| // 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. |
| |
| #include "flutter/shell/platform/common/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() = default; |
| |
| TextInputModel::~TextInputModel() = default; |
| |
| void TextInputModel::SetText(const std::string& text) { |
| std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> |
| utf16_converter; |
| text_ = utf16_converter.from_bytes(text); |
| selection_ = TextRange(0); |
| composing_range_ = TextRange(0); |
| } |
| |
| bool TextInputModel::SetSelection(const TextRange& range) { |
| if (composing_ && !range.collapsed()) { |
| return false; |
| } |
| if (!editable_range().Contains(range)) { |
| return false; |
| } |
| selection_ = range; |
| return true; |
| } |
| |
| bool TextInputModel::SetComposingRange(const TextRange& range, |
| size_t cursor_offset) { |
| if (!composing_ || !text_range().Contains(range)) { |
| return false; |
| } |
| composing_range_ = range; |
| selection_ = TextRange(range.start() + cursor_offset); |
| return true; |
| } |
| |
| void TextInputModel::BeginComposing() { |
| composing_ = true; |
| composing_range_ = TextRange(selection_.start()); |
| } |
| |
| void TextInputModel::UpdateComposingText(const std::u16string& text) { |
| // Preserve selection if we get a no-op update to the composing region. |
| if (text.length() == 0 && composing_range_.collapsed()) { |
| return; |
| } |
| DeleteSelected(); |
| text_.replace(composing_range_.start(), composing_range_.length(), text); |
| composing_range_.set_end(composing_range_.start() + text.length()); |
| selection_ = TextRange(composing_range_.end()); |
| } |
| |
| void TextInputModel::UpdateComposingText(const std::string& text) { |
| std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> |
| utf16_converter; |
| UpdateComposingText(utf16_converter.from_bytes(text)); |
| } |
| |
| void TextInputModel::CommitComposing() { |
| // Preserve selection if no composing text was entered. |
| if (composing_range_.collapsed()) { |
| return; |
| } |
| composing_range_ = TextRange(composing_range_.end()); |
| selection_ = composing_range_; |
| } |
| |
| void TextInputModel::EndComposing() { |
| composing_ = false; |
| composing_range_ = TextRange(0); |
| } |
| |
| bool TextInputModel::DeleteSelected() { |
| if (selection_.collapsed()) { |
| return false; |
| } |
| size_t start = selection_.start(); |
| text_.erase(start, selection_.length()); |
| selection_ = TextRange(start); |
| if (composing_) { |
| // This occurs only immediately after composing has begun with a selection. |
| composing_range_ = selection_; |
| } |
| return true; |
| } |
| |
| 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) { |
| DeleteSelected(); |
| if (composing_) { |
| // Delete the current composing text, set the cursor to composing start. |
| text_.erase(composing_range_.start(), composing_range_.length()); |
| selection_ = TextRange(composing_range_.start()); |
| composing_range_.set_end(composing_range_.start() + text.length()); |
| } |
| size_t position = selection_.position(); |
| text_.insert(position, text); |
| selection_ = TextRange(position + text.length()); |
| } |
| |
| 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 (DeleteSelected()) { |
| return true; |
| } |
| // There is no selection. Delete the preceding codepoint. |
| size_t position = selection_.position(); |
| if (position != editable_range().start()) { |
| int count = IsTrailingSurrogate(text_.at(position - 1)) ? 2 : 1; |
| text_.erase(position - count, count); |
| selection_ = TextRange(position - count); |
| if (composing_) { |
| composing_range_.set_end(composing_range_.end() - count); |
| } |
| return true; |
| } |
| return false; |
| } |
| |
| bool TextInputModel::Delete() { |
| if (DeleteSelected()) { |
| return true; |
| } |
