Fixes #97: SQLite is now async, optimized, tests

plugos/sqlite/deno-sqlite/src/error.ts

@@ -0,0 +1,57 @@
+import { Wasm } from "../build/sqlite.js";
+import { getStr } from "./wasm.ts";
+import { Status } from "./constants.ts";
+
+/**
+ * Errors which can occur while interacting with
+ * a database.
+ */
+export class SqliteError extends Error {
+  /**
+   * Extension over the standard JS Error object
+   * to also contain class members for error code
+   * and error code name.
+   *
+   * Instances of this class should not be constructed
+   * directly and should only be obtained
+   * from exceptions raised in this module.
+   */
+  constructor(context: Wasm | string, code?: Status) {
+    let message;
+    let status;
+    if (typeof context === "string") {
+      message = context;
+      status = Status.Unknown;
+    } else {
+      message = getStr(context, context.get_sqlite_error_str());
+      status = context.get_status();
+    }
+    super(message);
+    this.code = code ?? status;
+    this.name = "SqliteError";
+  }
+
+  /**
+   * The SQLite status code which caused this error.
+   *
+   * Errors that originate in the JavaScript part of
+   * the library will not have an associated status
+   * code. For these errors, the code will be
+   * `Status.Unknown`.
+   *
+   * These codes are accessible via
+   * the exported `Status` object.
+   */
+  code: Status;
+
+  /**
+   * Key of code in exported `status`
+   * object.
+   *
+   * E.g. if `code` is `19`,
+   * `codeName` would be `SqliteConstraint`.
+   */
+  get codeName(): keyof typeof Status {
+    return Status[this.code] as keyof typeof Status;
+  }
+}