Reland of Implement cache counting for the simple and memory backends - with fixed test.

net/disk_cache/backend_unittest.cc

 // 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.
 
 #include <stdint.h>
 
 #include "base/basictypes.h"
 #include "base/files/file_util.h"
 #include "base/metrics/field_trial.h"
 #include "base/run_loop.h"
@@ skipping 71 matching lines @@
   // will be filled with times, used by DoomEntriesSince and DoomEntriesBetween.
   // There are 4 entries after doomed_start and 2 after doomed_end.
   void InitSparseCache(base::Time* doomed_start, base::Time* doomed_end);
 
   bool CreateSetOfRandomEntries(std::set<std::string>* key_pool);
   bool EnumerateAndMatchKeys(int max_to_open,
                              TestIterator* iter,
                              std::set<std::string>* keys_to_match,
                              size_t* count);
 
+  // Computes the expected size of entry metadata, i.e. the total size without
+  // the actual data stored. This depends only on the entry's |key| size.
+  int GetEntryMetadataSize(std::string key);
+
   // Actual tests:
   void BackendBasics();
   void BackendKeying();
   void BackendShutdownWithPendingFileIO(bool fast);
   void BackendShutdownWithPendingIO(bool fast);
   void BackendShutdownWithPendingCreate(bool fast);
   void BackendSetSize();
   void BackendLoad();
   void BackendChain();
   void BackendValidEntry();
@@ skipping 173 matching lines @@
     EXPECT_EQ(1U, keys_to_match->erase(entry->GetKey()));
     entry->Close();
     ++(*count);
     if (max_to_open >= 0 && static_cast<int>(*count) >= max_to_open)
       break;
   };
 
   return true;
 }
 
+int DiskCacheBackendTest::GetEntryMetadataSize(std::string key) {
+  // For blockfile and memory backends, it is just the key size.
+  if (!simple_cache_mode_)
+    return key.size();
+
+  // For the simple cache, we must add the file header and EOF, and that for
+  // every stream.
+  return disk_cache::kSimpleEntryStreamCount *
+         (sizeof(disk_cache::SimpleFileHeader) +
+          sizeof(disk_cache::SimpleFileEOF) + key.size());
+}
+
 void DiskCacheBackendTest::BackendBasics() {
   InitCache();
   disk_cache::Entry *entry1 = NULL, *entry2 = NULL;
   EXPECT_NE(net::OK, OpenEntry("the first key", &entry1));
   ASSERT_EQ(net::OK, CreateEntry("the first key", &entry1));
   ASSERT_TRUE(NULL != entry1);
   entry1->Close();
   entry1 = NULL;
 
   ASSERT_EQ(net::OK, OpenEntry("the first key", &entry1));
@@ skipping 1377 matching lines @@
   start = end;
   end = base::Time::Now();
   DoomEntriesBetween(start, end);
   EXPECT_EQ(3, cache_->GetEntryCount());
 }
 
 void DiskCacheBackendTest::BackendCalculateSizeOfAllEntries() {
   InitCache();
 
   // The cache is initially empty.
-  if (memory_only_ || simple_cache_mode_) {
-    // TODO(msramek): Implement.
-    EXPECT_EQ(net::ERR_NOT_IMPLEMENTED, CalculateSizeOfAllEntries());
-  } else {
-    EXPECT_EQ(0, CalculateSizeOfAllEntries());
-  }
+  EXPECT_EQ(0, CalculateSizeOfAllEntries());
 
   // Generate random entries and populate them with data of respective
   // sizes 0, 1, ..., count - 1 bytes.
   std::set<std::string> key_pool;
   CreateSetOfRandomEntries(&key_pool);
 
   int count = 0;
   for (std::string key : key_pool) {
     std::string data(count, ' ');
     scoped_refptr<net::StringIOBuffer> buffer = new net::StringIOBuffer(data);
 
-    // Alternate between writing to the first and second stream to test that
-    // we are not taking just the first stream into account.
+    // Alternate between writing to first two streams to test that we do not
+    // take only one stream into account.
     disk_cache::Entry* entry;
     ASSERT_EQ(net::OK, OpenEntry(key, &entry));
     ASSERT_EQ(count, WriteData(entry, count % 2, 0, buffer.get(), count, true));
     entry->Close();
 
