C/C++ Coding Standards
The Mobile project uses a set of project-specific coding standards derived from general Samsung coding standards. The Mobile project standards could be rewritten by taking into account the language variances and other development constraints. For example, some compilers used in the Mobile project do not support exception handling. Therefore, it is impossible to detect resource allocation failures while an object's constructors are called. The Mobile project solves this problem by employing the well-known two-phase object construction technique described in the Mobile project coding standards: Divide an object initialization into the object allocation phase and the resource allocation phase to return the exception as a value (see Listing One).
class ResourceManager
{
ResourceManager(); // allocate only object
result Construct(); // allocate resources
// 'result' contains error code
};
int main()
{
// Two phase construction
ResourceManager aObject;
if (aObject.Construct() == FAIL)
printf("Resource allocation is failed");
}
Additionally, the Mobile project requires rigid conformance to coding standards. This project mainly targets a software framework to be used by other developers; it must be consistent and well organized to facilitate software development on this framework. The more project constraints there are, the greater the necessity for an automated tool. That's why the Mobile project adopted a coding standards checker.
C++test from Parasoft (www.parasoft.com) provides automated C/C++ unit testing, as well as automated coding standards checking. We chose C++test as our coding standards checker because it was the most effective solution for the majority of our considerations.
One of C++test's distinct features is its GUI-based rules. Figure 1 shows the GUI rule description for the rule "Each global variable must be initialized." Whenever a "global variable" is found while parsing the source code, the rule evaluates logic components. A violation is reported if any of the following conditions are not met:
- The detected global variable is an external declaration.
- It does not have an initializer.
- Its type is not an array or a class.
The GUI interface simplifies rule creation. Most C++ code checkers require scripting for rule creation; this is difficult and requires more C++ programming knowledge.
GUI-based rules can be easily understood and implemented because the available conditions are shown graphically. Having GUI-based rules could compromise extensibility because only predefined nodes and condition sets can be selected in a GUI. However, C++test provides Python scripting support to ensure extensibility.
