wiki:CodingStyle

Version 12 (modified by Simek, 16 years ago) (diff)

comments to HTML coding style

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

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

C++ specific

Includes

  • A .C file should have the minimum set of #includes to get that particular file to compile (e.g. the includes needed by foo.C should be in foo.C, not foo.h).
  • 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.C There should be no 'extern' statements in .C 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:

  • Inline functions.
  • 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, not XHTML. XHTML isn't supported by many browsers. Serving XHTML with a text/html MIME type is not a solution either (it's not XHTML anymore, it becomes invalid HTML).

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.