Difference between revisions of "Policies/Kdepim Coding Style"

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[http://techbase.kde.org/Policies/Kdelibs_Coding_Style Kdelibs coding style].
 
[http://techbase.kde.org/Policies/Kdelibs_Coding_Style Kdelibs coding style].
  
We need at least:
+
== Why is coding Style useful? ==
*a specification (a set of rules) for the coding style of the sources
+
 
*some tools to check the sources against the specification
+
Let us make a comparision with real life.
*some tools to change the sources
+
To make an addition, one can write:
 +
 
 +
{{Output| 1=123
 +
+      456
 +
  ==========
 +
    =      579
 +
}}
 +
 
 +
But we have learned in primary school to write:
 +
 
 +
{{Output| 1=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.
 +
 
 +
== 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'''
 +
 
 +
 
 +
[http://astyle.sourceforge.net/ 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.
  
astyle is a pretty 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 make most of the changes.
 
You can find below some awk-scripts which help us to make most of the changes.
 
The last part must be done manually.
 
The last part must be done manually.
Line 19: Line 49:
 
== The specification rules of coding style for kdepim and akonadi ==
 
== The specification rules of coding style for kdepim and akonadi ==
  
*Don't use any <TAB>s
+
*Indentation with four spaces, don't use any <TAB>s
 
*Trim the lines
 
*Trim the lines
 
*Only single empty lines
 
*Only single empty lines
*The first line, the last line(s) may not be empty
+
*The first line and the last line(s) may not be empty
*Use one space after each keyword, but not after a cast
+
*Only one statement per line
*No "one line" if-statement
+
*Variable declaration
*No ; after some macros
+
*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
 
*Use a space after the name of the class
*Don't use untyped enum
+
*include directive
*Don't use enum with empty member
+
*Place '''*''' and '''&''' next to the variable
*Place '''*''' and '''&''' near the variable
+
*Use '''namespace foo {''' in the same line
*Don't use '''&,''' without a variable
+
*Each member initialization of a method in a separate line
*No space for '''& >''', '''* >''', '''( )''' or '''(  )'''
+
*Surround all operators with spaces
*No space arround the index of an array
+
*Each initialization of a method in a separate line
+
 
*'''switch''' rules
 
*'''switch''' rules
 +
*'''try-catch''' rules
 
*'''if''', '''for''', '''while''' and similar macros rules
 
*'''if''', '''for''', '''while''' and similar macros rules
*No space arround an expression surrounded with braces
+
*'''typedef struct''' statement over more lines
*Surround all operators with spaces
+
*Don't use '''&,''' without a variable
*identation with four spaces
+
*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
 +
*No ''');''' alone in a line
  
 
== Migration ==
 
== Migration ==
Line 45: Line 87:
 
be reviewed to follow the coding style.  This will be done over a long time,
 
be reviewed to follow the coding style.  This will be done over a long time,
 
directory after directory, for each of the
 
directory after directory, for each of the
rules defined above.  For each rule, one can find one or two script(s).
+
rules defined above.  For each rule, there are one or two script(s).
  
 
The main part of the changes can be done with astyle:
 
The main part of the changes can be done with astyle:
 
http://astyle.sourceforge.net/
 
http://astyle.sourceforge.net/
  
 +
The results can be seen [http://techbase.kde.org/ResultsOfTheMigration here].
  
 +
== Download Coding Style ==
  
== The scripts ==
+
You can download the software with test files and install instructions.
  
The first script is '''to check''' a single file or a complete directory for all .h and
+
Download Coding Style: [[Media:CodingStyle.tar.gz]]
.cpp files.
+
  
If present, the second script '''makes the changes''' for a single file or a complete
+
== Two scripts '''to check all the rules''' and '''to make the all the changes''' ==
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.
+
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).
  
=== Don't test a subdirectory ===
+
There are two scripts that run all the checks and apply all the changes at once:
 +
*All-Check.sh
 +
*Change-All.sh
 +
 
 +
For each specification rule, the name of the scripts to check and apply the changes
 +
are given at the beginning of the section.
 +
 
 +
== 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.
 +
 
 +
=== 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_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)
 
If a '''.no_recursion''' file is present on a directory, we do not explore the subdirectory(ies)
  
=== don't use any <TAB>s ===
+
=== Indentation with four spaces, don't use any <TAB>s ===
 +
 
 
*coding-style-check-Tabs.sh
 
*coding-style-check-Tabs.sh
*The changes are well done with astyle
+
*The changes are well done with
 +
{{Output| 1=astyle --indent=spaces
 +
}}
  
Download the scripts: [[Media:Tabs.tar.gz]]
 
  
 
The output of the '''check''' script is:
 
The output of the '''check''' script is:
Line 80: Line 142:
 
326: Tab at 22:  case attATTACHMENT:        // try to get attachment info
 
326: Tab at 22:  case attATTACHMENT:        // try to get attachment info
 
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.
  
