feature: debug/state-check lib

[nopeslide]

Related Issues & PRs

none

Description

Objects that need initialization are not checked before use weither they got initialized or not.

Solution

Add a macro lib providing:

• optional compilation of provided features
• annotation-like constructs
• checks if object is usable
• function macros setting the initialization status
• function macros resetting the initialization status

Alternative solutions

• Non-macro lib
  • overhead if disabled
  • no annotation style
• Solve set/reset status via linker
  • wrap init/reset functions via linker
  • will always apply, can't be forgotten
  • no overhead if disabled (in combination with annotation macro)
  • solution is not directly visible in code

Context

#define CANARY 0xc0ffee
#define NEEDS_INIT uint _initialized;
#define SET_INIT(p) { (p)->_initialized = CANARY;  } //needs further checks
#define RESET_INIT(p) { (p)_initialized = 0x0; } //needs further checks
#define CHECK_INIT(p) { if ( (p)->initialized != CANARY ) { /*throw error*/ }  }

struct object {
  NEEDS_INIT;
  int foo;
};

void using_object( struct object *o) {
  CHECK_INIT(o);
  ...
}

void object_init( struct object *o ) {
  ...
  SET_INIT(o);
}

void object_reset( struct object *o) {
  RESET_INIT(o);
  ...
}