[BlobAsync] Patch 1: BlobStorageRegistry

Note: This patch is a no-op, and will be hooked up in a later patch.

Patches:
1: https://codereview.chromium.org/1287303002
2: https://codereview.chromium.org/1288373002
3: https://codereview.chromium.org/1292523002
4: https://codereview.chromium.org/1098853003
Hookup: https://codereview.chromium.org/1234813004

BUG=375297

Review URL: https://codereview.chromium.org/1287303002

Cr-Commit-Position: refs/heads/master@{#354050}

5 files changed, 229 insertions, 0 deletions

diff --git a/storage/browser/BUILD.gn b/storage/browser/BUILD.gn
index 6206f37..e3bfa81 100644
--- a/storage/browser/BUILD.gn
+++ b/storage/browser/BUILD.gn
@@ -18,6 +18,8 @@ component("browser") {
     "blob/blob_reader.h",
     "blob/blob_storage_context.cc",
     "blob/blob_storage_context.h",
+    "blob/blob_storage_registry.cc",
+    "blob/blob_storage_registry.h",
     "blob/blob_url_request_job.cc",
     "blob/blob_url_request_job.h",
     "blob/blob_url_request_job_factory.cc",
diff --git a/storage/browser/blob/blob_storage_registry.cc b/storage/browser/blob/blob_storage_registry.cc
new file mode 100644
index 0000000..805a677d
--- /dev/null
+++ b/storage/browser/blob/blob_storage_registry.cc
@@ -0,0 +1,116 @@
+// 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 "storage/browser/blob/blob_storage_registry.h"
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+#include "base/stl_util.h"
+#include "url/gurl.h"
+
+namespace storage {
+using BlobState = BlobStorageRegistry::BlobState;
+
+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));
+}
+
+}  // namespace
+
+BlobStorageRegistry::Entry::Entry(int refcount, BlobState state)
+    : refcount(refcount), state(state), exceeded_memory(false) {}
+
+BlobStorageRegistry::Entry::~Entry() {}
+
+bool BlobStorageRegistry::Entry::TestAndSetState(BlobState expected,
+                                                 BlobState set) {
+  if (state != expected)
+    return false;
+  state = set;
+  return true;
+}
+
+BlobStorageRegistry::BlobStorageRegistry() {}
+
+BlobStorageRegistry::~BlobStorageRegistry() {
+  // Note: We don't bother calling the construction complete callbacks, as we
+  // are only being destructed at the end of the life of the browser process.
+  // So it shouldn't matter.
+}
+
+BlobStorageRegistry::Entry* BlobStorageRegistry::CreateEntry(
+    const std::string& uuid) {
+  DCHECK(!ContainsKey(blob_map_, uuid));
+  Entry* entry = new Entry(1, BlobState::RESERVED);
+  blob_map_.add(uuid, make_scoped_ptr(entry));
+  return entry;
+}
+
+bool BlobStorageRegistry::DeleteEntry(const std::string& uuid) {
+  return blob_map_.erase(uuid) == 1;
+}
+
+BlobStorageRegistry::Entry* BlobStorageRegistry::GetEntry(
+    const std::string& uuid) {
+  BlobMap::iterator found = blob_map_.find(uuid);
+  if (found == blob_map_.end())
+    return nullptr;
+  return found->second;
+}
+
+bool BlobStorageRegistry::CreateUrlMapping(const GURL& blob_url,
+                                           const std::string& uuid) {
+  DCHECK(!BlobUrlHasRef(blob_url));
+  if (blob_map_.find(uuid) == blob_map_.end() || IsURLMapped(blob_url))
+    return false;
+  url_to_uuid_[blob_url] = uuid;
+  return true;
+}
+
+bool BlobStorageRegistry::DeleteURLMapping(const GURL& blob_url,
+                                           std::string* uuid) {
+  DCHECK(!BlobUrlHasRef(blob_url));
+  URLMap::iterator found = url_to_uuid_.find(blob_url);
+  if (found == url_to_uuid_.end())
+    return false;
+  if (uuid)
+    uuid->assign(found->second);
+  url_to_uuid_.erase(found);
+  return true;
+}
+
+bool BlobStorageRegistry::IsURLMapped(const GURL& blob_url) const {
+  return ContainsKey(url_to_uuid_, blob_url);
+}
+
+BlobStorageRegistry::Entry* BlobStorageRegistry::GetEntryFromURL(
+    const GURL& url,
+    std::string* uuid) {
+  URLMap::iterator found =
+      url_to_uuid_.find(BlobUrlHasRef(url) ? ClearBlobUrlRef(url) : url);
+  if (found == url_to_uuid_.end())
+    return nullptr;
+  Entry* entry = GetEntry(found->second);
+  if (entry && uuid)
+    uuid->assign(found->second);
+  return entry;
+}
+
+}  // namespace storage
diff --git a/storage/browser/blob/blob_storage_registry.h b/storage/browser/blob/blob_storage_registry.h
new file mode 100644
index 0000000..8a79493
--- /dev/null
+++ b/storage/browser/blob/blob_storage_registry.h
@@ -0,0 +1,108 @@
+// 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_STORAGE_REGISTRY_H_
+#define STORAGE_BROWSER_BLOB_BLOB_STORAGE_REGISTRY_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/callback_forward.h"
