New blobstoragecontext for use in the main browser process, not plugged in yet.

webkit/blob/blob_storage_context.cc

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright (c) 2013 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 "webkit/blob/blob_storage_controller.h"
+#include "webkit/blob/blob_storage_context.h"
 
+#include "base/bind.h"
+#include "base/location.h"
 #include "base/logging.h"
+#include "base/message_loop_proxy.h"
+#include "base/sys_info.h"
 #include "googleurl/src/gurl.h"
 #include "webkit/blob/blob_data.h"
 
 namespace webkit_blob {
 
 namespace {
 
 // We can't use GURL directly for these hash fragment manipulations
 // since it doesn't have specific knowlege of the BlobURL format. GURL
 // treats BlobURLs as if they were PathURLs which don't support hash
 // fragments.
 
 bool BlobUrlHasRef(const GURL& url) {
   return url.spec().find('#') != std::string::npos;
 }
 
 GURL ClearBlobUrlRef(const GURL& url) {
   size_t hash_pos = url.spec().find('#');
   if (hash_pos == std::string::npos)
     return url;
   return GURL(url.spec().substr(0, hash_pos));
 }
 
-static const int64 kMaxMemoryUsage = 1024 * 1024 * 1024;  // 1G
+// TODO(michaeln): use base::SysInfo::AmountOfPhysicalMemoryMB() in some
+// way to come up with a better limit.
+static const int64 kMaxMemoryUsage = 500 * 1024 * 1024;  // Half a gig.
 
 }  // namespace
 
-BlobStorageController::BlobStorageController()
+//-----------------------------------------------------------------------
+// BlobDataHandle
+//-----------------------------------------------------------------------
+
+BlobDataHandle::BlobDataHandle(BlobData* blob_data, BlobStorageContext* context,
+                               base::SequencedTaskRunner* task_runner)
+    : blob_data_(blob_data),
+      context_(context->AsWeakPtr()),
+      io_task_runner_(task_runner) {
+  // Ensures the uuid remains registered and the underlying data is not deleted.
+  DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
+  context_->IncrementBlobRefCount(blob_data->uuid());
+  blob_data_->AddRef();
+}
+
+BlobDataHandle::~BlobDataHandle() {
+  if (io_task_runner_->RunsTasksOnCurrentThread()) {
+    // Note: Do not test context_ on the wrong thread.

[michaeln, 2013/04/26 00:37:59]

changed this code comment to

    // Note: Do not test context_ or alter the blob_data_ refcount
    // on the wrong thread.

