[BlobAsync] Disk support for blob storage

storage/browser/blob/blob_storage_context.h

Index: storage/browser/blob/blob_storage_context.h
diff --git a/storage/browser/blob/blob_storage_context.h b/storage/browser/blob/blob_storage_context.h
index 8553d0266d2d8b6338a176f4e9d9ce9d7675fa85..79339eec0aade31b667d7740c8ac8d4bff24b26b 100644
--- a/storage/browser/blob/blob_storage_context.h
+++ b/storage/browser/blob/blob_storage_context.h
@@ -18,7 +18,9 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "base/single_thread_task_runner.h"
 #include "storage/browser/blob/blob_data_handle.h"
+#include "storage/browser/blob/blob_memory_controller.h"
 #include "storage/browser/blob/blob_storage_registry.h"
 #include "storage/browser/blob/internal_blob_data.h"
 #include "storage/browser/storage_browser_export.h"
@@ -75,14 +77,54 @@ class STORAGE_EXPORT BlobStorageContext
   bool RegisterPublicBlobURL(const GURL& url, const std::string& uuid);
   void RevokePublicBlobURL(const GURL& url);
 
-  size_t memory_usage() const { return memory_usage_; }
   size_t blob_count() const { return registry_.blob_count(); }
-  size_t memory_available() const {
-    return kBlobStorageMaxMemoryUsage - memory_usage_;
-  }
 
   const BlobStorageRegistry& registry() { return registry_; }
 
+  void EnableDisk(const base::FilePath storage_directory,
+                  scoped_refptr<base::SingleThreadTaskRunner> file_runner);
+
+  std::unique_ptr<BlobDataHandle> BuildBrokenBlob(
+      const std::string& uuid,
+      const std::string& content_type,
+      const std::string& content_disposition,
+      IPCBlobCreationCancelCode reason);
+
+  // If the handle is not broken, then we will call |can_populate_memory| when
+  // we're ready for the user data to be populated. This can happen
+  // synchronously
+  // or asynchronously.
+  // If the handle is broken, then the possible error cases are:
+  // * OUT_OF_MEMORY if we don't have enough memory to store the blob,
+  // * REFERENCED_BLOB_BROKEN if a referenced blob is broken or we're
+  //   referencing ourself.
+  std::unique_ptr<BlobDataHandle> BuildBlob(
+      const BlobDataBuilder& content,
+      const base::Callback<void(bool, IPCBlobCreationCancelCode)>&
+          can_populate_memory);
+
+  void BreakAndFinishBlob(const std::string& uuid,
+                          IPCBlobCreationCancelCode code);
+
+  // This notifies the construction system that the unpopulated data in the
+  // given blob has been populated.
+  void FinishedPopulatingBlob(const std::string& uuid);
+
+ protected:
+  friend struct BlobSlice;
+  friend struct BlobFlattener;
+
+  friend class content::BlobDispatcherHostTest;
+
+  // Not thread safe.
+  static uint64_t GetAndIncrementItemId();
+
+  BlobMemoryController* mutable_memory_controller() {
+    return &memory_controller_;
+  }
+
+  const BlobMemoryController& memory_controller() { return memory_controller_; }
+
  private:
   using BlobRegistryEntry = BlobStorageRegistry::Entry;
   using BlobConstructedCallback = BlobStorageRegistry::BlobConstructedCallback;
@@ -102,18 +144,20 @@ class STORAGE_EXPORT BlobStorageContext
                            TestUnknownBrokenAndBuildingBlobReference);
   friend class ViewBlobInternalsJob;
 
-  // CompletePendingBlob or CancelPendingBlob should be called after this.
-  void CreatePendingBlob(const std::string& uuid,
-                         const std::string& content_type,
-                         const std::string& content_disposition);
+  std::unique_ptr<BlobDataHandle> CreateHandle(const std::string& uuid,
+                                               BlobRegistryEntry* entry);
+
+  bool CanFinishBuilding(BlobRegistryEntry* entry);
 
-  // This includes resolving blob references in the builder. This will run the
-  // callbacks given in RunOnConstructionComplete.
-  void CompletePendingBlob(const BlobDataBuilder& external_builder);
+  void FinishBuilding(BlobRegistryEntry* entry);
 
-  // This will run the callbacks given in RunOnConstructionComplete.
-  void CancelPendingBlob(const std::string& uuid,
-                         IPCBlobCreationCancelCode reason);
+  void OnEnoughSizeForBlobData(const std::string& uuid, bool can_fit);
+
+  void OnDependentBlobFinished(const std::string& owning_blob_uuid,
+                               bool construction_success,
+                               IPCBlobCreationCancelCode reason);
+
+  void ClearAndFreeMemory(const std::string& uuid, BlobRegistryEntry* entry);
 
   void IncrementBlobRefCount(const std::string& uuid);
   void DecrementBlobRefCount(const std::string& uuid);
@@ -123,7 +167,9 @@ class STORAGE_EXPORT BlobStorageContext
   // TODO(dmurph): After we make the snapshot method in BlobHandle private, then
   // make this DCHECK on the blob not being complete.
   std::unique_ptr<BlobDataSnapshot> CreateSnapshot(const std::string& uuid);
+  // TODO(dmurph): Merge the next two methods.
   bool IsBroken(const std::string& uuid) const;
+  IPCBlobCreationCancelCode GetBrokenReason(const std::string& uuid) const;
   bool IsBeingBuilt(const std::string& uuid) const;
   // Runs |done| when construction completes, with true if it was successful,
   // and false if there was an error, which is reported in the second argument
@@ -131,37 +177,8 @@ class STORAGE_EXPORT BlobStorageContext
   void RunOnConstructionComplete(const std::string& uuid,
                                  const BlobConstructedCallback& done);
 
-  // Appends the given blob item to the blob builder.  The new blob
-  // retains ownership of data_item if applicable, and returns false if there
-  // was an error and pouplates the error_code.  We can either have an error of:
-  // OUT_OF_MEMORY: We are out of memory to store this blob.
-  // REFERENCED_BLOB_BROKEN: One of the referenced blobs is broken.
-  bool AppendAllocatedBlobItem(const std::string& target_blob_uuid,
-                               scoped_refptr<BlobDataItem> data_item,
-                               InternalBlobData::Builder* target_blob_data,
-                               IPCBlobCreationCancelCode* error_code);
-
-  // Allocates a shareable blob data item, with blob references resolved.  If
-  // there isn't enough memory, then a nullptr is returned.
-  scoped_refptr<ShareableBlobDataItem> AllocateShareableBlobDataItem(
-      const std::string& target_blob_uuid,
-      scoped_refptr<BlobDataItem> data_item);
-
-  // Deconstructs the blob and appends it's contents to the target blob.  Items
-  // are shared if possible, and copied if the given offset and length
-  // have to split an item.
-  bool AppendBlob(const std::string& target_blob_uuid,
-                  const InternalBlobData& blob,
-                  uint64_t offset,
-                  uint64_t length,
-                  InternalBlobData::Builder* target_blob_data);
-
   BlobStorageRegistry registry_;
-
-  // Used to keep track of how much memory is being utilized for blob data,
-  // we count only the items of TYPE_DATA which are held in memory and not
-  // items of TYPE_FILE.
-  size_t memory_usage_;
+  BlobMemoryController memory_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(BlobStorageContext);
 };