New code assist API

This is a re-work of our completion engine. Primary goals are:

- Allow the computation to run in a separate thread so the GUI is not locked.
- Support a model-based approach. QStrings are still needed (filtering, etc), but
internal structures are free to use more efficient representations.
- Unifiy all kinds of *assist* into a more reusable and extensible framework.
- Remove unnecessary dependencies on the text editor so we have more generic
and easily "plugable" components (still things to be resolved).

src/plugins/texteditor/codeassist/iassistproposal.cpp

@@ -0,0 +1,102 @@
+/**************************************************************************
+**
+** This file is part of Qt Creator
+**
+** Copyright (c) 2011 Nokia Corporation and/or its subsidiary(-ies).
+**
+** Contact: Nokia Corporation (info@qt.nokia.com)
+**
+**
+** GNU Lesser General Public License Usage
+**
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this file.
+** Please review the following information to ensure the GNU Lesser General
+** Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** Other Usage
+**
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at info@qt.nokia.com.
+**
+**************************************************************************/
+
+#include "iassistproposal.h"
+
+using namespace TextEditor;
+
+/*!
+    \class IAssistProposal
+    \brief The IAssistProposal is an interface for representing an assist proposal.
+
+    Known implenters of this interface are FunctionHintProposal and GenericProposal. The
+    former is recommended to be used when assisting function call constructs (overloads
+    and parameters) while the latter is quite generic so that it could be used to propose
+    snippets, refactoring operations (quickfixes), and contextual content (the member of
+    class or a string existent in the document, for example).
+
+    \sa IAssistProposalWidget, IAssistModel
+*/
+
+IAssistProposal::IAssistProposal()
+{}
+
+IAssistProposal::~IAssistProposal()
+{}
+
+/*!
+    \fn bool isFragile() const
+
+    Returns whether this is a fragile proposal. When a proposal is fragile it means that
+    it will be replaced by a new proposal in the case one is created, even if due to an
+    idle editor.
+*/
+
+/*!
+    \fn int basePosition() const
+
+    Returns the position from which this proposal starts.
+*/
+
+/*!
+    \fn bool isCorrective() const
+
+    Returns whether this proposal is also corrective. This could happen in C++, for example,
+    when a dot operator (.) needs to be replaced by an arrow operator (->) before the proposal
+    is displayed.
+*/
+
+/*!
+    \fn void makeCorrection(BaseTextEditor *editor)
+
+    This allows a correction to be made in the case this is a corrective proposal.
+*/
+
+/*!
+    \fn IAssistModel *model() const
+
+    Returns the model associated with this proposal.
+
+    Although the IAssistModel from this proposal may be used on its own, it needs to be
+    consistent with the widget returned by createWidget().
+
+    \sa createWidget()
+*/
+
+/*!
+    \fn IAssistProposalWidget *createWidget() const
+
+    Returns the widget associated with this proposal. The IAssistProposalWidget implementor
+    recommended for function hint proposals is FunctionHintProposalWidget. For snippets,
+    refactoring operations (quickfixes), and contextual content the recommeded implementor
+    is GenericProposalWidget.
+*/