+    if (context_.get())
+      context_->DecrementBlobRefCount(blob_data_->uuid());
+    blob_data_->Release();
+    return;
+  }
+
+  io_task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(&DeleteHelper, context_, base::Unretained(blob_data_)));
+}
+
+BlobData* BlobDataHandle::data() const {
+  DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
+  return blob_data_;
+}
+
+// static
+void BlobDataHandle::DeleteHelper(
+    base::WeakPtr<BlobStorageContext> context,
+    BlobData* blob_data) {
+  if (context.get())
+    context->DecrementBlobRefCount(blob_data->uuid());
+  blob_data->Release();
+}
+
+//-----------------------------------------------------------------------
+// BlobStorageHost
+//-----------------------------------------------------------------------
+
+BlobStorageHost::BlobStorageHost(BlobStorageContext* context)
+    : context_(context->AsWeakPtr()) {
+}
+
+BlobStorageHost::~BlobStorageHost() {
+  if (!context_)
+    return;
+  for (std::set<GURL>::iterator iter = public_blob_urls_.begin();
+       iter != public_blob_urls_.end(); ++iter) {
+    context_->RevokePublicBlobURL(*iter);
+  }
+  for (BlobReferenceMap::iterator iter = blobs_inuse_map_.begin();
+       iter != blobs_inuse_map_.end(); ++iter) {
+    for (int i = 0; i < iter->second; ++i)
+      context_->DecrementBlobRefCount(iter->first);
+  }
+}
+
+bool BlobStorageHost::StartBuildingBlob(const std::string& uuid) {
+  if (!context_ || uuid.empty() || context_->IsInUse(uuid))
+    return false;
+  context_->StartBuildingBlob(uuid);
+  blobs_inuse_map_[uuid] = 1;
+  return true;
+}
+
+bool BlobStorageHost::AppendBlobDataItem(
+    const std::string& uuid, const BlobData::Item& data_item) {
+  if (!context_ || !IsBeingBuiltInHost(uuid))
+    return false;
+  context_->AppendBlobDataItem(uuid, data_item);
+  return true;
+}
+
+bool BlobStorageHost::CancelBuildingBlob(const std::string& uuid) {
+  if (!context_ || !IsBeingBuiltInHost(uuid))
+    return false;
+  blobs_inuse_map_.erase(uuid);
+  context_->CancelBuildingBlob(uuid);
+  return true;
+}
+
+bool BlobStorageHost::FinishBuildingBlob(
+    const std::string& uuid, const std::string& content_type) {
+  if (!context_ || !IsBeingBuiltInHost(uuid))
+    return false;
+  context_->FinishBuildingBlob(uuid, content_type);
+  return true;
+}
+
+bool BlobStorageHost::IncrementBlobRefCount(const std::string& uuid) {
+  if (!context_ || !context_->IsInUse(uuid) || context_->IsBeingBuilt(uuid))
+    return false;
+  context_->IncrementBlobRefCount(uuid);
+  blobs_inuse_map_[uuid] += 1;
+  return true;
+}
+
+bool BlobStorageHost::DecrementBlobRefCount(const std::string& uuid) {
+  if (!context_ || !IsInUseInHost(uuid))
+    return false;
+  context_->DecrementBlobRefCount(uuid);
+  blobs_inuse_map_[uuid] -= 1;
+  if (blobs_inuse_map_[uuid] == 0)
+    blobs_inuse_map_.erase(uuid);
+  return true;
+}
+
+bool BlobStorageHost::RegisterPublicBlobURL(
+    const GURL& blob_url, const std::string& uuid) {
+  if (!context_ || !IsInUseInHost(uuid) || context_->IsUrlRegistered(blob_url))
+    return false;
+  context_->RegisterPublicBlobURL(blob_url, uuid);
+  public_blob_urls_.insert(blob_url);
+  return true;
+}
+
+bool BlobStorageHost::RevokePublicBlobURL(const GURL& blob_url) {
+  if (!context_ || !IsUrlRegisteredInHost(blob_url))
+    return false;
+  context_->RevokePublicBlobURL(blob_url);
+  public_blob_urls_.erase(blob_url);
+  return true;
+}
+
+bool BlobStorageHost::IsInUseInHost(const std::string& uuid) {
+  return blobs_inuse_map_.find(uuid) != blobs_inuse_map_.end();
+}
+
+bool BlobStorageHost::IsBeingBuiltInHost(const std::string& uuid) {
+  return IsInUseInHost(uuid) && context_->IsBeingBuilt(uuid);
+}
+
+bool BlobStorageHost::IsUrlRegisteredInHost(const GURL& blob_url) {
+  return public_blob_urls_.find(blob_url) != public_blob_urls_.end();
+}
+
+//-----------------------------------------------------------------------
+// BlobStorageContext
+//-----------------------------------------------------------------------
+
+BlobStorageContext::BlobMapEntry::BlobMapEntry()
+    : refcount(0), flags(0) {
+}
+
+BlobStorageContext::BlobMapEntry::BlobMapEntry(
+    int refcount, int flags, BlobData* data)
+    : refcount(refcount), flags(flags), data(data) {
+}
+
+BlobStorageContext::BlobMapEntry::~BlobMapEntry() {
+}
+
+BlobStorageContext::BlobStorageContext()
     : memory_usage_(0) {
 }
 
