[BlobAsync] Disk support for blob storage

storage/browser/blob/blob_async_builder_host.h

 // Copyright 2015 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.
 
 #ifndef STORAGE_BROWSER_BLOB_BLOB_ASYNC_BUILDER_HOST_H_
 #define STORAGE_BROWSER_BLOB_BLOB_ASYNC_BUILDER_HOST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/files/file.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/shared_memory_handle.h"
 #include "base/memory/weak_ptr.h"
 #include "storage/browser/blob/blob_async_transport_request_builder.h"
 #include "storage/browser/blob/blob_data_builder.h"
-#include "storage/browser/blob/blob_transport_result.h"
+#include "storage/browser/blob/blob_memory_controller.h"
 #include "storage/browser/storage_browser_export.h"
 #include "storage/common/blob_storage/blob_item_bytes_request.h"
 #include "storage/common/blob_storage/blob_item_bytes_response.h"
 #include "storage/common/blob_storage/blob_storage_constants.h"
 #include "storage/common/data_element.h"
 
 namespace base {
 class SharedMemory;
 }
 
 namespace storage {
 class BlobDataHandle;
 class BlobStorageContext;
 
-// This class
-// * holds all blobs that are currently being built asynchronously for a child
+// The responsibility of this class is to handle all transportation of data
+// between the renderer and the browser process, and correctly construct the
+// resulting blob using the BlobStorageContext. We:
+// * hold all blobs that are currently being built asynchronously for a child
 //   process,
-// * sends memory requests through the given callback in |StartBuildingBlob|,
-//   and uses the BlobTransportResult return value to signify other results,
+// * sends memory requests through the given callback in |RegisterBlob|,
+//   and uses the BlobStatus return value to signify other results,
 // * includes all logic for deciding which async transport strategy to use, and
 // * handles all blob construction communication with the BlobStorageContext.
 // The method |CancelAll| must be called by the consumer, it is not called on
 // destruction.
 class STORAGE_EXPORT BlobAsyncBuilderHost {
  public:
   using RequestMemoryCallback = base::Callback<void(
       std::unique_ptr<std::vector<storage::BlobItemBytesRequest>>,
       std::unique_ptr<std::vector<base::SharedMemoryHandle>>,
       std::unique_ptr<std::vector<base::File>>)>;
+
   BlobAsyncBuilderHost();
   ~BlobAsyncBuilderHost();
 
-  // This registers the given blob internally and adds it to the storage.
-  // Calling this method also guarentees that the referenced blobs are kept
-  // alive for the duration of the construction of this blob.
-  // We return
-  // * BAD_IPC if we already have the blob registered or if we reference ourself
-  //   in the referenced_blob_uuids.
-  // * CANCEL_REFERENCED_BLOB_BROKEN if one of the referenced blobs is broken or
-  //   doesn't exist. We store the blob in the context as broken  with code
-  //   REFERENCED_BLOB_BROKEN.
-  // * DONE if we successfully registered the blob.
-  BlobTransportResult RegisterBlobUUID(
-      const std::string& uuid,
-      const std::string& content_type,
-      const std::string& content_disposition,
-      const std::set<std::string>& referenced_blob_uuids,
-      BlobStorageContext* context);
-
-  // This method begins the construction of the blob given the descriptions. The
-  // blob uuid MUST be building in this object.
-  // When we return:
-  // * DONE: The blob is finished transfering right away, and is now
-  //   successfully saved in the context.
-  // * PENDING_RESPONSES: The async builder host is waiting for responses from
-  //   the renderer. It has called |request_memory| for these responses.
-  // * CANCEL_*: We have to cancel the blob construction. This function clears
-  //   the blob's internal state and marks the blob as broken in the context
-  //   before returning.
-  // * BAD_IPC: The arguments were invalid/bad. This marks the blob as broken in
-  //   the context before returning.
-  BlobTransportResult StartBuildingBlob(
-      const std::string& uuid,
-      const std::vector<DataElement>& elements,
-      size_t memory_available,
-      BlobStorageContext* context,
-      const RequestMemoryCallback& request_memory);
+  // This registers the given blob internally and adds it to the storage. The
+  // |status_callback| is used when we return PENDING, and reports an
+  // asynchronous error of if we're done transporting data. This function
+  // creates the blob with a default reference of 1.
+  // This function returns:
+  // * INVALID_CONSTRUCTION_ARGUMENTS if we have invalid input arguments/data.
+  //   We treat this as a critical error, and don't bother registering the blob
+  //   in the BlobStorageContext.
+  // * REFERENCED_BLOB_BROKEN if one of the referenced blobs is broken or
+  //   doesn't exist.
+  // * PENDING if we are waiting for responses from the renderer, and
+  // * DONE if the BlobStorageContext doesn't need any data transported and we
+  //   can clean up.
+  BlobStatus RegisterBlob(const std::string& uuid,
+                          const std::string& content_type,
+                          const std::string& content_disposition,
+                          const std::vector<DataElement>& elements,
+                          BlobStorageContext* context,
+                          const RequestMemoryCallback& request_memory,
+                          const BlobStatusCallback& status_callback);
 