+#include "base/containers/scoped_ptr_hash_map.h"
+#include "base/macros.h"
+#include "storage/browser/blob/internal_blob_data.h"
+#include "storage/browser/storage_browser_export.h"
+
+class GURL;
+
+namespace storage {
+
+// This class stores the blob data in the various states of construction, as
+// well as URL mappings to blob uuids.
+// Implementation notes:
+// * There is no implicit refcounting in this class, except for setting the
+//   refcount to 1 on registration.
+// * When removing a uuid registration, we do not check for URL mappings to that
+//   uuid. The user must keep track of these.
+class STORAGE_EXPORT BlobStorageRegistry {
+ public:
+  enum class BlobState {
+    // First the renderer reserves the uuid.
+    RESERVED = 1,
+    // Second, we are asynchronously transporting data to the browser.
+    ASYNC_TRANSPORTATION,
+    // Third, we construct the blob when we have all of the data.
+    CONSTRUCTION,
+    // Finally, the blob is built.
+    ACTIVE
+  };
+
+  struct STORAGE_EXPORT Entry {
+    size_t refcount;
+    BlobState state;
+    std::vector<base::Callback<void(bool)>> construction_complete_callbacks;
+
+    // Flags
+    bool exceeded_memory;
+
+    // data and data_builder are mutually exclusive.
+    scoped_ptr<InternalBlobData> data;
+    scoped_ptr<InternalBlobData::Builder> data_builder;
+
+    Entry() = delete;
+    Entry(int refcount, BlobState state);
+    ~Entry();
+
+    // Performs a test-and-set on the state of the given blob. If the state
+    // isn't as expected, we return false. Otherwise we set the new state and
+    // return true.
+    bool TestAndSetState(BlobState expected, BlobState set);
+  };
+
+  BlobStorageRegistry();
+  ~BlobStorageRegistry();
+
+  // Creates the blob entry with a refcount of 1 and a state of RESERVED. If
+  // the blob is already in use, we return null.
+  Entry* CreateEntry(const std::string& uuid);
+
+  // Removes the blob entry with the given uuid. This does not unmap any
+  // URLs that are pointing to this uuid. Returns if the entry existed.
+  bool DeleteEntry(const std::string& uuid);
+
+  // Gets the blob entry for the given uuid. Returns nullptr if the entry
+  // does not exist.
+  Entry* GetEntry(const std::string& uuid);
+
+  // Creates a url mapping from blob uuid to the given url. Returns false if
+  // the uuid isn't mapped to an entry or if there already is a map for the URL.
+  bool CreateUrlMapping(const GURL& url, const std::string& uuid);
+
+  // Removes the given URL mapping. Optionally populates a uuid string of the
+  // removed entry uuid. Returns false if the url isn't mapped.
+  bool DeleteURLMapping(const GURL& url, std::string* uuid);
+
+  // Returns if the url is mapped to a blob uuid.
+  bool IsURLMapped(const GURL& blob_url) const;
+
+  // Returns the entry from the given url, and optionally populates the uuid for
+  // that entry. Returns a nullptr if the mapping or entry doesn't exist.
+  Entry* GetEntryFromURL(const GURL& url, std::string* uuid);
+
+  size_t blob_count() const { return blob_map_.size(); }
+  size_t url_count() const { return url_to_uuid_.size(); }
+
+ private:
+  using BlobMap = base::ScopedPtrHashMap<std::string, scoped_ptr<Entry>>;
+  using URLMap = std::map<GURL, std::string>;
+
+  BlobMap blob_map_;
+  URLMap url_to_uuid_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlobStorageRegistry);
+};
+
+}  // namespace storage
+#endif  // STORAGE_BROWSER_BLOB_BLOB_STORAGE_REGISTRY_H_
diff --git a/storage/browser/blob/internal_blob_data.h b/storage/browser/blob/internal_blob_data.h
index aa47101..7ec2bf8 100644
--- a/storage/browser/blob/internal_blob_data.h
+++ b/storage/browser/blob/internal_blob_data.h
@@ -23,6 +23,7 @@ class InternalBlobData {
 
  protected:
   friend class BlobStorageContext;
+  friend class BlobStorageRegistry;
   friend class ViewBlobInternalsJob;
 
   // Removes the given blob uuid from the internal ShareableBlobDataItems.
diff --git a/storage/storage_browser.gyp b/storage/storage_browser.gyp
index de1d166..3f4b7ea 100644
--- a/storage/storage_browser.gyp
+++ b/storage/storage_browser.gyp
@@ -37,6 +37,8 @@
         'browser/blob/blob_reader.h',
         'browser/blob/blob_storage_context.cc',
         'browser/blob/blob_storage_context.h',
+        'browser/blob/blob_storage_registry.cc',
+        'browser/blob/blob_storage_registry.h',
         'browser/blob/blob_url_request_job.cc',
         'browser/blob/blob_url_request_job.h',
         'browser/blob/blob_url_request_job_factory.cc',