-BlobStorageController::~BlobStorageController() {
-}
-
-void BlobStorageController::StartBuildingBlob(const GURL& url) {
-  DCHECK(url.SchemeIs("blob"));
-  DCHECK(!BlobUrlHasRef(url));
-  BlobData* blob_data = new BlobData;
-  unfinalized_blob_map_[url.spec()] = blob_data;
-  IncrementBlobDataUsage(blob_data);
-}
-
-void BlobStorageController::AppendBlobDataItem(
-    const GURL& url, const BlobData::Item& item) {
-  DCHECK(url.SchemeIs("blob"));
-  DCHECK(!BlobUrlHasRef(url));
-  BlobMap::iterator found = unfinalized_blob_map_.find(url.spec());
-  if (found == unfinalized_blob_map_.end())
-    return;
-  BlobData* target_blob_data = found->second;
+BlobStorageContext::~BlobStorageContext() {
+}
+
+scoped_ptr<BlobDataHandle> BlobStorageContext::GetBlobDataFromUUID(
+    const std::string& uuid) {
+  scoped_ptr<BlobDataHandle> result;
+  BlobMap::iterator found = blob_map_.find(uuid);
+  if (found == blob_map_.end())
+    return result.Pass();
+  if (found->second.flags & EXCEEDED_MEMORY)
+    return result.Pass();
+  DCHECK(!(found->second.flags & BEING_BUILT));
+  result.reset(new BlobDataHandle(found->second.data, this,
+                                  base::MessageLoopProxy::current()));
+  return result.Pass();
+}
+
+scoped_ptr<BlobDataHandle> BlobStorageContext::GetBlobDataFromPublicURL(
+    const GURL& url) {
+  BlobURLMap::iterator found = public_blob_urls_.find(
+      BlobUrlHasRef(url) ? ClearBlobUrlRef(url) : url);
+  if (found == public_blob_urls_.end())
+    return scoped_ptr<BlobDataHandle>();
+  return GetBlobDataFromUUID(found->second);
+}
+
+scoped_ptr<BlobDataHandle> BlobStorageContext::AddFinishedBlob(
+    const BlobData* data) {
+  StartBuildingBlob(data->uuid());
+  for (std::vector<BlobData::Item>::const_iterator iter =
+           data->items().begin();
+       iter != data->items().end(); ++iter) {
+    AppendBlobDataItem(data->uuid(), *iter);
+  }
+  FinishBuildingBlob(data->uuid(), data->content_type());
+  scoped_ptr<BlobDataHandle> handle = GetBlobDataFromUUID(data->uuid());
+  DecrementBlobRefCount(data->uuid());
+  return handle.Pass();
+}
+
+void BlobStorageContext::StartBuildingBlob(const std::string& uuid) {
+  DCHECK(!IsInUse(uuid) && !uuid.empty());
+  blob_map_[uuid] = BlobMapEntry(1, BEING_BUILT, new BlobData(uuid));
+}
+
+void BlobStorageContext::AppendBlobDataItem(
+    const std::string& uuid, const BlobData::Item& item) {
+  DCHECK(IsBeingBuilt(uuid));
+  BlobMap::iterator found = blob_map_.find(uuid);
+  if (found == blob_map_.end())
+    return;
+  if (found->second.flags & EXCEEDED_MEMORY)
+    return;
+  BlobData* target_blob_data = found->second.data;
   DCHECK(target_blob_data);
 
-  memory_usage_ -= target_blob_data->GetMemoryUsage();
-
-  // The blob data is stored in the "canonical" way. That is, it only contains a
-  // list of Data and File items.
-  // 1) The Data item is denoted by the raw data and the range.
+  bool exceeded_memory = false;
+
+  // The blob data is stored in the canonical way which only contains a
+  // list of Data, File, and FileSystem items. Aggregated TYPE_BLOB items
+  // are expanded into the primitive constituent types.
+  // 1) The Data item is denoted by the raw data and length.
   // 2) The File item is denoted by the file path, the range and the expected
   //    modification time.
   // 3) The FileSystem File item is denoted by the FileSystem URL, the range
   //    and the expected modification time.
-  // All the Blob items in the passing blob data are resolved and expanded into
-  // a set of Data and File items.
+  // 4) The Blob items are expanded.
+  // TODO(michaeln): Would be nice to avoid copying Data items when expanding.
 
