pdf/pdf_engine.h - chromium/src - Git at Google

 // Copyright 2012 The Chromium Authors
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #ifndef PDF_PDF_ENGINE_H_
 #define PDF_PDF_ENGINE_H_

 #include <stdint.h>

 #include <memory>
 #include <string>
 #include <vector>

 #include "base/containers/span.h"
 #include "base/functional/callback.h"
 #include "base/time/time.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "pdf/document_layout.h"
 #include "printing/mojom/print.mojom-forward.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/base/cursor/mojom/cursor_type.mojom-forward.h"
 #include "ui/base/window_open_disposition.h"
 #include "ui/gfx/geometry/point_f.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/rect_f.h"

 #if BUILDFLAG(IS_WIN)
 #include <windows.h>
 #endif

 class SkBitmap;

 namespace blink {
 class WebInputEvent;
 struct WebPrintParams;
 }  // namespace blink

 namespace gfx {
 class Point;
 class Rect;
 class Size;
 class SizeF;
 class Vector2d;
 }  // namespace gfx

 namespace chrome_pdf {

 class Thumbnail;
 class UrlLoader;
 struct AccessibilityActionData;
 struct AccessibilityFocusInfo;
 struct AccessibilityLinkInfo;
 struct AccessibilityHighlightInfo;
 struct AccessibilityImageInfo;
 struct AccessibilityTextFieldInfo;
 struct AccessibilityTextRunInfo;
 struct DocumentAttachmentInfo;
 struct DocumentMetadata;

 using SendThumbnailCallback = base::OnceCallback<void(Thumbnail)>;

 enum class FontMappingMode {
   // Do not perform font mapping.
   kNoMapping,
   // Perform font mapping in renderer processes using Blink/content APIs.
   kBlink,
 };

 enum class DocumentPermission {
   kCopy,
   kCopyAccessible,
   kPrintLowQuality,
   kPrintHighQuality,
 };

 // Do one time initialization of the SDK.
 // If `enable_v8` is false, then the PDFEngine will not be able to run
 // JavaScript.
 // When `use_skia` is true, the PDFEngine will use Skia renderer. Otherwise, it
 // will use AGG renderer.
 void InitializeSDK(bool enable_v8,
                    bool use_skia,
                    FontMappingMode font_mapping_mode);
 // Tells the SDK that we're shutting down.
 void ShutdownSDK();

 // This class encapsulates a PDF rendering engine.
 class PDFEngine {
  public:
   // Maximum number of parameters a nameddest view can contain.
   static constexpr size_t kMaxViewParams = 4;

   enum class FocusFieldType {
     // Focus is not on any form field.
     kNoFocus,
     // Focus is on a form text field or form combobox text field.
     kText,
     // Focus is on a non-text field.
     kNonText,
   };

   // Named destination in a document.
   struct NamedDestination {
     // 0-based page number.
     unsigned long page;

     // View fit type (see table 8.2 "Destination syntax" on page 582 of PDF
     // Reference 1.7). Empty string if not present.
     std::string view;

     // Number of parameters for the view.
     unsigned long num_params;

     // Parameters for the view. Their meaning depends on the `view` and their
     // number is defined by `num_params` but is at most `kMaxViewParams`. Note:
     // If a parameter stands for the x/y coordinates, it should be transformed
     // into the corresponding in-screen coordinates before it's sent to the
     // viewport.
     float params[kMaxViewParams];

     // A string of parameters for view fit type XYZ in the format of "x,y,zoom",
     // where x and y parameters are the in-screen coordinates and zoom is the
     // zoom level. If a parameter is "null", then current value of that
     // parameter in the viewport should be retained. Note: This string is empty
     // if the view's fit type is not XYZ.
     std::string xyz_params;
   };

   // The interface that's provided to the rendering engine.
   class Client {
    public:
     virtual ~Client() = default;

     // Proposes a document layout to the client. For the proposed layout to
     // become effective, the client must call PDFEngine::ApplyDocumentLayout()
     // with the new layout options (although this call can be asynchronous).
     virtual void ProposeDocumentLayout(const DocumentLayout& layout) = 0;

     // Informs the client that the given rect needs to be repainted.
     virtual void Invalidate(const gfx::Rect& rect) {}

     // Informs the client to scroll the plugin area by the given offset.
     virtual void DidScroll(const gfx::Vector2d& offset) {}

     // Scroll the horizontal/vertical scrollbars to a given position.
     // Values are in screen coordinates, where 0 is the top/left of the document
     // and a positive value is the distance in pixels from that line.
     virtual void ScrollToX(int x_screen_coords) {}
     virtual void ScrollToY(int y_screen_coords) {}

