arc: Add utility functions to implement ARC content file system

chrome/browser/chromeos/arc/fileapi/intent_helper_util.cc

+// Copyright 2016 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/arc/fileapi/intent_helper_util.h"
+
+#include "components/arc/arc_bridge_service.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace arc {
+
+namespace intent_helper_util {
+
+namespace {
+
+void OnGetFileSize(
+    const mojom::IntentHelperInstance::GetFileSizeCallback& callback,
+    int64_t size) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  content::BrowserThread::PostTask(content::BrowserThread::IO, FROM_HERE,
+                                   base::Bind(callback, size));
+}
+
+void GetFileSizeOnUIThread(
+    const GURL& arc_url,
+    const mojom::IntentHelperInstance::GetFileSizeCallback& callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  auto* arc_bridge_service = arc::ArcBridgeService::Get();
+  if (!arc_bridge_service) {
+    LOG(ERROR) << "Failed to get ArcBridgeService.";
+    OnGetFileSize(callback, -1);
+    return;
+  }
+  mojom::IntentHelperInstance* intent_helper_instance =
+      arc_bridge_service->intent_helper()->GetInstanceForMethod("GetFileSize",
+                                                                15);
+  if (!intent_helper_instance) {
+    LOG(ERROR) << "Failed to get IntentHelperInstance.";
+    OnGetFileSize(callback, -1);
+    return;
+  }
+  intent_helper_instance->GetFileSize(arc_url.spec(),
+                                      base::Bind(&OnGetFileSize, callback));
+}
+
+void OnOpenFileToRead(
+    const mojom::IntentHelperInstance::OpenFileToReadCallback& callback,
+    mojo::ScopedHandle handle) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  content::BrowserThread::PostTask(content::BrowserThread::IO, FROM_HERE,
+                                   base::Bind(callback, base::Passed(&handle)));
+}
+
+void OpenFileToReadOnUIThread(
+    const GURL& arc_url,
+    const mojom::IntentHelperInstance::OpenFileToReadCallback& callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  auto* arc_bridge_service = arc::ArcBridgeService::Get();
+  if (!arc_bridge_service) {
+    LOG(ERROR) << "Failed to get ArcBridgeService.";
+    OnOpenFileToRead(callback, mojo::ScopedHandle());
+    return;
+  }
+  mojom::IntentHelperInstance* intent_helper_instance =
+      arc_bridge_service->intent_helper()->GetInstanceForMethod(
+          "OpenFileToRead", 15);
+  if (!intent_helper_instance) {
+    LOG(ERROR) << "Failed to get IntentHelperInstance.";
+    OnOpenFileToRead(callback, mojo::ScopedHandle());
+    return;
+  }
+  intent_helper_instance->OpenFileToRead(
+      arc_url.spec(), base::Bind(&OnOpenFileToRead, callback));
+}
+
+}  // namespace
+
+void GetFileSizeOnIOThread(
+    const GURL& arc_url,
+    const mojom::IntentHelperInstance::GetFileSizeCallback& callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&GetFileSizeOnUIThread, arc_url, callback));
+}
+
+void OpenFileToReadOnIOThread(
+    const GURL& arc_url,
+    const mojom::IntentHelperInstance::OpenFileToReadCallback& callback) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&OpenFileToReadOnUIThread, arc_url, callback));
+}
+
+}  // namespace intent_helper_util
+
+}  // namespace arc