   DCHECK(item.length() > 0);
   switch (item.type()) {
     case BlobData::Item::TYPE_BYTES:
       DCHECK(!item.offset());
-      target_blob_data->AppendData(item.bytes(), item.length());
+      exceeded_memory = !AppendBytesItem(target_blob_data,
+                                         item.bytes(),
+                                         static_cast<int64>(item.length()));
       break;
     case BlobData::Item::TYPE_FILE:
       AppendFileItem(target_blob_data,
                      item.path(),
                      item.offset(),
                      item.length(),
                      item.expected_modification_time());
       break;
     case BlobData::Item::TYPE_FILE_FILESYSTEM:
       AppendFileSystemFileItem(target_blob_data,
-                               item.url(),
+                               item.filesystem_url(),
                                item.offset(),
                                item.length(),
                                item.expected_modification_time());
       break;
     case BlobData::Item::TYPE_BLOB: {
-      BlobData* src_blob_data = GetBlobDataFromUrl(item.url());
-      DCHECK(src_blob_data);
-      if (src_blob_data)
-        AppendStorageItems(target_blob_data,
-                           src_blob_data,
-                           item.offset(),
-                           item.length());
+      scoped_ptr<BlobDataHandle> src = GetBlobDataFromUUID(item.blob_uuid());
+      DCHECK(src.get());

[michaeln, 2013/04/26 00:26:57]

in exceeded_mem situations, this dcheck will trip... i'll remove it

+      if (src.get())
+        exceeded_memory = !ExpandStorageItems(target_blob_data,
+                                              src->data(),
+                                              item.offset(),
+                                              item.length());
       break;
     }
     default:
       NOTREACHED();
       break;
   }
 
-  memory_usage_ += target_blob_data->GetMemoryUsage();
-
-  // If we're using too much memory, drop this blob.
+  // If we're using too much memory, drop this blob's data.
   // TODO(michaeln): Blob memory storage does not yet spill over to disk,
-  // until it does, we'll prevent memory usage over a max amount.
-  if (memory_usage_ > kMaxMemoryUsage)
-    RemoveBlob(url);
+  // as a stop gap, we'll prevent memory usage over a max amount.
+  if (exceeded_memory) {
+    memory_usage_ -= target_blob_data->GetMemoryUsage();
+    found->second.flags |= EXCEEDED_MEMORY;
+    found->second.data = new BlobData(uuid);
+    return;
+  }
 }
 
-void BlobStorageController::FinishBuildingBlob(
-    const GURL& url, const std::string& content_type) {
-  DCHECK(url.SchemeIs("blob"));
-  DCHECK(!BlobUrlHasRef(url));
-  BlobMap::iterator found = unfinalized_blob_map_.find(url.spec());
-  if (found == unfinalized_blob_map_.end())
+void BlobStorageContext::FinishBuildingBlob(
+    const std::string& uuid, const std::string& content_type) {
+  DCHECK(IsBeingBuilt(uuid));
+  BlobMap::iterator found = blob_map_.find(uuid);
+  if (found == blob_map_.end())
     return;
-  found->second->set_content_type(content_type);
-  blob_map_[url.spec()] = found->second;
-  unfinalized_blob_map_.erase(found);
+  found->second.data->set_content_type(content_type);
+  found->second.flags &= ~BEING_BUILT;
 }
 
