Implement Pepper proxy for PPB_DirectoryReader

ppapi/proxy/directory_reader_resource.cc

+// Copyright (c) 2013 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 "ppapi/proxy/directory_reader_resource.h"
+
+#include "base/bind.h"
+#include "ipc/ipc_message.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/proxy/dispatch_reply_message.h"
+#include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/proxy/ppb_file_ref_proxy.h"
+#include "ppapi/shared_impl/ppapi_globals.h"
+#include "ppapi/shared_impl/resource_tracker.h"
+#include "ppapi/shared_impl/tracked_callback.h"
+#include "ppapi/thunk/enter.h"
+#include "ppapi/thunk/ppb_file_ref_api.h"
+
+using ppapi::proxy::PPB_FileRef_Proxy;
+
+namespace ppapi {
+namespace proxy {
+
+DirectoryReaderResource::DirectoryReaderResource(
+    Connection connection,
+    PP_Instance instance,
+    PP_Resource directory_ref)
+    : PluginResource(connection, instance),
+      output_(NULL),
+      has_more_(true) {
+  directory_resource_ =
+      PpapiGlobals::Get()->GetResourceTracker()->GetResource(directory_ref);
+}
+
+DirectoryReaderResource::~DirectoryReaderResource() {
+}
+
+thunk::PPB_DirectoryReader_API*
+DirectoryReaderResource::AsPPB_DirectoryReader_API() {
+  return this;
+}
+
+int32_t DirectoryReaderResource::GetNextEntry(
+    PP_DirectoryEntry_Dev* entry,
+    scoped_refptr<TrackedCallback> callback) {
+  if (TrackedCallback::IsPending(callback_))
+    return PP_ERROR_INPROGRESS;
+
+  output_ = entry;
+  callback_ = callback;
+
+  if (FillUpEntry())
+    return PP_OK;
+
+  if (!sent_create_to_renderer())
+    SendCreate(RENDERER, PpapiHostMsg_DirectoryReader_Create());
+
+  PpapiHostMsg_DirectoryReader_GetEntries msg(
+      directory_resource_->host_resource());
+  Call<PpapiPluginMsg_DirectoryReader_GetEntriesReply>(
+      RENDERER, msg,
+      base::Bind(&DirectoryReaderResource::OnPluginMsgGetEntriesReply, this));
+  return PP_OK_COMPLETIONPENDING;
+}
+
+void DirectoryReaderResource::OnPluginMsgGetEntriesReply(
+    const ResourceMessageReplyParams& params,
+    const std::vector<ppapi::PPB_FileRef_CreateInfo>& infos,
+    const std::vector<PP_FileType>& file_types) {
+  CHECK_EQ(infos.size(), file_types.size());
+
+  for (std::vector<ppapi::PPB_FileRef_CreateInfo>::size_type i = 0;
+       i < infos.size(); ++i) {
+    DirectoryEntry entry;
+    entry.file_resource = ScopedPPResource(
+        ScopedPPResource::PassRef(),
+        PPB_FileRef_Proxy::DeserializeFileRef(infos[i]));
+    entry.file_type = file_types[i];
+    entries_.push(entry);
+  }
+  has_more_ = false;

[dmichael (off chromium), 2013/02/06 22:44:21]

has_more_ is a confusing name to me, given that we get all the entries in one
message. Maybe it would be clearer if it was instead
"did_receive_get_entries_reply_" (obviously true/false would be swapped)?

[nhiroki, 2013/02/07 09:37:27]

Done.

+
+  if (!TrackedCallback::IsPending(callback_))
+    return;
+
+  FillUpEntry();
+  callback_->Run(params.result());
+}
+
+bool DirectoryReaderResource::FillUpEntry() {
+  DCHECK(output_);
+

[dmichael (off chromium), 2013/02/06 22:44:21]

Couldn't you bail early if you haven't received the message? I think your code
is correct; I just found it a little hard to follow at first, so this is just an
optional suggestion for restructuring this method...
i.e.,
if (!did_receive_get_entries_reply_)
  return false;

[nhiroki, 2013/02/07 09:37:27]

Done.

+  if (!entries_.empty()) {
+    DirectoryEntry entry = entries_.front();
+    entries_.pop();
+    output_->file_ref = entry.file_resource.Release();

[dmichael (off chromium), 2013/02/06 22:44:21]

The API doc says:
"If entry->file_ref is non-zero when passed to GetNextEntry, it will be released
before the next file_ref is stored."

So should we release a ResourceTracker reference for output_file_ref?

[nhiroki, 2013/02/07 09:37:27]

Oops... I missed it. Thank you for catching. Done.

+    output_->file_type = entry.file_type;
+    output_ = NULL;
+    return true;
+  }
+
+  if (!has_more_) {

[dmichael (off chromium), 2013/02/06 22:44:21]

This could instead be an else if you bailed early as I suggested above.  i.e.,
if we get here, we know we have received the message, but our queue is now
empty.

That seems clearer to me personally.

[nhiroki, 2013/02/07 09:37:27]

Done.

+    output_->file_ref = 0;

[dmichael (off chromium), 2013/02/06 22:44:21]

I think you also need to release output_->file_ref here.

[nhiroki, 2013/02/07 09:37:27]

Done.

+    output_->file_type = PP_FILETYPE_OTHER;
+    output_ = NULL;
+    return true;
+  }
+
+  return false;
+}
+
+}  // namespace proxy
+}  // namespace ppapi