flutter_flutter/shell/platform/common/cpp/text_input_model.h
Chris Bracken b715d3f21d
Migrate TextInputPlugin API to TextRange (#21854)
Replaces selection_base() and selection_extent() with selection() and
SetSelection(int, int) with SetSelection(range).

This also adds the following convenience methods to TextRange:
* reversed()
* Contains(size_t position)
* Contains(const TextRange& range)

as well as operator== for use in unit tests. When Flutter migrates to
C++20, we can replace that method with a default declaration.
2020-10-15 09:54:06 -07:00

128 lines
3.9 KiB
C++

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef FLUTTER_SHELL_PLATFORM_CPP_TEXT_INPUT_MODEL_H_
#define FLUTTER_SHELL_PLATFORM_CPP_TEXT_INPUT_MODEL_H_
#include <memory>
#include <string>
#include "flutter/shell/platform/common/cpp/text_range.h"
namespace flutter {
// Handles underlying text input state, using a simple ASCII model.
//
// Ignores special states like "insert mode" for now.
class TextInputModel {
public:
TextInputModel();
virtual ~TextInputModel();
// Sets the text.
//
// Resets the selection base and extent.
void SetText(const std::string& text);
// Attempts to set the text selection.
//
// Returns false if the selection is not within the bounds of the text.
bool SetSelection(const TextRange& range);
// Adds a Unicode code point.
//
// Either appends after the cursor (when selection base and extent are the
// same), or deletes the selected text, replacing it with the given
// code point.
void AddCodePoint(char32_t c);
// Adds UTF-16 text.
//
// Either appends after the cursor (when selection base and extent are the
// same), or deletes the selected text, replacing it with the given text.
void AddText(const std::u16string& text);
// Adds UTF-8 text.
//
// Either appends after the cursor (when selection base and extent are the
// same), or deletes the selected text, replacing it with the given text.
void AddText(const std::string& text);
// Deletes either the selection, or one character ahead of the cursor.
//
// Deleting one character ahead of the cursor occurs when the selection base
// and extent are the same.
//
// Returns true if any deletion actually occurred.
bool Delete();
// Deletes text near the cursor.
//
// A section is made starting at @offset code points past the cursor (negative
// values go before the cursor). @count code points are removed. The selection
// may go outside the bounds of the text and will result in only the part
// selection that covers the available text being deleted. The existing
// selection is ignored and removed after this operation.
//
// Returns true if any deletion actually occurred.
bool DeleteSurrounding(int offset_from_cursor, int count);
// Deletes either the selection, or one character behind the cursor.
//
// Deleting one character behind the cursor occurs when the selection base
// and extent are the same.
//
// Returns true if any deletion actually occurred.
bool Backspace();
// Attempts to move the cursor backward.
//
// Returns true if the cursor could be moved. If a selection is active, moves
// to the start of the selection.
bool MoveCursorBack();
// Attempts to move the cursor forward.
//
// Returns true if the cursor could be moved. If a selection is active, moves
// to the end of the selection.
bool MoveCursorForward();
// Attempts to move the cursor to the beginning.
//
// Returns true if the cursor could be moved.
bool MoveCursorToBeginning();
// Attempts to move the cursor to the back.
//
// Returns true if the cursor could be moved.
bool MoveCursorToEnd();
// Gets the current text as UTF-8.
std::string GetText() const;
// Gets the cursor position as a byte offset in UTF-8 string returned from
// GetText().
int GetCursorOffset() const;
// The current selection.
TextRange selection() const { return selection_; }
private:
// Deletes the current selection, if any.
//
// Returns true if any text is deleted. The selection base and extent are
// reset to the start of the selected range.
bool DeleteSelected();
// Returns a range covering the entire text.
TextRange text_range() const { return TextRange(0, text_.length()); }
std::u16string text_;
TextRange selection_ = TextRange(0);
};
} // namespace flutter
#endif // FLUTTER_SHELL_PLATFORM_CPP_TEXT_INPUT_MODEL_H_