[BlobAsync] Disk support for blob storage

content/browser/blob_storage/blob_dispatcher_host.cc

 // Copyright 2016 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.
 
 #include "content/browser/blob_storage/blob_dispatcher_host.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/metrics/histogram_macros.h"
 #include "content/browser/bad_message.h"
 #include "content/browser/blob_storage/chrome_blob_storage_context.h"
 #include "content/common/fileapi/webblob_messages.h"
 #include "ipc/ipc_platform_file.h"
+#include "storage/browser/blob/blob_data_handle.h"
 #include "storage/browser/blob/blob_storage_context.h"
-#include "storage/browser/blob/blob_transport_result.h"
+#include "storage/browser/blob/internal_blob_data.h"
 #include "storage/common/blob_storage/blob_item_bytes_request.h"
 #include "storage/common/blob_storage/blob_item_bytes_response.h"
 #include "storage/common/data_element.h"
 #include "url/gurl.h"
 
 using storage::BlobStorageContext;
 using storage::BlobStorageRegistry;
-using storage::BlobTransportResult;
-using storage::IPCBlobCreationCancelCode;
+using storage::BlobStatus;
 
 namespace content {
 namespace {
 
 // These are used for UMA stats, don't change.
 enum RefcountOperation {
   BDH_DECREMENT = 0,
   BDH_INCREMENT,
   BDH_TRACING_ENUM_LAST
 };
@@ skipping 11 matching lines @@
 
 void BlobDispatcherHost::OnChannelClosing() {
   ClearHostFromBlobStorageContext();
   public_blob_urls_.clear();
   blobs_inuse_map_.clear();
 }
 
 bool BlobDispatcherHost::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(BlobDispatcherHost, message)
-    IPC_MESSAGE_HANDLER(BlobStorageMsg_RegisterBlobUUID, OnRegisterBlobUUID)
-    IPC_MESSAGE_HANDLER(BlobStorageMsg_StartBuildingBlob, OnStartBuildingBlob)
+    IPC_MESSAGE_HANDLER(BlobStorageMsg_RegisterBlob, OnRegisterBlob)
     IPC_MESSAGE_HANDLER(BlobStorageMsg_MemoryItemResponse, OnMemoryItemResponse)
-    IPC_MESSAGE_HANDLER(BlobStorageMsg_CancelBuildingBlob, OnCancelBuildingBlob)
+    IPC_MESSAGE_HANDLER(BlobStorageMsg_SendBlobStatus, OnCancelBuildingBob)
     IPC_MESSAGE_HANDLER(BlobHostMsg_IncrementRefCount, OnIncrementBlobRefCount)
     IPC_MESSAGE_HANDLER(BlobHostMsg_DecrementRefCount, OnDecrementBlobRefCount)
     IPC_MESSAGE_HANDLER(BlobHostMsg_RegisterPublicURL, OnRegisterPublicBlobURL)
     IPC_MESSAGE_HANDLER(BlobHostMsg_RevokePublicURL, OnRevokePublicBlobURL)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
-void BlobDispatcherHost::OnRegisterBlobUUID(
+void BlobDispatcherHost::OnRegisterBlob(
     const std::string& uuid,
     const std::string& content_type,
     const std::string& content_disposition,
-    const std::set<std::string>& referenced_blob_uuids) {
+    const std::vector<storage::DataElement>& descriptions) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   BlobStorageContext* context = this->context();
   if (uuid.empty() || context->registry().HasEntry(uuid) ||
       async_builder_.IsBeingBuilt(uuid)) {
     bad_message::ReceivedBadMessage(this, bad_message::BDH_UUID_REGISTERED);
     return;
   }
   blobs_inuse_map_[uuid] = 1;
-  BlobTransportResult result = async_builder_.RegisterBlobUUID(
-      uuid, content_type, content_disposition, referenced_blob_uuids, context);
-  switch (result) {
-    case BlobTransportResult::BAD_IPC:
-      blobs_inuse_map_.erase(uuid);
-      bad_message::ReceivedBadMessage(this,
-                                      bad_message::BDH_CONSTRUCTION_FAILED);
-      break;
-    case BlobTransportResult::CANCEL_REFERENCED_BLOB_BROKEN:
-      // The async builder builds the blob as broken, and we just need to send
-      // the cancel message back to the renderer.
-      Send(new BlobStorageMsg_CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::REFERENCED_BLOB_BROKEN));
-      break;
-    case BlobTransportResult::DONE:
-      break;
-    case BlobTransportResult::CANCEL_MEMORY_FULL:
-    case BlobTransportResult::CANCEL_FILE_ERROR:
-    case BlobTransportResult::CANCEL_UNKNOWN:
-    case BlobTransportResult::PENDING_RESPONSES:
-      NOTREACHED();
-      break;
-  }
-}
-
-void BlobDispatcherHost::OnStartBuildingBlob(
-    const std::string& uuid,
-    const std::vector<storage::DataElement>& descriptions) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (uuid.empty()) {
-    SendIPCResponse(uuid, BlobTransportResult::BAD_IPC);
-    return;
-  }
-  BlobStorageContext* context = this->context();
-  const BlobStorageRegistry::Entry* entry = context->registry().GetEntry(uuid);
-  if (!entry || entry->state == BlobStorageRegistry::BlobState::BROKEN) {
-    // We ignore messages for blobs that don't exist to handle the case where
-    // the renderer de-refs a blob that we're still constructing, and there are
-    // no references to that blob. We ignore broken as well, in the case where
-    // we decided to break a blob after RegisterBlobUUID is called.
-    // Second, if the last dereference of the blob happened on a different host,
-    // then we still haven't gotten rid of the 'building' state in the original
-    // host. So we call cancel, and send the message just in case that happens.
-    if (async_builder_.IsBeingBuilt(uuid)) {
-      async_builder_.CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING,
-          context);
-      Send(new BlobStorageMsg_CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING));
-    }
-    return;
-  }
-  if (!async_builder_.IsBeingBuilt(uuid)) {
-    SendIPCResponse(uuid, BlobTransportResult::BAD_IPC);
-    return;
-  }
-  // |this| owns async_builder_ so using base::Unretained(this) is safe.
-  BlobTransportResult result = async_builder_.StartBuildingBlob(
-      uuid, descriptions, context->memory_available(), context,
+  BlobStatus result = async_builder_.RegisterBlob(
+      uuid, content_type, content_disposition, descriptions, context,
       base::Bind(&BlobDispatcherHost::SendMemoryRequest, base::Unretained(this),
-                 uuid));
-  SendIPCResponse(uuid, result);
+                 uuid),
+      base::Bind(&BlobDispatcherHost::MaybeSendFinalBlobStatus,

