CodingStyle

CodingStyle

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+Ceph Coding style
+-----------------
+
+Coding style is most important for new code and (to a lesser extent)
+revised code.  It is not worth the churn to simply reformat old code.
+
+C code
+------
+
+For C code, we conform by the Linux kernel coding standards:
+
+    http://lxr.linux.no/linux/Documentation/CodingStyle
+
+
+C++ code
+--------
+
+For C++ code, things are a bit more complex.  As a baseline, we use Google's
+coding guide:
+
+       http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml
+
+
+As an addendum to the above, we add the following guidelines, organized
+by section.
+
+* Naming > Type Names:
+
+    Google uses CamelCaps for all type names.  We use two naming schemes:
+
+    - for structs (simple data containers), lower case with _t suffix:
+        struct my_type_t {
+          int a, b;
+          my_type_t() : a(0), b(0) {}
+        };
+    - for regular classes, CamelCaps, private: section, etc.
+
+* Naming > Variable Names:
+
+   Google uses _ suffix for class members.  We haven't up until now.  Should we?
+
+* Naming > Constant Names:
+
+   Google uses kSomeThing for constants.  We prefere SOME_THING.
+
+* Naming > Function Names:
+
+   Google uses CamelCaps.  We use_function_names_with_underscores().
+
+   Accessors are the same, {get,set}_field().
+
+* Naming > Enumerator Names:
+
+   Name them like constants, as above (SOME_THING).
+
+* Comments > File Comments:
+
+   Don't sweat it, unless the license varies from that of the project (LGPL2) or
+the code origin isn't reflected by the git history.
+
+* Formatting > Conditionals:
+
+   - No spaces inside conditionals please, e.g.
+
+        if (foo) {   // okay
+
+	if ( foo ) { // no
+
+   - Always use newline following if:
+
+ 	if (foo)
+	  bar;         // okay
+
+        if (foo) bar;  // no, usually hardler to visually parse
+
+       
+
+
+The following guidelines have not been followed in the legacy code,
+but are worth mentioning and should be followed strictly for new code:
+
+* Header Files > Function Parameter Ordering:
+
+    Inputs, then outputs.
+
+* Classes > Explicit Constructors:
+
+    You should normally mark constructors explicit to avoid getting silent
+type conversions.
+
+* Classes > Copy Constructors:
+
+    - Use defaults for basic struct-style data objects.
+
+    - Most other classes should DISALLOW_COPY_AND_ASSIGN.
+
+    - In rare cases we can define a proper copy constructor and operator=.
+
+* Other C++ Features > Reference Arguments:
+
+    Only use const references.  Use pointers for output arguments.
+
+* Other C++ Features > Avoid Default Arguments:
+
+    They obscure the interface.