-void BlobStorageController::AddFinishedBlob(const GURL& url,
-                                            const BlobData* data) {
-  StartBuildingBlob(url);
-  for (std::vector<BlobData::Item>::const_iterator iter =
-           data->items().begin();
-       iter != data->items().end(); ++iter) {
-    AppendBlobDataItem(url, *iter);
-  }
-  FinishBuildingBlob(url, data->content_type());
+void BlobStorageContext::CancelBuildingBlob(const std::string& uuid) {
+  DCHECK(IsBeingBuilt(uuid));
+  DecrementBlobRefCount(uuid);
 }
 
-void BlobStorageController::CloneBlob(
-    const GURL& url, const GURL& src_url) {
-  DCHECK(url.SchemeIs("blob"));
-  DCHECK(!BlobUrlHasRef(url));
-
-  BlobData* blob_data = GetBlobDataFromUrl(src_url);
-  DCHECK(blob_data);
-  if (!blob_data)
+void BlobStorageContext::IncrementBlobRefCount(const std::string& uuid) {
+  BlobMap::iterator found = blob_map_.find(uuid);
+  if (found == blob_map_.end()) {
+    DCHECK(false);
     return;
-
-  blob_map_[url.spec()] = blob_data;
-  IncrementBlobDataUsage(blob_data);
+  }
+  ++(found->second.refcount);
 }
 
-void BlobStorageController::RemoveBlob(const GURL& url) {
-  DCHECK(url.SchemeIs("blob"));
-  DCHECK(!BlobUrlHasRef(url));
-
-  if (!RemoveFromMapHelper(&unfinalized_blob_map_, url))
-    RemoveFromMapHelper(&blob_map_, url);
+void BlobStorageContext::DecrementBlobRefCount(const std::string& uuid) {
+  BlobMap::iterator found = blob_map_.find(uuid);
+  if (found == blob_map_.end())
+    return;
+  DCHECK_EQ(found->second.data->uuid(), uuid);
+  if (--(found->second.refcount) == 0) {
+    memory_usage_ -= found->second.data->GetMemoryUsage();
+    blob_map_.erase(found);
+  }
 }
 
-bool BlobStorageController::RemoveFromMapHelper(
-    BlobMap* map, const GURL& url) {
-  BlobMap::iterator found = map->find(url.spec());
-  if (found == map->end())
-    return false;
-  if (DecrementBlobDataUsage(found->second))
-    memory_usage_ -= found->second->GetMemoryUsage();
-  map->erase(found);
-  return true;
+void BlobStorageContext::RegisterPublicBlobURL(
+    const GURL& blob_url, const std::string& uuid) {
+  DCHECK(!BlobUrlHasRef(blob_url));
+  DCHECK(IsInUse(uuid));
+  DCHECK(!IsUrlRegistered(blob_url));
+  IncrementBlobRefCount(uuid);
+  public_blob_urls_[blob_url] = uuid;
 }
 
-
-BlobData* BlobStorageController::GetBlobDataFromUrl(const GURL& url) {
-  BlobMap::iterator found = blob_map_.find(
-      BlobUrlHasRef(url) ? ClearBlobUrlRef(url).spec() : url.spec());
-  return (found != blob_map_.end()) ? found->second : NULL;
+void BlobStorageContext::RevokePublicBlobURL(const GURL& blob_url) {
+  DCHECK(!BlobUrlHasRef(blob_url));
+  if (!IsUrlRegistered(blob_url))
+    return;
+  DecrementBlobRefCount(public_blob_urls_[blob_url]);
+  public_blob_urls_.erase(blob_url);
 }
 
-void BlobStorageController::AppendStorageItems(
+bool BlobStorageContext::ExpandStorageItems(
     BlobData* target_blob_data, BlobData* src_blob_data,
     uint64 offset, uint64 length) {
   DCHECK(target_blob_data && src_blob_data &&
          length != static_cast<uint64>(-1));
 
   std::vector<BlobData::Item>::const_iterator iter =
       src_blob_data->items().begin();
   if (offset) {
     for (; iter != src_blob_data->items().end(); ++iter) {
       if (offset >= iter->length())
         offset -= iter->length();
       else
         break;
     }
   }
 
