add Function.if_nest_level() returning max

nesting level

README.markdown

@@ -15,6 +15,45 @@ data = analyze("tests/test_file1.c")
 [func.name for func in data.functions if func.it_calls("read")]
 ```
 
+Get max if nest level:
+
+```python
+from qc.parser import analyze
+code = """
+    int main (int argc, char *argv[]) {
+        char *space;
+        space = malloc(sizeof(char) * 10);
+        if (space == NULL) {
+            if (1 > 2) {
+                if (3 == 4) {
+                    return -1;
+                }
+            } else {
+                if (1 == 1) {
+                    return -1;
+                } else {
+                    if (1 == 2) {
+                        return -1;
+                    } else {
+                        if (1 == 2) {
+                            return -1;
+                        } else {
+                            return -1;
+                        }
+                    }
+                }
+            }
+            return -1;
+        }
+        return 0;
+    }
+"""
+
+parsed_content = parse(code, "<string>")
+main = parsed_content.functions[0]
+assert 5 == main.if_nest_level()
+```
+
 ## Testing
 
 ```sh

qc/domain.py

@@ -16,5 +16,36 @@ def it_calls(self, inner_function_name):
                              isinstance(call.rvalue, c_ast.FuncCall) and
                              call.rvalue.name.name == inner_function_name)])
 
+    def if_nest_level(self):
+        def nest_meter(if_statement):
+            values = []
+            if hasattr(if_statement, 'iftrue') and if_statement.iftrue and \
+               len(if_statement.iftrue.block_items):
+                nested_ifs = [if_stm for if_stm
+                                     in if_statement.iftrue.block_items
+                                     if isinstance(if_stm, c_ast.If)]
+                for nested_if in nested_ifs:
+                    values.append(1 + nest_meter(nested_if))
+            if hasattr(if_statement, 'iffalse') and if_statement.iffalse and \
+               len(if_statement.iffalse.block_items):
+                nested_ifs = [if_stm for if_stm
+                                     in if_statement.iffalse.block_items
+                                     if isinstance(if_stm, c_ast.If)]
+                for nested_if in nested_ifs:
+                    values.append(1 + nest_meter(nested_if))
+
+            if not values:
+                return 1
+
+            return max(values)
+
+        values = []
+        for block in self.blocks:
+            if isinstance(block, c_ast.If):
+                values.append(nest_meter(block))
+
+        return max(values)
+
+
     def __str__(self):
         return str(self.node)

qc/tests/test_qc_parser.py

@@ -43,3 +43,61 @@ def test_parse_check_functions_calling_malloc():
     assert "main" == [function.name for function
                                     in parsed_content.functions
                                     if function.it_calls("malloc")][0]
+
+def test_parse_check_if_nest_level():
+    code = """
+        int main (int argc, char *argv[]) {
+            char *space;
+            space = malloc(sizeof(char) * 10);
+            if (space == NULL) {
+                if (1 > 2) {
+                    if (3 == 4) {
+                        return -1;
+                    }
+                }
+                return -1;
+            }
+            return 0;
+        }
+    """
+    parsed_content = parse(code, "<string>")
+    assert parsed_content
+    assert 1 == len(parsed_content.functions)
+    assert "main" == parsed_content.functions[0].name
+    assert 3 == parsed_content.functions[0].if_nest_level()
+
+def test_parse_check_if_else_nest_level():
+    code = """
+        int main (int argc, char *argv[]) {
+            char *space;
+            space = malloc(sizeof(char) * 10);
+            if (space == NULL) {
+                if (1 > 2) {
+                    if (3 == 4) {
+                        return -1;
+                    }
+                } else {
+                    if (1 == 1) {
+                        return -1;
+                    } else {
+                        if (1 == 2) {
+                            return -1;
+                        } else {
+                            if (1 == 2) {
+                                return -1;
+                            } else {
+                                return -1;
+                            }
+                        }
+                    }
+                }
+                return -1;
+            }
+            return 0;
+        }
+    """
+    parsed_content = parse(code, "<string>")
+    assert parsed_content
+    assert 1 == len(parsed_content.functions)
+    assert "main" == parsed_content.functions[0].name
+    assert 5 == parsed_content.functions[0].if_nest_level()