[glom] Fixed the parser to perform stateless async file operations

[Michael Hasselmann <mikhas src gnome org>]

commit f8f1988bd51bcb9882cfe7bc0bbaed7b733ec15b
Author: Michael Hasselmann <michaelh openismus com>
Date:   Wed Jan 27 18:04:59 2010 +0100

    Fixed the parser to perform stateless async file operations
    
    * glom/import_csv/csv_parser.[h|cc]: The parser relied on a member variable for
    its async giomm operations, which was able to cause interleaving state
    changes to it, corrupting the object in the worst case. This commit uses the
    source object as a slot parameter to avoid this state problem (working around
    BGO bug #608269).

 glom/import_csv/csv_parser.cc |   28 +++++++++++++---------------
 glom/import_csv/csv_parser.h  |    6 ++----
 2 files changed, 15 insertions(+), 19 deletions(-)
---
diff --git a/glom/import_csv/csv_parser.cc b/glom/import_csv/csv_parser.cc
index 3e48785..f4af1c7 100644
--- a/glom/import_csv/csv_parser.cc
+++ b/glom/import_csv/csv_parser.cc
@@ -69,14 +69,15 @@ void CsvParser::set_file_and_start_parsing(const std::string& file_uri)
   // TODO: Check URI validity?
   g_return_if_fail(!file_uri.empty());
 
-  m_file = Gio::File::create_for_uri(file_uri);
-  g_return_if_fail(m_file->query_exists());
+  Glib::RefPtr<Gio::File> file = Gio::File::create_for_uri(file_uri);
 
-  m_file->read_async(sigc::mem_fun(*this, &CsvParser::on_file_read));
   set_state(CsvParser::STATE_PARSING);
 
   // Query the display name of the file to set in the title:
-  m_file->query_info_async(sigc::mem_fun(*this, &CsvParser::on_file_query_info), G_FILE_ATTRIBUTE_STANDARD_DISPLAY_NAME);
+  file->query_info_async(sigc::bind(sigc::mem_fun(*this, &CsvParser::on_file_query_info), file),
+                         G_FILE_ATTRIBUTE_STANDARD_DISPLAY_NAME);
+
+  file->read_async(sigc::bind(sigc::mem_fun(*this, &CsvParser::on_file_read), file));
 }
 
 
@@ -259,7 +260,6 @@ Glib::ustring::const_iterator CsvParser::advance_field(const Glib::ustring::cons
 
 void CsvParser::clear()
 {
-  m_file.reset();
   m_buffer.reset(0);
 
   //m_stream.reset();
@@ -491,7 +491,7 @@ void CsvParser::do_line_scanned(const Glib::ustring& line, guint line_number)
   signal_line_scanned().emit(row, line_number);
 }
 
-void CsvParser::on_file_read(const Glib::RefPtr<Gio::AsyncResult>& result)
+void CsvParser::on_file_read(const Glib::RefPtr<Gio::AsyncResult>& result, const Glib::RefPtr<Gio::File>& source)
 {
   // TODO: Introduce CsvParser::is_idle_handler_connected() instead?
   if(!m_idle_connection.connected())
@@ -503,7 +503,7 @@ void CsvParser::on_file_read(const Glib::RefPtr<Gio::AsyncResult>& result)
 #ifdef GLIBMM_EXCEPTIONS_ENABLED
   try
   {
-    m_stream = m_file->read_finish(result);
+    m_stream = source->read_finish(result);
 
     m_buffer.reset(new Buffer);
     m_stream->read_async(m_buffer->buf, sizeof(m_buffer->buf), sigc::mem_fun(*this, &CsvParser::on_buffer_read));
@@ -515,7 +515,7 @@ void CsvParser::on_file_read(const Glib::RefPtr<Gio::AsyncResult>& result)
   }
 #else
   std::auto_ptr<Glib::Error> error;
-  m_stream = m_file->read_finish(result, error);
+  m_stream = source->read_finish(result, error);
   if (!error.get())
   {
     m_buffer.reset(new Buffer);
@@ -543,7 +543,6 @@ void CsvParser::copy_buffer_and_continue_reading(gssize size)
     //TODO: put in proper data reset method?
     m_buffer.reset(0);
     m_stream.reset();
-    m_file.reset();
   }
 }
 
@@ -575,30 +574,29 @@ void CsvParser::on_buffer_read(const Glib::RefPtr<Gio::AsyncResult>& result)
 #endif
 }
 
-void CsvParser::on_file_query_info(const Glib::RefPtr<Gio::AsyncResult>& result)
+void CsvParser::on_file_query_info(const Glib::RefPtr<Gio::AsyncResult>& result, const Glib::RefPtr<Gio::File>& source)
 {
 #ifdef GLIBMM_EXCEPTIONS_ENABLED
   try
   {
-    // Why is m_file null? Did we clear the parser before reading the file info?
-    Glib::RefPtr<Gio::FileInfo> info = m_file->query_info_finish(result);
+    Glib::RefPtr<Gio::FileInfo> info = source->query_info_finish(result);
     if(info)
       signal_have_display_name().emit(info->get_display_name());
   }
   catch(const Glib::Exception& ex)
   {
-    std::cerr << "Failed to fetch display name of uri " << m_file->get_uri() << ": " << ex.what() << std::endl;
+    std::cerr << "Failed to fetch display name of uri " << source->get_uri() << ": " << ex.what() << std::endl;
   }
 #else
   std::auto_ptr<Glib::Error> error;
-  Glib::RefPtr<Gio::FileInfo> info = m_file->query_info_finish(result, error);
+  Glib::RefPtr<Gio::FileInfo> info = source->query_info_finish(result, error);
   if (!error.get())
   {
     if(info)
       signal_have_display_name().emit(info->get_display_name());
   }
   else
-    std::cerr << "Failed to fetch display name of uri " << m_file->get_uri() << ": " << error->what() << std::endl;
+    std::cerr << "Failed to fetch display name of uri " << source->get_uri() << ": " << error->what() << std::endl;
 #endif
 }
 
diff --git a/glom/import_csv/csv_parser.h b/glom/import_csv/csv_parser.h
index c90e9d0..d99c4cb 100644
--- a/glom/import_csv/csv_parser.h
+++ b/glom/import_csv/csv_parser.h
@@ -164,10 +164,10 @@ private:
   //TODO: Document this:
   static Glib::ustring::const_iterator advance_field(const Glib::ustring::const_iterator& iter, const Glib::ustring::const_iterator& end, Glib::ustring& field);
 
-  void on_file_read(const Glib::RefPtr<Gio::AsyncResult>& result);
+  void on_file_read(const Glib::RefPtr<Gio::AsyncResult>& result, const Glib::RefPtr<Gio::File>& source);
   void copy_buffer_and_continue_reading(gssize size);
   void on_buffer_read(const Glib::RefPtr<Gio::AsyncResult>& result);
-  void on_file_query_info(const Glib::RefPtr<Gio::AsyncResult>& result);
+  void on_file_query_info(const Glib::RefPtr<Gio::AsyncResult>& result, const Glib::RefPtr<Gio::File>& source);
 
   void set_state(State state);
 
@@ -200,8 +200,6 @@ private:
   type_signal_finished_parsing m_finished_parsing;
   type_signal_state_changed m_signal_state_changed;
 
-  Glib::RefPtr<Gio::File> m_file;
-
   struct Buffer
   {
     char buf[1024];