(s) may not be empty''" and some more test/change below (''adding some blocks'' with { and }).
 +
 
 +
For this reason it is no more possible to compare the objects.
 +
We have to compare the assembler files.
 +
This works pretty well for the version with '''CMAKE_BUILD_TYPE''' set to ''release''.
 +
For the version with '''CMAKE_BUILD_TYPE''' set to ''debug'', we must remove all the debug information before the comparision can take place.
 +
 
 +
=== Generate the assembler files ===
 +
 
 +
To generate the assembler files, we only need to modify the ''build.make'' in every folder.
 +
 
 +
The script '''Prepare-build_make_files.sh''' works on the all directory, finds the line with the compiler command,
 +
duplicates the line, add a ''-S option'' and changes the name of the output to ''somename.s''.
 +
After a new ''make'' command, we can save all the assembler files with the script '''Check-the-assembler_code.sh'''.
 +
Download the script: [[Media:Prepare.tar.gz]]
 +
 
 +
=== Remove the debug information ===
 +
 
 +
The debug information changes with the changes of line numbers.
 +
We drop all the debug information before making the test.
 +
 
 +
The script to check the assembler files can be used in the same way as the one above (Check-the-Objects.sh).
 +
To check this, one uses the '''Check-the-assembler_code.sh'''. Download the script: [[]]
 +
 
 +
The script can be used with one of the commands:
 +
* save
 +
* test
 +
* clean
 +
 
 +
== The results of the migration ==
 +
 
 +
The results can be seen [[here]].

Latest revision as of 17:38, 18 April 2014

Contents

[edit] Purpose of this document

This document describes the recommended coding style for kdepim and akonadi. Nobody is forced to use this style, but to have consistent formatting of the source code files it is strongly recommended to make use of it.

In short: Kdepim and akonadi coding style follows the Kdelibs coding style.

[edit] Why is coding Style useful?

Let us make a comparision with real life. To make an addition, one can write:

123
+      456
  ==========
     =      579

But we have learned in primary school to write:

Addition
  123
 +456
 ====
 =579

Which is much more readable, easy to control (or debug).

This is Coding Style: not mandatory but very useful and pretty to read.

[edit] What do we need?

We need at least:

  • a specification (a set of rules) for the coding style of the sources
  • some tools to check the sources against the specification
  • some tools to change the sources


astyle is a suitable tool to make such changes. But astyle doesn't implement (yet) all the specification rules.

You can find below some awk-scripts which help us to check all the rules.

You can find below some awk-scripts which help us to make most of the changes. The last part must be done manually.

[edit] The specification rules of coding style for kdepim and akonadi

  • Indentation with four spaces, don't use any <TAB>s
  • Trim the lines
  • Only single empty lines
  • The first line and the last line(s) may not be empty
  • Only one statement per line
  • Variable declaration
  • Only one declaration per line
  • Use a space after each keyword, but not after a cast
  • Use a space after the name of the class
  • include directive
  • Place * and & next to the variable
  • Use namespace foo { in the same line
  • Each member initialization of a method in a separate line
  • Surround all operators with spaces
  • switch rules
  • try-catch rules
  • if, for, while and similar macros rules
  • typedef struct statement over more lines
  • Don't use &, without a variable
  • Don't use untyped enum
  • Don't use enum with empty member
  • No ; after some macros
  • No "one line" if for while statement
  • No code after {
  • No code before '} (but else)
  • No header and body code in the same line, even empty body
  • No space between some keywords
  • No space around the index of an array
  • No space around an expression surrounded with braces
  • No space before : in a case statement
  • No space before ; at the end of statement

[edit] Migration

As discussed at the KDEPIM meeting, Berlin, 3 March 2013, all the files of KDEPIM will be reviewed to follow the coding style. This will be done over a long time, directory after directory, for each of the rules defined above. For each rule, there are one or two script(s).

The main part of the changes can be done with astyle: http://astyle.sourceforge.net/

The results can be seen here.

