Implement snapshotting for non-Drive non-local file systems.

chrome/browser/chromeos/file_manager/snapshot_manager.cc

+// Copyright 2014 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 "chrome/browser/chromeos/file_manager/snapshot_manager.h"
+
+#include "base/bind.h"
+#include "chrome/browser/chromeos/file_manager/app_id.h"
+#include "chrome/browser/chromeos/file_manager/fileapi_util.h"
+#include "content/public/browser/browser_thread.h"
+#include "google_apis/drive/task_util.h"
+#include "webkit/browser/fileapi/file_system_context.h"
+#include "webkit/common/blob/shareable_file_reference.h"
+
+namespace file_manager {
+namespace {
+
+// Part of CreateManagedSnapshot. Runs CreateSnapshotFile method of fileapi.
+void CreateSnapshotFileOnIOThread(
+    scoped_refptr<fileapi::FileSystemContext> context,
+    const fileapi::FileSystemURL& url,
+    const fileapi::FileSystemOperation::SnapshotFileCallback& callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  context->operation_runner()->CreateSnapshotFile(url, callback);
+}
+
+// Utility for destructing the bound |file_refs| on IO thread. This is meant
+// to be used together with base::Bind. After this function finishes, the
+// Bind callback should destruct the bound argument.
+void FreeReferenceOnIOThread(const std::vector<
+    scoped_refptr<webkit_blob::ShareableFileReference> >& file_refs) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+}
+
+}  // namespace
+
+SnapshotManager::SnapshotManager(Profile* profile)
+    : profile_(profile), weak_ptr_factory_(this) {
+}
+
+SnapshotManager::~SnapshotManager() {
+  if (!file_refs_.empty()) {
+    bool posted = content::BrowserThread::PostTask(
+        content::BrowserThread::IO,
+        FROM_HERE,
+        base::Bind(&FreeReferenceOnIOThread, file_refs_));
+    DCHECK(posted);
+  }
+}
+
+void SnapshotManager::CreateManagedSnapshot(
+    const base::FilePath& absolute_file_path,
+    const LocalPathCallback& callback) {
+  fileapi::FileSystemContext* context =
+      util::GetFileSystemContextForExtensionId(profile_, kFileManagerAppId);
+  DCHECK(context);
+
+  GURL url;
+  if (!util::ConvertAbsoluteFilePathToFileSystemUrl(
+          profile_, absolute_file_path, kFileManagerAppId, &url)) {
+    callback.Run(base::FilePath());
+    return;
+  }
+
+  // TODO(kinaba): crbug.com/386519 evict old |file_refs_| before creating a new
+  // one if necessary.
+  content::BrowserThread::PostTask(
+      content::BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&CreateSnapshotFileOnIOThread,
+                 make_scoped_refptr(context),
+                 context->CrackURL(url),
+                 google_apis::CreateRelayCallback(
+                     base::Bind(&SnapshotManager::OnCreateSnapshotFile,
+                                weak_ptr_factory_.GetWeakPtr(),
+                                callback))));
+}
+
+void SnapshotManager::OnCreateSnapshotFile(
+    const LocalPathCallback& callback,
+    base::File::Error result,
+    const base::File::Info& file_info,
+    const base::FilePath& platform_path,
+    const scoped_refptr<webkit_blob::ShareableFileReference>& file_ref) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+  if (result != base::File::FILE_OK) {
+    callback.Run(base::FilePath());
+    return;
+  }
+
+  file_refs_.push_back(file_ref);
+  callback.Run(platform_path);
+}
+
+}  // namespace file_manager