Add the pdf plugin's source in src\pdf.

pdf/document_loader.cc

+// 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.
+
+#include "pdf/document_loader.h"
+
+#include "base/logging.h"
+#include "base/strings/string_util.h"
+#include "net/http/http_util.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/cpp/url_loader.h"
+#include "ppapi/cpp/url_request_info.h"
+#include "ppapi/cpp/url_response_info.h"
+
+namespace chrome_pdf {
+
+// Document below size will be downloaded in one chunk.
+const uint32 kMinFileSize = 64*1024;
+
+DocumentLoader::DocumentLoader(Client* client)
+    : client_(client), partial_document_(false), request_pending_(false),
+      current_pos_(0), current_chunk_size_(0), current_chunk_read_(0),
+      document_size_(0), header_request_(true), is_multipart_(false) {
+  loader_factory_.Initialize(this);
+}
+
+DocumentLoader::~DocumentLoader() {
+}
+
+bool DocumentLoader::Init(const pp::URLLoader& loader,
+                          const std::string& url,
+                          const std::string& headers) {
+  DCHECK(url_.empty());
+  url_ = url;
+  loader_ = loader;
+
+  std::string response_headers;
+  if (!headers.empty()) {
+    response_headers = headers;
+  } else {
+    pp::URLResponseInfo response = loader_.GetResponseInfo();
+    pp::Var headers_var = response.GetHeaders();
+
+    if (headers_var.is_string()) {
+      response_headers = headers_var.AsString();
+    }
+  }
+
+  bool accept_ranges_bytes = false;
+  bool content_encoded = false;
+  uint32 content_length = 0;
+  std::string type;
+  std::string disposition;
+  if (!response_headers.empty()) {
+    net::HttpUtil::HeadersIterator it(response_headers.begin(),
+                                      response_headers.end(), "\n");
+    while (it.GetNext()) {
+      if (LowerCaseEqualsASCII(it.name(), "content-length")) {
+        content_length = atoi(it.values().c_str());
+      } else if (LowerCaseEqualsASCII(it.name(), "accept-ranges")) {
+        accept_ranges_bytes = LowerCaseEqualsASCII(it.values(), "bytes");
+      } else if (LowerCaseEqualsASCII(it.name(), "content-encoding")) {
+        content_encoded = true;
+      } else if (LowerCaseEqualsASCII(it.name(), "content-type")) {
+        type = it.values();
+        size_t semi_colon_pos = type.find(';');
+        if (semi_colon_pos != std::string::npos) {
+          type = type.substr(0, semi_colon_pos);
+        }
+        TrimWhitespace(type, base::TRIM_ALL, &type);
+      } else if (LowerCaseEqualsASCII(it.name(), "content-disposition")) {
+        disposition = it.values();
+      }
+    }
+  }
+  if (!type.empty() &&
+      !EndsWith(type, "/pdf", false) &&
+      !EndsWith(type, ".pdf", false) &&
+      !EndsWith(type, "/x-pdf", false) &&
+      !EndsWith(type, "/*", false) &&
+      !EndsWith(type, "/acrobat", false) &&
+      !EndsWith(type, "/unknown", false) &&
+      !StartsWithASCII(url, "blob:", false)) {
+    return false;
+  }
+  if (StartsWithASCII(disposition, "attachment", false)) {
+    return false;
+  }
+
+  if (content_length > 0)
+    chunk_stream_.Preallocate(content_length);
+
+  document_size_ = content_length;
+  requests_count_ = 0;
+
+  // Document loading strategy.
+  // Following table shows the growth on the minimal request size depending
+  // on the number requests that has been made already.
+  chunk_size_table_[10] = 32*1024;
+  chunk_size_table_[20] = 64*1024;
+  chunk_size_table_[30] = 128*1024;
+  chunk_size_table_[40] = 256*1024;
+  chunk_size_table_[50] = 512*1024;
+  chunk_size_table_[60] = 1024*1024;
+  chunk_size_table_[70] = 2048*1024;
+
+  // Enable partial loading only if file size is above the threshold.
+  // It will allow avoiding latency for multiple requests.
+  if (content_length > kMinFileSize &&
+      accept_ranges_bytes &&
+      !content_encoded) {
+    LoadPartialDocument();
+  } else {
+    LoadFullDocument();
+  }
+  return true;
+}
+
+void DocumentLoader::LoadPartialDocument() {
+  partial_document_ = true;
+  // Force the main request to be cancelled, since if we're a full-frame plugin
+  // there could be other references to the loader.