[edit] Two scripts to check all the rules and to make the all the changes

Most of the rules can be checked with the scripts below. For some of the rules, we don't have a script to change the sources. It is better first to make a check for such a rule, second to make the modification(s) manually to suscript the rule(s).

There are two scripts that run all the checks and apply all the changes at once:

  • All-Check.sh
  • Change-All.sh

Download the scripts: Media:ALL-Coding-Style.tar.gz

For each specification rule, the name of the scripts to check and apply the changes are given at the beginning of the section.

[edit] The scripts to check and to make the changes

The first script is to check a single file or all .h and .cpp files in a directory.

If present, the second script applies the changes. For some complicated situations, the script makes no change.

You can use the scripts for your own work. It is recommended to use them in this order.

[edit] Don't test all directories

If a .no_coding_style file is present on a directory, the test will not be done.

If a .no_recursion file is present on a directory, we do not explore the subdirectory(ies)

[edit] Indentation with four spaces, don't use any <TAB>s

  • coding-style-check-Tabs.sh
  • The changes are well done with
astyle --indent=spaces

Download the scripts: Media:Tabs.tar.gz

The output of the check script is:

check the file ktnefparser.cpp
308: Tab at 16:   stream_ >> i;              // i <- attribute type & name
311: Tab at 16:   stream_ >> i;              // i <- data length
326: Tab at 22:   case attATTACHMENT:        // try to get attachment info
367: Tab at 16:   stream_ >> u;      // u <- checksum

This shows:

  • the name of the file which is under test.
  • the line number, the position found and the line itself.

[edit] Trim the lines

  • coding-style-check-Trim.sh
  • The changes are well done with:
astyle --indent=spaces

Download the scripts: Media:Trim.tar.gz

The output of the check script is:

check the file trim.cpp
51: Space(s) at end of line (28):   QVariant m_matchData;

This shows:

  • the name of the file which is under test.
  • the line number, the position found and the line itself.

[edit] Only single empty lines

Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Whitespace

  • coding-style-check-Twice.sh
  • coding-style-change-Twice.sh
  • astyle cannot (yet) do it

Download the scripts: Media:Twice.tar.gz

The output of the check script is:

check the file enclosure.cpp
25: multiple empty line found
26: multiple empty line found
30: multiple empty line found

This shows:

  • the name of the file which is under test.
  • the line numbers.

The change script:

  • removes all the multiple empty line(s).

[edit] The first line and the last line(s) may not be empty

Some of the sources have empty lines at the beginning of the file. Some have one or more empty last line(s).

  • coding-style-check-First-Last.sh
  • coding-style-change-First-Last.sh
  • astyle cannot (yet) do it

Download the scripts: Media:First.tar.gz

The output of the check script is:

check the file trim.cpp
The first line is empty
The last line is empty

The change script:

  • removes the first line if empty, all the last empty line(s).

[edit] Only one statement per line

We don't provide (yet) any check for this rule.

[edit] Variable declaration

We follow the kdelibs rule: [[1]] We don't provide (yet) any check for this rule.

[edit] Only one declaration per line

We follow the kdelibs rule: [[2]] We don't provide (yet) any check for this rule.

[edit] Use one space after each keyword, but not after a cast

Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Whitespace

For most of the keywords, it is not necessary to make a test. Because the sources have been already compiled. For example this code never appear in a compiled source:

intmyVariableAa;
floatmyVariableBb;

In this case, the missing space leads to a syntax error which is detected by the compiler. We don't need to check this manually.

Some of the keywords are alone in the statement, such as break and continue. No test is necessary.