     // Scroll by a given delta relative to the current position.
     virtual void ScrollBy(const gfx::Vector2d& delta) {}

     // Scroll to zero-based `page`.
     virtual void ScrollToPage(int page) {}

     // Navigate to the given url.
     virtual void NavigateTo(const std::string& url,
                             WindowOpenDisposition disposition) {}

     // Navigate to the given destination. Zero-based `page` index. `x`, `y` and
     // `zoom` are optional and can be nullptr.
     virtual void NavigateToDestination(int page,
                                        const float* x,
                                        const float* y,
                                        const float* zoom) {}

     // Updates the cursor.
     virtual void UpdateCursor(ui::mojom::CursorType new_cursor_type) {}

     // Updates the tick marks in the vertical scrollbar.
     virtual void UpdateTickMarks(const std::vector<gfx::Rect>& tickmarks) {}

     // Updates the number of find results for the current search term.  If
     // there are no matches 0 should be passed in.  Only when the plugin has
     // finished searching should it pass in the final count with `final_result`
     // set to true.
     virtual void NotifyNumberOfFindResultsChanged(int total,
                                                   bool final_result) {}

     // Updates the index of the currently selected search item. Set
     // `final_result` to true only when there is no subsequent
     // `NotifyNumberOfFindResultsChanged()` call.
     virtual void NotifySelectedFindResultChanged(int current_find_index,
                                                  bool final_result) {}

     virtual void NotifyTouchSelectionOccurred() {}

     // Prompts the user for a password to open this document. The callback is
     // called when the password is retrieved.
     virtual void GetDocumentPassword(
         base::OnceCallback<void(const std::string&)> callback) {}

     // Play a "beeping" sound.
     virtual void Beep() {}

     // Puts up an alert with the given message.
     virtual void Alert(const std::string& message) {}

     // Puts up a confirm with the given message, and returns true if the user
     // presses OK, or false if they press cancel.
     virtual bool Confirm(const std::string& message) = 0;

     // Puts up a prompt with the given message and default answer and returns
     // the answer.
     virtual std::string Prompt(const std::string& question,
                                const std::string& default_answer) = 0;

     // Returns the url of the pdf.
     virtual std::string GetURL() = 0;

     // Send an email.
     virtual void Email(const std::string& to,
                        const std::string& cc,
                        const std::string& bcc,
                        const std::string& subject,
                        const std::string& body) {}

     // Put up the print dialog.
     virtual void Print() {}

     // Submit the data using HTTP POST.
     virtual void SubmitForm(const std::string& url,
                             const void* data,
                             int length) {}

     // Creates and returns new URL loader for partial document requests.
     virtual std::unique_ptr<UrlLoader> CreateUrlLoader() = 0;

     // Searches the given string for "term" and returns the results.  Unicode-
     // aware.
     struct SearchStringResult {
       int start_index;
       int length;
     };
     virtual std::vector<SearchStringResult> SearchString(
         const char16_t* string,
         const char16_t* term,
         bool case_sensitive) = 0;

     // Notifies the client that the document has finished loading.
     virtual void DocumentLoadComplete() {}

     // Notifies the client that the document has failed to load.
     virtual void DocumentLoadFailed() {}

     // Notifies that an unsupported feature in the PDF was encountered.
     virtual void DocumentHasUnsupportedFeature(const std::string& feature) {}

     // Notifies the client about document load progress.
     virtual void DocumentLoadProgress(uint32_t available, uint32_t doc_size) {}

     // Notifies the client about focus changes for form fields.
     virtual void FormFieldFocusChange(FocusFieldType type) {}

     // Returns true if the plugin has been opened within print preview.
     virtual bool IsPrintPreview() const = 0;

     // Get the background color of the PDF.
     virtual SkColor GetBackgroundColor() const = 0;

     // Sets selection status.
     virtual void SetIsSelecting(bool is_selecting) {}

     virtual void SelectionChanged(const gfx::Rect& left,
                                   const gfx::Rect& right) {}

     // The caret position in the editable form (if applicable) changed.
     virtual void CaretChanged(const gfx::Rect& caret_rect) {}

     // Notifies the client that the PDF has been edited.
     virtual void EnteredEditMode() {}

     // Notifies the client about focus changes for the document.
     virtual void DocumentFocusChanged(bool document_has_focus) {}

     // Sets selected text.
     virtual void SetSelectedText(const std::string& selected_text) = 0;

     // Sets the link under cursor.
     virtual void SetLinkUnderCursor(const std::string& link_under_cursor) = 0;

