| // 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. |
| // FLUTTER_NOLINT |
| |
| #include "flutter/shell/platform/common/cpp/text_input_model.h" |
| |
| #include <algorithm> |
| #include <codecvt> |
| #include <locale> |
| |
| #if defined(_MSC_VER) |
| // TODO(naifu): This temporary code is to solve link error.(VS2015/2017) |
| // https://social.msdn.microsoft.com/Forums/vstudio/en-US/8f40dcd8-c67f-4eba-9134-a19b9178e481/vs-2015-rc-linker-stdcodecvt-error |
| std::locale::id std::codecvt<char16_t, char, _Mbstatet>::id; |
| #endif // defined(_MSC_VER) |
| |
| namespace flutter { |
| |
| namespace { |
| |
| // Returns true if |code_point| is a leading surrogate of a surrogate pair. |
| bool IsLeadingSurrogate(char32_t code_point) { |
| return (code_point & 0xFFFFFC00) == 0xD800; |
| } |
| // Returns true if |code_point| is a trailing surrogate of a surrogate pair. |
| bool IsTrailingSurrogate(char32_t code_point) { |
| return (code_point & 0xFFFFFC00) == 0xDC00; |
| } |
| |
| } // namespace |
| |
| TextInputModel::TextInputModel() |
| : selection_base_(text_.begin()), selection_extent_(text_.begin()) {} |
| |
| TextInputModel::~TextInputModel() = default; |
| |
| bool TextInputModel::SetEditingState(size_t selection_base, |
| size_t selection_extent, |
| const std::string& text) { |
| if (selection_base > text.size() || selection_extent > text.size()) { |
| return false; |
| } |
| std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> |
| utf16_converter; |
| text_ = utf16_converter.from_bytes(text); |
| selection_base_ = text_.begin() + selection_base; |
| selection_extent_ = text_.begin() + selection_extent; |
| return true; |
| } |
| |
| void TextInputModel::DeleteSelected() { |
| selection_base_ = text_.erase(selection_start(), selection_end()); |
| selection_extent_ = selection_base_; |
| } |
| |
| void TextInputModel::AddCodePoint(char32_t c) { |
| if (c <= 0xFFFF) { |
| AddText(std::u16string({static_cast<char16_t>(c)})); |
| } else { |
| char32_t to_decompose = c - 0x10000; |
| AddText(std::u16string({ |
| // High surrogate. |
| static_cast<char16_t>((to_decompose >> 10) + 0xd800), |
| // Low surrogate. |
| static_cast<char16_t>((to_decompose % 0x400) + 0xdc00), |
| })); |
| } |
| } |
| |
| void TextInputModel::AddText(const std::u16string& text) { |
| if (selection_base_ != selection_extent_) { |
| DeleteSelected(); |
| } |
| selection_extent_ = text_.insert(selection_extent_, text.begin(), text.end()); |
| selection_extent_ += text.length(); |
| selection_base_ = selection_extent_; |
| } |
| |
| void TextInputModel::AddText(const std::string& text) { |
| std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> |
| utf16_converter; |
| AddText(utf16_converter.from_bytes(text)); |
| } |
| |
| bool TextInputModel::Backspace() { |
| if (selection_base_ != selection_extent_) { |
| DeleteSelected(); |
| return true; |
| } |
| if (selection_base_ != text_.begin()) { |
| int count = IsTrailingSurrogate(*(selection_base_ - 1)) ? 2 : 1; |
| selection_base_ = text_.erase(selection_base_ - count, selection_base_); |
| selection_extent_ = selection_base_; |
| return true; |
| } |
| return false; // No edits happened. |
| } |
| |
| bool TextInputModel::Delete() { |
| if (selection_base_ != selection_extent_) { |
| DeleteSelected(); |
| return true; |
| } |
| if (selection_base_ != text_.end()) { |
| int count = IsLeadingSurrogate(*selection_base_) ? 2 : 1; |
| selection_base_ = text_.erase(selection_base_, selection_base_ + count); |
| selection_extent_ = selection_base_; |
| return true; |
| } |
| return false; |
| } |
| |
| bool TextInputModel::DeleteSurrounding(int offset_from_cursor, int count) { |
| auto start = selection_extent_; |
| if (offset_from_cursor < 0) { |
| for (int i = 0; i < -offset_from_cursor; i++) { |
| // If requested start is before the available text then reduce the |
| // number of characters to delete. |
| if (start == text_.begin()) { |
| count = i; |
| break; |
| } |
| start -= IsTrailingSurrogate(*(start - 1)) ? 2 : 1; |
| } |
| } else { |
| for (int i = 0; i < offset_from_cursor && start != text_.end(); i++) { |
| start += IsLeadingSurrogate(*start) ? 2 : 1; |
| } |
| } |
| |
| auto end = start; |
| for (int i = 0; i < count && end != text_.end(); i++) { |
| end += IsLeadingSurrogate(*start) ? 2 : 1; |
| } |
| |
| if (start == end) { |
| return false; |
| } |
| |
| auto new_base = text_.erase(start, end); |
| |
| // Cursor moves only if deleted area is before it. |
| if (offset_from_cursor <= 0) { |
| selection_base_ = new_base; |
| } |
| |
| // Clear selection. |
| selection_extent_ = selection_base_; |
| |
| return true; |
| } |
| |
| bool TextInputModel::MoveCursorToBeginning() { |
| if (selection_base_ == text_.begin() && selection_extent_ == text_.begin()) |
| return false; |
| |
| selection_base_ = text_.begin(); |
| selection_extent_ = text_.begin(); |
| |
| return true; |
| } |
| |
| bool TextInputModel::MoveCursorToEnd() { |
| if (selection_base_ == text_.end() && selection_extent_ == text_.end()) |
| return false; |
| |
| selection_base_ = text_.end(); |
| selection_extent_ = text_.end(); |
| |
| return true; |
| } |
| |
| bool TextInputModel::MoveCursorForward() { |
| // If about to move set to the end of the highlight (when not selecting). |
| if (selection_base_ != selection_extent_) { |
| selection_base_ = selection_end(); |
| selection_extent_ = selection_base_; |
| return true; |
| } |
| // If not at the end, move the extent forward. |
| if (selection_extent_ != text_.end()) { |
| int count = IsLeadingSurrogate(*selection_base_) ? 2 : 1; |
| selection_base_ += count; |
| selection_extent_ = selection_base_; |
| return true; |
| } |
| return false; |
| } |
| |
| bool TextInputModel::MoveCursorBack() { |
| // If about to move set to the beginning of the highlight |
| // (when not selecting). |
| if (selection_base_ != selection_extent_) { |
| selection_base_ = selection_start(); |
| selection_extent_ = selection_base_; |
| return true; |
| } |
| // If not at the start, move the beginning backward. |
| if (selection_base_ != text_.begin()) { |
| int count = IsTrailingSurrogate(*(selection_base_ - 1)) ? 2 : 1; |
| selection_base_ -= count; |
| selection_extent_ = selection_base_; |
| return true; |
| } |
| return false; |
| } |
| |
| std::string TextInputModel::GetText() const { |
| std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> |
| utf8_converter; |
| return utf8_converter.to_bytes(text_); |
| } |
| |
| int TextInputModel::GetCursorOffset() const { |
| // Measure the length of the current text up to the cursor. |
| // There is probably a much more efficient way of doing this. |
| auto leading_text = text_.substr(0, selection_extent_ - text_.begin()); |
| std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> |
| utf8_converter; |
| return utf8_converter.to_bytes(leading_text).size(); |
| } |
| |
| } // namespace flutter |