The only tests we have to do are the ones where a keyword is (or can be) followed by a sign ( { [ :

These are: alignas decltype alignof noexcept typeid asm static_assert switch if catch while for sizeof new Q_FOREACH do try enum union Q_FOREVER bool char char16_t char32_t double float int long wchar_t signed unsigned short

For only one keyword:

  • coding-style-check-SpaceAfterKeyword.sh
  • coding-style-change-SpaceAfterKeyword.sh


For all keywords above:

  • coding-style-check-SpaceAfter.sh
  • coding-style-change-SpaceAfter.sh

Download the scripts: Media:SpaceAfter.tar.gz

[edit] Use a space after the name of the class

We prefer having a space before the keyword public at the definition of a new class:

class DbException : public Akonadi::Exception
{
  ...
};
  • coding-style-check-Public.sh
  • coding-style-change-Public.sh
  • astyle cannot (yet) do it

Download the scripts: Media:Public.tar.gz

The output of the check script is:

check the file contactstreemodel.cpp
98:  if( at 10:           if(contact.realName().isEmpty()) {
99:  if( at 12:             if(contact.preferredEmail().isEmpty()) {

The change script:

  • puts a space after the keyword.

[edit] #include directive

Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Qt_Includes

We prefer no space at the beginning of the directive. Some (not many) files need to be corrected to unify to all the other files.

// some files use this
# include <A/b>

// we prefer to unify the coding style
#include <A/b>
  • coding-style-check-Space-Include.sh

Download the scripts: Media:Space-Include.tar.gz

[edit] Place * and & next to the variable

The declaration S *D; declares D as a pointer to the type determined by decl-specifier-seq S.

For most compilers, the three declarations below are semantically the same:

int *a;
int* b;
int * c

We prefer the first one, without a space beetwen the star and the name of the variable:

int *a;

The same rule may be use for:

myFunction(int &a, int& b, int & c)
{
    // some lines
}

We prefer:

myFunction(int &a, int &b, int &c)

The awk-script checks also the occurences of:

  • &,
  • & >
  • * >
  • ( ) and ( ) empty function call
  • enum { untyped enum

Not all the ouputs are real errors. Some codings might be correct.

  • coding-style-check-NO-Space.sh
  • using astyle to make the changes:
astyle --reference=name --align-pointer=name


Some lines with "type & name..." must be manually corrected.

Download the scripts: Media:NO-Space.tar.gz

The script gives information about the found line(s).

[edit] Use namespace foo { in the same line

We prefer having all in one line:

namespace foo {
  ...
}
  • coding-style-check-Namespace.sh

Download the scripts: Media:Namespace.tar.gz

[edit] Each member initialization of a method in separate line

This example shows the indentation we prefer:

class myClass {
    // some lines
public:
    myClass(int r, int b, int i, int j)
        : r(0)
        , b(i)
        , i(5)
        , j(13)
{
    // more lines
}
  • coding-style-check-Default-1.sh
  • coding-style-check-Default-2.sh
  • coding-style-change-Default-1.sh
  • coding-style-change-Default-2.sh
  • astyle cannot (yet) do it

Download the scripts: Media:Default-1.tar.gz Download the scripts: Media:Default-2.tar.gz

[edit] Surround all operators with spaces

This is well done with astyle:

astyle --pad-oper

[edit] switch rules

This example shows the indentation we prefer:

switch (a) {
case one:
    // some lines
    break;
case two: {
    // some lines
    break;
}
default:
    // some lines
    break;
}
  • coding-style-check-Switch.sh
  • astyle

Download the scripts: Media:Switch.tar.gz

[edit] try-catch rules

This example shows the indentation we prefer:

try {
    // some lines
} catch (...) {
}
  • coding-style-check-Try.sh

Download the scripts: Media:Try-Catch.tar.gz

[edit] if, for, while (and similar macros) rules

Even for blocks with only one statement, we prefer to use braces such as:

if (condition) {
    statement;
}

This should be used with the keywords if, for, while and similar macros. The output of the check script is:

check the file test-if.cpp
62: if without { at end of line:     if ( collection.cachePolicyLocalParts() )
  • coding-style-check-If.sh
  • coding-style-check-Else.sh
  • coding-style-check-For.sh
  • coding-style-check-While.sh
  • astyle

Download the scripts: Media:If.tar.gz Download the scripts: Media:Else.tar.gz Download the scripts: Media:For.tar.gz Download the scripts: Media:While.tar.gz

