mediaview: Implement ArcDocumentsProviderRoot.

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_document.h

+// 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.
+
+#ifndef CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_DOCUMENTS_PROVIDER_DOCUMENT_H_
+#define CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_DOCUMENTS_PROVIDER_DOCUMENT_H_
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "base/files/file_path.h"
+#include "base/macros.h"
+#include "components/arc/common/file_system.mojom.h"
+
+namespace arc {
+
+// ArcDocumentsProviderDocument represents a document in DocumentsProvider.
+//
+// Since Android DocumentProvider is more permissive about display names
+// (e.g. duplicated file names in the same directory are allowed), we need
+// to expose some files to Chrome with rewritten file names. This object
+// will remember the mapping from rewritten file names to its child documents.
+//
+// WARNING: This class is thread-unsafe. Must be accessed only from a single

[Luis Héctor Chávez, 2016/12/15 02:40:31]

Can you add one of these?
https://cs.chromium.org/chromium/src/base/threading/thread_checker.h?type=cs&...

[Shuhei Takahashi, 2016/12/15 06:50:57]

Sure.

+// thread.
+class ArcDocumentsProviderDocument {
+ public:
+  // A mapping from rewritten file names to documents.
+  using ChildMap = std::map<base::FilePath::StringType,
+                            std::unique_ptr<ArcDocumentsProviderDocument>>;
+
+  ArcDocumentsProviderDocument(const std::string& document_id,
+                               bool is_directory);
+  ~ArcDocumentsProviderDocument();
+
+  static ArcDocumentsProviderDocument* CreateFromDocument(
+      const mojom::Document& document);
+
+  const std::string& document_id() { return document_id_; }

[Luis Héctor Chávez, 2016/12/15 02:40:31]

You can make all of the inlined accessors const:

const std::string& document_id() const { ... }

[Shuhei Takahashi, 2016/12/15 06:50:57]

Done.

+  bool is_directory() { return is_directory_; }
+
+  // Must not be called unless is_directory() == true.
+  const ChildMap& children() { return *children_; }
+
+  // Recursively looks up a descendant document with a relative path.
+  // If a document with the specific relative path is not found, nullptr is
+  // returned.
+  ArcDocumentsProviderDocument* Lookup(const base::FilePath& path);
+
+  // Updates the child mapping with info retrieved from Android.
+  void UpdateWithChildDocuments(
+      const std::vector<mojom::DocumentPtr>& children);
+
+ private:
+  // Computes a file name for a document.
+  static base::FilePath::StringType GetFileNameForDocument(
+      const mojom::DocumentPtr& document);
+
+  const std::string document_id_;
+  const bool is_directory_;
+  // This will be non-null only when this entry is for a directory.
+  const std::unique_ptr<ChildMap> children_;
+
+  DISALLOW_COPY_AND_ASSIGN(ArcDocumentsProviderDocument);
+};
+
+}  // namespace arc
+
+#endif  // CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_DOCUMENTS_PROVIDER_DOCUMENT_H_