Add cache test.

chrome/test/data/indexeddb/perf_test.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var overallTestStartTime = Date.now();
 var kUseIndex = true;
 var kDontUseIndex = false;
 var kReadKeysOnly = true;
 var kReadDataToo = false;
 var kWriteToo = true;
@@ skipping 59 matching lines @@
   [testSporadicWrites, 5, 0],
 // Make large batches of random writes into a store, triggered by periodic
 // setTimeout calls.
   [testSporadicWrites, 500, 0],
 // Make batches of random writes into a store with many indices, triggered by
 // periodic setTimeout calls.
   [testSporadicWrites, 5, 10],
 // Make large batches of random writes into a store with many indices, triggered
 // by periodic setTimeout calls.
   [testSporadicWrites, 500, 10],
+// Make a small bunch of batches of reads of the same keys from an object store.
+  [testReadCache, 10, kDontUseIndex],
+// Make a bunch of batches of reads of the same keys from an index.
+  [testReadCache, 50, kUseIndex],
+// Make a small bunch of batches of reads of the same keys from an object store.
+  [testReadCache, 10, kDontUseIndex],
+// Make a bunch of batches of reads of the same keys from an index.
+  [testReadCache, 50, kUseIndex],
 // Create and delete an index on a store that already contains data [produces
 // a timing result for each of creation and deletion].
   [testCreateAndDeleteIndex, 5000]
 ];
 
 var currentTest = 0;
 
 function test() {
   runNextTest();
 }
@@ skipping 146 matching lines @@
           }
         });
 
     getRandomValues(transaction, objectStoreNames, numReadsPerTransaction,
         numKeys, indexName);
     putRandomValues(transaction, objectStoreNames, numWritesPerTransaction,
         numKeys);
   }
 }
 
+function testReadCache(numTransactions, useIndexForReads, onTestComplete) {
+  var numKeys = 10000;
+  var numReadsPerTransaction = 50;
+  var numTransactionsLeft = numTransactions;
+  var indexName;
+  if (useIndexForReads)
+    indexName = "index";
+  var testName = getDisplayName(arguments);
+  var objectStoreNames = ["store"];
+  var numTransactionsRunning;
+  var keys = [];
+
+  for (var i=0; i < numReadsPerTransaction; ++i) {
+    keys.push(getSimpleKey(Math.floor(Math.random() * numKeys)));
+  }
+
+  automation.setStatus("Creating database.");
+  var options;
+  if (useIndexForReads) {
+    options = [{
+      indexName: indexName,
+      indexKeyPath: "",
+      indexIsUnique: false,
+      indexIsMultiEntry: false,
+    }];
+  }
+  createDatabase(testName, objectStoreNames, onCreated, onError, options);
+
+  function onCreated(db) {
+    automation.setStatus("Setting up test database.");
+    var transaction = getTransaction(db, objectStoreNames, "readwrite",
+        function() { onSetupComplete(db); });
+    putLinearValues(transaction, objectStoreNames, numKeys, getSimpleKey,
+        function () { return "test value"; });

[jsbell, 2012/08/09 17:58:18]

Nit: space between function keyword and ()

[ericu, 2012/08/15 17:56:22]

Done.

+  }
+
+  var completionFunc;
+  function onSetupComplete(db) {
+    automation.setStatus("Setup complete.");
+    completionFunc =
+        getCompletionFunc(db, testName, Date.now(), onTestComplete);
+    runOneBatch(db);
+  }
+
+  function runOneBatch(db) {

[jsbell, 2012/08/09 17:58:18]

This runOneBatch() pattern seems to be re-used in many tests. Factor out?

[ericu, 2012/08/15 17:56:22]

It's used in 3 places, but one is actually different than the others [running
the transactions from a timer instead of just chaining them together].  I pulled
out the common pattern from the 2 that matched, and that'll probably get reused
in a bunch more tests.

+    if (numTransactionsLeft <= 0) {
+      return;
+    }
+    --numTransactionsLeft;
+    ++numTransactionsRunning;
+    var transaction = getTransaction(db, objectStoreNames, "readonly",
+        function() {
+          assert(!--numTransactionsRunning);
+          if (numTransactionsLeft <= 0) {
+            completionFunc();
+          } else {
+            runOneBatch(db);
+          }
+        });
+
+    getSpecificValues(transaction, objectStoreNames, indexName, keys);
+  }
+}
+
 function testCreateAndDeleteIndex(numKeys, onTestComplete) {
   var testName = getDisplayName(arguments);
   var objectStoreNames = ["store"];
 
   automation.setStatus("Creating database.");
   createDatabase(testName, objectStoreNames, onCreated, onError);
 
   var startTime;
   function onCreated(db) {
     automation.setStatus("Initializing data.");
@@ skipping 172 matching lines @@
 
     var mode = "readonly";
     if (numWritesPerTransaction)
       mode = "readwrite";
 
     var transaction = getTransaction(db, objectStoreNames, mode, batchComplete);
     putRandomValues(transaction, objectStoreNames, numWritesPerTransaction,
         numKeys);
   }
 }