     // If the link cannot be converted to JS payload struct, then it is not
     // possible to pass it to JS. In this case, ignore the link like other PDF
     // viewers.
     // See https://crbug.com/312882 for an example.
     virtual bool IsValidLink(const std::string& url) = 0;
   };

   virtual ~PDFEngine() = default;

   // Most of these functions are similar to the Pepper functions of the same
   // name, so not repeating the description here unless it's different.
   virtual void PageOffsetUpdated(const gfx::Vector2d& page_offset) = 0;
   virtual void PluginSizeUpdated(const gfx::Size& size) = 0;
   virtual void ScrolledToXPosition(int position) = 0;
   virtual void ScrolledToYPosition(int position) = 0;
   // Paint is called a series of times. Before these n calls are made, PrePaint
   // is called once. After Paint is called n times, PostPaint is called once.
   virtual void PrePaint() = 0;
   virtual void Paint(const gfx::Rect& rect,
                      SkBitmap& image_data,
                      std::vector<gfx::Rect>& ready,
                      std::vector<gfx::Rect>& pending) = 0;
   virtual void PostPaint() = 0;
   virtual bool HandleInputEvent(const blink::WebInputEvent& event) = 0;
   virtual void PrintBegin() = 0;
   virtual std::vector<uint8_t> PrintPages(
       const std::vector<int>& page_index,
       const blink::WebPrintParams& print_params) = 0;
   virtual void PrintEnd() = 0;
   virtual void StartFind(const std::u16string& text, bool case_sensitive) = 0;
   virtual bool SelectFindResult(bool forward) = 0;
   virtual void StopFind() = 0;
   virtual void ZoomUpdated(double new_zoom_level) = 0;
   virtual void RotateClockwise() = 0;
   virtual void RotateCounterclockwise() = 0;
   virtual bool IsReadOnly() const = 0;
   virtual void SetReadOnly(bool enable) = 0;
   virtual void SetDocumentLayout(DocumentLayout::PageSpread page_spread) = 0;
   virtual void DisplayAnnotations(bool display) = 0;

   // Applies the document layout options proposed by a call to
   // PDFEngine::Client::ProposeDocumentLayout(), returning the overall size of
   // the new effective layout.
   virtual gfx::Size ApplyDocumentLayout(
       const DocumentLayout::Options& options) = 0;