| // There is no selection. Delete the preceding codepoint. |
| size_t position = selection_.position(); |
| if (position < editable_range().end()) { |
| int count = IsLeadingSurrogate(text_.at(position)) ? 2 : 1; |
| text_.erase(position, count); |
| if (composing_) { |
| composing_range_.set_end(composing_range_.end() - count); |
| } |
| return true; |
| } |
| return false; |
| } |
| |
| bool TextInputModel::DeleteSurrounding(int offset_from_cursor, int count) { |
| size_t max_pos = editable_range().end(); |
| size_t 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 == editable_range().start()) { |
| count = i; |
| break; |
| } |
| start -= IsTrailingSurrogate(text_.at(start - 1)) ? 2 : 1; |
| } |
| } else { |
| for (int i = 0; i < offset_from_cursor && start != max_pos; i++) { |
| start += IsLeadingSurrogate(text_.at(start)) ? 2 : 1; |
| } |
| } |
| |
| auto end = start; |
| for (int i = 0; i < count && end != max_pos; i++) { |
| end += IsLeadingSurrogate(text_.at(start)) ? 2 : 1; |
| } |
| |
| if (start == end) { |
| return false; |
| } |
| |
| auto deleted_length = end - start; |
| text_.erase(start, deleted_length); |
| |
| // Cursor moves only if deleted area is before it. |
| selection_ = TextRange(offset_from_cursor <= 0 ? start : selection_.start()); |
| |
| // Adjust composing range. |
| if (composing_) { |
| composing_range_.set_end(composing_range_.end() - deleted_length); |
| } |
| return true; |
| } |
| |
| bool TextInputModel::MoveCursorToBeginning() { |
| size_t min_pos = editable_range().start(); |
| if (selection_.collapsed() && selection_.position() == min_pos) { |
| return false; |
| } |
| selection_ = TextRange(min_pos); |
| return true; |
| } |
| |
| bool TextInputModel::MoveCursorToEnd() { |
| size_t max_pos = editable_range().end(); |
| if (selection_.collapsed() && selection_.position() == max_pos) { |
| return false; |
| } |
| selection_ = TextRange(max_pos); |
| return true; |
| } |
| |
| bool TextInputModel::SelectToBeginning() { |
| size_t min_pos = editable_range().start(); |
| if (selection_.collapsed() && selection_.position() == min_pos) { |
| return false; |
| } |
| selection_ = TextRange(selection_.base(), min_pos); |
| return true; |
| } |
| |
| bool TextInputModel::SelectToEnd() { |
| size_t max_pos = editable_range().end(); |
| if (selection_.collapsed() && selection_.position() == max_pos) { |
| return false; |
| } |
| selection_ = TextRange(selection_.base(), max_pos); |
| return true; |
| } |
| |
| bool TextInputModel::MoveCursorForward() { |
| // If there's a selection, move to the end of the selection. |
| if (!selection_.collapsed()) { |
| selection_ = TextRange(selection_.end()); |
| return true; |
| } |
| // Otherwise, move the cursor forward. |
| size_t position = selection_.position(); |
| if (position != editable_range().end()) { |
| int count = IsLeadingSurrogate(text_.at(position)) ? 2 : 1; |
| selection_ = TextRange(position + count); |
| return true; |
| } |
| return false; |
| } |
| |
| bool TextInputModel::MoveCursorBack() { |
| // If there's a selection, move to the beginning of the selection. |
| if (!selection_.collapsed()) { |
| selection_ = TextRange(selection_.start()); |
| return true; |
| } |
| // Otherwise, move the cursor backward. |
| size_t position = selection_.position(); |
| if (position != editable_range().start()) { |
| int count = IsTrailingSurrogate(text_.at(position - 1)) ? 2 : 1; |
| selection_ = TextRange(position - count); |
| 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 selection extent. |
| // There is probably a much more efficient way of doing this. |
| auto leading_text = text_.substr(0, selection_.extent()); |
| std::wstring_convert<std::codecvt_utf8_utf16<char16_t>, char16_t> |
| utf8_converter; |
| return utf8_converter.to_bytes(leading_text).size(); |
| } |
| |
| } // namespace flutter |