Project

General

Profile

CodeStyle » History » Version 16

Alex Afanasyev, 03/28/2014 09:23 AM

1 1 Junxiao Shi
# NFD code style guidelines
2
3
NFD adopts [NDN Platform C++, C, C#, Java and JavaScript Code Guidelines](http://named-data.net/codebase/platform/documentation/ndn-platform-development-guidelines/cpp-code-guidelines/), with the following exceptions:
4
5 10 Alex Afanasyev
*   (amended 8) Names representing generic template types should be a single uppercase letter
6
7
        template<class T> ...
8
        template<class C, class D> ...
9
10
    However, when template parameter represents a certain concept and expected to have a certain interface, the name should be explicitly spelled out:
11
12
        template<class FaceBase> ...
13
        template<class Packet> ...
14
15 8 Junxiao Shi
*   (amended 10)
16
    Global variables should have `g_` prefix
17 1 Junxiao Shi
18 8 Junxiao Shi
*   (amended 11)
19 15 Alex Afanasyev
    **Private** class variables should have `m_` prefix.
20
    **Static** class variables should have `s_` prefix.
21 8 Junxiao Shi
22 11 Alex Afanasyev
*   (amended 26)
23
    Allow commonly used abbreviated **next/prev** pair in addition to **next/previous**
24
25 12 Alex Afanasyev
    Pair **insert/erase** should be used for any new code, already implemented code can keep **insert/delete** if it does not conflict with C++ delete keyword.
26
27 13 Alex Afanasyev
*   (amended 27)
28 14 Alex Afanasyev
    In cases when full word is too long, a commonly accepted abbreviation can be used.  For example, **dest** instead of **destination**.
29 13 Alex Afanasyev
30 8 Junxiao Shi
*   (amended 31)
31
    Exceptions can be used in the code, but should be used only in **exceptional** cases and not in the primary processing path.
32
33
    Exceptions can be suffixed with either `Exception` (eg. SecurityException) or `Error` (eg. SecurityError).  Alternatively (and it is a recommended method), one should declare exception class `Exception` or `Error` as an inner class, from which the exception is thrown. For example, when declaring class Foo that can throw errors, one can write the following:
34
35 5 Alex Afanasyev
        #include <stdexcept>
36 1 Junxiao Shi
        
37
        class Foo
38 5 Alex Afanasyev
        {
39 1 Junxiao Shi
            struct Error : std::runtime_exception
40
            {
41
                Error(const std::string& what) : std::runtime_error(what) {}
42
            };
43
        };
44
45 8 Junxiao Shi
    In addition to that, if class Foo is a base class or interface for some class hierarchy, then child classes should should define their own `Error` or `Exception` classes that are inherited from the parent's Error class.
46 1 Junxiao Shi
47 8 Junxiao Shi
*   (amended 33)
48
    We will use only `.cpp` and `.hpp` extensions
49 1 Junxiao Shi
50 8 Junxiao Shi
*   (removed 35)
51
    Lines should be within a reasonable range. >100 column-lines should be generally avoided.
52
53
*   (removed 44)
54
    Implicit conversion is generally allowed.
55
56
    Implicit conversion between integer and floating point numbers can cause problems and should be avoided.
57
58
    Implicit conversion in single-argument constructor is usually undesirable. Therefore, all single-argument constructors should be marked 'explicit', unless implicit conversion is desirable. In that case, a comment should document the reason.
59
60
    Avoid C-style casts.  Use `static_cast`, `dynamic_cast`, `reinterpret_cast`, `const_cast` instead where appropriate.
61
62 16 Alex Afanasyev
*   (replaced 48)
63
    In most cases, class variables should never be declared public.
64
    
65
    The concept of information hiding and encapsulation is violated by public variables. Use private variables and access functions instead. One exception to this rule is when the class is essentially a dumb data structure with no behavior (equivalent to a C struct).  In this case it is appropriate to make the class' instance variables public by using ``struct``.
66
67 8 Junxiao Shi
*   (amended 68)
68
    All three presented styles ARE acceptable.  First and third ARE recommended (these are actually GNU styles).
69
70
*   (amended 69)
71
    The class declarations should have the following form:
72
73 3 Alex Afanasyev
        class SomeClass : public BaseClass 
74 4 Junxiao Shi
        { 
75 3 Alex Afanasyev
        public: 
76 4 Junxiao Shi
          ... <public methods> ...
77 3 Alex Afanasyev
        protected: 
78
          ... <protected methods> ...
79
        private: 
80 1 Junxiao Shi
          ... <private methods> ...
81
        
82
        public: 
83
          ... <public data> ...
84 3 Alex Afanasyev
        protected: 
85
          ... <protected data> ...
86
        private: 
87
          ... <private data> ...
88
        };
89
90
    ``public``, ``protected``, ``private`` may be repeated several times without interleaving (e.g. public, public, public, private, private) if this allows better readability of the code.
91
92 8 Junxiao Shi
*   (amended 70)
93
    When declaring/defining function/method, the return type should be put on a separate line before function/method name.
94
95
    Method and function definitions should have the following form:
96 3 Alex Afanasyev
97
        void
98
        someMethod() 
99
        { 
100
          ... 
101 1 Junxiao Shi
        }
102 9 Alex Afanasyev
103
*   (amended 76) No space requirement before : in switch statements
104
105
        switch (condition) { 
106
          case ABC:
107
            statements; 
108
            // Fallthrough 
109
        
110
          case DEF: 
111
            statements; 
112
            break;
113
        
114
          case XYZ: 
115
            statements; 
116
            break; 
117
        
118
          default: 
119
            statements; 
120
            break;
121
        }