But we get some false alarm with statements that extend over more than one line:

if (condition_1
    && condition_2) {
    statement;
}

[edit] typedef struct statement over more lines

This example shows the indentation we prefer:

typedef struct foo {
    // some lines
}
  • coding-style-check-TypedefStruct.sh

Download the scripts: Media:TypedefStruct.tar.gz

[edit] Don't use & without a variable

[edit] Don't use untyped enum

Instead of having an untyped enum such as:

enum {
    aElement= 123
}

we prefer a #define directive:

#define aElement 123

Download the scripts: Media:Enum.tar.gz

[edit] Don't use enum with empty member

The most compilers do not complain such a code:

enum mytype {
    aElement,
    bElement,
}

The last element is empty. We prefer a "pedantic" code such as:

enum mytype {
    aElement,
    bElement
}
  • coding-style-check-Enum-Pedantic.sh

The output of the check script is:

check the file enum-example.cpp
enum with ,} found at
3->    bElement,
4->  }

Download the scripts: Media:Enum-Pedantic.tar.gz

[edit] No ; after some macros

Looking over the git-history, one can find some "pedantic" changes. These are changes to make a better code. The most of them are at the use of macro, where it is not necessary to have a ; at the end ofthe command. The script make a check over all these: AKTEST_MAIN;MAKE_CMD_ROW;Q_DECLARE_FLAGS;Q_PRIVATE_SLOT;Q_DECLARE_METATYPE;Q_DECLARE_OPERATORS_FOR_FLAGS;Q_DE CLARE_PRIVATE;Q_DECLARE_PUBLIC;Q_DISABLE_COPY;K_GLOBAL_STATIC;Q_IMPORT_PLUGIN;Q_PROPERTY;QTEST_KDEMAIN;QTEST_MAIN

  • coding-style-check-Pedantic.sh
  • astyle cannot (yet) do it

Download the scripts: Media:Pedantic.tar.gz

[edit] No "one line" if for while statement

Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Braces

The following code:

if (a > b) c = 123;

is correct, but we prefer the block:

if (a > b) {
   c = 123;
}

which is easier to debug, to read and to modify.

It is also possible to put a breakpoint at the line in the block.

As the awk-script is too simple to recognize all the if-statements, we get some false alarm and we can't make the changes automatically.

  • coding-style-check-OneLine-If.sh

Download the scripts: Media:One-Line-If.tar.gz

The output of the check script is:

check the file if-example.cpp
25: one-line-if found

[edit] No space between some keywords

We don't want to have a space:

  • after a * (star), but at the multiplication
  • between & and >
  • between * and >
  • between ( and ), an empty parameter list.
  • coding-style-check-No-Space.sh

The output of the check script is:

check the file NO-space-example.cpp
15: Star<Space> found. Check it.   int * myA;
28: AND<Space> found. Check it.   abc( & myA);

Download the scripts: Media:NO-Space.tar.gz

[edit] No space around the index of an array

We don't want to have spaces around the index of an array element.

  • coding-style-check-No-Space.sh

The output of the check script is:

check the file NO-space-example.cpp
15: [<Space> found. Check it.   a = b[ i ];
15: <Space>] found. Check it.   a = b[ i ];

Download the scripts: Media:NO-Space.tar.gz

[edit] No space around an expression surrounded with braces

We prefer function definition and function call with no space after the opening brace and before the closing brace.

  • coding-style-check-Parenthesis.sh
  • This is well done with astyle:
astyle --unpad-paren

Note that astyle makes also changes within the macros SIGNAL and SLOT, which aren't desired. This can be corrected with a Qt-utility qt5/qtrepotools/util/normalize/normalize:

normalize --modify filename

[edit] No space before : in a case statement

We don't provide (yet) any check for this rule.

[edit] No space before ; at the end of statement

We don't provide (yet) any check for this rule.

[edit] Use all the scripts

All the scripts can be used with one only script.

Download the scripts: Media:CodingStyle.tar.gz

[edit] Check the objects and the libs

Since the changes described above are only coding style changes, they are ignored by the compiler. Therefore, the result of the compilation is expected to be exactly the same after applying any of the rules.

