feat: swing-store-simple: add isSwingStore() query

refs #953
Agoric · Apr 17, 2020 · 17b93f6 · 17b93f6
1 parent 0b94ecc
commit 17b93f6
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diff --git a/packages/swing-store-simple/simpleSwingStore.js b/packages/swing-store-simple/simpleSwingStore.js
@@ -296,3 +296,27 @@ export function setAllState(storage, stuff) {
     storage.set(k, stuff[k]);
   }
 }
+
+/**
+ * Is this directory a compatible swing store?
+ *
+ * @param dirPath  Path to a directory in which database files might be present.
+ *   This directory need not actually exist
+ *
+ * @return boolean
+ *   If the directory is present and contains the files created by initSwingStore
+ *   or openSwingStore, returns true. Else returns false.
+ *
+ */
+export function isSwingStore(dirPath) {
+  if (`${dirPath}` !== dirPath) {
+    throw new Error('dirPath must be a string');
+  }
+  if (fs.existsSync(dirPath)) {
+    const storeFile = path.resolve(dirPath, 'swingset-kernel-state.jsonlines');
+    if (fs.existsSync(storeFile)) {
+      return true;
+    }
+  }
+  return false;
+}
diff --git a/packages/swing-store-simple/test/test-state.js b/packages/swing-store-simple/test/test-state.js
@@ -1,10 +1,12 @@
 import fs from 'fs';
+import path from 'path';
 
 import { test } from 'tape-promise/tape';
 import {
   initSwingStore,
   openSwingStore,
   getAllState,
+  isSwingStore,
 } from '../simpleSwingStore';
 
 function testStorage(t, storage) {
@@ -45,15 +47,28 @@ test('storageInMemory', t => {
 });
 
 test('storageInFile', t => {
+  t.equal(isSwingStore('testdb'), false);
   const { storage, commit, close } = initSwingStore('testdb');
   testStorage(t, storage);
   commit();
   const before = getAllState(storage);
   close();
+  t.equal(isSwingStore('testdb'), true);
 
   const { storage: after } = openSwingStore('testdb');
   t.deepEqual(getAllState(after), before, 'check state after reread');
+  t.equal(isSwingStore('testdb'), true);
+  t.end();
+});
+
+test('rejectLMDB', t => {
+  const notSimpleDir = 'testdb-lmdb';
+  fs.mkdirSync(notSimpleDir, { recursive: true });
+  fs.writeFileSync(path.resolve(notSimpleDir, 'data.mdb'), 'some data\n');
+  fs.writeFileSync(path.resolve(notSimpleDir, 'lock.mdb'), 'lock stuff\n');
+  t.equal(isSwingStore(notSimpleDir), false);
   t.end();
 });
 
 test.onFinish(() => fs.rmdirSync('testdb', { recursive: true }));
+test.onFinish(() => fs.rmdirSync('testdb-lmdb', { recursive: true }));