   // This is called when we have responses from the Renderer to our calls to
   // the request_memory callback above. See above for return value meaning.
-  BlobTransportResult OnMemoryResponses(
+  BlobStatus OnMemoryResponses(
       const std::string& uuid,
       const std::vector<BlobItemBytesResponse>& responses,
       BlobStorageContext* context);
 
   // This removes the BlobBuildingState from our map and flags the blob as
   // broken in the context. This can be called both from our own logic to cancel
   // the blob, or from the DispatcherHost (Renderer). The blob MUST be being
   // built in this builder.
   // Note: if the blob isn't in the context (renderer dereferenced it before we
   // finished constructing), then we don't bother touching the context.
   void CancelBuildingBlob(const std::string& uuid,
-                          IPCBlobCreationCancelCode code,
+                          BlobStatus code,
                           BlobStorageContext* context);
 
   // This clears this object of pending construction. It also handles marking
   // blobs that haven't been fully constructed as broken in the context if there
   // are any references being held by anyone. We know that they're being used
   // by someone else if they still exist in the context.
   void CancelAll(BlobStorageContext* context);
 
   bool IsEmpty() const { return async_blob_map_.empty(); }
 
   size_t blob_building_count() const { return async_blob_map_.size(); }
 
   bool IsBeingBuilt(const std::string& key) const {
     return async_blob_map_.find(key) != async_blob_map_.end();
   }
 
-  // For testing use only.  Must be called before StartBuildingBlob.
-  void SetMemoryConstantsForTesting(size_t max_ipc_memory_size,
-                                    size_t max_shared_memory_size,
-                                    uint64_t max_file_size) {
-    max_ipc_memory_size_ = max_ipc_memory_size;
-    max_shared_memory_size_ = max_shared_memory_size;
-    max_file_size_ = max_file_size;
-  }
-
  private:
   struct BlobBuildingState {
     // |refernced_blob_handles| should be all handles generated from the set
     // of |refernced_blob_uuids|.
-    BlobBuildingState(
-        const std::string& uuid,
-        std::set<std::string> referenced_blob_uuids,
-        std::vector<std::unique_ptr<BlobDataHandle>>* referenced_blob_handles);
+    BlobBuildingState(const std::string& uuid);
     ~BlobBuildingState();
 
+    IPCBlobItemRequestStrategy strategy = IPCBlobItemRequestStrategy::UNKNOWN;
     BlobAsyncTransportRequestBuilder request_builder;
     BlobDataBuilder data_builder;
     std::vector<bool> request_received;
+    size_t num_fulfilled_requests = 0;
+
+    RequestMemoryCallback request_memory_callback;
+    BlobStatusCallback status_callback;
+
+    // Used by shared memory strategy.
     size_t next_request = 0;
-    size_t num_fulfilled_requests = 0;
     std::unique_ptr<base::SharedMemory> shared_memory_block;
     // This is the number of requests that have been sent to populate the above
     // shared data. We won't ask for more data in shared memory until all
     // requests have been responded to.
     size_t num_shared_memory_requests = 0;
     // Only relevant if num_shared_memory_requests is > 0
     size_t current_shared_memory_handle_index = 0;
 
