mediaview: Implement ArcDocumentsProviderRoot.

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.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_ROOT_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_DOCUMENTS_PROVIDER_ROOT_H_
 
+#include <map>
 #include <string>
+#include <vector>
 
+#include "base/callback.h"

[hashimoto, 2016/12/20 04:55:07]

nit: Can't be replaced with callback_forward.h?

[Shuhei Takahashi, 2016/12/20 06:08:24]

Done.

 #include "base/files/file_path.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/optional.h"
+#include "components/arc/common/file_system.mojom.h"
 #include "storage/browser/fileapi/async_file_util.h"
 
 namespace arc {
 
 // Represents a file system root in Android Documents Provider.
 //
 // All methods must be called on the IO thread.
+// If this object is deleted while there are in-flight operations, callbacks
+// for those operations will be never called.
 class ArcDocumentsProviderRoot {
  public:
   using GetFileInfoCallback = storage::AsyncFileUtil::GetFileInfoCallback;
   using ReadDirectoryCallback = storage::AsyncFileUtil::ReadDirectoryCallback;
 
   ArcDocumentsProviderRoot(const std::string& authority,
                            const std::string& root_document_id);
   ~ArcDocumentsProviderRoot();
 
   // Queries information of a file just like AsyncFileUtil.GetFileInfo().
   void GetFileInfo(const base::FilePath& path,
                    const GetFileInfoCallback& callback);
 
   // Queries a list of files under a directory just like
   // AsyncFileUtil.ReadDirectory().
   void ReadDirectory(const base::FilePath& path,
                      const ReadDirectoryCallback& callback);
 
  private:
+  // Thin representation of a document in documents provider.
+  struct ThinDocument {
+    std::string document_id;
+    bool is_directory;
+  };
+
+  // Mapping from a file name to a ThinDocument.
+  using NameMapping = std::map<base::FilePath::StringType, ThinDocument>;

[hashimoto, 2016/12/20 04:55:07]

nit: "NameMapping" sounds like a mapping from names to names.
How about something like NameToDocumentMap?

[Shuhei Takahashi, 2016/12/20 06:08:24]

Done.

+
+  using ResolveToDocumentIdCallback =
+      base::Callback<void(const std::string& document_id)>;
+  using ReadDirectoryInternalCallback =
+      base::Callback<void(NameMapping mapping)>;
+
+  void GetFileInfoWithDocumentId(const GetFileInfoCallback& callback,
+                                 const std::string& document_id);
+  void GetFileInfoWithDocument(const GetFileInfoCallback& callback,
+                               mojom::DocumentPtr document);
+
+  void ReadDirectoryWithDocumentId(const ReadDirectoryCallback& callback,
+                                   const std::string& document_id);
+  void ReadDirectoryWithNameMapping(const ReadDirectoryCallback& callback,
+                                    NameMapping mapping);
+
+  // Resolves |path| to a document ID. Failures are indicated by an empty
+  // document ID.
+  void ResolveToDocumentId(const base::FilePath& path,
+                           const ResolveToDocumentIdCallback& callback);
+  void ResolveToDocumentIdRecursively(
+      const std::string& document_id,
+      const std::vector<base::FilePath::StringType>& components,
+      const ResolveToDocumentIdCallback& callback);
+  void ResolveToDocumentIdRecursivelyWithNameMapping(
+      const std::vector<base::FilePath::StringType>& components,
+      const ResolveToDocumentIdCallback& callback,
+      NameMapping mapping);
+
+  // Enumerates child documents of a directory specified by |document_id|.
+  // The result is returned as a NameMapping.
+  void ReadDirectoryInternal(const std::string& document_id,
+                             const ReadDirectoryInternalCallback& callback);
+  void ReadDirectoryInternalWithChildDocuments(
+      const ReadDirectoryInternalCallback& callback,
+      base::Optional<std::vector<mojom::DocumentPtr>> maybe_children);
+
+  const std::string authority_;
+  const std::string root_document_id_;
+  base::WeakPtrFactory<ArcDocumentsProviderRoot> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(ArcDocumentsProviderRoot);
 };
 
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_DOCUMENTS_PROVIDER_ROOT_H_