 
=== Trim the lines ===
 
=== Trim the lines ===
  
 
*coding-style-check-Trim.sh
 
*coding-style-check-Trim.sh
*The changes are well done with astyle
+
*The changes are well done with:
 +
{{Output| 1=astyle --indent=spaces
 +
}}
  
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 trim.cpp
 
  {{Output|1=check the file trim.cpp
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.
  
=== 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
  
Line 108: Line 172:
 
* astyle cannot (yet) do it
 
* astyle cannot (yet) do it
  
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 enclosure.cpp
 
{{Output|1=check the file enclosure.cpp
25: next empty line found
+
25: multiple empty line found
26: next empty line found
+
26: multiple empty line found
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
 
*astyle cannot (yet) do it
  
Download the scripts: [[Media:First.tar.gz]]
 
  
 
The output of the '''check''' script is:
 
The output of the '''check''' script is:
Line 136: Line 199:
 
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
Download the scripts: [[Media:One-Line-If.tar.gz]]
+
*coding-style-change-SpaceAfter.sh
 
+
The output of the '''check''' script is:
+
{{Output|1=check the file if-example.cpp
+
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
+
*astyle cannot (yet) do it
+
 
+
Download the scripts: [[Media:Pedantic.tar.gz]]
+
  
===Public===
+
=== 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:
 
We prefer having a space before the keyword public at the definition of a new class:
Line 209: Line 256:
 
*astyle cannot (yet) do it
 
*astyle cannot (yet) do it
  
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 220: Line 275:
 
# 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>}}
  
 
*coding-style-check-Space-Include.sh
 
*coding-style-check-Space-Include.sh
  
Download the scripts: [[Media:Space-Include.tar.gz]]
+
=== Place '''*''' and '''&''' next to the variable ===
 
+
===enum without any type===
+
 
+
Instead of having an untyped enum such as:
+
{{Output|1=  enum {
+
    aElement= 123
+
}
+
}}
+
we prefer a #define directive:
+
{{Output|1=#define aElement 123
+
}}
+
 
+
Download the scripts: [[Media:Enum.tar.gz]]
+
 
+
===enum without empty element===
+
 
+
The most compilers do not complain such a code:
+
 
+
{{Output|1=  enum mytype {
+
    aElement,
+
    bElement,
+
}
+
}}
+
 
+
The last element is empty.
+
We prefer a "pedantic" code such as:
+
 
+
{{Output|1=  enum mytype {
+
    aElement,
+
    bElement
+
}
+
}}
+
 
+
*coding-style-check-Enum-Pedantic.sh
+
 
+
The output of the '''check''' script is:
+
{{Output|1=check the file enum-example.cpp
+
enum with ,} found at
+
3->    bElement,
+
4->  }
+
}}
+
 
+
Download the scripts: [[Media:Enum-Pedantic.tar.gz]]
+
 
+
=== Some more space(s)  ===
+
  
 
The declaration S *D; declares D as a pointer to the type determined by decl-specifier-seq S.
 
The declaration S *D; declares D as a pointer to the type determined by decl-specifier-seq S.
  
The most compilers do not make any difference for such lines of code:
+
For most compilers, the three declarations below are semantically the same:
  
 
{{Output|1=int *a;
 
{{Output|1=int *a;
 
int* b;
 
int* b;
int * c}}
+
int * c
 +
}}
  
 
We prefer the first one, without a space beetwen the star and the name of the variable:
 
We prefer the first one, without a space beetwen the star and the name of the variable:
  
{{Output|1=int *a;}}
+
{{Output|1=int *a;
 +
}}
  
 
The same rule may be use for:
 
The same rule may be use for:
Line 293: Line 305:
  
 
We prefer:
 
We prefer:
{{Output|1=myFunction(int &a, int &b, int &c) }}
+
{{Output|1=myFunction(int &a, int &b, int &c)
 +
}}
  
