[NaCl SDK] Expose Google Drive to nacl_io.

native_client_sdk/src/libraries/nacl_io/googledrivefs/googledrivefs.cc

Index: native_client_sdk/src/libraries/nacl_io/googledrivefs/googledrivefs.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/googledrivefs/googledrivefs.cc b/native_client_sdk/src/libraries/nacl_io/googledrivefs/googledrivefs.cc
new file mode 100644
index 0000000000000000000000000000000000000000..706c1b627aa38fd308d253a85631baab3ce3c29e
--- /dev/null
+++ b/native_client_sdk/src/libraries/nacl_io/googledrivefs/googledrivefs.cc
@@ -0,0 +1,292 @@
+// 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 "nacl_io/googledrivefs/googledrivefs.h"
+
+#include <map>
+
+#include "nacl_io/filesystem.h"
+#include "nacl_io/statuscode.h"
+#include "nacl_io/googledrivefs/googledrivefs_node.h"
+#include "nacl_io/googledrivefs/googledrivefs_util.h"
+
+namespace nacl_io {
+
+GoogleDriveFs::GoogleDriveFs() {}
+
+GoogleDriveFs::~GoogleDriveFs() {}
+
+Error GoogleDriveFs::Init(const FsInitArgs& args) {
+  Error error = Filesystem::Init(args);
+  if (error) {
+    return error;
+  }
+
+  std::map<std::string, std::string>::const_iterator instance_it =
+      args.string_map.find("instance");
+
+  if (instance_it == args.string_map.end()) {
+    return EINVAL;
+  }
+
+  instance_ = atoi(instance_it->second.c_str());

[binji, 2016/08/22 19:21:52]

you don't need to get this instance from the user, it is accessible through
ppapi_->GetInstance().

[chanpatorikku, 2016/08/29 17:14:03]

Done.

+
+  std::map<std::string, std::string>::const_iterator token_it =

[binji, 2016/08/22 19:21:52]

nit: Use StringMap_t instead of std::map<std::string, std::string>

[chanpatorikku, 2016/08/29 17:14:03]

Done.

StringMap_t is defined the same in http_fs_node.cc and filesystem.h as:

typedef std::map<std::string, std::string> StringMap_t;

Could you please reply if you would like to refactor to have 1 copy of
StringMap_t in some other CL, as it is out of scope of GoogleDriveFs?

[binji, 2016/08/30 01:39:34]

It's fine to redefine it.

+      args.string_map.find("token");
+
+  if (token_it == args.string_map.end()) {
+    return EINVAL;
+  }
+
+  token_ = token_it->second;
+
+  return 0;
+}
+
+void GoogleDriveFs::Destroy() {}
+
+Error GoogleDriveFs::OpenWithMode(const Path& path,
+                                  int open_flags,
+                                  mode_t mode,
+                                  ScopedNode* out_node) {
+  ScopedNode node(new GoogleDriveFsNode(this, path));
+
+  Error error = node->Init(open_flags);
+  if (error) {
+    return error;
+  }
+
+  *out_node = node;
+
+  return 0;
+}
+
+Error GoogleDriveFs::Mkdir(const Path& path, int permissions) {
+  URLLoaderInterface* url_loader_iface = ppapi()->GetURLLoaderInterface();

[binji, 2016/08/22 19:21:52]

you could cache these interface pointers as members (see html5_fs for example)

[chanpatorikku, 2016/08/29 17:14:02]

The interface pointers in googledrivefs are not cached since the interface
pointers in html5_fs looked not to be for caching but for logging.

The code review of the CL when the interface pointers were added is:
Issue 349703003: [NaCl SDK] Add some more logging to nacl_io. (Closed)
https://codereview.chromium.org/349703003/#ps1

Some errors were logged and some were not.
Verifying if an interface pointer is NULL and showing an error on NULL pointers
seems to be a good idea, but not all interface pointers were verified if they
are NULL.

There are interface pointers that are not cached in other Filesystem.

