[BlobAsync] Disk support for blob storage

storage/common/blob_storage/blob_storage_constants.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_COMMON_BLOB_STORAGE_BLOB_STORAGE_CONSTANTS_H_
 #define STORAGE_COMMON_BLOB_STORAGE_BLOB_STORAGE_CONSTANTS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
+#include "base/callback_forward.h"
+#include "storage/common/storage_common_export.h"
+
 namespace storage {
 
+// All sizes are in bytes.
 // TODO(michaeln): use base::SysInfo::AmountOfPhysicalMemoryMB() in some
 // way to come up with a better limit.
-const int64_t kBlobStorageMaxMemoryUsage = 500 * 1024 * 1024;  // Half a gig.
-const size_t kBlobStorageIPCThresholdBytes = 250 * 1024;
-const size_t kBlobStorageMaxSharedMemoryBytes = 10 * 1024 * 1024;
-const uint64_t kBlobStorageMaxFileSizeBytes = 100 * 1024 * 1024;
-const uint64_t kBlobStorageMinFileSizeBytes = 1 * 1024 * 1024;
-const size_t kBlobStorageMaxBlobMemorySize =
-    kBlobStorageMaxMemoryUsage - kBlobStorageMinFileSizeBytes;
+struct BlobStorageQuotas {

[michaeln, 2016/08/23 01:31:55]

not sure about calling this Quotas since that term is loaded? Also, seems like
this could be a nested struct since it directly applies to the 

+  size_t GetTotalMemorySpace() const {

[michaeln, 2016/08/23 01:31:55]

nit: total_memory_space()

+    return max_blob_in_memory_space + in_flight_space;
+  }
+
+  // This is the maximum amount of memory we can send in an IPC.
+  size_t max_ipc_memory_size = 250 * 1024;
+  // This is the maximum size of a shared memory handle.
+  size_t max_shared_memory_size = 10 * 1024 * 1024;
+
+  // This is the maximum amount of memory we can use to store blobs.
+  size_t max_blob_in_memory_space = 495 * 1024 * 1024;
+  // This is the maximum amount of extra memory we can temporarily allocate
+  // towards blob items that we're currently writing to disk.
+  size_t in_flight_space = 5 * 1024 * 1024;
+
+  // This is the maximum amount of disk space we can use.
+  uint64_t max_blob_disk_space = 5ull * 1024 * 1024 * 1024;
+
+  // This is the minimum file size we can use when paging blob items to disk.
+  // We combine items until we reach at least this size.
+  uint64_t min_page_file_size = 5 * 1024 * 1024;
+  // This is the maximum file size we can create.
+  uint64_t max_file_size = 100 * 1024 * 1024;
+};
 
 enum class IPCBlobItemRequestStrategy {
   UNKNOWN = 0,
   IPC,
   SHARED_MEMORY,
   FILE,
   LAST = FILE
 };
 
-// These items cannot be reordered or renumbered because they're recorded to
-// UMA. New items must be added immediately before LAST, and LAST must be set to
-// the the last item.
-enum class IPCBlobCreationCancelCode {
-  UNKNOWN = 0,
-  OUT_OF_MEMORY = 1,
+// This is the enum to rule them all in the blob system.
+// These values are used in UMA metrics, so they should not be changed. Please
+// update LAST_ERROR if you add an error condition and LAST if you add new
+// state.
+enum class BlobStatus {
+  // Error case section:
+  // The construction arguments are invalid. This is considered a bad ipc.
+  ERR_INVALID_CONSTRUCTION_ARGUMENTS = 0,
+  // We don't have enough memory for the blob.
+  ERR_OUT_OF_MEMORY = 1,
   // We couldn't create or write to a file. File system error, like a full disk.
-  FILE_WRITE_FAILED = 2,
+  ERR_FILE_WRITE_FAILED = 2,
   // The renderer was destroyed while data was in transit.
-  SOURCE_DIED_IN_TRANSIT = 3,
+  ERR_SOURCE_DIED_IN_TRANSIT = 3,
   // The renderer destructed the blob before it was done transferring, and there
   // were no outstanding references (no one is waiting to read) to keep the
   // blob alive.
-  BLOB_DEREFERENCED_WHILE_BUILDING = 4,
+  ERR_BLOB_DEREFERENCED_WHILE_BUILDING = 4,
   // A blob that we referenced during construction is broken, or a browser-side
   // builder tries to build a blob with a blob reference that isn't finished
   // constructing.
-  REFERENCED_BLOB_BROKEN = 5,
-  LAST = REFERENCED_BLOB_BROKEN
+  ERR_REFERENCED_BLOB_BROKEN = 5,
+  LAST_ERROR = ERR_REFERENCED_BLOB_BROKEN,
+
+  // Blob state section:
+  // The blob is finished constructing.
+  DONE = 200,
+  // The system is pending on quota being granted, the transport layer
+  // populating pending data, and/or copying data from dependent blobs. See
+  // InternalBlobData::BuildingState determine which of these are happening, as
+  // they all can happen concurrently.
+  PENDING = 201,
+  LAST = PENDING
 };
 
+using BlobStatusCallback = base::Callback<void(BlobStatus)>;
+
+// Returns if the status is an error code.
+STORAGE_COMMON_EXPORT bool BlobStatusIsError(BlobStatus status);
+
+// Returns if the status is a bad enough error to flag the IPC as bad. This is
+// only INVALID_CONSTRUCTION_ARGUMENTS.
+STORAGE_COMMON_EXPORT bool BlobStatusIsBadIPC(BlobStatus status);
+
 }  // namespace storage
 
 #endif  // STORAGE_COMMON_BLOB_STORAGE_BLOB_STORAGE_CONSTANTS_H_