 
The awk-script checks also the occurences of:
 
The awk-script checks also the occurences of:
Line 300: Line 313:
 
* '''* >'''
 
* '''* >'''
 
* '''( )''' and '''(  )''' ''empty function call''
 
* '''( )''' and '''(  )''' ''empty function call''
* '''[ ''' and ''' ]''' ''index of an array''
+
 
 
* '''enum {''' ''untyped enum''
 
* '''enum {''' ''untyped enum''
  
Line 306: Line 319:
  
 
*coding-style-check-NO-Space.sh
 
*coding-style-check-NO-Space.sh
*astyle --reference=name
+
*using astyle to make the changes:
Note that astyle makes also changes within the macros SIGNAL and SLOT, which aren't desired.
+
{{Output| 1=astyle --reference=name --align-pointer=name
This can be corrected with a Qt-utility:
+
}}
normalize ''filename''
+
 
  
 
Some lines with "type & name..." must be manually corrected.
 
Some lines with "type & name..." must be manually corrected.
  
Download the scripts: [[Media:NO-Space.tar.gz]]
 
  
The script gives informations about the found line(s).
+
The script gives information about the found line(s).
  
=== Member initialization in a class  ===
+
=== Use '''namespace foo {''' in the same line ===
 +
 
 +
We prefer having all in one line:
 +
{{Output|1=namespace foo {
 +
  ...
 +
}
 +
}}
 +
 
 +
*coding-style-check-Namespace.sh
 +
 
 +
=== Each member initialization of a method in separate line ===
  
 
This example shows the indentation we prefer:
 
This example shows the indentation we prefer:
Line 324: Line 346:
 
     // some lines
 
     // some lines
 
public:
 
public:
     myClass( int i )
+
     myClass(int r, int b, int i, int j)
         : r(a)
+
         : r(0)
 
         , b(i)
 
         , b(i)
         , i(i)
+
         , i(5)
         , j(this->i)
+
         , j(13)
 
{
 
{
 
     // more lines
 
     // more lines
Line 334: Line 356:
 
}}
 
}}
  
*coding-style-check-Default.sh
+
*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
 
*astyle cannot (yet) do it
  
Download the scripts: [[Media:Default.tar.gz]]
+
=== Surround all operators with spaces ===
  
But the script produces a false alarm with the code:
+
This is well done with astyle:
{{Output| 1=if (''<expression>'') ? a : b;
+
{{Output| 1=astyle --pad-oper
 
}}
 
}}
  
The changes must be done manualy
+
=== '''switch''' rules ===
 
+
=== Parenthesis ===
+
 
+
We prefer function definition and function call with no space after the opening brace and before the closing brace.
+
 
+
*coding-style-check-Parenthesis.sh
+
*astyle
+
 
+
Download the scripts: [[Media:Parenthesis.tar.gz]]
+
 
+
=== Switch statement ===
+
  
 
This example shows the indentation we prefer:
 
This example shows the indentation we prefer:
Line 362: Line 376:
 
     // some lines
 
     // some lines
 
     break;
 
     break;
case ''two'':
+
case ''two'': {
 
     // some lines
 
     // some lines
 
     break;
 
     break;
 +
}
 
default:
 
default:
 
     // some lines
 
     // some lines
Line 374: Line 389:
 
*astyle
 
*astyle
  
Download the scripts: [[Media:Switch.tar.gz]]
+
=== '''try-catch''' rules ===
  
=== Use block  braces ===
+
This example shows the indentation we prefer:
 +
 
 +
{{Output|1=try {
 +
    // some lines
 +
} catch (...) {
 +
}
 +
}}
 +
 
 +
*coding-style-check-TryCatch.sh
 +
 
 +
=== '''if''', '''for''', '''while''' (and similar macros) rules ===
  
Even for block with only one statement, we prefer to use braces such as:
+
Even for blocks with only one statement, we prefer to use braces such as:
  
 
{{Output|1=if (''condition'') {
 
{{Output|1=if (''condition'') {
Line 385: Line 410:
 
}}
 
}}
  
This should be used with the keywords '''if''', '''for''', '''while''' and '''FOREACH'''.
+
This should be used with the keywords '''if''', '''for''', '''while''' and similar macros.
 
