longjmp.c

// ExecutionPlan.c
function Query_Execute() {
	/* Set an exception-handling breakpoint to capture run-time errors.
	 * encountered_error will be set to 0 when setjmp is invoked, and will be nonzero if
	 * a downstream exception returns us to this breakpoint. */
	QueryCtx *ctx = pthread_getspecific(_tlsQueryCtxKey);
	if(!ctx->breakpoint) ctx->breakpoint = rm_malloc(sizeof(jmp_buf));
	int encountered_error = setjmp(*ctx->breakpoint);
  
	if(encountered_error) {
		// Encountered a run-time error; return immediately.
		reportError();
		return;
	}
	
	/* Start executing, if an exception is thrown somewhere down the road
	 * we will resume execution at: if(encountered_error) above. */
	ExecutionPlan_Execute();
}

/* ArithmeticExpression.c
 * AR_EXP_Evaluate is called from various points in our code base 
 * all originating from Query_Execute. */
SIValue AR_EXP_Evaluate(AR_ExpNode *root, const Record r) {
	SIValue result;
	AR_EXP_Result res = _AR_EXP_Evaluate(root, r, &result);
	if(res != EVAL_OK) {
		/* An error was encountered during evaluation!
		 * Exit this routine and return to the point on the stack where the handler was
		 * instantiated. */
		jmp_buf *env = _QueryCtx_GetExceptionHandler();
		longjmp(*env, 1);
	}
	return result;
}