-    // We save these to double check that the RegisterBlob and StartBuildingBlob
-    // messages are in sync.
-    std::set<std::string> referenced_blob_uuids;
-    // These are the blobs that are referenced in the newly constructed blob.
-    // We use these to make sure they stay alive while we create the new blob,
-    // and to wait until any blobs that are not done building are fully
-    // constructed.
-    std::vector<std::unique_ptr<BlobDataHandle>> referenced_blob_handles;
-
-    // These are the number of blobs we're waiting for before we can start
-    // building.
-    size_t num_referenced_blobs_building = 0;
-
-    BlobAsyncBuilderHost::RequestMemoryCallback request_memory_callback;
+    // Used by file strategy.
+    std::vector<scoped_refptr<ShareableFileReference>> files;
   };
 
   typedef std::map<std::string, std::unique_ptr<BlobBuildingState>>
       AsyncBlobMap;
 
+  BlobStatus StartRequests(const std::string& uuid,
+                           BlobBuildingState* state,
+                           BlobStorageContext* context);
+
+  void OnCanStartBuildingBlob(const std::string& uuid,
+                              base::WeakPtr<BlobStorageContext> context,
+                              BlobStatus status);
+
+  void SendIPCRequests(BlobBuildingState* state, BlobStorageContext* context);
+  BlobStatus OnIPCResponses(const std::string& uuid,
+                            BlobBuildingState* state,
+                            const std::vector<BlobItemBytesResponse>& responses,
+                            BlobStorageContext* context);
+
   // This is the 'main loop' of our memory requests to the renderer.
-  BlobTransportResult ContinueBlobMemoryRequests(const std::string& uuid,
-                                                 BlobStorageContext* context);
+  BlobStatus ContinueSharedMemoryRequests(const std::string& uuid,
+                                          BlobBuildingState* state,
+                                          BlobStorageContext* context);
 
-  // This is our callback for when we want to finish the blob and we're waiting
-  // for blobs we reference to be built. When the last callback occurs, we
-  // complete the blob and erase our internal state.
-  void ReferencedBlobFinished(const std::string& uuid,
-                              base::WeakPtr<BlobStorageContext> context,
-                              bool construction_success,
-                              IPCBlobCreationCancelCode reason);
+  BlobStatus OnSharedMemoryResponses(
+      const std::string& uuid,
+      BlobBuildingState* state,
+      const std::vector<BlobItemBytesResponse>& responses,
+      BlobStorageContext* context);
+
+  void OnFileCreated(const std::string& uuid,
+                     size_t handle_index,
+                     BlobMemoryController::FileCreationInfo file_info);
+
+  BlobStatus OnFileResponses(
+      const std::string& uuid,
+      BlobBuildingState* state,
+      const std::vector<BlobItemBytesResponse>& responses,
+      BlobStorageContext* context);
 
   // This finishes creating the blob in the context, decrements blob references
   // that we were holding during construction, and erases our state.
   void FinishBuildingBlob(BlobBuildingState* state,
                           BlobStorageContext* context);
 
   AsyncBlobMap async_blob_map_;
-
-  // Here for testing.
-  size_t max_ipc_memory_size_ = kBlobStorageIPCThresholdBytes;
-  size_t max_shared_memory_size_ = kBlobStorageMaxSharedMemoryBytes;
-  uint64_t max_file_size_ = kBlobStorageMaxFileSizeBytes;
-
   base::WeakPtrFactory<BlobAsyncBuilderHost> ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BlobAsyncBuilderHost);
 };
 
 }  // namespace storage
 #endif  // STORAGE_BROWSER_BLOB_BLOB_ASYNC_BUILDER_HOST_H_