[michaeln, 2016/08/15 22:44:42]

Seems odd that the builder is expected to call this closure upon completion in
some cases, yet not in others, such that this class also has to call it in
various places. It's hard to know whos supposed to do what?

I'm not sure if this is possible/practical, but if the builder were always
responsible for calling the completion callback or never responsible for it so
the DispatcherHost were always repsonsible for sending the 'done' message, that
could make a cleaner division of labor.

[dmurph, 2016/08/19 00:18:31]

Done.

[michaeln, 2016/08/23 01:31:54]

Looks like this was done for OnStart handling specifically but not in general.

+                 base::Unretained(this), uuid));
+  MaybeSendFinalBlobStatus(uuid, result);
 }
 
 void BlobDispatcherHost::OnMemoryItemResponse(
     const std::string& uuid,
     const std::vector<storage::BlobItemBytesResponse>& responses) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (uuid.empty()) {
-    SendIPCResponse(uuid, BlobTransportResult::BAD_IPC);
+    bad_message::ReceivedBadMessage(this, bad_message::BDH_CONSTRUCTION_FAILED);
     return;
   }
   BlobStorageContext* context = this->context();
-  const BlobStorageRegistry::Entry* entry = context->registry().GetEntry(uuid);
-  if (!entry || entry->state == BlobStorageRegistry::BlobState::BROKEN) {
+  const storage::InternalBlobData* entry = context->registry().GetEntry(uuid);
+  if (!entry || BlobStatusIsError(entry->status())) {
     // We ignore messages for blobs that don't exist to handle the case where
     // the renderer de-refs a blob that we're still constructing, and there are
     // no references to that blob. We ignore broken as well, in the case where
     // we decided to break a blob after sending the memory request.
     // Note: if a blob is broken, then it can't be in the async_builder.
     // Second, if the last dereference of the blob happened on a different host,
     // then we still haven't gotten rid of the 'building' state in the original
     // host. So we call cancel, and send the message just in case that happens.
     if (async_builder_.IsBeingBuilt(uuid)) {
       async_builder_.CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING,
-          context);
-      Send(new BlobStorageMsg_CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING));
+          uuid, BlobStatus::ERR_BLOB_DEREFERENCED_WHILE_BUILDING, context);
+      MaybeSendFinalBlobStatus(
+          uuid, BlobStatus::ERR_BLOB_DEREFERENCED_WHILE_BUILDING);
     }
     return;
   }
   if (!async_builder_.IsBeingBuilt(uuid)) {
-    SendIPCResponse(uuid, BlobTransportResult::BAD_IPC);
+    bad_message::ReceivedBadMessage(this, bad_message::BDH_CONSTRUCTION_FAILED);
     return;
   }
-  BlobTransportResult result =
+  BlobStatus result =
       async_builder_.OnMemoryResponses(uuid, responses, context);
-  SendIPCResponse(uuid, result);
+  MaybeSendFinalBlobStatus(uuid, result);
 }
 
