[BlobAsync] Disk support for blob storage

content/browser/blob_storage/chrome_blob_storage_context.cc

 // Copyright (c) 2012 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/chrome_blob_storage_context.h"
 
 #include <utility>
 
 #include "base/bind.h"
+#include "base/files/file.h"
+#include "base/files/file_enumerator.h"
+#include "base/files/file_util.h"
 #include "base/guid.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/single_thread_task_runner.h"
+#include "base/task_runner.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "content/public/browser/blob_handle.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "storage/browser/blob/blob_data_builder.h"
 #include "storage/browser/blob/blob_data_handle.h"
 #include "storage/browser/blob/blob_storage_context.h"
 
+using base::FilePath;
 using base::UserDataAdapter;
 using storage::BlobStorageContext;
 
 namespace content {
 
 namespace {
+const char kBlobStorageParentDirectory[] = "blob_storage";
+
+void CreateBlobDirectory(const FilePath& blob_storage_dir,
+                         scoped_refptr<base::TaskRunner> io_runner,
+                         const base::Closure& done) {
+  base::File::Error error;
+  bool success = base::CreateDirectoryAndGetError(blob_storage_dir, &error);
+  LOCAL_HISTOGRAM_BOOLEAN("Storage.Blob.DirectorySuccess", success);
+  if (!success) {
+    LOCAL_HISTOGRAM_ENUMERATION("Storage.Blob.DirectorySuccess.Error", -error,
+                                -base::File::FILE_ERROR_MAX);
+  } else {
+    io_runner->PostTask(FROM_HERE, done);
+  }
+}
+
+// Removes all folders in the parent directory except for the
+// |current_run_dir| folder. If this path is empty, then we delete all folders.
+void RemoveOldBlobStorageDirectories(const FilePath& blob_storage_parent,
+                                     const FilePath& current_run_dir) {
+  if (!base::DirectoryExists(blob_storage_parent)) {
+    return;
+  }
+  base::FileEnumerator enumerator(blob_storage_parent, false,
+                                  base::FileEnumerator::DIRECTORIES);
+  std::vector<std::string> components;
+  bool success = true;
+  for (base::FilePath name = enumerator.Next(); !name.empty();
+       name = enumerator.Next()) {
+    if (current_run_dir.empty() || name != current_run_dir)
+      success &= base::DeleteFile(name, true);
+  }
+  LOCAL_HISTOGRAM_BOOLEAN("Storage.Blob.CleanupSuccess", success);
+}
 
 const char kBlobStorageContextKeyName[] = "content_blob_storage_context";
 
 class BlobHandleImpl : public BlobHandle {
  public:
   explicit BlobHandleImpl(std::unique_ptr<storage::BlobDataHandle> handle)
       : handle_(std::move(handle)) {}
 
   ~BlobHandleImpl() override {}
 
   std::string GetUUID() override { return handle_->uuid(); }
 
  private:
   std::unique_ptr<storage::BlobDataHandle> handle_;
 };
 
 }  // namespace
 
 ChromeBlobStorageContext::ChromeBlobStorageContext() {}
 
 ChromeBlobStorageContext* ChromeBlobStorageContext::GetFor(
     BrowserContext* context) {
   if (!context->GetUserData(kBlobStorageContextKeyName)) {
     scoped_refptr<ChromeBlobStorageContext> blob =
         new ChromeBlobStorageContext();
     context->SetUserData(
         kBlobStorageContextKeyName,
         new UserDataAdapter<ChromeBlobStorageContext>(blob.get()));
+
     // Check first to avoid memory leak in unittests.
-    if (BrowserThread::IsMessageLoopValid(BrowserThread::IO)) {
+    bool io_thread_valid = BrowserThread::IsMessageLoopValid(BrowserThread::IO);
+    if (io_thread_valid) {
       BrowserThread::PostTask(
           BrowserThread::IO, FROM_HERE,
           base::Bind(&ChromeBlobStorageContext::InitializeOnIOThread, blob));
     }
+
+    // If we're not incognito mode, schedule all of our file tasks to enable
+    // disk on the storage context.
+    if (!context->IsOffTheRecord() && io_thread_valid &&
+        BrowserThread::IsMessageLoopValid(BrowserThread::FILE)) {

[Marijn Kruisselbrink, 2016/07/12 21:33:06]

Does this check still make sense now you're not actually using the FILE thread
anymore?

