Rebuild CFDE_TextEditEngine.

This CL rebuilds the text edit engine in a simpler fashion. Instead of
depending on multiple pages, paragraphs and buffer fields there is a
single text edit engine which contains a gap buffer.

This makes the code easier to understand and follow.

Change-Id: I10fe85603fa9ed15a647eaac2d931f113cd0c7b0
Reviewed-on: https://pdfium-review.googlesource.com/11990
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Reviewed-by: Ryan Harrison <rharrison@chromium.org>

1 files changed, 241 insertions, 0 deletions

diff --git a/xfa/fde/cfde_texteditengine.h b/xfa/fde/cfde_texteditengine.h
new file mode 100644
index 0000000000..35d9664f99
--- /dev/null
+++ b/xfa/fde/cfde_texteditengine.h
@@ -0,0 +1,241 @@
+// Copyright 2017 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#ifndef XFA_FDE_CFDE_TEXTEDITENGINE_H_
+#define XFA_FDE_CFDE_TEXTEDITENGINE_H_
+
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "core/fxcrt/cfx_retain_ptr.h"
+#include "core/fxcrt/fx_string.h"
+#include "core/fxcrt/ifx_chariter.h"
+#include "core/fxge/cfx_renderdevice.h"
+#include "core/fxge/fx_dib.h"
+#include "xfa/fgas/font/cfgas_gefont.h"
+#include "xfa/fgas/layout/cfx_txtbreak.h"
+
+struct FDE_TEXTEDITPIECE {
+  FDE_TEXTEDITPIECE();
+  FDE_TEXTEDITPIECE(const FDE_TEXTEDITPIECE& that);
+  ~FDE_TEXTEDITPIECE();
+
+  int32_t nStart;
+  int32_t nCount;
+  int32_t nBidiLevel;
+  CFX_RectF rtPiece;
+  uint32_t dwCharStyles;
+};
+
+inline FDE_TEXTEDITPIECE::FDE_TEXTEDITPIECE() = default;
+inline FDE_TEXTEDITPIECE::FDE_TEXTEDITPIECE(const FDE_TEXTEDITPIECE& that) =
+    default;
+inline FDE_TEXTEDITPIECE::~FDE_TEXTEDITPIECE() = default;
+
+class CFDE_TextEditEngine {
+ public:
+  class Iterator : public IFX_CharIter {
+   public:
+    explicit Iterator(CFDE_TextEditEngine* engine);
+    ~Iterator() override;
+
+    bool Next(bool bPrev = false) override;
+    wchar_t GetChar() const override;
+    void SetAt(int32_t nIndex) override;
+    int32_t GetAt() const override;
+    bool IsEOF(bool bTail = true) const override;
+    std::unique_ptr<IFX_CharIter> Clone() const override;
+
+   private:
+    CFX_UnownedPtr<CFDE_TextEditEngine> engine_;
+    int32_t current_position_;
+  };
+
+  class Operation {
+   public:
+    virtual ~Operation() = default;
+    virtual void Redo() const = 0;
+    virtual void Undo() const = 0;
+  };
+
+  class Delegate {
+   public:
+    virtual void NotifyTextFull() = 0;
+
+    virtual void OnCaretChanged() = 0;
+    virtual void OnTextChanged(const CFX_WideString& prevText) = 0;
+    virtual void OnSelChanged() = 0;
+    virtual bool OnValidate(const CFX_WideString& wsText) = 0;
+    virtual void SetScrollOffset(float fScrollOffset) = 0;
+  };
+
+  enum class RecordOperation {
+    kInsertRecord,
+    kSkipRecord,
+  };
+
+  CFDE_TextEditEngine();
+  ~CFDE_TextEditEngine();
+
+  void SetDelegate(Delegate* delegate) { delegate_ = delegate; }
+  void Clear();
+
+  void Insert(size_t idx,
+              const CFX_WideString& text,
+              RecordOperation add_operation = RecordOperation::kInsertRecord);
+  CFX_WideString Delete(
+      size_t start_idx,
+      size_t length,
+      RecordOperation add_operation = RecordOperation::kInsertRecord);
+  CFX_WideString GetText() const;
+  size_t GetLength() const;
+
+  // Non-const so we can force a layout.
+  CFX_RectF GetContentsBoundingBox();
+  void SetAvailableWidth(size_t width);
+
+  void SetFont(CFX_RetainPtr<CFGAS_GEFont> font);
+  CFX_RetainPtr<CFGAS_GEFont> GetFont() const { return font_; }
+  void SetFontSize(float size);
+  float GetFontSize() const { return font_size_; }
+  void SetFontColor(FX_ARGB color) { font_color_ = color; }
+  FX_ARGB GetFontColor() const { return font_color_; }
+  float GetFontAscent() const {
+    return (static_cast<float>(font_->GetAscent()) * font_size_) / 1000;
+  }
+
+  void SetAlignment(uint32_t alignment);
+  float GetLineSpace() const { return line_spacing_; }
+  void SetLineSpace(float space) { line_spacing_ = space; }
+  void SetAliasChar(wchar_t alias) { password_alias_ = alias; }
+  void SetHasCharacterLimit(bool limit);
+  void SetCharacterLimit(size_t limit);