-void BlobDispatcherHost::OnCancelBuildingBlob(
-    const std::string& uuid,
-    const storage::IPCBlobCreationCancelCode code) {
+void BlobDispatcherHost::OnCancelBuildingBob(const std::string& uuid,
+                                             const storage::BlobStatus code) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   if (uuid.empty()) {
-    SendIPCResponse(uuid, BlobTransportResult::BAD_IPC);
+    bad_message::ReceivedBadMessage(this, bad_message::BDH_CONSTRUCTION_FAILED);
     return;
   }
   BlobStorageContext* context = this->context();
-  const BlobStorageRegistry::Entry* entry = context->registry().GetEntry(uuid);
-  if (!entry || entry->state == BlobStorageRegistry::BlobState::BROKEN) {
+  const storage::InternalBlobData* entry = context->registry().GetEntry(uuid);
+  if (!entry || BlobStatusIsError(entry->status())) {
     // We ignore messages for blobs that don't exist to handle the case where
     // the renderer de-refs a blob that we're still constructing, and there are
     // no references to that blob. We ignore broken as well, in the case where
     // we decided to break a blob and the renderer also decided to cancel.
     // Note: if a blob is broken, then it can't be in the async_builder.
     // Second, if the last dereference of the blob happened on a different host,
     // then we still haven't gotten rid of the 'building' state in the original
     // host. So we call cancel just in case this happens.
     if (async_builder_.IsBeingBuilt(uuid)) {
       async_builder_.CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING,
-          context);
+          uuid, BlobStatus::ERR_BLOB_DEREFERENCED_WHILE_BUILDING, context);
     }
     return;
   }
-  if (!async_builder_.IsBeingBuilt(uuid)) {
-    SendIPCResponse(uuid, BlobTransportResult::BAD_IPC);
+  // We should only get these messages for errors.
+  if (!async_builder_.IsBeingBuilt(uuid) || !storage::BlobStatusIsError(code)) {
+    bad_message::ReceivedBadMessage(this, bad_message::BDH_CONSTRUCTION_FAILED);
     return;
   }
   VLOG(1) << "Blob construction of " << uuid << " cancelled by renderer. "
           << " Reason: " << static_cast<int>(code) << ".";
   async_builder_.CancelBuildingBlob(uuid, code, context);
 }
 
 void BlobDispatcherHost::OnIncrementBlobRefCount(const std::string& uuid) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   BlobStorageContext* context = this->context();
@@ skipping 27 matching lines @@
   context->DecrementBlobRefCount(uuid);
   blobs_inuse_map_[uuid] -= 1;
   if (blobs_inuse_map_[uuid] == 0) {
     blobs_inuse_map_.erase(uuid);
     // If the blob has been deleted in the context and we're still building it,
     // this means we have no references waiting to read it. Clear the building
     // state and send a cancel message to the renderer.
     if (async_builder_.IsBeingBuilt(uuid) &&
         !context->registry().HasEntry(uuid)) {
       async_builder_.CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING,
-          context);
-      Send(new BlobStorageMsg_CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING));
+          uuid, BlobStatus::ERR_BLOB_DEREFERENCED_WHILE_BUILDING, context);
+      MaybeSendFinalBlobStatus(
+          uuid, BlobStatus::ERR_BLOB_DEREFERENCED_WHILE_BUILDING);

[michaeln, 2016/08/15 22:44:42]

at callsites where there's no maybe about it, maybe...

   Send(new BlobStorageMsg_SendBlobStatus(
       uuid, ERR_BLOB_DEREFERENCED_WHILE_BUILDING));

[dmurph, 2016/08/19 00:18:31]

No more maybe.

