wiki:CodingStyle

Version 24 (modified by davea, 12 years ago) (diff)

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BOINC coding style

All languages

Code factoring

  • If code is repeated, factor it out and make it into a function.
  • If a function becomes longer than 100 lines or so, split it up.
  • If a file is becoming 'landfill', split it up.
  • C++ .h files often contain both interface and implementation. Clearly divide these.

Code documentation

  • .cpp files have a comment at the top saying what's in the file (and perhaps what isn't).
  • Functions are preceded by a comment saying what they do.
  • structs and classes are preceded by a comment saying what they are.

Naming

  • Names should be descriptive without being verbose (local variables names may be short).
  • Class and type names, and #defined symbols, are all upper case, with underscores to separate words.
  • Variable and function names are all lower case, with underscores to separate words.
  • No mixed case names.

Indentation

  • Each level of indentation is 4 spaces (not a tab).
  • Multi-line function call:
    func(
        blah, blah, blah, blah, blah,
        blah, blah, blah, blah, blah
    );
    
  • switch statements: case labels are at same indent level as switch:
    switch (foo) {
    case 1:
        ...
        break;
    case 2:
        ...
        break;
    }
    

Constants

  • There should be few numeric constants in code. Generally they should be #defines.

Braces

  • Opening curly brace goes at end of line (not next line):
    if (foobar) {
        ...
    } else if (blah) {
        ...
    } else {
        ...
    }
    
  • Always use curly braces on multi-line if statements.
    if (foo)
        return blah;     // WRONG
    
  • 1-line if() statements are OK:
    if (foo) return blah;
    

Comments and #ifdefs

  • Use /// for all comments. The documentation is generated using Doxygen, so you should have a look at this example:
/// Brief description for class test.

/// A more elaborate description for class test,
/// could be more than one line.
class Test
{
  public:

    /// A constructor.
      
    /// A more elaborate description of the constructor.
    Test();

    /// A destructor.
    /// A more elaborate description of the destructor.
    ~Test();
    
    /// a normal member taking two arguments and returning an integer value.
    /// @param a an integer argument.
    /// @param s a constant character pointer.
    /// @see Test()
    /// @see ~Test()
    /// @see testMeToo()
    /// @see publicVar()
    /// @return The test results
    int testMe(int a,const char *s);
       
    /// A pure virtual member.
    /// @see testMe()
    /// @param c1 the first argument.
    /// @param c2 the second argument.
    virtual void testMeToo(char c1,char c2) = 0;
   
    /// a public variable.

    /// Details.
    int publicVar;
       
    /// a function variable.

    /// Details.
    int (*handler)(int a,int b);
};

  • Comment out blocks of code as follows:
    #if 0
        ...
    #endif
    

C++ specific

Includes

  • A .cpp file should have the minimum set of #includes to get that particular file to compile (e.g. the includes needed by foo.cpp should be in foo.cpp, not foo.h).
  • foo.cpp should include foo.h first; after that, includes should be ordered from general (<stdio.h>) to specific (thisfile.h).

Extern declarations

  • foo.h should have 'extern' declarations for all public functions and variables in foo.cpp There should be no 'extern' statements in .cpp files.

Use of static

  • If a function or variable is used in only one file, declare it static.

Things to avoid unless there's a truly compelling reason:

  • Operator or function overloading.
  • Templates.

Things to avoid

  • Use typedef (not #define) to define types.
  • Don't use memset() or memcpy() to initialize or copy classes that are non-C compatible. Write a default constructor and a copy constructor instead.

Error codes

  • (Almost) all functions should return an integer error code. Nonzero means error. See lib/error_numbers.h for a list of error codes.
  • Calls to functions that return an error code should check the code. Generally they should return non-zero on error, e.g.:
    retval = blah();
    if (retval) return retval;
    

Structure definitions

struct FOO {
    ...
};

You can then declare variables as:

FOO x;

PHP specific

HTML

PHP scripts should output "HTML 4.01 Transitional". The HTML should pass the W3C validator. This means, e.g., you must have quotes around attributes that have non-alpha characters in them. However, all-alpha attributes need not have quotes, and tags like <br> and <p> need not be closed.

The HTML need not be XHTML.

This means no self-closing tags like <br />.

Getting POST and GET data

Do not access $_POST or $_GET directly. Use get_int(), get_str(), post_int() and post_str() (from util.inc) to get POST and GET data. These undo the effects of PHP magic quotes.

Database access

  • Use the database abstraction layer.
  • If a POST or GET value will be used in a database query, use BoincDb::escape_string to escape it.