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#include "base/perftimer.h"
#include "base/scoped_handle.h"
#include "base/timer.h"
#include "net/base/net_errors.h"
#include "net/disk_cache/disk_cache.h"
#include "net/disk_cache/disk_cache_test_util.h"
#include "net/disk_cache/hash.h"
#include "testing/gtest/include/gtest/gtest.h"

extern int g_cache_tests_max_id;
extern volatile int g_cache_tests_received;
extern volatile bool g_cache_tests_error;

namespace {

bool EvictFileFromSystemCache(const wchar_t* name) {
  // Overwrite it with no buffering.
  ScopedHandle file(CreateFile(name, GENERIC_READ | GENERIC_WRITE,
                               FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
                               OPEN_EXISTING, FILE_FLAG_NO_BUFFERING, NULL));
  if (!file.IsValid())
    return false;

  // Execute in chunks. It could be optimized. We want to do few of these since
  // these opterations will be slow without the cache.
  char buffer[128 * 1024];
  int total_bytes = 0;
  DWORD bytes_read;
  for (;;) {
    if (!ReadFile(file, buffer, sizeof(buffer), &bytes_read, NULL))
      return false;
    if (bytes_read == 0)
      break;

    bool final = false;
    if (bytes_read < sizeof(buffer))
      final = true;

    DWORD to_write = final ? sizeof(buffer) : bytes_read;

    DWORD actual;
    SetFilePointer(file, total_bytes, 0, FILE_BEGIN);
    if (!WriteFile(file, buffer, to_write, &actual, NULL))
      return false;
    total_bytes += bytes_read;

    if (final) {
      SetFilePointer(file, total_bytes, 0, FILE_BEGIN);
      SetEndOfFile(file);
      break;
    }
  }
  return true;
}

struct TestEntry {
  std::string key;
  int data_len;
};
typedef std::vector<TestEntry> TestEntries;

const int kMaxSize = 16 * 1024 - 1;

// Creates num_entries on the cache, and writes 200 bytes of metadata and up
// to kMaxSize of data to each entry.
int TimeWrite(int num_entries, disk_cache::Backend* cache,
              TestEntries* entries) {
  char buffer1[200];
  char buffer2[kMaxSize];

  CacheTestFillBuffer(buffer1, sizeof(buffer1), false);
  CacheTestFillBuffer(buffer2, sizeof(buffer2), false);

  CallbackTest callback(1);
  g_cache_tests_error = false;
  g_cache_tests_max_id = 1;
  g_cache_tests_received = 0;
  int expected = 0;

  MessageLoopHelper helper;

  PerfTimeLogger timer("Write disk cache entries");

  for (int i = 0; i < num_entries; i++) {
    TestEntry entry;
    entry.key = GenerateKey(true);
    entry.data_len = rand() % sizeof(buffer2);
    entries->push_back(entry);

    disk_cache::Entry* cache_entry;
    if (!cache->CreateEntry(entry.key, &cache_entry))
      break;
    int ret = cache_entry->WriteData(0, 0, buffer1, sizeof(buffer1), &callback,
                                     false);
    if (net::ERR_IO_PENDING == ret)
      expected++;
    else if (sizeof(buffer1) != ret)
      break;

    ret = cache_entry->WriteData(1, 0, buffer2, entry.data_len, &callback,
                                 false);
    if (net::ERR_IO_PENDING == ret)
      expected++;
    else if (entry.data_len != ret)
      break;
    cache_entry->Close();
  }

  helper.WaitUntilCacheIoFinished(expected);
  timer.Done();

  return expected;
}

// Reads the data and metadata from each entry listed on |entries|.
int TimeRead(int num_entries, disk_cache::Backend* cache,
             const TestEntries& entries, bool cold) {
  char buffer1[200];
  char buffer2[kMaxSize];

  CacheTestFillBuffer(buffer1, sizeof(buffer1), false);
  CacheTestFillBuffer(buffer2, sizeof(buffer2), false);

  CallbackTest callback(1);
  g_cache_tests_error = false;
  g_cache_tests_max_id = 1;
  g_cache_tests_received = 0;
  int expected = 0;

  MessageLoopHelper helper;

  const char* message = cold ? "Read disk cache entries (cold)" :
                        "Read disk cache entries (warm)";
  PerfTimeLogger timer(message);

  for (int i = 0; i < num_entries; i++) {
    disk_cache::Entry* cache_entry;
    if (!cache->OpenEntry(entries[i].key, &cache_entry))
      break;
    int ret = cache_entry->ReadData(0, 0, buffer1, sizeof(buffer1), &callback);
    if (net::ERR_IO_PENDING == ret)
      expected++;
    else if (sizeof(buffer1) != ret)
      break;

    ret = cache_entry->ReadData(1, 0, buffer2, entries[i].data_len, &callback);
    if (net::ERR_IO_PENDING == ret)
      expected++;
    else if (entries[i].data_len != ret)
      break;
    cache_entry->Close();
  }

  helper.WaitUntilCacheIoFinished(expected);
  timer.Done();

  return expected;
}

}  // namespace

TEST(DiskCacheTest, Hash) {
  int seed = static_cast<int>(Time::Now().ToInternalValue());
  srand(seed);

  PerfTimeLogger timer("Hash disk cache keys");
  for (int i = 0; i < 300000; i++) {
    std::string key = GenerateKey(true);
    uint32 hash = disk_cache::Hash(key);
  }
  timer.Done();
}

TEST(DiskCacheTest, CacheBackendPerformance) {
  std::wstring path = GetCachePath();
  ASSERT_TRUE(DeleteCache(path.c_str()));
  disk_cache::Backend* cache = disk_cache::CreateCacheBackend(path, false, 0);
  ASSERT_TRUE(NULL != cache);

  int seed = static_cast<int>(Time::Now().ToInternalValue());
  srand(seed);

  TestEntries entries;
  int num_entries = 1000;

  int ret = TimeWrite(num_entries, cache, &entries);
  EXPECT_EQ(ret, g_cache_tests_received);

  delete cache;

  ASSERT_TRUE(EvictFileFromSystemCache((path + L"\\index").c_str()));
  ASSERT_TRUE(EvictFileFromSystemCache((path + L"\\data_0").c_str()));
  ASSERT_TRUE(EvictFileFromSystemCache((path + L"\\data_1").c_str()));
  ASSERT_TRUE(EvictFileFromSystemCache((path + L"\\data_2").c_str()));
  ASSERT_TRUE(EvictFileFromSystemCache((path + L"\\data_3").c_str()));

  cache = disk_cache::CreateCacheBackend(path, false, 0);
  ASSERT_TRUE(NULL != cache);

  ret = TimeRead(num_entries, cache, entries, true);
  EXPECT_EQ(ret, g_cache_tests_received);

  ret = TimeRead(num_entries, cache, entries, false);
  EXPECT_EQ(ret, g_cache_tests_received);

  delete cache;
}