+  loader_.Close();
+  loader_ = pp::URLLoader();
+  // Download file header.
+  header_request_ = true;
+  RequestData(0, std::min(GetRequestSize(), document_size_));
+}
+
+void DocumentLoader::LoadFullDocument() {
+  partial_document_ = false;
+  chunk_buffer_.clear();
+  ReadMore();
+}
+
+bool DocumentLoader::IsDocumentComplete() const {
+  if (document_size_ == 0)  // Document size unknown.
+    return false;
+  return IsDataAvailable(0, document_size_);
+}
+
+uint32 DocumentLoader::GetAvailableData() const {
+  if (document_size_ == 0) {  // If document size is unknown.
+    return current_pos_;
+  }
+
+  std::vector<std::pair<size_t, size_t> > ranges;
+  chunk_stream_.GetMissedRanges(0, document_size_, &ranges);
+  uint32 available = document_size_;
+  std::vector<std::pair<size_t, size_t> >::iterator it;
+  for (it = ranges.begin(); it != ranges.end(); ++it) {
+    available -= it->second;
+  }
+  return available;
+}
+
+void DocumentLoader::ClearPendingRequests() {
+  // The first item in the queue is pending (need to keep it in the queue).
+  if (pending_requests_.size() > 1) {
+    // Remove all elements except the first one.
+    pending_requests_.erase(++pending_requests_.begin(),
+                            pending_requests_.end());
+  }
+}
+
+bool DocumentLoader::GetBlock(uint32 position, uint32 size, void* buf) const {
+  return chunk_stream_.ReadData(position, size, buf);
+}
+
+bool DocumentLoader::IsDataAvailable(uint32 position, uint32 size) const {
+  return chunk_stream_.IsRangeAvailable(position, size);
+}
+
+void DocumentLoader::RequestData(uint32 position, uint32 size) {
+  DCHECK(partial_document_);
+
+  // We have some artefact request from
+  // PDFiumEngine::OnDocumentComplete() -> FPDFAvail_IsPageAvail after
+  // document is complete.
+  // We need this fix in PDFIum. Adding this as a work around.
+  // Bug: http://code.google.com/p/chromium/issues/detail?id=79996
+  // Test url:
+  // http://www.icann.org/en/correspondence/holtzman-to-jeffrey-02mar11-en.pdf
+  if (IsDocumentComplete())
+    return;
+
+  pending_requests_.push_back(std::pair<size_t, size_t>(position, size));
+  DownloadPendingRequests();
+}
+
+void DocumentLoader::DownloadPendingRequests() {
+  if (request_pending_ || pending_requests_.empty())
+    return;
+
+  // Remove already completed requests.
+  // By design DownloadPendingRequests() should have at least 1 request in the
+  // queue. ReadComplete() will remove the last pending comment from the queue.
+  while (pending_requests_.size() > 1) {
+    if (IsDataAvailable(pending_requests_.front().first,
+                        pending_requests_.front().second)) {
+      pending_requests_.pop_front();
+    } else {
+      break;
+    }
+  }
+
+  uint32 pos = pending_requests_.front().first;
+  uint32 size = pending_requests_.front().second;
+  if (IsDataAvailable(pos, size)) {
+    ReadComplete();
+    return;
+  }
+
+  // If current request has been partially downloaded already, split it into
+  // a few smaller requests.
+  std::vector<std::pair<size_t, size_t> > ranges;
+  chunk_stream_.GetMissedRanges(pos, size, &ranges);
+  if (ranges.size() > 0) {
+    pending_requests_.pop_front();
+    pending_requests_.insert(pending_requests_.begin(),
+                             ranges.begin(), ranges.end());
+    pos = pending_requests_.front().first;
+    size = pending_requests_.front().second;
+  }
+
+  uint32 cur_request_size = GetRequestSize();
+  // If size is less than default request, try to expand download range for
+  // more optimal download.
+  if (size < cur_request_size && partial_document_) {
+    // First, try to expand block towards the end of the file.
+    uint32 new_pos = pos;
+    uint32 new_size = cur_request_size;
+    if (pos + new_size > document_size_)
+      new_size = document_size_ - pos;
+
+    std::vector<std::pair<size_t, size_t> > ranges;
+    if (chunk_stream_.GetMissedRanges(new_pos, new_size, &ranges)) {
+      new_pos = ranges[0].first;
+      new_size = ranges[0].second;
+    }
+
+    // Second, try to expand block towards the beginning of the file.
