gdata: Convert FindEntryByResourceIdSync() to asynchronous.

chrome/browser/chromeos/gdata/gdata_protocol_handler.cc

 // Copyright (c) 2012 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/gdata/gdata_protocol_handler.h"
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 131 matching lines @@
   // GDataFileSystem::GetFileByResourceId().
   void OnGetFileByResourceId(base::PlatformFileError error,
                              const FilePath& local_file_path,
                              const std::string& mime_type,
                              GDataFileType file_type);
 
   // Helper callback for GetFileSizeOnBlockingPool that sets |remaining_bytes_|
   // to |file_size|, and notifies result for Start().
   void OnGetFileSize(int64 *file_size);
 
+  // Helper callback for FindEntryByResourceId invoked by StartAsync.
+  void OnFindEntryByResourceId(const std::string& resource_id,
+                               base::PlatformFileError error,
+                               GDataEntry* entry);
+
   // Helper methods for ReadRawData to open file and read from its corresponding
   // stream in a streaming fashion.
   bool ContinueReadFromFile(int* bytes_read);
   void ReadFromFile();
   void ReadFileStream(int bytes_to_read);
 
   // Helper callback for handling async responses from FileStream::Open().
   void OnFileOpen(int bytes_to_read, int open_result);
 
     // Helper callback for handling async responses from FileStream::Read().
@@ skipping 151 matching lines @@
         base::Bind(&CancelGDataDownloadOnUIThread,
                    gdata_file_path_));
   }
 
   net::URLRequestJob::Kill();
   weak_ptr_factory_->InvalidateWeakPtrs();
 }
 
 bool GDataURLRequestJob::GetMimeType(std::string* mime_type) const {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-
-  if (!file_system_)
-    return false;
-
-  std::string resource_id;
-  std::string unused_file_name;
-  if (!ParseDriveUrl(request_->url().spec(), &resource_id)) {
-    return false;
-  }
-
-  GDataEntry* entry = NULL;
-  file_system_->FindEntryByResourceIdSync(
-      resource_id, base::Bind(&ReadOnlyFindEntryCallback, &entry));
-  if (!entry || !entry->AsGDataFile())
-    return false;
-  mime_type->assign(entry->AsGDataFile()->content_mime_type());
+  mime_type->assign(mime_type_);
   return !mime_type->empty();
 }
 
 void GDataURLRequestJob::GetResponseInfo(net::HttpResponseInfo* info) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   if (response_info_.get())
     *info = *response_info_;
 }
 
 int GDataURLRequestJob::GetResponseCode() const {
@@ skipping 128 matching lines @@
     return;
   }
 
   std::string resource_id;
   if (!ParseDriveUrl(request_->url().spec(), &resource_id)) {
     NotifyStartError(net::URLRequestStatus(net::URLRequestStatus::FAILED,
                                            net::ERR_INVALID_URL));
     return;
   }
 
-  // First, check if file metadata is matching our expectations.
-  GDataEntry* entry = NULL;
-  file_system_->FindEntryByResourceIdSync(
-      resource_id, base::Bind(&ReadOnlyFindEntryCallback, &entry));
-  if (entry && entry->AsGDataFile()) {
+  file_system_->FindEntryByResourceId(
+      resource_id,
+      base::Bind(&GDataURLRequestJob::OnFindEntryByResourceId,
+                 weak_ptr_factory_->GetWeakPtr(),
+                 resource_id));
+}
+
+void GDataURLRequestJob::OnFindEntryByResourceId(
+    const std::string& resource_id,
+    base::PlatformFileError error,
+    GDataEntry* entry) {
+  if (error == base::PLATFORM_FILE_OK && entry && entry->AsGDataFile()) {

[achuithb, 2012/06/11 21:48:41]

So this is on the UI thread now? Is it safe for members of this class to be
modified on IO/UI threads?

[hshi1, 2012/06/11 22:42:21]

No, this callback is run on the caller thread. See my comment in
gdata_file_system.h.

On 2012/06/11 21:48:41, achuith.bhandarkar wrote:

     mime_type_ = entry->AsGDataFile()->content_mime_type();
     gdata_file_path_ = entry->GetFilePath();
     initial_file_size_ = entry->file_info().size;
   } else {
     mime_type_.clear();
     gdata_file_path_.clear();
     initial_file_size_ = 0;
   }
   remaining_bytes_ = initial_file_size_;
 
@@ skipping 404 matching lines @@
 GDataProtocolHandler::~GDataProtocolHandler() {
 }
 
 net::URLRequestJob* GDataProtocolHandler::MaybeCreateJob(
     net::URLRequest* request) const {
   DVLOG(1) << "Handling url: " << request->url().spec();
   return new GDataURLRequestJob(request);
 }
 
 }  // namespace gdata