+  void SetCombText(bool enable);
+  void SetTabWidth(float width);
+  void SetVisibleLineCount(size_t lines);
+
+  void EnableValidation(bool val) { validation_enabled_ = val; }
+  void EnablePasswordMode(bool val) { password_mode_ = val; }
+  void EnableMultiLine(bool val);
+  void EnableLineWrap(bool val);
+  void LimitHorizontalScroll(bool val);
+  void LimitVerticalScroll(bool val);
+
+  bool CanUndo() const;
+  bool CanRedo() const;
+  bool Redo();
+  bool Undo();
+  void ClearOperationRecords();
+
+  // TODO(dsinclair): Implement ....
+  size_t GetIndexBefore(size_t pos) { return 0; }
+  size_t GetIndexLeft(size_t pos) { return 0; }
+  size_t GetIndexRight(size_t pos) { return 0; }
+  size_t GetIndexUp(size_t pos) { return 0; }
+  size_t GetIndexDown(size_t pos) { return 0; }
+  size_t GetIndexAtStartOfLine(size_t pos) { return 0; }
+  size_t GetIndexAtEndOfLine(size_t pos) { return 0; }
+
+  void SelectAll();
+  void SetSelection(size_t start_idx, size_t end_idx);
+  void ClearSelection();
+  bool HasSelection() const { return has_selection_; }
+  // Returns <start, end> indices of the selection.
+  std::pair<size_t, size_t> GetSelection() const {
+    return {selection_.start_idx, selection_.end_idx};
+  }
+  CFX_WideString GetSelectedText() const;
+  CFX_WideString DeleteSelectedText(
+      RecordOperation add_operation = RecordOperation::kInsertRecord);
+  void ReplaceSelectedText(const CFX_WideString& str);
+
+  void Layout();
+
+  wchar_t GetChar(size_t idx) const;
+  // Non-const so we can force a Layout() if needed.
+  size_t GetWidthOfChar(size_t idx);
+  // Non-const so we can force a Layout() if needed.
+  size_t GetIndexForPoint(const CFX_PointF& point);
+
+  // Returns <bidi level, character rect>
+  std::pair<int32_t, CFX_RectF> GetCharacterInfo(int32_t start_idx);
+  std::vector<CFX_RectF> GetCharacterRectsInRange(int32_t start_idx,
+                                                  int32_t count);
+
+  CFX_TxtBreak* GetTextBreak() { return &text_break_; }
+
+  const std::vector<FDE_TEXTEDITPIECE>& GetTextPieces() {
+    // Force a layout if needed.
+    Layout();
+    return text_piece_info_;
+  }
+
+  std::vector<FXTEXT_CHARPOS> GetDisplayPos(const FDE_TEXTEDITPIECE& info);
+
+  void SetMaxEditOperationsForTesting(size_t max);
+
+ private:
+  void SetCombTextWidth();
+  void AdjustGap(size_t idx, size_t length);
+  void RebuildPieces();
+  size_t CountCharsExceedingSize(const CFX_WideString& str,
+                                 size_t num_to_check);
+  void AddOperationRecord(std::unique_ptr<Operation> op);
+
+  bool IsAlignedRight() const {
+    return !!(character_alignment_ & CFX_TxtLineAlignment_Left);
+  }
+
+  bool IsAlignedCenter() const {
+    return !!(character_alignment_ & CFX_TxtLineAlignment_Center);
+  }
+  std::vector<CFX_RectF> GetCharRects(const FDE_TEXTEDITPIECE& piece);
+
+  struct Selection {
+    size_t start_idx;
+    size_t end_idx;
+  };
+
+  CFX_RectF contents_bounding_box_;
+  CFX_UnownedPtr<Delegate> delegate_;
+  std::vector<FDE_TEXTEDITPIECE> text_piece_info_;
+  std::vector<size_t> char_widths_;
+  CFX_TxtBreak text_break_;
+  CFX_RetainPtr<CFGAS_GEFont> font_;
+  FX_ARGB font_color_;
+  float font_size_;
+  float line_spacing_;
+  std::vector<CFX_WideString::CharType> content_;
+  size_t text_length_;
+  size_t gap_position_;
+  size_t gap_size_;
+  size_t available_width_;
+  size_t character_limit_;
+  size_t visible_line_count_;
+  // Ring buffer of edit operations
+  std::vector<std::unique_ptr<Operation>> operation_buffer_;
+  // Next edit operation to undo.
+  size_t next_operation_index_to_undo_;
+  // Next index to insert an edit operation into.
+  size_t next_operation_index_to_insert_;
+  size_t max_edit_operations_;
+  uint32_t character_alignment_;
+  bool has_character_limit_;
+  bool is_comb_text_;
+  bool is_dirty_;
+  bool validation_enabled_;
+  bool is_multiline_;
+  bool is_linewrap_enabled_;
+  bool limit_horizontal_area_;
+  bool limit_vertical_area_;
+  bool password_mode_;
+  wchar_t password_alias_;
+  bool has_selection_;
+  Selection selection_;
+};
+
+#endif  // XFA_FDE_CFDE_TEXTEDITENGINE_H_