[Blob] Blob paging to disk patch.

storage/browser/blob/blob_memory_controller.h

Index: storage/browser/blob/blob_memory_controller.h
diff --git a/storage/browser/blob/blob_memory_controller.h b/storage/browser/blob/blob_memory_controller.h
new file mode 100644
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+++ b/storage/browser/blob/blob_memory_controller.h
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+// Copyright 2015 The Chromium Authors. All rihts reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef STORAGE_BROWSER_BLOB_BLOB_MEMORY_CONTROLLER_H_
+#define STORAGE_BROWSER_BLOB_BLOB_MEMORY_CONTROLLER_H_
+
+#include <stdint.h>
+#include <algorithm>
+#include <list>
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/callback_forward.h"
+#include "base/containers/mru_cache.h"
+#include "base/files/file.h"
+#include "base/files/file_path.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
+#include "storage/common/blob_storage/blob_storage_constants.h"
+#include "storage/common/data_element.h"
+
+namespace base {
+class TaskRunner;
+}
+
+namespace storage {
+
+class ShareableBlobDataItem;
+class ShareableFileReference;
+
+// There should be no memory sizes of 0.
+// This class is responsible for
+// * our current memory usage for blobs, both on disk and in memory,
+// * when we can add a blob w/ a given size,
+// * creating temporary files,
+// * paging blobs to disk, and
+// * refcounting blob page files.
+class BlobMemoryController
+    : public base::SupportsWeakPtr<BlobMemoryController> {
+ public:
+  enum class BlobTrasportationMemoryStrategyResult {
+    // We don't have enough memory for this blob.
+    TOO_LARGE,
+    // There isn't any memory that needs transporting.
+    NONE_NEEDED,
+    // Sh transportation strategies.
+    SHORTCUT,
+    IPC,
+    SHARED_MEMORY,
+    FILE
+  };
+  struct FileCreationInfo {
+    FileCreationInfo();
+    ~FileCreationInfo();
+
+    base::File::Error error = base::File::FILE_ERROR_FAILED;
+    scoped_refptr<ShareableFileReference> file_reference;
+    base::Time last_modified;
+  };
+
+  // Using this constructor means that the disk is disabled.
+  BlobMemoryController();
+  BlobMemoryController(bool enable_disk,
+                       const base::FilePath& blob_storage_dir,
+                       scoped_refptr<base::TaskRunner> file_runner);
+  virtual ~BlobMemoryController();
+
+  void SetMemoryLimits(size_t max_blob_in_memory_size_bytes,
+                       size_t max_blob_memory_space_bytes,
+                       uint64_t max_blob_disk_space_bytes,
+                       size_t in_flight_space_bytes,
+                       uint64_t min_page_file_size) {
+    max_blob_in_memory_size_ = max_blob_in_memory_size_bytes;
+    max_blob_memory_space_ = max_blob_memory_space_bytes;
+    max_blob_disk_space_ = max_blob_disk_space_bytes;
+    in_flight_space_ = in_flight_space_bytes;
+    min_page_file_size_ = min_page_file_size;
+  }
+
+  // Returns if the data in the descriptions is good data (not a bad IPC).
+  bool DecideBlobTransportationMemoryStrategy(
+      const std::vector<DataElement>& descriptions,
+      uint64_t* total_bytes,
+      BlobTrasportationMemoryStrategyResult* result);
+
+  // Creates a temporary file that we store in our blob temporary directory.
+  // This temp file is not registered with the ref count system, and the client
+  // must call IncreaseTempFileRefCount to have the file correctly deleted when
+  // unused.
+  void CreateTemporaryFileForRenderer(
+      uint64_t size_bytes,
+      base::Callback<void(const FileCreationInfo&)> done);
+
+  // Notifies the caller when a blob of the given size can be stored in our blob
+  // system. This assumes the caller has called CanNewBlobFit, and does not
+  // check whether the size will fit.
+  // The argument on can_request is true if we can create the blob, and
+  // false if there was an error and the new blob needs to be broken.
+  void NotifyWhenBlobCanBeRequested(uint64_t memory_size_bytes,
+                                    base::Callback<void(bool)> can_request);
+
+  void UpdateBlobItemInRecents(ShareableBlobDataItem* item);
+  void RemoveBlobItemInRecents(uint64_t id);
+
+  // Disables the disk.
+  void DisableDisk();
+
+  bool disk_enabled() const { return disk_used_; }
+
+ private:
+  // Returns if we didn't overflow our total size.
+  static bool CalculateBlobMemorySize(
+      const std::vector<DataElement>& descriptions,
+      size_t* shortcut_bytes,
+      uint64_t* total_bytes);
+
+  // Creates a file in the given directory w/ the given filename and size.
+  static FileCreationInfo CreateFile(const base::FilePath& directory_path,
+                                     const std::string& file_name,
+                                     size_t size_bytes);
+
+  static FileCreationInfo WriteItemsToFile(
+      std::vector<scoped_refptr<ShareableBlobDataItem>>* items,
+      size_t total_size_bytes,
+      const base::FilePath& directory_path,
+      const std::string& file_name);
+
+  // We add a delete callback to the file reference to decrement our disk usage.
+  void OnCreateFile(uint64_t file_size,
+                    base::Callback<void(const FileCreationInfo&)> done,
+                    FileCreationInfo result);
+
+  // Returns the size we'll be freeing.
+  size_t ScheduleBlobPaging();
+  void SchedulePagingUntilWeCanFit(size_t total_memory_needed);
+
+  // Called when we've completed paging a list of items
+  void OnPagingComplete(
+      scoped_ptr<std::vector<scoped_refptr<ShareableBlobDataItem>>> items,
+      size_t total_items_size,
+      FileCreationInfo result);
+
+  void RecordTracingCounters();
+  size_t GetAvailableMemoryForBlobs();
+  uint64_t GetAvailableDiskSpaceForBlobs();
+
+  // We decrement the disk space used.
+  void OnBlobFileDelete(uint64_t size, const base::FilePath& path);
+
+  using RecentItemsCache = base::MRUCache<uint64_t, ShareableBlobDataItem*>;
+
+  size_t blob_memory_used_ = 0;
+  size_t in_flight_memory_used_ = 0;
+  uint64_t disk_used_ = 0;
+
+  std::map<base::FilePath, size_t> page_file_references_;
+
+  scoped_refptr<base::TaskRunner> file_runner_;
+  std::list<std::pair<uint64_t, base::Callback<void(bool)>>>
+      blobs_waiting_for_paging_;
+  size_t blobs_waiting_for_paging_size_ = 0;
+
+  size_t max_ipc_memory_size_ = kBlobStorageIPCThresholdBytes;
+  size_t max_blob_in_memory_size_ = kBlobStorageMaxBlobMemorySize;
+  size_t max_blob_memory_space_ = kBlobStorageMaxMemoryUsage;
+  uint64_t max_blob_disk_space_ = kBlobStorageMaxDiskSpace;
+  size_t in_flight_space_ = kBlobStorageInFlightMemory;
+  uint64_t min_page_file_size_ = kBlobStorageMinFileSizeBytes;
+  bool enable_disk_ = false;
+
+  base::FilePath blob_storage_dir_;
+  uint64_t current_file_num_ = 0;
+
+  // Lifetime of the ShareableBlobDataItem objects is handles externally in the
+  // BlobStorageContext class.
+  RecentItemsCache recent_item_cache_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlobMemoryController);
+};
+
+}  // namespace storage
+#endif  // STORAGE_BROWSER_BLOB_BLOB_MEMORY_CONTROLLER_H_