Python: Add more snippets

Author: RasmusWL

python/.vscode/ql.code-snippets

@@ -152,4 +152,62 @@
         ]
     },
 
+    "Type tracking class": {
+        "scope": "ql",
+        "prefix": "type tracking class",
+        "body": [
+            "/**",
+            " * Provides models for the `${TM_SELECTED_TEXT}` class",
+            " *",
+            " * See ${1:https://apiref (TODO)}.",
+            " */",
+            "module ${TM_SELECTED_TEXT/^(.*)\\.([^.]+)$/$2/} {",
+            "  /** Gets a reference to the `${TM_SELECTED_TEXT}` class. */",
+            "  private API::Node classRef() {",
+            "    result = API::moduleImport(\"${TM_SELECTED_TEXT/\\.([^.]+)/\").getMember(\"$1/g}\")",
+            "  }",
+            "",
+            "  /**",
+            "   * A source of instances of `${TM_SELECTED_TEXT}`, extend this class to model new instances.",
+            "   *",
+            "   * This can include instantiations of the class, return values from function",
+            "   * calls, or a special parameter that will be set when functions are called by an external",
+            "   * library.",
+            "   *",
+            "   * Use the predicate `${TM_SELECTED_TEXT/^(.*)\\.([^.]+)$/$2/}::instance()` to get references to instances of `${TM_SELECTED_TEXT}`.",
+            "   */",
+            "  abstract class InstanceSource extends DataFlow::LocalSourceNode { }",
+            "",
+            "  /** A direct instantiation of `${TM_SELECTED_TEXT}`. */",
+            "  private class ClassInstantiation extends InstanceSource, DataFlow::CallCfgNode {",
+            "      override CallNode node;",
+            "",
+            "      ClassInstantiation() { this = classRef().getACall() }",
+            "  }",
+            "",
+            "  /** Gets a reference to an instance of `${TM_SELECTED_TEXT}`. */",
+            "  private DataFlow::TypeTrackingNode instance(DataFlow::TypeTracker t) {",
+            "    t.start() and",
+            "    result instanceof InstanceSource",
+            "    or",
+            "    exists(DataFlow::TypeTracker t2 | result = instance(t2).track(t2, t))",
+            "  }",
+            "",
+            "  /** Gets a reference to an instance of `${TM_SELECTED_TEXT}`. */",
+            "  DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }",
+            "",
+            "  DataFlow::Node instance() { instance(DataFlow::TypeTracker::end()).flowsTo(result) }",
+            "}",
+        ],
+        "description": "Type tracking class (select full class path before inserting)",
+    },
+
+    "API graph .getMember chain": {
+        "scope": "ql",
+        "prefix": "api graph .getMember chain",
+        "body": [
+            "API::moduleImport(\"${TM_SELECTED_TEXT/\\.([^.]+)/\").getMember(\"$1/g}\")"
+        ],
+        "description": "API graph .getMember chain (select full path before inserting)",
+    },
 }