   virtual std::string GetSelectedText() = 0;
   // Returns true if focus is within an editable form text area.
   virtual bool CanEditText() const = 0;
   // Returns true if focus is within an editable form text area and the text
   // area has text.
   virtual bool HasEditableText() const = 0;
   // Replace selected text within an editable form text area with another
   // string. If there is no selected text, append the replacement text after the
   // current caret position.
   virtual void ReplaceSelection(const std::string& text) = 0;
   // Methods to check if undo/redo is possible, and to perform them.
   virtual bool CanUndo() const = 0;
   virtual bool CanRedo() const = 0;
   virtual void Undo() = 0;
   virtual void Redo() = 0;
   // Handles actions invoked by Accessibility clients.
   virtual void HandleAccessibilityAction(
       const AccessibilityActionData& action_data) = 0;
   virtual std::string GetLinkAtPosition(const gfx::Point& point) = 0;
   // Checks the permissions associated with this document.
   virtual bool HasPermission(DocumentPermission permission) const = 0;
   virtual void SelectAll() = 0;
   // Gets the list of DocumentAttachmentInfo from the document.
   virtual const std::vector<DocumentAttachmentInfo>&
   GetDocumentAttachmentInfoList() const = 0;
   // Gets the content of an attachment by the attachment's `index`. `index`
   // must be in the range of [0, attachment_count-1), where `attachment_count`
   // is the number of attachments embedded in the document.
   // The caller of this method is responsible for checking whether the
   // attachment is readable, attachment size is not 0 byte, and the return
   // value's size matches the corresponding DocumentAttachmentInfo's
   // `size_bytes`.
   virtual std::vector<uint8_t> GetAttachmentData(size_t index) = 0;
   // Gets metadata about the document.
   virtual const DocumentMetadata& GetDocumentMetadata() const = 0;
   // Gets the number of pages in the document.
   virtual int GetNumberOfPages() const = 0;
   // Gets the named destination by name.
   virtual absl::optional<PDFEngine::NamedDestination> GetNamedDestination(
       const std::string& destination) = 0;
   // Gets the index of the most visible page, or -1 if none are visible.
   virtual int GetMostVisiblePage() = 0;
   // Gets the rectangle of the page not including the shadow.
   virtual gfx::Rect GetPageBoundsRect(int index) = 0;
   // Gets the rectangle of the page excluding any additional areas.
   virtual gfx::Rect GetPageContentsRect(int index) = 0;
   // Returns a page's rect in screen coordinates, as well as its surrounding
   // border areas and bottom separator.
   virtual gfx::Rect GetPageScreenRect(int page_index) const = 0;
   // Return a page's bounding box rectangle, or an empty rectangle if
   // `page_index` is invalid.
   virtual gfx::RectF GetPageBoundingBox(int page_index) = 0;
   // Set color / grayscale rendering modes.
   virtual void SetGrayscale(bool grayscale) = 0;
   // Get the number of characters on a given page.
   virtual int GetCharCount(int page_index) = 0;
   // Get the bounds in page pixels of a character on a given page.
   virtual gfx::RectF GetCharBounds(int page_index, int char_index) = 0;
   // Get a given unicode character on a given page.
   virtual uint32_t GetCharUnicode(int page_index, int char_index) = 0;
   // Given a start char index, find the longest continuous run of text that's
   // in a single direction and with the same text style. Return a filled out
   // AccessibilityTextRunInfo on success or absl::nullopt on failure. e.g. When
   // `start_char_index` is out of bounds.
   virtual absl::optional<AccessibilityTextRunInfo> GetTextRunInfo(
       int page_index,
       int start_char_index) = 0;
   // For all the links on page `page_index`, get their urls, underlying text
   // ranges and bounding boxes.
   virtual std::vector<AccessibilityLinkInfo> GetLinkInfo(
       int page_index,
       const std::vector<AccessibilityTextRunInfo>& text_runs) = 0;
   // For all the images in page `page_index`, get their alt texts and bounding
   // boxes. If the alt text is empty or unavailable, and if the user has
   // requested that the OCR service tag the PDF so that it is made accessible,
   // transfer the raw image pixels in the `image_data` field. Otherwise do not
   // populate the `image_data` field.
   virtual std::vector<AccessibilityImageInfo> GetImageInfo(
       int page_index,
       uint32_t text_run_count) = 0;
   // Returns the image as a 32-bit bitmap format for OCR.
   virtual SkBitmap GetImageForOcr(int page_index, int image_index) = 0;
   // For all the highlights in page `page_index`, get their underlying text
   // ranges and bounding boxes.
   virtual std::vector<AccessibilityHighlightInfo> GetHighlightInfo(
       int page_index,
       const std::vector<AccessibilityTextRunInfo>& text_runs) = 0;
   // For all the text fields in page `page_index`, get their properties like
   // name, value, bounding boxes etc.
   virtual std::vector<AccessibilityTextFieldInfo> GetTextFieldInfo(
       int page_index,
       uint32_t text_run_count) = 0;

   // Gets the PDF document's print scaling preference. True if the document can
   // be scaled to fit.
   virtual bool GetPrintScaling() = 0;
   // Returns number of copies to be printed.
   virtual int GetCopiesToPrint() = 0;
   // Returns the duplex setting.
   virtual printing::mojom::DuplexMode GetDuplexMode() = 0;
   // Returns the uniform page size of the document in points. Returns
   // `absl::nullopt` if the document has more than one page size.
   virtual absl::optional<gfx::Size> GetUniformPageSizePoints() = 0;

   // Returns a list of Values of Bookmarks. Each Bookmark is a dictionary Value
   // which contains the following key/values:
   // - "title" - a string Value.
   // - "page" - an int Value.
   // - "children" - a list of Values, with each entry containing
   //   a dictionary Value of the same structure.
   virtual base::Value::List GetBookmarks() = 0;

   // Append blank pages to make a 1-page document to a `num_pages` document.
   // Always retain the first page data.
   virtual void AppendBlankPages(size_t num_pages) = 0;
   // Append the first page of the document loaded with the `engine` to this
   // document at page `index`.
   virtual void AppendPage(PDFEngine* engine, int index) = 0;

   virtual std::vector<uint8_t> GetSaveData() = 0;

   virtual void SetCaretPosition(const gfx::Point& position) = 0;
   virtual void MoveRangeSelectionExtent(const gfx::Point& extent) = 0;
   virtual void SetSelectionBounds(const gfx::Point& base,
                                   const gfx::Point& extent) = 0;
   virtual void GetSelection(uint32_t* selection_start_page_index,
                             uint32_t* selection_start_char_index,
                             uint32_t* selection_end_page_index,
                             uint32_t* selection_end_char_index) = 0;

