Add constants for bqrs column kinds

Author: jcreedcmu

extensions/ql-vscode/src/bqrs-cli-types.ts

@@ -1,14 +1,33 @@
 
 export const PAGE_SIZE = 1000;
 
-export type ColumnKind = "f" | "i" | "s" | "b" | "d" | "e";
+/**
+ * The single-character codes used in the bqrs format for the the kind
+ * of a result column. This namespace is intentionally not an enum, see
+ * the "for the sake of extensibility" comment in messages.ts.
+ */
+export namespace ColumnKindCode {
+  export const FLOAT = "f";
+  export const INTEGER = "i";
+  export const STRING = "s";
+  export const BOOLEAN = "b";
+  export const DATE = "d";
+  export const ENTITY = "e";
+}
+
+export type ColumnKind =
+  | typeof ColumnKindCode.FLOAT
+  | typeof ColumnKindCode.INTEGER
+  | typeof ColumnKindCode.STRING
+  | typeof ColumnKindCode.BOOLEAN
+  | typeof ColumnKindCode.DATE
+  | typeof ColumnKindCode.ENTITY;
 
 export interface Column {
   name?: string;
   kind: ColumnKind;
 }
 
-
 export interface ResultSetSchema {
   name: string;
   rows: number;

extensions/ql-vscode/src/definitions.ts

@@ -3,7 +3,7 @@ import * as yaml from 'js-yaml';
 import * as tmp from 'tmp';
 import * as vscode from "vscode";
 import { decodeSourceArchiveUri, zipArchiveScheme } from "./archive-filesystem-provider";
-import { EntityValue, getResultSetSchema, LineColumnLocation, UrlValue } from "./bqrs-cli-types";
+import { EntityValue, getResultSetSchema, LineColumnLocation, UrlValue, ColumnKindCode } from "./bqrs-cli-types";
 import { CodeQLCliServer } from "./cli";
 import { DatabaseItem, DatabaseManager } from "./databases";
 import * as helpers from './helpers';
@@ -156,9 +156,9 @@ async function getLinksFromResults(results: QueryWithResults, cli: CodeQLCliServ
   const info = await cli.bqrsInfo(bqrsPath);
   const selectInfo = getResultSetSchema(SELECT_QUERY_NAME, info);
   if (selectInfo && selectInfo.columns.length == 3
-    && selectInfo.columns[0].kind == "e"
-    && selectInfo.columns[1].kind == "e"
-    && selectInfo.columns[2].kind == "s") {
+    && selectInfo.columns[0].kind == ColumnKindCode.ENTITY
+    && selectInfo.columns[1].kind == ColumnKindCode.ENTITY
+    && selectInfo.columns[2].kind == ColumnKindCode.STRING) {
     // TODO: Page this
     const allTuples = await cli.bqrsDecode(bqrsPath, SELECT_QUERY_NAME);
     for (const tuple of allTuples.tuples) {