[BlobAsync] Patch 3: Renderer Classes & Logic

content/child/blob_storage/blob_transport_temporary_holder.cc

+// 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.
+
+#include "content/child/blob_storage/blob_transport_temporary_holder.h"
+
+#include <utility>
+
+#include "base/containers/scoped_ptr_hash_map.h"
+#include "base/stl_util.h"
+#include "content/child/blob_storage/blob_consolidation.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"
+
+using base::SharedMemory;
+using base::SharedMemoryHandle;
+using storage::BlobItemBytesRequest;
+using storage::BlobItemBytesResponse;
+using storage::IPCBlobItemRequestStrategy;
+using storage::DataElement;
+
+namespace content {
+
+using ConsolidatedItem = BlobConsolidation::ConsolidatedItem;
+using ReadStatus = BlobConsolidation::ReadStatus;
+using ResponsesStatus = BlobTransportTemporaryHolder::ResponsesStatus;
+
+BlobTransportTemporaryHolder::BlobTransportTemporaryHolder() {}
+
+BlobTransportTemporaryHolder::~BlobTransportTemporaryHolder() {
+  STLDeleteValues(&blob_storage_);
+}
+
+bool BlobTransportTemporaryHolder::HoldBlobConsolidation(
+    const std::string& uuid,
+    scoped_ptr<BlobConsolidation> consolidation) {
+  if (blob_storage_.find(uuid) != blob_storage_.end()) {

[michaeln, 2015/10/21 02:22:24]

probably a DCHECK(blob_storage_.find(uuid) != blob_storage_.end()) would be
sufficient and a void return type.

[dmurph, 2015/10/21 21:47:57]

I want to make sure we exit early in production in case this ever happens, so I
still return bool here and DCHECK in the caller instead.

But GetDescirptions doesn't have a return anymore.