+
 
The output of the '''check''' script is:
 
The output of the '''check''' script is:
  
Line 394: Line 418:
  
 
*coding-style-check-If.sh
 
*coding-style-check-If.sh
 +
*coding-style-check-Else.sh
 +
*coding-style-check-For.sh
 +
*coding-style-check-While.sh
 
*astyle
 
*astyle
  
Download the scripts: [[Media:If.tar.gz]]
 
  
But we get some false alarm with statement over more than one line:
+
But we get some false alarm with statements that extend over more than one line:
  
 
{{Output|1=if (''condition_1''
 
{{Output|1=if (''condition_1''
Line 406: Line 432:
 
}}
 
}}
  
=== Use one space after each keyword, but not after a cast ===
+
=== '''typedef struct''' statement over more lines ===
  
Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Whitespace
+
This example shows the indentation we prefer:
  
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:
+
{{Output|1=typedef struct foo {
{{Output|1=inta;
+
    // some lines
floatb;}}
+
}
 +
}}
  
Some of the keywords are alone in the statement, such as '''break''' and '''continue'''. No test is necessary.
+
*coding-style-check-TypedefStruct.sh
  
The only tests we have to do are the ones where a keyword is (or can be) followed
+
=== Don't use '''&''' without a variable ===
by a sign '''( { [ :'''
+
  
These are:
+
=== Don't use untyped '''enum''' ===
'''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:
+
Instead of having an untyped enum such as:
*coding-style-check-SpaceAfterKeyword.sh
+
{{Output|1=  enum {
*coding-style-change-SpaceAfterKeyword.sh
+
    aElement= 123
 +
}
 +
}}
 +
we prefer a #define directive:
 +
{{Output|1=#define aElement 123
 +
}}
  
 +
=== Don't use '''enum''' with empty member ===
  
For '''all''' keywords above:
+
The most compilers do not complain such a code:
*coding-style-check-SpaceAfter.sh
+
*coding-style-change-SpaceAfter.sh
+
  
 +
{{Output|1=  enum mytype {
 +
    aElement,
 +
    bElement,
 +
}
 +
}}
  
Download the scripts: [[Media:SpaceAfter.tar.gz]]
+
The last element is empty.
 +
We prefer a "pedantic" code such as:
 +
 
 +
{{Output|1=  enum mytype {
 +
    aElement,
 +
    bElement
 +
}
 +
}}
 +
 
 +
*coding-style-check-Enum-Pedantic.sh
  
 
The output of the '''check''' script is:
 
The output of the '''check''' script is:
{{Output|1=check the file contactstreemodel.cpp
+
{{Output|1=check the file enum-example.cpp
98:  if( at 10:          if(contact.realName().isEmpty()) {
+
enum with ,} found at
99: if( at 12:            if(contact.preferredEmail().isEmpty()) {
+
3->    bElement,
 +
4-> }
 
}}
 
}}
  
The '''change''' script:
+
=== No ''';''' after some macros ===
*puts a space after the keyword.
+
 
 +
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
 +
 
 +
=== No "one line" '''if''' '''else''' '''for''' '''while''' statement ===
 +
 
 +
Refer to http://techbase.kde.org/Policies/Kdelibs_Coding_Style#Braces
 +
 
 +
The following code:
 +
{{Output|1=if (a > b) c = 123;}}
 +
is correct, but we prefer the block:
 +
{{Output|1=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
 +
*coding-style-check-OneLine-Else.sh
 +
 
 +
 
 +
The output of the '''check''' script is:
 +
{{Output|1=check the file if-example.cpp
 +
25: one-line-if found
 +
}}
 +
 
 +
=== No space between some keywords ===
 +
 
 +
We don't want to have a space:
 +
*between '''&''' and '''>'''
 +
*between '''*''' and '''>'''
 +
*between '''(''' and ''')''', an empty parameter list.
 +
 
 +
*coding-style-check-No-Space.sh
 +
 
 +
The output of the '''check''' script is:
 +
{{Output|1=check the file NO-space-example.cpp
 +
15: Star<Space> found. Check it.  int * myA;
 +
28: AND<Space> found. Check it.  abc( & myA);
 +
}}
 +
 
 +
=== 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:
 +
{{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 ];
 +
}}
 +
 
 +
=== 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:
 +
{{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''
 +
}}
 +
 
 +
=== No space before ''':''' in a case statement ===
 +
 
 +
We don't provide (yet) any check for this rule.
 +
 
 +
=== No space before ''';''' at the end of statement ===
 +
 
 +
We don't provide (yet) any check for this rule.
 +
 
 +
=== No ''');''' alone in a line ===
 +
 
 +
This is sometime to be find with a function call with many arguments, listed on many lines.
 +
*coding-style-check-Parenthesis-alone.sh
  
 
== Use all the scripts ==
 
== Use all the scripts ==
  
 
All the scripts can be used with one only script.
 