To check this, one uses the Md5sum-the-Objects.sh. Download the script: Media:Md5sum-the-Objects.tar.gz Same for the libs. Use the Md5sum-the-Libs.sh. Download the script: Media:Md5sum-the-Libs.tar.gz

The script can be used with one of the commands:

  • save
  • test
  • clean

An example:

cd <some_kdepim_directory>
mkdir build
cd build
ccmake ../
make
Scanning dependencies of target gpgmepp
[  0%] Building CXX object gpgme++/CMakeFiles/gpgmepp.dir/gpgmepp_automoc.cpp.o
[  0%] Building CXX object gpgme++/CMakeFiles/gpgmepp.dir/exception.cpp.o
[  0%] Building CXX object gpgme++/CMakeFiles/gpgmepp.dir/context.cpp.o
...
Check-the-Objects.sh save

The script makes a copy of all the objects and a "time stamp":

save the object ./kholidays/tests/CMakeFiles/testzodiac.dir/testzodiac.cpp.o
save the object ./kholidays/tests/CMakeFiles/testzodiac.dir/testzodiac_automoc.cpp.o
...
all objects are saved

Now, one makes somes change(s) on the source(s) and:

make

Depending on the Makefile, some objects will be compiled again:

Scanning dependencies of target akonadi-kde
[ 17%] Building CXX object akonadi/CMakeFiles/akonadi-kde.dir/entitytreeview.cpp.o
[ 17%] Building CXX object akonadi/CMakeFiles/akonadi-kde.dir/itemfetchjob.cpp.o
[ 17%] Building CXX object akonadi/CMakeFiles/akonadi-kde.dir/statisticsproxymodel.cpp.o
...
Scanning dependencies of target akonadi-kmime
[ 56%] Building CXX object akonadi/kmime/CMakeFiles/akonadi-kmime.dir/standardmailactionmanager.cpp.o
Check-the-Objects.sh test

The script finds all the new objects, makes a comparision with the saved version:

test the object ./akonadi/CMakeFiles/akonadi-kde.dir/statisticsproxymodel.cpp.o
test the object ./akonadi/CMakeFiles/akonadi-kde.dir/entitytreeview.cpp.o
test the object ./akonadi/CMakeFiles/akonadi-kde.dir/itemfetchjob.cpp.o
test the object ./akonadi/kmime/CMakeFiles/akonadi-kmime.dir/standardmailactionmanager.cpp.o
all tests are OK

[edit] Check the assembler files

If we add or remove some lines, the debug information included in the object file will change also.

This is the case with the test/change of "Only single empty lines should be used", "First line, last line(s) may not be empty" and some more test/change below (adding some blocks with { and }).

For this reason it is no more possible to compare the objects. We have to compare the assembler files. This works pretty well for the version with CMAKE_BUILD_TYPE set to release. For the version with CMAKE_BUILD_TYPE set to debug, we must remove all the debug information before the comparision can take place.

[edit] Generate the assembler files

To generate the assembler files, we only need to modify the build.make in every folder.

The script Prepare-build_make_files.sh works on the all directory, finds the line with the compiler command, duplicates the line, add a -S option and changes the name of the output to somename.s. After a new make command, we can save all the assembler files with the script Check-the-assembler_code.sh. Download the script: Media:Prepare.tar.gz

[edit] Remove the debug information

The debug information changes with the changes of line numbers. We drop all the debug information before making the test.

The script to check the assembler files can be used in the same way as the one above (Check-the-Objects.sh). To check this, one uses the Check-the-assembler_code.sh. Download the script: [[]]

The script can be used with one of the commands:

  • save
  • test
  • clean

[edit] The results of the migration

The results can be seen here.


This page was last modified on 18 April 2014, at 17:38. This page has been accessed 12,187 times. Content is available under Creative Commons License SA 3.0 as well as the GNU Free Documentation License 1.2.
KDE® and the K Desktop Environment® logo are registered trademarks of KDE e.V.Legal