gdata: Convert FindEntryByResourceIdSync() to asynchronous.

chrome/browser/chromeos/gdata/gdata_protocol_handler.cc

Index: chrome/browser/chromeos/gdata/gdata_protocol_handler.cc
diff --git a/chrome/browser/chromeos/gdata/gdata_protocol_handler.cc b/chrome/browser/chromeos/gdata/gdata_protocol_handler.cc
index ea671cfd385b9239aa43d8d85731843ac0930f9a..e61fbea3d31bca351408d5edbcc70e63852b159b 100644
--- a/chrome/browser/chromeos/gdata/gdata_protocol_handler.cc
+++ b/chrome/browser/chromeos/gdata/gdata_protocol_handler.cc
@@ -149,6 +149,11 @@ class GDataURLRequestJob : public net::URLRequestJob {
   // 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);
@@ -320,22 +325,7 @@ void GDataURLRequestJob::Kill() {
 
 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();
 }
 
@@ -484,11 +474,18 @@ void GDataURLRequestJob::StartAsync(GDataFileSystem** file_system) {
     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;