libclayer/CONTRIBUTING.md

Common

• Add your name to COPYING.
• Don't add your name to AUTHORS - it's for maintainers.
• Add copyright notice in the beginning of changed files except the headers.
• If you change the behavior (even just fix a bug) of libkernaux (stable) or libc, add a record to ChangeLog.

Prohibitions:

• Don't commit binary files
• Don't commit configuration files of your editor or IDE
• Don't use encodings other than ASCII and UTF-8
• Don't use alphabets other than Latin
• Don't use languages other than English
• Don't use tabulations (I don't hate tabs, but people can not use them properly)
• Don't leave trailing whitespaces
• Don't forget the newline character in the end of files

The following statements are recommendations, but highly encouraged:

• Write documentation
• Write tests
• Keep lines less than 80 characters long for better experience on split screen

Things to review periodically

• git grep -i fixme
• git grep -i todo
• git grep -i cppcheck-suppress
• git grep -i rubocop:disable

Programming mistakes

• Always check documentation, manuals and specifications

Avoid stupid errors with:

• Manual memory management
  • malloc may return NULL
  • Memory leak (forget to free)
  • Use after free/realloc
  • Double free/realloc
  • freeing/reallocating unallocated memory
  • Changing the original pointer to the allocated memory (use const!)
• NULL pointers and nil/None/whatever objects
• Division by zero
• Pointer arithmetic - consider type size
• Type sizes (like long on 32-bit and 64-bit)
• Integer arithmetic overflow
• Bit shift
• Endianness (byte order)
• Data packing
• Data alignment
• Thread safety
• Undefined behavior
• Logical expressions (tautology, whatever)
• Checking for an error (return value, pointer argument, whatever)
• Use of not fully initialized data
• Not reading beyond a buffer, array or string
  • The index of the last item, which is less than the buffer size
  • Negative indices
  • The terminating null character in a string
• Allowed values of arguments
• Possible values of parameters
• Operator precedence
• Default case in switch statements
• Braces (curly brackets) around code blocks

C language

Use cppcheck.

• Name regular functions (not methods) and variables in lower snake case (example: foo_bar).

• Name macros in upper snake case (example: FOO_BAR).

• Name types (structures, unions, enumerations and type definitions) in Pascal case (example: FooBar).

• Name nested types in Pascal case and with the prefix of the surrounding type in Pascal case, separate type names with underscores (example: FooBar_CarCdr).

• Name methods (functions that belong to a specific type) in lower snake case and with the prefix of the type name in Pascal case (example: FooBar_car_cdr).

• Name public (defined in the headers and exported as symbols) regular functions (not methods) and variables with the prefix kernaux_ (example: kernaux_foo_bar).

• Name public (defined in the headers) macros with the prefix KERNAUX_ (example: KERNAUX_FOO_BAR).

• Name public (defined in the headers) types with the prefix KernAux_ (example: KernAux_FooBar).

• Name public (defined in the headers) with the prefix KernAux_ and with the prefix of the surrounding type, separate type names with underscore (example: KernAux_FooBar_CarCdr).

• Name public (defined in the headers) methods with the prefix KernAux_ and with the prefix of the type name (example: KernAux_FooBar_car_cdr).

• Use postfix size for a byte size.

• Use postfix slen for C string length without terminating \0 character (size - 1).

• Use postfix count for a number of elements in an array.

• Create typedefs with the names of related structs. Use this name with a prefix struct to declare the data itself, withoth the prefix to declare a pointer or an array:

typedef struct FooBar { int car; } *FooBar;

static struct FooBar FooBar_create();
static void FooBar FooBar_init(FooBar foobar);

static void FooBar_do_something(FooBar foobar);

// Initialize:
struct FooBar foobar = FooBar_create();
// or
struct FooBar foobar;
FooBar_init(&foobar);

// Use:
FooBar foobar_ptr = &foobar;
FooBar_do_something(&foobar);

typedef struct FooBar { int car; } FooBar[1];

static struct FooBar FooBar_create();
static void FooBar FooBar_init(FooBar foobar);

static void FooBar_do_something(FooBar foobar);

// Initialize:
FooBar foobar = { FooBar_create() };
// or
FooBar foobar;
FooBar_init(foobar);

// Use:
FooBar_do_something(foobar);

• Mark variables and parameters with const if you don't plan to modify them
• Only omit braces (curly brackets) of a block if it's statement is placed on the same line as conditional statement:

// Good:
if (foo) return bar;
if (foo) {
    return bar;
}

// Bad:
if (foo)
    return bar;