Improve linearized pdf load/show time.

pdf/document_loader.h

 // Copyright (c) 2010 The Chromium 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 PDF_DOCUMENT_LOADER_H_
 #define PDF_DOCUMENT_LOADER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <list>
+#include <memory>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "pdf/chunk_stream.h"
-#include "ppapi/cpp/url_loader.h"
 #include "ppapi/utility/completion_callback_factory.h"
 
 namespace chrome_pdf {
 
+class URLLoaderWrapper;
+
 class DocumentLoader {
  public:
   class Client {
    public:
     virtual ~Client();
 
     // Gets the pp::Instance object.
     virtual pp::Instance* GetPluginInstance() = 0;
     // Creates new URLLoader based on client settings.
-    virtual pp::URLLoader CreateURLLoader() = 0;
-    // Notification called when partial information about document is available.
-    // Only called for urls that returns full content size and supports byte
-    // range requests.
-    virtual void OnPartialDocumentLoaded() = 0;
+    virtual std::unique_ptr<URLLoaderWrapper> CreateURLLoader() = 0;
     // Notification called when all outstanding pending requests are complete.
     virtual void OnPendingRequestComplete() = 0;
     // Notification called when new data is available.
     virtual void OnNewDataAvailable() = 0;
     // Notification called when document is fully loaded.
     virtual void OnDocumentComplete() = 0;
+    // Notification called when document loading is canceled.
+    virtual void OnDocumentCanceled() = 0;
+    // Called when initial loader was closed.
+    virtual void CancelBrowserDownload() = 0;
   };
 
   explicit DocumentLoader(Client* client);
   ~DocumentLoader();
 
-  bool Init(const pp::URLLoader& loader,
-            const std::string& url,
-            const std::string& headers);
+  bool Init(std::unique_ptr<URLLoaderWrapper> loader, const std::string& url);
 
   // Data access interface. Return true is successful.
   bool GetBlock(uint32_t position, uint32_t size, void* buf) const;
 
   // Data availability interface. Return true data available.
   bool IsDataAvailable(uint32_t position, uint32_t size) const;
 
   // Data availability interface. Return true data available.
   void RequestData(uint32_t position, uint32_t size);
 
   bool IsDocumentComplete() const;
-  uint32_t document_size() const { return document_size_; }
-
-  // Return number of bytes available.
-  uint32_t GetAvailableData() const;
+  uint32_t GetDocumentSize() const;
+  uint32_t count_of_bytes_received() const { return count_of_bytes_received_; }
+  float GetProgress() const;
 
   // Clear pending requests from the queue.
   void ClearPendingRequests();
 
-  bool is_partial_document() const { return partial_document_; }
+  void SetPartialLoadingEnabled(bool enabled);
+
+  bool is_partial_loader_active() const { return is_partial_loader_active_; }
+
+  static uint32_t default_request_size() { return kDefaultRequestSize; }
 
  private:
+  // Number was chosen in crbug.com/78264#c8
+  static constexpr uint32_t kDefaultRequestSize = 65536;
+
+  using DataStream = ChunkStream<kDefaultRequestSize>;
+  struct Chunk {
+    Chunk();
+    ~Chunk();
+
+    void Clear();
+
+    uint32_t chunk_index = 0;
+    uint32_t data_size = 0;
+    std::unique_ptr<DataStream::ChunkData> chunk_data;
+  };
+
   // Called by the completion callback of the document's URLLoader.
-  void DidOpen(int32_t result);
+  void DidOpenPartial(int32_t result);
   // Call to read data from the document's URLLoader.
   void ReadMore();
   // Called by the completion callback of the document's URLLoader.
   void DidRead(int32_t result);
 
-  // Called when we detect that partial document load is possible.
-  void LoadPartialDocument();
-  // Called when we have to load full document.
-  void LoadFullDocument();
-  // Download pending requests.
-  void DownloadPendingRequests();
-  // Remove completed ranges.
-  void RemoveCompletedRanges();
-  // Returns true if we are already in progress satisfying the request, or just
-  // about ready to start. This helps us avoid expensive jumping around, and
-  // even worse leaving tiny gaps in the byte stream that might have to be
-  // filled later.
-  bool SatisfyingRequest(size_t pos, size_t size) const;
-  // Called when we complete server request and read all data from it.
+  bool ShouldCancelLoading() const;
+  void ContinueDownload();
+  // Called when we complete server request.
   void ReadComplete();
-  // Creates request to download size byte of data data starting from position.
-  pp::URLRequestInfo GetRequest(uint32_t position, uint32_t size) const;
-  // Updates the rendering by the Client.
-  void UpdateRendering();
 
-  // Document below size will be downloaded in one chunk.
-  static const uint32_t kMinFileSize = 64 * 1024;
-  // Number was chosen in crbug.com/78264#c8
-  enum { kDefaultRequestSize = 65536 };
+  bool SaveChunkData(char* input, uint32_t input_size);
 
   Client* const client_;
   std::string url_;
-  pp::URLLoader loader_;
+  std::unique_ptr<URLLoaderWrapper> loader_;
+
   pp::CompletionCallbackFactory<DocumentLoader> loader_factory_;
-  ChunkStream chunk_stream_;
-  bool partial_document_;
-  bool request_pending_;
-  typedef std::list<std::pair<size_t, size_t> > PendingRequests;
-  PendingRequests pending_requests_;
-  // The starting position of the HTTP request currently being processed.
-  size_t current_request_offset_;
-  // The size of the byte range the current HTTP request must download before
-  // being cancelled.
-  size_t current_request_size_;
-  // The actual byte range size of the current HTTP request. This may be larger
-  // than |current_request_size_| and the request may be cancelled before
-  // reaching |current_request_offset_| + |current_request_extended_size_|.
-  size_t current_request_extended_size_;
-  char buffer_[kDefaultRequestSize];
-  uint32_t current_pos_;
-  uint32_t current_chunk_size_;
-  uint32_t current_chunk_read_;
-  uint32_t document_size_;
-  bool header_request_;
-  bool is_multipart_;
-  std::string multipart_boundary_;
-  uint32_t requests_count_;
-  std::vector<std::vector<unsigned char> > chunk_buffer_;
+
+  DataStream chunk_stream_;
+  bool partial_loading_enabled_ = true;
+  bool is_partial_loader_active_ = false;
+  char buffer_[DataStream::kChunkSize];
+
+  Chunk chunk_;
+  RangeSet pending_requests_;
+  uint32_t count_of_bytes_received_ = 0;
 };
 
 }  // namespace chrome_pdf
 
 #endif  // PDF_DOCUMENT_LOADER_H_