[dmurph, 2016/07/14 01:04:30]

Done.

+      // Resolve our storage directories.
+      base::FilePath blob_storage_parent =
+          context->GetPath().Append(kBlobStorageParentDirectory);
+      base::FilePath blob_storage_dir =
+          blob_storage_parent.Append(base::GenerateGUID());
+
+      scoped_refptr<base::SingleThreadTaskRunner> io_runner =
+          BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO);
+      scoped_refptr<base::SequencedWorkerPool> file_pool =
+          BrowserThread::GetBlockingPool();
+
+      // This creates our directory and calls |OnBlobDirectoryCreated| if we're
+      // successful.
+      file_pool->PostWorkerTaskWithShutdownBehavior(
+          FROM_HERE,
+          base::Bind(
+              &CreateBlobDirectory, blob_storage_dir, io_runner,
+              base::Bind(&ChromeBlobStorageContext::OnBlobDirectoryCreated,
+                         blob, blob_storage_dir)),
+          base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+
+      // Removes our old blob directories if they exist.
+      file_pool->PostWorkerTaskWithShutdownBehavior(
+          FROM_HERE, base::Bind(&RemoveOldBlobStorageDirectories,
+                                blob_storage_parent, blob_storage_dir),
+          base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+    }
   }
 
   return UserDataAdapter<ChromeBlobStorageContext>::Get(
       context, kBlobStorageContextKeyName);
 }
 
 void ChromeBlobStorageContext::InitializeOnIOThread() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   context_.reset(new BlobStorageContext());
+  if (!blob_storage_dir_.empty()) {
+    // This happens if we create our blob storage folder before this method is
+    // called, so we enable disk here.
+    context_->EnableDisk(blob_storage_dir_, BrowserThread::GetBlockingPool());
+  }
 }
 
 std::unique_ptr<BlobHandle> ChromeBlobStorageContext::CreateMemoryBackedBlob(
     const char* data,
     size_t length) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
   std::string uuid(base::GenerateGUID());
   storage::BlobDataBuilder blob_data_builder(uuid);
   blob_data_builder.AppendData(data, length);
@@ skipping 25 matching lines @@
     return std::unique_ptr<BlobHandle>();
 
   std::unique_ptr<BlobHandle> blob_handle(
       new BlobHandleImpl(std::move(blob_data_handle)));
   return blob_handle;
 }
 
 ChromeBlobStorageContext::~ChromeBlobStorageContext() {}
 
 void ChromeBlobStorageContext::DeleteOnCorrectThread() const {
+  // Schedule a task to delete all blob directories.
+  if (!blob_storage_dir_.empty()) {
+    BrowserThread::PostTask(
+        BrowserThread::FILE, FROM_HERE,

[Marijn Kruisselbrink, 2016/07/12 21:33:06]

Should this also be on the blocking pool rather than the file thread?

[dmurph, 2016/07/14 01:04:30]

Done.

+        base::Bind(&RemoveOldBlobStorageDirectories,
+                   blob_storage_dir_.DirName(), base::FilePath()));
+  }
   if (BrowserThread::IsMessageLoopValid(BrowserThread::IO) &&
       !BrowserThread::CurrentlyOn(BrowserThread::IO)) {
     BrowserThread::DeleteSoon(BrowserThread::IO, FROM_HERE, this);
     return;
   }
   delete this;
 }
 
+void ChromeBlobStorageContext::OnBlobDirectoryCreated(
+    const base::FilePath& blob_storage_directory) {
+  LOG(ERROR) << "Blob directory successfully created "
+             << blob_storage_directory.value();
+  DCHECK(blob_storage_dir_.empty());
+  blob_storage_dir_ = blob_storage_directory;
+  if (context_) {
+    context_->EnableDisk(blob_storage_dir_, BrowserThread::GetBlockingPool());
+  }
+}
+
 }  // namespace content