Wired GDataFileSystem::GetFile() method with internal cache.

chrome/browser/chromeos/gdata/gdata_operations.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_operations.h"
 
 #include "base/bind.h"
 #include "base/json/json_reader.h"
 #include "base/string_number_conversions.h"
 #include "chrome/browser/chromeos/gdata/gdata_util.h"
@@ skipping 165 matching lines @@
   DCHECK(!auth_token.empty());
 
   GURL url = GetURL();
   DCHECK(!url.is_empty());
   DVLOG(1) << "URL: " << url.spec();
 
   url_fetcher_.reset(URLFetcher::Create(url, GetRequestType(), this));
   url_fetcher_->SetRequestContext(profile_->GetRequestContext());
   // Always set flags to neither send nor save cookies.
   url_fetcher_->SetLoadFlags(
       net::LOAD_DO_NOT_SEND_COOKIES | net::LOAD_DO_NOT_SAVE_COOKIES);

[kuan, 2012/03/20 03:22:19]

these same load flags are used by DownloadFileOperation; browser caching wil not
be disabled without net::LOAD_DISABLE_CACHE flag, resulting in 2 local copies of
the files when DownloadFile is invoked.

[zel, 2012/03/20 04:31:17]

goo catch. i don't think we ever want to cache anything here from the browser
side

   if (save_temp_file_) {
     url_fetcher_->SaveResponseToTemporaryFile(
         BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE));
+  } else if (!output_file_path_.empty()){
+    url_fetcher_->SaveResponseToFileAtPath(output_file_path_,
+        BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE));
   }
 
   // Add request headers.
   // Note that SetExtraRequestHeaders clears the current headers and sets it
   // to the passed-in headers, so calling it for each header will result in
   // only the last header being set in request headers.
   url_fetcher_->AddExtraRequestHeader(kGDataVersionHeader);
   url_fetcher_->AddExtraRequestHeader(
         base::StringPrintf(kAuthorizationHeaderFormat, auth_token.data()));
   std::vector<std::string> headers = GetExtraRequestHeaders();
@@ skipping 220 matching lines @@
   return AddStandardUrlParams(GURL(kAccountMetadataURL));
 }
 
 //============================ DownloadFileOperation ===========================
 
 DownloadFileOperation::DownloadFileOperation(
     GDataOperationRegistry* registry,
     Profile* profile,
     const DownloadActionCallback& callback,
     const GURL& document_url,
-    const FilePath& virtual_path)
+    const FilePath& virtual_path,
+    const FilePath& output_file_path)
     : UrlFetchOperationBase(registry,
                             GDataOperationRegistry::OPERATION_DOWNLOAD,
                             virtual_path,
                             profile),
       callback_(callback),
       document_url_(document_url) {
   // Make sure we download the content into a temp file.
-  save_temp_file_ = true;
+  if (output_file_path.empty())
+    save_temp_file_ = true;
+  else
+    output_file_path_ = output_file_path;
 }
 
 DownloadFileOperation::~DownloadFileOperation() {}
 
 // Overridden from UrlFetchOperationBase.
 GURL DownloadFileOperation::GetURL() const {
   return document_url_;
 }
 
 void DownloadFileOperation::OnURLFetchDownloadProgress(const URLFetcher* source,
@@ skipping 465 matching lines @@
 }
 
 void ResumeUploadOperation::OnURLFetchUploadProgress(
     const content::URLFetcher* source, int64 current, int64 total) {
   // Adjust the progress values according to the range currently uploaded.
   NotifyProgress(params_.start_range + current, params_.content_length);
 }
 
 
 }  // namespace gdata