   for (; iter != src_blob_data->items().end() && length > 0; ++iter) {
     uint64 current_length = iter->length() - offset;
     uint64 new_length = current_length > length ? length : current_length;
     if (iter->type() == BlobData::Item::TYPE_BYTES) {
-      target_blob_data->AppendData(
-          iter->bytes() + static_cast<size_t>(iter->offset() + offset),
-          static_cast<uint32>(new_length));
+      if (!AppendBytesItem(
+              target_blob_data,
+              iter->bytes() + static_cast<size_t>(iter->offset() + offset),
+              static_cast<int64>(new_length))) {
+        return false;  // exceeded memory
+      }
     } else if (iter->type() == BlobData::Item::TYPE_FILE) {
       AppendFileItem(target_blob_data,
                      iter->path(),
                      iter->offset() + offset,
                      new_length,
                      iter->expected_modification_time());
     } else {
       DCHECK(iter->type() == BlobData::Item::TYPE_FILE_FILESYSTEM);
       AppendFileSystemFileItem(target_blob_data,
-                               iter->url(),
+                               iter->filesystem_url(),
                                iter->offset() + offset,
                                new_length,
                                iter->expected_modification_time());
     }
     length -= new_length;
     offset = 0;
   }
+  return true;
 }
 
-void BlobStorageController::AppendFileItem(
+bool BlobStorageContext::AppendBytesItem(
+    BlobData* target_blob_data, const char* bytes, int64 length) {
+  if (length < 0) {
+    DCHECK(false);
+    return false;
+  }
+  if (memory_usage_ + length > kMaxMemoryUsage)
+    return false;
+  target_blob_data->AppendData(bytes, static_cast<size_t>(length));
+  memory_usage_ += length;
+  return true;
+}
+
+void BlobStorageContext::AppendFileItem(
     BlobData* target_blob_data,
     const base::FilePath& file_path, uint64 offset, uint64 length,
     const base::Time& expected_modification_time) {
   target_blob_data->AppendFile(file_path, offset, length,
                                expected_modification_time);
 
   // It may be a temporary file that should be deleted when no longer needed.
   scoped_refptr<ShareableFileReference> shareable_file =
       ShareableFileReference::Get(file_path);
   if (shareable_file)
     target_blob_data->AttachShareableFileReference(shareable_file);
 }
 
-void BlobStorageController::AppendFileSystemFileItem(
+void BlobStorageContext::AppendFileSystemFileItem(
     BlobData* target_blob_data,
-    const GURL& url, uint64 offset, uint64 length,
+    const GURL& filesystem_url, uint64 offset, uint64 length,
     const base::Time& expected_modification_time) {
-  target_blob_data->AppendFileSystemFile(url, offset, length,
+  target_blob_data->AppendFileSystemFile(filesystem_url, offset, length,
                                          expected_modification_time);
 }
 
-void BlobStorageController::IncrementBlobDataUsage(BlobData* blob_data) {
-  blob_data_usage_count_[blob_data] += 1;
+bool BlobStorageContext::IsInUse(const std::string& uuid) {
+  return blob_map_.find(uuid) != blob_map_.end();
 }
 
-bool BlobStorageController::DecrementBlobDataUsage(BlobData* blob_data) {
-  BlobDataUsageMap::iterator found = blob_data_usage_count_.find(blob_data);
-  DCHECK(found != blob_data_usage_count_.end());
-  if (--(found->second))
-    return false;  // Still in use
-  blob_data_usage_count_.erase(found);
-  return true;
+bool BlobStorageContext::IsBeingBuilt(const std::string& uuid) {
+  BlobMap::iterator found = blob_map_.find(uuid);
+  if (found == blob_map_.end())
+    return false;
+  return found->second.flags & BEING_BUILT;
+}
+
+bool BlobStorageContext::IsUrlRegistered(const GURL& blob_url) {
+  return public_blob_urls_.find(blob_url) != public_blob_urls_.end();
 }
 
 }  // namespace webkit_blob