     }
   }
 }
 
 void BlobDispatcherHost::OnRegisterPublicBlobURL(const GURL& public_url,
                                                  const std::string& uuid) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   BlobStorageContext* context = this->context();
   if (uuid.empty()) {
     bad_message::ReceivedBadMessage(this,
@@ skipping 24 matching lines @@
   context()->RevokePublicBlobURL(public_url);
   public_blob_urls_.erase(public_url);
 }
 
 storage::BlobStorageContext* BlobDispatcherHost::context() {
   return blob_storage_context_->context();
 }
 
 void BlobDispatcherHost::SendMemoryRequest(
     const std::string& uuid,
-    std::unique_ptr<std::vector<storage::BlobItemBytesRequest>> requests,
-    std::unique_ptr<std::vector<base::SharedMemoryHandle>> memory_handles,
-    std::unique_ptr<std::vector<base::File>> files) {
+    std::vector<storage::BlobItemBytesRequest> requests,
+    std::vector<base::SharedMemoryHandle> memory_handles,
+    std::vector<base::File> files) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   std::vector<IPC::PlatformFileForTransit> file_handles;
-  // TODO(dmurph): Support file-backed blob transportation.
-  DCHECK(files->empty());
-  Send(new BlobStorageMsg_RequestMemoryItem(uuid, *requests, *memory_handles,
+  for (base::File& file : files) {
+    file_handles.push_back(IPC::TakePlatformFileForTransit(std::move(file)));
+  }
+  Send(new BlobStorageMsg_RequestMemoryItem(uuid, requests, memory_handles,
                                             file_handles));
 }
 
-void BlobDispatcherHost::SendIPCResponse(const std::string& uuid,
-                                         storage::BlobTransportResult result) {
-  switch (result) {
-    case BlobTransportResult::BAD_IPC:
-      bad_message::ReceivedBadMessage(this,
-                                      bad_message::BDH_CONSTRUCTION_FAILED);
-      return;
-    case BlobTransportResult::CANCEL_MEMORY_FULL:
-      Send(new BlobStorageMsg_CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::OUT_OF_MEMORY));
-      return;
-    case BlobTransportResult::CANCEL_FILE_ERROR:
-      Send(new BlobStorageMsg_CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::FILE_WRITE_FAILED));
-      return;
-    case BlobTransportResult::CANCEL_REFERENCED_BLOB_BROKEN:
-      Send(new BlobStorageMsg_CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::REFERENCED_BLOB_BROKEN));
-      return;
-    case BlobTransportResult::CANCEL_UNKNOWN:
-      Send(new BlobStorageMsg_CancelBuildingBlob(
-          uuid, IPCBlobCreationCancelCode::UNKNOWN));
-      return;
-    case BlobTransportResult::PENDING_RESPONSES:
-      return;
-    case BlobTransportResult::DONE:
-      Send(new BlobStorageMsg_DoneBuildingBlob(uuid));
-      return;
+void BlobDispatcherHost::MaybeSendFinalBlobStatus(const std::string& uuid,
+                                                  BlobStatus status) {
+  if (storage::BlobStatusIsBadIPC(status)) {
+    blobs_inuse_map_.erase(uuid);
+    bad_message::ReceivedBadMessage(this, bad_message::BDH_CONSTRUCTION_FAILED);
+    return;
   }
-  NOTREACHED();
+  if (BlobStatusIsPending(status))
+    return;
+  Send(new BlobStorageMsg_SendBlobStatus(uuid, status));
 }
 
 bool BlobDispatcherHost::IsInUseInHost(const std::string& uuid) {
   return blobs_inuse_map_.find(uuid) != blobs_inuse_map_.end();
 }
 
 bool BlobDispatcherHost::IsUrlRegisteredInHost(const GURL& blob_url) {
   return public_blob_urls_.find(blob_url) != public_blob_urls_.end();
 }
 
 void BlobDispatcherHost::ClearHostFromBlobStorageContext() {
   BlobStorageContext* context = this->context();
   for (const auto& url : public_blob_urls_) {
     context->RevokePublicBlobURL(url);
   }
   for (const auto& uuid_refnum_pair : blobs_inuse_map_) {
     for (int i = 0; i < uuid_refnum_pair.second; ++i)
       context->DecrementBlobRefCount(uuid_refnum_pair.first);
   }
   async_builder_.CancelAll(context);
 }
 
 }  // namespace content