+    if (new_size < cur_request_size) {
+      uint32 block_end = new_pos + new_size;
+      if (block_end > cur_request_size) {
+        new_pos = block_end - cur_request_size;
+      } else {
+        new_pos = 0;
+      }
+      new_size = block_end - new_pos;
+
+      if (chunk_stream_.GetMissedRanges(new_pos, new_size, &ranges)) {
+        new_pos = ranges.back().first;
+        new_size = ranges.back().second;
+      }
+    }
+    pos = new_pos;
+    size = new_size;
+  }
+
+  size_t last_byte_before = chunk_stream_.GetLastByteBefore(pos);
+  size_t first_byte_after = chunk_stream_.GetFirstByteAfter(pos + size - 1);
+  if (pos - last_byte_before < cur_request_size) {
+    size = pos + size - last_byte_before;
+    pos = last_byte_before;
+  }
+
+  if ((pos + size < first_byte_after) &&
+      (pos + size + cur_request_size >= first_byte_after))
+    size = first_byte_after - pos;
+
+  request_pending_ = true;
+
+  // Start downloading first pending request.
+  loader_.Close();
+  loader_ = client_->CreateURLLoader();
+  pp::CompletionCallback callback =
+      loader_factory_.NewCallback(&DocumentLoader::DidOpen);
+  pp::URLRequestInfo request = GetRequest(pos, size);
+  requests_count_++;
+  int rv = loader_.Open(request, callback);
+  if (rv != PP_OK_COMPLETIONPENDING)
+    callback.Run(rv);
+}
+
+pp::URLRequestInfo DocumentLoader::GetRequest(uint32 position,
+                                              uint32 size) const {
+  pp::URLRequestInfo request(client_->GetPluginInstance());
+  request.SetURL(url_.c_str());
+  request.SetMethod("GET");
+  request.SetFollowRedirects(true);
+
+  const size_t kBufSize = 100;
+  char buf[kBufSize];
+  // According to rfc2616, byte range specifies position of the first and last
+  // bytes in the requested range inclusively. Therefore we should subtract 1
+  // from the position + size, to get index of the last byte that needs to be
+  // downloaded.
+  base::snprintf(buf, kBufSize, "Range: bytes=%d-%d", position,
+                 position + size - 1);
+  pp::Var header(buf);
+  request.SetHeaders(header);
+
+  return request;
+}
+
+void DocumentLoader::DidOpen(int32_t result) {
+  if (result != PP_OK) {
+    NOTREACHED();
+    return;
+  }
+
+  is_multipart_ = false;
+  current_chunk_size_ = 0;
+  current_chunk_read_ = 0;
+
+  pp::Var headers_var = loader_.GetResponseInfo().GetHeaders();
+  std::string headers;
+  if (headers_var.is_string())
+    headers = headers_var.AsString();
+
+  std::string boundary = GetMultiPartBoundary(headers);
+  if (boundary.size()) {
+    // Leave position untouched for now, when we read the data we'll get it.
+    is_multipart_ = true;
+    multipart_boundary_ = boundary;
+  } else {
+    // Need to make sure that the server returned a byte-range, since it's
+    // possible for a server to just ignore our bye-range request and just
+    // return the entire document even if it supports byte-range requests.