Designs on the interface pointers can vary, depending on the situations.  There
are times when the code is good for a purpose and later on finds another purpose
that is also excellent for.  

Perhaps double checking in various perspectives is a good follow-up.

+  PP_Resource url_loader_object = url_loader_iface->Create(instance());
+  URLRequestInfoInterface* url_request_info_iface =
+      ppapi()->GetURLRequestInfoInterface();
+  PP_Resource url_request_info_object =
+      url_request_info_iface->Create(instance());
+  PP_Resource url_response_info_object = 0;
+  Error error(0);
+  std::string parent_dir_id = "";

[binji, 2016/08/22 19:21:52]

nit: it's not necessary to initialize to "", that is the default value of
std::string.

[chanpatorikku, 2016/08/29 17:14:02]

Done.

+  std::string item_id = "";
+  static const char base_url[] = "https://www.googleapis.com/drive/v3/files";
+  RequestUrlParams p;
+
+  // Error on making the root directory
+  if (path.Size() < 2) {
+    error = EEXIST;
+    goto done;
+  }
+
+  error = RequestParentDirId(path, this, &parent_dir_id);
+  if (error) {
+    goto done;
+  }
+
+  error = RequestItemId(parent_dir_id, path.Basename(), this, &item_id);
+
+  if (!error) {
+    error = EEXIST;
+    goto done;
+  } else if (error == ENOENT) {
+    // mkdir does not create a directory when a file with path.Basename()
+    // already exists.
+
+    p.url = base_url;

[chanpatorikku, 2016/08/07 02:41:02]

Lines 99-113 are samples of how codes imitate the Drive example.

They are continuing the comments in patch set 1:

"Each URL may be different.
I don't know if the current submission, which imitates how the Drive example
implements the URL strings, 
is practical.
Please review the codes that imitates the Drive example on implementing the URL
strings.
The lines of codes are commented for review."

+    p.method = "POST";
+
+    p.headers = "";
+    AddHeaders("Content-type", "application/json", &p.headers);
+    AddHeaders("Authorization", "Bearer " + token_, &p.headers);
+
+    p.body = "";
+    AddBody("{", &p.body);
+    AddBody("  \"name\": \"" + path.Basename() + "\",", &p.body);
+    AddBody("  \"mimeType\": \"application/vnd.google-apps.folder\",", &p.body);
+    AddBody("  \"parents\": [", &p.body);
+    AddBody("     \"" + parent_dir_id + "\"", &p.body);
+    AddBody("  ]", &p.body);
+    AddBody("}", &p.body);
+
+    error = MakeRequest(ppapi(), url_loader_object, url_request_info_object, p);
+
+    if (error) {
+      goto done;
+    }
+
+    error = FinishPreparingResponse(ppapi(), url_loader_object,
+                                    &url_response_info_object);
+
+    if (error) {
+      goto done;
+    }
+
+    if (ReadStatusCode(ppapi(), url_response_info_object) != STATUSCODE_OK) {
+      error = EPERM;
+      goto done;
+    }
+
+    error = 0;
+  }
+
+done:
+  if (url_loader_object) {

[binji, 2016/08/22 19:21:52]

Use the ScopedResource instead (see pepper_interface.h)

[chanpatorikku, 2016/08/29 17:14:03]

Done.

+    ppapi()->ReleaseResource(url_loader_object);
+  }
+  if (url_request_info_object) {
+    ppapi()->ReleaseResource(url_request_info_object);
+  }
+  if (url_response_info_object) {
+    ppapi()->ReleaseResource(url_response_info_object);
+  }
+
+  return error;
+}
+
+Error GoogleDriveFs::Rmdir(const Path& path) {
+  URLLoaderInterface* url_loader_iface = ppapi()->GetURLLoaderInterface();
+  PP_Resource url_loader_object = url_loader_iface->Create(instance());
+  URLRequestInfoInterface* url_request_info_iface =
+      ppapi()->GetURLRequestInfoInterface();
+  PP_Resource url_request_info_object =
+      url_request_info_iface->Create(instance());
+  PP_Resource url_response_info_object = 0;
+  Error error(0);
+  std::string parent_dir_id = "";
+  std::string dir_id = "";
+  std::string item_id = "";
+  bool is_empty_dir = true;
+  static const char base_url[] = "https://www.googleapis.com/drive/v3/files";

[binji, 2016/08/22 19:21:52]

This seems to be repeated quite a bit, can you move it to a shared location?

