Implement cache counting for the simple and memory backends.

This is a followup to https://codereview.chromium.org/1304363013/, which implemented it for the blockfile backend.

BUG=510028

Review URL: https://codereview.chromium.org/1398053002

Cr-Commit-Position: refs/heads/master@{#354037}

6 files changed, 68 insertions, 54 deletions

diff --git a/net/disk_cache/backend_unittest.cc b/net/disk_cache/backend_unittest.cc
index 8833729..cf82a5b 100644
--- a/net/disk_cache/backend_unittest.cc
+++ b/net/disk_cache/backend_unittest.cc
@@ -89,6 +89,10 @@ class DiskCacheBackendTest : public DiskCacheTestWithCache {
                              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();
@@ -282,6 +286,18 @@ bool DiskCacheBackendTest::EnumerateAndMatchKeys(
   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;
@@ -1679,12 +1695,7 @@ 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.
@@ -1697,10 +1708,15 @@ void DiskCacheBackendTest::BackendCalculateSizeOfAllEntries() {
     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.
+    // we are not taking just the first stream into account. For convenience,
+    // the last written stream should be 0. This is because writing to
+    // the stream 1 in simple cache triggers a write to the stream 0 as well.
+    // This will happen asynchronously and possibly later than our call to
+    // |CalculateSizeOfAllEntries|.
     disk_cache::Entry* entry;
     ASSERT_EQ(net::OK, OpenEntry(key, &entry));
-    ASSERT_EQ(count, WriteData(entry, count % 2, 0, buffer.get(), count, true));
+    ASSERT_EQ(count,
+              WriteData(entry, (count + 1) % 2, 0, buffer.get(), count, true));
     entry->Close();
 
     ++count;
@@ -1708,16 +1724,10 @@ void DiskCacheBackendTest::BackendCalculateSizeOfAllEntries() {
 
   // 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.
@@ -1734,32 +1744,16 @@ void DiskCacheBackendTest::BackendCalculateSizeOfAllEntries() {
     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) {
diff --git a/net/disk_cache/memory/mem_backend_impl.cc b/net/disk_cache/memory/mem_backend_impl.cc
index ca8cf1b..9948660 100644
--- a/net/disk_cache/memory/mem_backend_impl.cc
+++ b/net/disk_cache/memory/mem_backend_impl.cc
@@ -184,8 +184,7 @@ int MemBackendImpl::DoomEntriesSince(const base::Time initial_time,
 
 int MemBackendImpl::CalculateSizeOfAllEntries(
     const CompletionCallback& callback) {
-  // TODO(msramek): Implement.
-  return net::ERR_NOT_IMPLEMENTED;
+  return current_size_;
 }
 
 class MemBackendImpl::MemIterator : public Backend::Iterator {
diff --git a/net/disk_cache/simple/simple_backend_impl.cc b/net/disk_cache/simple/simple_backend_impl.cc
index f985e58..d1c111e 100644
--- a/net/disk_cache/simple/simple_backend_impl.cc
+++ b/net/disk_cache/simple/simple_backend_impl.cc
@@ -442,19 +442,6 @@ int SimpleBackendImpl::DoomAllEntries(const CompletionCallback& callback) {
   return DoomEntriesBetween(Time(), Time(), callback);
 }
 
-void SimpleBackendImpl::IndexReadyForDoom(Time initial_time,
-                                          Time end_time,
-                                          const CompletionCallback& callback,
-                                          int result) {
-  if (result != net::OK) {
-    callback.Run(result);
-    return;
-  }
-  scoped_ptr<std::vector<uint64> > removed_key_hashes(
-      index_->GetEntriesBetween(initial_time, end_time).release());
-  DoomEntries(removed_key_hashes.get(), callback);
-}
-
 int SimpleBackendImpl::DoomEntriesBetween(
     const Time initial_time,
     const Time end_time,
@@ -472,8 +459,8 @@ int SimpleBackendImpl::DoomEntriesSince(
 
 int SimpleBackendImpl::CalculateSizeOfAllEntries(
     const CompletionCallback& callback) {
-  // TODO(msramek): Implement.
-  return net::ERR_NOT_IMPLEMENTED;
+  return index_->ExecuteWhenReady(base::Bind(
+      &SimpleBackendImpl::IndexReadyForSizeCalculation, AsWeakPtr(), callback));
 }
 
 class SimpleBackendImpl::SimpleIterator final : public Iterator {
@@ -570,6 +557,27 @@ void SimpleBackendImpl::InitializeIndex(const CompletionCallback& callback,
   callback.Run(result.net_error);
 }
 
+void SimpleBackendImpl::IndexReadyForDoom(Time initial_time,
+                                          Time end_time,
+                                          const CompletionCallback& callback,
+                                          int result) {
+  if (result != net::OK) {
+    callback.Run(result);
+    return;
+  }
+  scoped_ptr<std::vector<uint64>> removed_key_hashes(
+      index_->GetEntriesBetween(initial_time, end_time).release());
+  DoomEntries(removed_key_hashes.get(), callback);
+}
+
+void SimpleBackendImpl::IndexReadyForSizeCalculation(
+    const CompletionCallback& callback,
+    int result) {
+  if (result == net::OK)
+    result = static_cast<int>(index_->GetCacheSize());
+  callback.Run(result);
+}
+
 SimpleBackendImpl::DiskStatResult SimpleBackendImpl::InitCacheStructureOnDisk(
     const base::FilePath& path,
     uint64 suggested_max_size) {
diff --git a/net/disk_cache/simple/simple_backend_impl.h b/net/disk_cache/simple/simple_backend_impl.h
index c9debd0..c8cac21 100644
--- a/net/disk_cache/simple/simple_backend_impl.h
+++ b/net/disk_cache/simple/simple_backend_impl.h
@@ -140,6 +140,10 @@ class NET_EXPORT_PRIVATE SimpleBackendImpl : public Backend,
                          const CompletionCallback& callback,
                          int result);
 
+  // Calculates the size of the entire cache. Invoked when the index is ready.
+  void IndexReadyForSizeCalculation(const CompletionCallback& callback,
+                                    int result);
+
   // Try to create the directory if it doesn't exist. This must run on the IO
   // thread.
   static DiskStatResult InitCacheStructureOnDisk(const base::FilePath& path,
diff --git a/net/disk_cache/simple/simple_index.cc b/net/disk_cache/simple/simple_index.cc
index fd01abd..5557801 100644
--- a/net/disk_cache/simple/simple_index.cc
+++ b/net/disk_cache/simple/simple_index.cc
@@ -239,6 +239,11 @@ int32 SimpleIndex::GetEntryCount() const {
   return entries_set_.size();
 }
 
+uint64 SimpleIndex::GetCacheSize() const {
+  DCHECK(initialized_);
+  return cache_size_;
+}
+
 void SimpleIndex::Insert(uint64 entry_hash) {
   DCHECK(io_thread_checker_.CalledOnValidThread());
   // Upon insert we don't know yet the size of the entry.
diff --git a/net/disk_cache/simple/simple_index.h b/net/disk_cache/simple/simple_index.h
index 11adab9..5a8046d 100644
--- a/net/disk_cache/simple/simple_index.h
+++ b/net/disk_cache/simple/simple_index.h
@@ -130,6 +130,10 @@ class NET_EXPORT_PRIVATE SimpleIndex
   // Returns number of indexed entries.
   int32 GetEntryCount() const;
 
+  // Returns the size of the entire cache in bytes. Can only be called after the
+  // index has been initialized.
+  uint64 GetCacheSize() const;
+
   // Returns whether the index has been initialized yet.
   bool initialized() const { return initialized_; }