Swift: rename to getImmediateParent and use hidden AST

Author: redsun82

swift/codegen/generators/qlgen.py

@@ -120,8 +120,8 @@ def generate(opts, renderer):
     renderer.render(all_imports, include_file)
 
     print(include_file)
-    renderer.render(ql.Children(classes=classes, imports=[get_import(include_file, opts.swift_dir)]),
-                    out / 'Children.qll')
+    renderer.render(ql.GetParentImplementation(classes=classes, imports=[get_import(include_file, opts.swift_dir)]),
+                    out / 'GetImmediateParent.qll')
 
     renderer.cleanup(existing)
     if opts.ql_format:

swift/codegen/lib/ql.py

@@ -95,8 +95,8 @@ class ImportList:
 
 
 @dataclass
-class Children:
-    template: ClassVar = 'ql_children'
+class GetParentImplementation:
+    template: ClassVar = 'ql_parent'
 
-    imports: List[str] = field(default_factory=list)
     classes: List[Class] = field(default_factory=list)
+    imports: List[str] = field(default_factory=list)

swift/codegen/templates/ql_children.mustache

@@ -0,0 +1,45 @@
+// generated by {{generator}}
+
+{{#imports}}
+import {{.}}
+{{/imports}}
+
+// we are defining this class mainly to leverage existing generation machinery
+// when we generate getters in classes we use the db predicate with `this`. In order to reuse that we need a class here
+// as well
+private class ElementWithChildAccessor extends Element {
+    // why does this look more complicated than it should?
+    // * the none()  simplifies generation, as we can append `or ...` without a special case for the first item
+    // * the `exists` and the `x` variables are there to reuse the same generation done in classes (where the variables
+    //   are used to hide nodes via resolution)
+    Element getAnImmediateChild() {
+      none()
+      {{#classes}}
+      {{#properties}}
+      {{#is_child}}
+      or
+      exists({{type}} {{local_var}}{{#is_repeated}}, int index{{/is_repeated}} | {{tablename}}({{#tableparams}}{{^first}}, {{/first}}{{param}}{{/tableparams}}) and result = {{local_var}})
+      {{/is_child}}
+      {{/properties}}
+      {{/classes}}
+   }
+}
+
+/**
+ * Gets any of the "immediate" children of `e`. "Immediate" means not taking into account node resolution: for example
+ * if the AST child is the first of a series of conversions that would normally be hidden away, this will select the
+ * next conversion down the hidden AST tree instead of the corresponding fully uncoverted node at the bottom.
+ * This predicate is mainly intended to be used to test uniqueness of parents.
+ */
+cached
+Element getAnImmediateChild(Element e) {
+   result = e.(ElementWithChildAccessor).getAnImmediateChild()
+}
+
+/**
+ * Gets the "immediate" parent of `e`. "Immediate" means not taking into account node resolution: for example
+ * if `e` has conversions, `getImmediateParent(e)` will give the bottom conversion in the hidden AST.
+ */
+ Element getImmediateParent(Element e) {
+   result = unique(Element x | e = getAnImmediateChild(x) | x)
+}

swift/codegen/templates/ql_parent.mustache

@@ -17,7 +17,7 @@ def run_mock():
 stub_path = lambda: paths.swift_dir / "ql/lib/stub/path"
 ql_output_path = lambda: paths.swift_dir / "ql/lib/other/path"
 import_file = lambda: stub_path().with_suffix(".qll")
-children_file = lambda: ql_output_path() / "Children.qll"
+children_file = lambda: ql_output_path() / "GetImmediateParent.qll"
 stub_import = "stub.path"
 stub_import_prefix = f"{stub_import}."
 gen_import_prefix = "other.path."
@@ -69,7 +69,7 @@ def generate_classes(opts, renderer):
 def test_empty(opts, input, renderer):
     assert generate(opts, renderer) == {
         import_file(): ql.ImportList(),
-        children_file(): ql.Children(imports=[stub_import]),
+        children_file(): ql.GetParentImplementation(imports=[stub_import]),
     }
 
 
@@ -120,7 +120,7 @@ def test_hierarchy_children(opts, input, renderer):
         schema.Class("B", bases={"A"}, derived={"D"}),
         schema.Class("A", derived={"B", "C"}),
     ]
-    assert generate_children_implementations(opts, renderer) == ql.Children(
+    assert generate_children_implementations(opts, renderer) == ql.GetParentImplementation(
         classes=[ql.Class(name="A"),
                  ql.Class(name="B", bases=["A"], imports=[stub_import_prefix + "A"]),
                  ql.Class(name="C", bases=["A"], imports=[stub_import_prefix + "A"]),

swift/codegen/test/test_qlgen.py

@@ -1,6 +1,4 @@
+// generated by codegen/codegen.py, remove this comment if you wish to edit this file
 private import codeql.swift.generated.AstNode
-private import codeql.swift.generated.Children
 
-class AstNode extends AstNodeBase {
-  AstNode getParent() { result = unique(AstNode x | this = getAChild(x) | x) }
-}
+class AstNode extends AstNodeBase { }