All the scripts can be used with one only script.
 
Download the scripts: [[Media:All.tar.gz]]
 
  
 
== Check the objects and the libs ==
 
== Check the objects and the libs ==
  
As a first approach, not any object may have binary change after applying one of the rules.
+
Since the changes described above are only coding style changes, they are ignored by the compiler.
To check this, one uses the '''Md5sum-the-Objects.sh'''. Download the script: [[Media:Md5sum-the-Objects.sh.gz]]
+
Therefore, the result of the compilation is expected to be exactly the same after applying any of the rules.
Same for the libs. Use the '''Md5sum-the-Libs.sh'''. Download the script: [[Media:Md5sum-the-Libs.sh.gz]]
+
 
 +
To check this, one uses the '''Md5sum-the-Objects.sh'''.
 +
Same for the libs. Use the '''Md5sum-the-Libs.sh'''.
  
 
The script can be used with one of the commands:
 
The script can be used with one of the commands:
Line 505: Line 637:
  
 
== Check the assembler files ==
 
== Check the assembler files ==
If we add or remove some lines, the debug informations included in the object file will be change also.
+
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 }).
 
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 }).
Line 512: Line 644:
 
We have to compare the assembler files.
 
We have to compare the assembler files.
 
This works pretty well for the version with '''CMAKE_BUILD_TYPE''' set to ''release''.
 
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.
+
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 ===
 
=== Generate the assembler files ===
Line 521: Line 653:
 
duplicates the line, add a ''-S option'' and changes the name of the output to ''somename.s''.
 
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'''.
 
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-build_make_files.gz]]
 
  
=== Remove the debug informations ===
+
=== Remove the debug information ===
  
The debug informations change with the changes of line numbers.
+
The debug information changes with the changes of line numbers.
We drop all these debug informations before making the test.
+
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).
 
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: [[Media:Check-the-assembler_code.sh.gz]]
+
To check this, one uses the '''Check-the-assembler_code.sh'''.
  
 
The script can be used with one of the commands:
 
The script can be used with one of the commands:
Line 535: Line 666:
 
* test
 
* test
 
* clean
 
* clean
 +
 +
== The results of the migration ==
 +
 +
The results can be seen [http://techbase.kde.org/ResultsOfTheMigration here].

Revision as of 13:34, 13 June 2014

Contents

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.

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.

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.

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
  • No ); alone in a line

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.

Download Coding Style

You can download the software with test files and install instructions.

Download Coding Style: Media:CodingStyle.tar.gz

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

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

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.

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)

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

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


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.

Trim the lines

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


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.

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


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).

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


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).

Only one statement per line

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

Variable declaration

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

Only one declaration per line

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

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

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


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.

#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

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.


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

Use namespace foo { in the same line

We prefer having all in one line:

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

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

Surround all operators with spaces

This is well done with astyle:

astyle --pad-oper

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

try-catch rules

This example shows the indentation we prefer:

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

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


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

if (condition_1
    && condition_2) {
    statement;
}

typedef struct statement over more lines

This example shows the indentation we prefer:

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

Don't use & without a variable

Don't use untyped enum

Instead of having an untyped enum such as:

enum {
    aElement= 123
}

we prefer a #define directive:

#define aElement 123

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->  }

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

No "one line" if else 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
  • coding-style-check-OneLine-Else.sh


The output of the check script is:

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

No space between some keywords

We don't want to have a space:

  • 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);

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 ];

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

No space before : in a case statement

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

No space before ; at the end of statement

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

No ); alone in a line

This is sometime to be find with a function call with many arguments, listed on many lines.

  • coding-style-check-Parenthesis-alone.sh

Use all the scripts

All the scripts can be used with one only script.

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. Same for the libs. Use the Md5sum-the-Libs.sh.

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

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.

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.

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.

The script can be used with one of the commands:

  • save
  • test
  • clean

The results of the migration

The results can be seen here.


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