Fix various issues in RedirectToFileResourceHandler.

content/browser/loader/redirect_to_file_resource_handler.h

Index: content/browser/loader/redirect_to_file_resource_handler.h
diff --git a/content/browser/loader/redirect_to_file_resource_handler.h b/content/browser/loader/redirect_to_file_resource_handler.h
index 3d62835e8888d734a8e144356177d6a1faa87ea2..9d14cea62148519a632a36aa2c30cc777068dcdb 100644
--- a/content/browser/loader/redirect_to_file_resource_handler.h
+++ b/content/browser/loader/redirect_to_file_resource_handler.h
@@ -5,6 +5,7 @@
 #ifndef CONTENT_BROWSER_LOADER_REDIRECT_TO_FILE_RESOURCE_HANDLER_H_
 #define CONTENT_BROWSER_LOADER_REDIRECT_TO_FILE_RESOURCE_HANDLER_H_
 
+#include "base/callback_forward.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ -24,19 +25,49 @@ class ShareableFileReference;
 }
 
 namespace content {
-class ResourceDispatcherHostImpl;
 
-// Redirects network data to a file.  This is intended to be layered in front
-// of either the AsyncResourceHandler or the SyncResourceHandler.
-class RedirectToFileResourceHandler : public LayeredResourceHandler {
+// A factory for creating the temporary stream. This removes the dependency on
+// ResourceDispatcherHost and gives a hook for mocking in errors in unit tests.
+class TemporaryFileStreamFactory {

[mmenke, 2013/12/04 20:55:48]

This should be an inner class for RedirectToFileResourceHandler

[davidben, 2013/12/04 22:44:04]

Done.

+ public:
+  typedef base::Callback<
+      void(base::PlatformFileError,
+           scoped_ptr<net::FileStream>,
+           scoped_refptr<webkit_blob::ShareableFileReference>)> Callback;
+
+  virtual ~TemporaryFileStreamFactory() {}
+
+  // Creates a temporary file for a request. |callback| is called asynchronously
+  // with a net::FileStream to read from and a ShareableFileReference. The
+  // caller should retain a reference to the ShareableFileReference until it is
+  // done writing to it. When all references to the ShareableFileReference are
+  // released, the temporary is deleted. The factory itself may retain its own
+  // reference to the file.
+  //
+  // If there is an error in creating the temporary, |callback| is called with a
+  // base::PlatformFileError.
+  virtual void CreateTemporary(int child_id,
+                               int request_id,
+                               const Callback& callback) = 0;
+};
+
+// Redirects network data to a file.  This is intended to be layered in front of
+// either the AsyncResourceHandler or the SyncResourceHandler.  The downstream
+// resource handler does not see OnWillRead or OnReadCompleted calls. Instead,
+// the ResourceResponse contains the path to a temporary file and
+// OnDataDownloaded is called as the file downloads.
+//
+// The temporary is vended through a TemporaryFileStreamFactory interface.
+class CONTENT_EXPORT RedirectToFileResourceHandler
+    : public LayeredResourceHandler {
  public:
   RedirectToFileResourceHandler(
       scoped_ptr<ResourceHandler> next_handler,
       net::URLRequest* request,
-      ResourceDispatcherHostImpl* resource_dispatcher_host);
+      TemporaryFileStreamFactory* file_stream_factory);

[mmenke, 2013/12/04 20:55:48]

Should mention lifetime requirements here.

[davidben, 2013/12/04 22:44:04]

Done.

   virtual ~RedirectToFileResourceHandler();
 
-  // ResourceHandler implementation:
+  // LayeredResourceHandler implementation:
   virtual bool OnResponseStarted(int request_id,
                                  ResourceResponse* response,
                                  bool* defer) OVERRIDE;
@@ -55,18 +86,19 @@ class RedirectToFileResourceHandler : public LayeredResourceHandler {
                                    const std::string& security_info,
                                    bool* defer) OVERRIDE;
 
- private:
-  void DidCreateTemporaryFile(base::PlatformFileError error_code,
-                              base::PassPlatformFile file_handle,
-                              const base::FilePath& file_path);
+  // Called by RedirectToFileResourceHandler::Writer.
   void DidWriteToFile(int result);
+
+ private:
+  void DidCreateTemporaryFile(
+      base::PlatformFileError error_code,
+      scoped_ptr<net::FileStream> file_stream,
+      scoped_refptr<webkit_blob::ShareableFileReference> deletable_file);
   bool WriteMore();
   bool BufIsFull() const;
   void ResumeIfDeferred();
 
-  base::WeakPtrFactory<RedirectToFileResourceHandler> weak_factory_;
-
-  ResourceDispatcherHostImpl* host_;
+  TemporaryFileStreamFactory* file_stream_factory_;
 
   // We allocate a single, fixed-size IO buffer (buf_) used to read from the
   // network (buf_write_pending_ is true while the system is copying data into
@@ -79,8 +111,11 @@ class RedirectToFileResourceHandler : public LayeredResourceHandler {
   bool buf_write_pending_;
   int write_cursor_;
 
-  scoped_ptr<net::FileStream> file_stream_;
-  bool write_callback_pending_;
+  // Helper writer object which maintains references to the net::FileStream and
+  // webkit_blob::ShareableFileReference. This is maintained separately so that,
+  // on Windows, the temporary file isn't deleted until after it is closed.
+  class Writer;
+  scoped_ptr<Writer> writer_;
 
   // |next_buffer_size_| is the size of the buffer to be allocated on the next
   // OnWillRead() call.  We exponentially grow the size of the buffer allocated
@@ -89,16 +124,15 @@ class RedirectToFileResourceHandler : public LayeredResourceHandler {
   // was filled, up to a maximum size of 512k.
   int next_buffer_size_;
 
-  // We create a ShareableFileReference that's deletable for the temp
-  // file created as  a result of the download.
-  scoped_refptr<webkit_blob::ShareableFileReference> deletable_file_;
-
-  bool did_defer_ ;
+  bool did_defer_;
 
   bool completed_during_write_;
+  GURL will_start_url_;
   net::URLRequestStatus completed_status_;
   std::string completed_security_info_;
 
+  base::WeakPtrFactory<RedirectToFileResourceHandler> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(RedirectToFileResourceHandler);
 };