Experimental support for syncing Google Documents (issue #46)

FIXME:
- Files are "remote changed" and re-downloaded after being uploaded, which is
  indeed correct because they really differ after re-downloading, but should be fixed
- Extension is added to filename after uploading

README.md

@@ -76,6 +76,7 @@ Enjoy!
 - ignore regexp does not persist anymore (note that Grive will still track it to not
   accidentally delete remote files when changing ignore regexp)
 - added options to limit upload and download speed
+- added ability to sync google documents
 
 ### Grive2 v0.5
 

libgrive/src/base/Resource.cc

@@ -169,7 +169,9 @@ void Resource::FromRemoteFile( const Entry& remote )
 	{
 		Trace( "file %1% change stamp = %2%", Path(), remote.ChangeStamp() ) ;
 		
-		if ( remote.MTime().Sec() > m_mtime.Sec() || remote.MD5() != m_md5 || remote.ChangeStamp() > 0 )
+		if ( remote.MTime().Sec() > m_mtime.Sec() ||
+			( !remote.MD5().empty() && remote.MD5() != m_md5 ) ||
+			remote.ChangeStamp() > 0 )
 		{
 			Log( "file %1% is created in remote (change %2%)", path,
 				remote.ChangeStamp(), log::verbose ) ;
@@ -182,17 +184,17 @@ void Resource::FromRemoteFile( const Entry& remote )
 			m_state = local_deleted ;
 		}
 	}
-	
-	// remote checksum unknown, assume the file is not changed in remote
-	else if ( remote.MD5().empty() )
+
+	// remote download URL unknown, skip file
+	else if ( remote.ContentSrc().empty() )
 	{
-		Log( "file %1% has unknown checksum in remote. assumed in sync",
+		Log( "file %1% has unknown download URL. assumed in sync",
 			Path(), log::verbose ) ;
 		m_state = sync ;
 	}
-	
+
 	// if checksum is equal, no need to compare the mtime
-	else if ( remote.MD5() == m_md5 )
+	else if ( !remote.MD5().empty() && remote.MD5() == m_md5 )
 	{
 		Log( "file %1% is already in sync", Path(), log::verbose ) ;
 		m_state = sync ;
@@ -209,13 +211,21 @@ void Resource::FromRemoteFile( const Entry& remote )
 			Log( "file %1% is changed in remote", path, log::verbose ) ;
 			m_state = remote_changed ;
 		}
-		
+
+		// google document
+		else if ( remote.MD5().empty() && m_state == remote_deleted )
+		{
+			Log( "file %1% has no MD5 and is in sync", path, log::verbose ) ;
+			m_state = sync ;
+		}
+
 		// remote also has the file, so it's not new in local
 		else if ( m_state == local_new || m_state == remote_deleted )
 		{
 			Log( "file %1% is changed in local", path, log::verbose ) ;
 			m_state = local_changed ;
 		}
+
 		else
 			Trace( "file %1% state is %2%", m_name, m_state ) ;
 	}

libgrive/src/base/State.cc

@@ -151,7 +151,7 @@ void State::FromRemote( const Entry& e )
 
 	// common checkings
 	if ( !e.IsDir() && ( fn.empty() || e.ContentSrc().empty() ) )
-		Log( "%1% \"%2%\" is a google document, ignored", k, e.Name(), log::verbose ) ;
+		Log( "%1% \"%2%\" has no download link or filename, ignored", k, e.Name(), log::verbose ) ;
 	
 	else if ( fn.find('/') != fn.npos )
 		Log( "%1% \"%2%\" contains a slash in its name, ignored", k, e.Name(), log::verbose ) ;

libgrive/src/drive2/Entry2.cc

@@ -66,10 +66,33 @@ void Entry2::Update( const Val& item )
 		m_is_removed	= file["labels"]["trashed"].Bool() ;
 		if ( !m_is_dir )
 		{
-			if ( !file.Has( "md5Checksum" ) || !file.Has("downloadUrl") )
+			if ( !file.Has( "md5Checksum" ) && file.Has( "exportLinks" ) )
 			{
-				// This is either a google docs document or a not-yet-uploaded file. Ignore it.
-				// FIXME: We'll need to compare timestamps to support google docs.
+				// This is a google docs document.
+				const Val::Object& obj = file["exportLinks"].AsObject() ;
+				const char ooxml[] = "application/vnd.openxmlformats-officedocument";
+				for ( Val::Object::const_iterator i = obj.begin() ; i != obj.end() ; ++i )
+					if ( i->first.substr( 0, sizeof( ooxml ) - 1 ) == ooxml )
+						m_content_src = i->second.Str();
+				if ( m_content_src.empty() )
+					m_content_src = obj.begin()->second.Str();
+				if ( !m_content_src.empty() )
+				{
+					size_t pos = m_content_src.find( "exportFormat=" );
+					if ( pos != std::string::npos )
+					{
+						size_t end = m_content_src.find( '&', pos+13 );
+						if ( end == std::string::npos )
+							end = m_content_src.length();
+						std::string fmt = m_content_src.substr( pos+13, end-pos-13 );
+						if ( m_filename.substr( m_filename.length() - fmt.length() - 1 ) != "."+fmt )
+							m_filename += "."+fmt;
+					}
+				}
+			}
+			else if ( !file.Has( "md5Checksum" ) || !file.Has("downloadUrl") )
+			{
+				// This is a not-yet-uploaded file. Ignore it.
 				m_is_removed = true;
 			}
 			else