     ++count;
   }
 
   // The resulting size should be (0 + 1 + ... + count - 1) plus keys.
   int result = CalculateSizeOfAllEntries();
-  if (memory_only_ || simple_cache_mode_) {
-    // TODO(msramek): Implement.
-    EXPECT_EQ(net::ERR_NOT_IMPLEMENTED, result);
-  } else {
-    int total_key_size = 0;
-    for (std::string key : key_pool)
-      total_key_size += key.size();
-
-    EXPECT_EQ((count - 1) * count / 2 + total_key_size, result);
-  }
+  int total_metadata_size = 0;
+  for (std::string key : key_pool)
+    total_metadata_size += GetEntryMetadataSize(key);
+  EXPECT_EQ((count - 1) * count / 2 + total_metadata_size, result);
 
   // Add another entry and test if the size is updated. Then remove it and test
   // if the size is back to original value.
   {
     const int last_entry_size = 47;
     std::string data(last_entry_size, ' ');
     scoped_refptr<net::StringIOBuffer> buffer = new net::StringIOBuffer(data);
 
     disk_cache::Entry* entry;
     std::string key = GenerateKey(true);
     ASSERT_EQ(net::OK, CreateEntry(key, &entry));
     ASSERT_EQ(last_entry_size,
               WriteData(entry, 0, 0, buffer.get(), last_entry_size, true));
     entry->Close();
 
     int new_result = CalculateSizeOfAllEntries();
-    if (memory_only_ || simple_cache_mode_) {
-      // TODO(msramek): Implement.
-      EXPECT_EQ(net::ERR_NOT_IMPLEMENTED, new_result);
-    } else {
-      EXPECT_EQ(result + last_entry_size + static_cast<int>(key.size()),
-                new_result);
-    }
+    EXPECT_EQ(result + last_entry_size + GetEntryMetadataSize(key), new_result);
 
     DoomEntry(key);
     new_result = CalculateSizeOfAllEntries();
-    if (memory_only_ || simple_cache_mode_) {
-      // TODO(msramek): Implement.
-      EXPECT_EQ(net::ERR_NOT_IMPLEMENTED, new_result);
-    } else {
-      EXPECT_EQ(result, new_result);
-    }
+    EXPECT_EQ(result, new_result);
   }
 
   // After dooming the entries, the size should be back to zero.
   ASSERT_EQ(net::OK, DoomAllEntries());
-  if (memory_only_ || simple_cache_mode_) {
-    // TODO(msramek): Implement.
-    EXPECT_EQ(net::ERR_NOT_IMPLEMENTED, CalculateSizeOfAllEntries());
-  } else {
-    EXPECT_EQ(0, CalculateSizeOfAllEntries());
-  }
+  EXPECT_EQ(0, CalculateSizeOfAllEntries());
 }
 
 TEST_F(DiskCacheBackendTest, CalculateSizeOfAllEntries) {
   BackendCalculateSizeOfAllEntries();
 }
 
 TEST_F(DiskCacheBackendTest, MemoryOnlyCalculateSizeOfAllEntries) {
   SetMemoryOnlyMode();
   BackendCalculateSizeOfAllEntries();
 }
 
 TEST_F(DiskCacheBackendTest, SimpleCacheCalculateSizeOfAllEntries) {
+  // Use net::APP_CACHE to make size estimations deterministic via
+  // non-optimistic writes.
+  SetCacheType(net::APP_CACHE);
   SetSimpleCacheMode();
   BackendCalculateSizeOfAllEntries();
 }
 
 void DiskCacheBackendTest::BackendTransaction(const std::string& name,
                                               int num_entries, bool load) {
   success_ = false;
   ASSERT_TRUE(CopyTestCache(name));
   DisableFirstCleanup();
 
@@ skipping 1840 matching lines @@
 // after closing.
 // NOTE: IF THIS TEST IS FLAKY THEN IT IS FAILING. See https://crbug.com/416940
 TEST_F(DiskCacheBackendTest, SimpleCacheDeleteQuickly) {
   SetSimpleCacheMode();
   for (int i = 0; i < 100; ++i) {
     InitCache();
     cache_.reset();
     EXPECT_TRUE(CleanupCacheDir());
   }
 }