   // Remove focus from form widgets, consolidating the user input.
   virtual void KillFormFocus() = 0;

   // Notify whether the PDF currently has the focus or not.
   virtual void UpdateFocus(bool has_focus) = 0;

   // Returns the focus info of current focus item.
   virtual AccessibilityFocusInfo GetFocusInfo() = 0;

   virtual uint32_t GetLoadedByteSize() = 0;
   virtual bool ReadLoadedBytes(uint32_t length, void* buffer) = 0;

   // Requests for a thumbnail to be sent using a callback when the page is ready
   // to be rendered. `send_callback` is run with the thumbnail data when ready.
   virtual void RequestThumbnail(int page_index,
                                 float device_pixel_ratio,
                                 SendThumbnailCallback send_callback) = 0;
 };

 // Interface for exports that wrap the PDF engine.
 class PDFEngineExports {
  public:
   struct RenderingSettings {
     RenderingSettings(const gfx::Size& dpi,
                       const gfx::Rect& bounds,
                       bool fit_to_bounds,
                       bool stretch_to_bounds,
                       bool keep_aspect_ratio,
                       bool center_in_bounds,
                       bool autorotate,
                       bool use_color,
                       bool render_for_printing);
     RenderingSettings(const RenderingSettings& that);

     gfx::Size dpi;
     gfx::Rect bounds;
     bool fit_to_bounds;
     bool stretch_to_bounds;
     bool keep_aspect_ratio;
     bool center_in_bounds;
     bool autorotate;
     bool use_color;
     bool render_for_printing;
   };

   PDFEngineExports() {}
   virtual ~PDFEngineExports() {}

   static PDFEngineExports* Get();

 #if BUILDFLAG(IS_CHROMEOS)
   // See the definition of CreateFlattenedPdf in pdf.cc for details.
   virtual std::vector<uint8_t> CreateFlattenedPdf(
       base::span<const uint8_t> input_buffer) = 0;
 #endif  // BUILDFLAG(IS_CHROMEOS)

 #if BUILDFLAG(IS_WIN)
   // See the definition of RenderPDFPageToDC in pdf.cc for details.
   virtual bool RenderPDFPageToDC(base::span<const uint8_t> pdf_buffer,
                                  int page_index,
                                  const RenderingSettings& settings,
                                  HDC dc) = 0;

   virtual void SetPDFUsePrintMode(int mode) = 0;
 #endif  // BUILDFLAG(IS_WIN)

   // See the definition of RenderPDFPageToBitmap in pdf.cc for details.
   virtual bool RenderPDFPageToBitmap(base::span<const uint8_t> pdf_buffer,
                                      int page_index,
                                      const RenderingSettings& settings,
                                      void* bitmap_buffer) = 0;

   // See the definition of ConvertPdfPagesToNupPdf in pdf.cc for details.
   virtual std::vector<uint8_t> ConvertPdfPagesToNupPdf(
       std::vector<base::span<const uint8_t>> input_buffers,
       size_t pages_per_sheet,
       const gfx::Size& page_size,
       const gfx::Rect& printable_area) = 0;

   // See the definition of ConvertPdfDocumentToNupPdf in pdf.cc for details.
   virtual std::vector<uint8_t> ConvertPdfDocumentToNupPdf(
       base::span<const uint8_t> input_buffer,
       size_t pages_per_sheet,
       const gfx::Size& page_size,
       const gfx::Rect& printable_area) = 0;

   virtual bool GetPDFDocInfo(base::span<const uint8_t> pdf_buffer,
                              int* page_count,
                              float* max_page_width) = 0;

   // Whether the PDF is Tagged (see 10.7 "Tagged PDF" in PDF Reference 1.7).
   // Returns true if it's a tagged (accessible) PDF, false if it's a valid
   // PDF but untagged, and nullopt if the PDF can't be parsed.
   virtual absl::optional<bool> IsPDFDocTagged(
       base::span<const uint8_t> pdf_buffer) = 0;

   // Given a tagged PDF (see IsPDFDocTagged, above), return the portion of
   // the structure tree for a given page as a hierarchical tree of base::Values.
   virtual base::Value GetPDFStructTreeForPage(
       base::span<const uint8_t> pdf_buffer,
       int page_index) = 0;

   // See the definition of GetPDFPageSizeByIndex in pdf.cc for details.
   virtual absl::optional<gfx::SizeF> GetPDFPageSizeByIndex(
       base::span<const uint8_t> pdf_buffer,
       int page_index) = 0;
 };

 }  // namespace chrome_pdf

 #endif  // PDF_PDF_ENGINE_H_