[chanpatorikku, 2016/08/29 17:14:02]

Yes. Done.

+  RequestUrlParams p;
+
+  // Error on removing the root directory
+  if (path.Size() < 2) {
+    error = EEXIST;
+    goto done;
+  }
+
+  error = RequestParentDirId(path, this, &parent_dir_id);
+  if (error) {
+    goto done;
+  }
+
+  error = RequestDirId(parent_dir_id, path.Basename(), this, &dir_id);
+  if (error == ENOENT) {
+    error = RequestItemId(parent_dir_id, path.Basename(), this, &item_id);
+
+    if (error) {
+      goto done;
+    }
+
+    error = ENOTDIR;
+    goto done;
+  } else if (error) {
+    goto done;
+  }
+
+  error = IsEmpty(dir_id, &is_empty_dir);
+  if (error) {
+    goto done;
+  }
+
+  if (!is_empty_dir) {
+    error = ENOTEMPTY;
+    goto done;
+  }
+
+  p.url = base_url;
+  AddUrlPath(dir_id, &p.url);
+
+  p.method = "DELETE";
+
+  p.headers = "";
+  AddHeaders("Content-type", "application/json", &p.headers);
+  AddHeaders("Authorization", "Bearer " + token_, &p.headers);
+
+  error = MakeRequest(ppapi(), url_loader_object, url_request_info_object, p);
+
+  if (error) {
+    goto done;
+  }
+
+  error = FinishPreparingResponse(ppapi(), url_loader_object,
+                                  &url_response_info_object);
+
+  if (error) {
+    goto done;
+  }
+
+  if (ReadStatusCode(ppapi(), url_response_info_object) !=
+      STATUSCODE_NO_CONTENT) {
+    error = EPERM;
+    goto done;
+  }
+
+done:
+  if (url_loader_object) {
+    ppapi()->ReleaseResource(url_loader_object);
+  }
+  if (url_request_info_object) {
+    ppapi()->ReleaseResource(url_request_info_object);
+  }
+  if (url_response_info_object) {
+    ppapi()->ReleaseResource(url_response_info_object);
+  }
+
+  return error;
+}
+
+Error GoogleDriveFs::Rename(const Path& path, const Path& newPath) {
+  // TODO: support rename
+  LOG_ERROR("rename not supported.");
+  return EPERM;
+}
+
+Error GoogleDriveFs::Unlink(const Path& path) {
+  // TODO: support unlink
+  LOG_ERROR("unlink not supported.");
+  return EPERM;
+}
+
+Error GoogleDriveFs::Remove(const Path& path) {
+  // TODO: support remove
+  LOG_ERROR("remove not supported.");
+  return EPERM;
+}
+
+Error GoogleDriveFs::IsEmpty(const std::string& dir_id,
+                             bool* out_is_empty_dir) {
+  static const char base_url[] = "https://www.googleapis.com/drive/v3/files";
+
+  std::string url = base_url;
+  AddUrlFirstQueryParameter("q", "%27" + dir_id + "%27+in+parents", &url);
+
+  std::string response_body;
+  Error error = GetListFileResponseBody(url, this, &response_body);
+  if (error) {
+    return error;
+  }
+
+  std::string name_value = "";
+  int name_index = 0;
+
+  GetValue(response_body, "name", name_index, &name_value, &name_index);
+
+  *out_is_empty_dir = (name_index == -1);
+
+  return 0;
+}
+
+std::string GoogleDriveFs::token() {
+  return token_;
+}
+
+PP_Instance GoogleDriveFs::instance() {
+  return instance_;
+}
+
+}  // namespace nacl_io