+    return false;
+  }
+  blob_storage_.insert(std::make_pair(uuid, consolidation.release()));
+  return true;
+}
+
+bool BlobTransportTemporaryHolder::GetDescriptions(
+    const std::string& uuid,
+    size_t max_data_population,
+    std::vector<storage::DataElement>* out) {
+  DCHECK(out->empty());
+  BlobConsolidation* consolidation = GetConsolidation(uuid);
+  if (!consolidation) {
+    return false;
+  }
+  const auto& consolidated_items = consolidation->consolidated_items();
+
+  size_t current_memory_population = 0;
+  size_t current_item = 0;
+  out->reserve(consolidated_items.size());
+  for (const ConsolidatedItem& item : consolidated_items) {
+    out->push_back(DataElement());
+    auto& element = out->back();
+
+    switch (item.type) {
+      case DataElement::TYPE_BYTES: {
+        size_t bytes_length = static_cast<size_t>(item.length);
+        if (current_memory_population + bytes_length <= max_data_population) {
+          element.SetToAllocatedBytes(bytes_length);
+          consolidation->ReadMemory(current_item, 0, bytes_length,
+                                    element.mutable_bytes());
+          current_memory_population += bytes_length;
+        } else {
+          element.SetToBytesDescription(bytes_length);
+        }
+        break;
+      }
+      case DataElement::TYPE_FILE: {
+        element.SetToFilePathRange(
+            item.path, item.offset, item.length,
+            base::Time::FromDoubleT(item.expected_modification_time));
+        break;
+      }
+      case DataElement::TYPE_BLOB: {
+        element.SetToBlobRange(item.blob_uuid, item.offset, item.length);
+        break;
+      }
+      case DataElement::TYPE_FILE_FILESYSTEM: {
+        element.SetToFileSystemUrlRange(
+            item.filesystem_url, item.offset, item.length,
+            base::Time::FromDoubleT(item.expected_modification_time));
+        break;
+      }
+      case DataElement::TYPE_DISK_CACHE_ENTRY:
+      case DataElement::TYPE_BYTES_DESCRIPTION:
+      case DataElement::TYPE_UNKNOWN:
+        NOTREACHED();
+    }
+    ++current_item;
+  }
+  return true;
+}
+
+ResponsesStatus BlobTransportTemporaryHolder::GetResponses(
+    const std::string& uuid,
+    const std::vector<BlobItemBytesRequest>& requests,
+    std::vector<SharedMemoryHandle>* memory_handles,
+    const std::vector<IPC::PlatformFileForTransit>& file_handles,
+    std::vector<BlobItemBytesResponse>* out) {
+  DCHECK(out->empty());
+  BlobConsolidation* consolidation = GetConsolidation(uuid);
+  if (!consolidation)
+    return ResponsesStatus::BLOB_NOT_FOUND;
+  const auto& consolidated_items = consolidation->consolidated_items();
+
+  base::ScopedPtrHashMap<size_t, scoped_ptr<SharedMemory>> opened_memory;
+  for (const BlobItemBytesRequest& request : requests) {
+    if (request.renderer_item_index >= consolidated_items.size())
+      return ResponsesStatus::INVALID_ITEM_INDEX;
+
+    const ConsolidatedItem& item =
+        consolidated_items[request.renderer_item_index];
+    if (request.renderer_item_offset + request.size > item.length)
+      return ResponsesStatus::INVALID_DATA_RANGE;
+    if (item.type != DataElement::TYPE_BYTES)
+      return ResponsesStatus::INVALID_ITEM;
+
+    out->push_back(BlobItemBytesResponse(request.request_number));
+    switch (request.transport_strategy) {
+      case IPCBlobItemRequestStrategy::IPC: {
+        BlobItemBytesResponse& response = out->back();
+        ReadStatus status = consolidation->ReadMemory(
+            request.renderer_item_index, request.renderer_item_offset,
+            request.size, response.allocate_mutable_data(request.size));
+        CHECK(status == ReadStatus::OK)
+            << "Error reading from consolidated blob: "
+            << static_cast<int>(status);
+        break;
+      }
+      case IPCBlobItemRequestStrategy::SHARED_MEMORY: {
+        if (request.handle_index >= memory_handles->size()) {
+          DCHECK_LT(request.handle_index, memory_handles->size());
+          return ResponsesStatus::INVALID_HANDLE_INDEX;
+        }
+        SharedMemory* memory = nullptr;
+        auto memory_it = opened_memory.find(request.handle_index);
+        if (memory_it == opened_memory.end()) {
+          SharedMemoryHandle& handle = (*memory_handles)[request.handle_index];
+          DCHECK(SharedMemory::IsHandleValid(handle));
+          scoped_ptr<SharedMemory> shared_memory(
+              new SharedMemory(handle, false));
+          if (!shared_memory->Map(request.size)) {
+            return ResponsesStatus::SHARED_MEMORY_MAP_FAILED;
+          }
+          memory = shared_memory.get();
+          opened_memory.add(request.handle_index, shared_memory.Pass());
+        } else {
+          memory = memory_it->second;
+        }
+        CHECK(memory->memory()) << "Couldn't map memory for blob transfer.";
+        ReadStatus status = consolidation->ReadMemory(
+            request.renderer_item_index, request.renderer_item_offset,
+            request.size,
+            static_cast<char*>(memory->memory()) + request.handle_offset);
+        CHECK(status == ReadStatus::OK)
+            << "Error reading from consolidated blob: "
+            << static_cast<int>(status);
+        break;
+      }
+      case IPCBlobItemRequestStrategy::FILE:
+        NOTREACHED() << "TODO(dmurph): Not implemented.";
+        break;
+      case IPCBlobItemRequestStrategy::UNKNOWN:
+        NOTREACHED();
+        break;
+    }
+  }
+  return ResponsesStatus::SUCCESS;
+}
+
+void BlobTransportTemporaryHolder::ReleaseBlob(const std::string& uuid) {
+  auto iter = blob_storage_.find(uuid);
+  if (iter != blob_storage_.end()) {
+    BlobConsolidation* consolidation = iter->second;
+    delete consolidation;
+    blob_storage_.erase(iter);
+  }
+}
+
+BlobConsolidation* BlobTransportTemporaryHolder::GetConsolidation(
+    const std::string& uuid) {
+  auto iter = blob_storage_.find(uuid);
+  if (iter == blob_storage_.end()) {
+    return nullptr;
+  } else {
+    return iter->second;
+  }

[michaeln, 2015/10/21 02:22:24]

style nit: maybe could be more early returnish with fewer brackets

auto iter = blob_storage_.find(uuid);
if (iter == blob_storage_.end()) 
  return nullptr;
return iter->second;

[dmurph, 2015/10/21 21:47:57]

Done.

+}
+
+}  // namespace content