+    // i.e. sniff response to
+    // http://www.act.org/compass/sample/pdf/geometry.pdf
+    current_pos_ = 0;
+    uint32 start_pos, end_pos;
+    if (GetByteRange(headers, &start_pos, &end_pos)) {
+      current_pos_ = start_pos;
+      if (end_pos && end_pos > start_pos)
+        current_chunk_size_ = end_pos - start_pos + 1;
+    }
+  }
+
+  ReadMore();
+}
+
+bool DocumentLoader::GetByteRange(const std::string& headers, uint32* start,
+                                  uint32* end) {
+  net::HttpUtil::HeadersIterator it(headers.begin(), headers.end(), "\n");
+  while (it.GetNext()) {
+    if (LowerCaseEqualsASCII(it.name(), "content-range")) {
+      std::string range = it.values().c_str();
+      if (StartsWithASCII(range, "bytes", false)) {
+        range = range.substr(strlen("bytes"));
+        std::string::size_type pos = range.find('-');
+        std::string range_end;
+        if (pos != std::string::npos)
+          range_end = range.substr(pos + 1);
+        TrimWhitespaceASCII(range, base::TRIM_LEADING, &range);
+        TrimWhitespaceASCII(range_end, base::TRIM_LEADING, &range_end);
+        *start = atoi(range.c_str());
+        *end = atoi(range_end.c_str());
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+std::string DocumentLoader::GetMultiPartBoundary(const std::string& headers) {
+  net::HttpUtil::HeadersIterator it(headers.begin(), headers.end(), "\n");
+  while (it.GetNext()) {
+    if (LowerCaseEqualsASCII(it.name(), "content-type")) {
+      std::string type = StringToLowerASCII(it.values());
+      if (StartsWithASCII(type, "multipart/", true)) {
+        const char* boundary = strstr(type.c_str(), "boundary=");
+        if (!boundary) {
+          NOTREACHED();
+          break;
+        }
+
+        return std::string(boundary + 9);
+      }
+    }
+  }
+  return std::string();
+}
+
+void DocumentLoader::ReadMore() {
+  pp::CompletionCallback callback =
+        loader_factory_.NewCallback(&DocumentLoader::DidRead);
+  int rv = loader_.ReadResponseBody(buffer_, sizeof(buffer_), callback);
+  if (rv != PP_OK_COMPLETIONPENDING)
+    callback.Run(rv);
+}
+
+void DocumentLoader::DidRead(int32_t result) {
+  if (result > 0) {
+    char* start = buffer_;
+    size_t length = result;
+    if (is_multipart_ && result > 2) {
+      for (int i = 2; i < result; ++i) {
+        if ((buffer_[i - 1] == '\n' && buffer_[i - 2] == '\n') ||
+            (i >= 4 &&
+             buffer_[i - 1] == '\n' && buffer_[i - 2] == '\r' &&
+             buffer_[i - 3] == '\n' && buffer_[i - 4] == '\r')) {
+          uint32 start_pos, end_pos;
+          if (GetByteRange(std::string(buffer_, i), &start_pos, &end_pos)) {
+            current_pos_ = start_pos;
+            start += i;
+            length -= i;
+            if (end_pos && end_pos > start_pos)
+              current_chunk_size_ = end_pos - start_pos + 1;
+          }
+          break;
+        }
+      }
+
+      // Reset this flag so we don't look inside the buffer in future calls of
+      // DidRead for this response.  Note that this code DOES NOT handle multi-
+      // part responses with more than one part (we don't issue them at the
+      // moment, so they shouldn't arrive).
+      is_multipart_ = false;
+    }
+
+    if (current_chunk_size_ &&
+        current_chunk_read_ + length > current_chunk_size_)
+      length = current_chunk_size_ - current_chunk_read_;
+
+    if (length) {
+      if (document_size_ > 0) {
+        chunk_stream_.WriteData(current_pos_, start, length);
+      } else {
+        // If we did not get content-length in the response, we can't
+        // preallocate buffer for the entire document. Resizing array causing
+        // memory fragmentation issues on the large files and OOM exceptions.
+        // To fix this, we collect all chunks of the file to the list and
+        // concatenate them together after request is complete.
+        chunk_buffer_.push_back(std::vector<unsigned char>());
+        chunk_buffer_.back().resize(length);
+        memcpy(&(chunk_buffer_.back()[0]), start, length);
+      }
+      current_pos_ += length;
+      current_chunk_read_ += length;
+      client_->OnNewDataAvailable();
+    }
+    ReadMore();
+  } else if (result == PP_OK) {
+    ReadComplete();
+  } else {
+    NOTREACHED();
+  }
+}
+
+void DocumentLoader::ReadComplete() {
+  if (!partial_document_) {
+    if (document_size_ == 0) {
+      // For the document with no 'content-length" specified we've collected all
+      // the chunks already. Let's allocate final document buffer and copy them
+      // over.
+      chunk_stream_.Preallocate(current_pos_);
+      uint32 pos = 0;
+      std::list<std::vector<unsigned char> >::iterator it;
+      for (it = chunk_buffer_.begin(); it != chunk_buffer_.end(); ++it) {
+        chunk_stream_.WriteData(pos, &((*it)[0]), it->size());
+        pos += it->size();
+      }
+      chunk_buffer_.clear();
+    }
+    document_size_ = current_pos_;
+    client_->OnDocumentComplete();
+    return;
+  }
+
+  request_pending_ = false;
+  pending_requests_.pop_front();
+
+  // If there are more pending request - continue downloading.
+  if (!pending_requests_.empty()) {
+    DownloadPendingRequests();
+    return;
+  }
+
+  if (IsDocumentComplete()) {
+    client_->OnDocumentComplete();
+    return;
+  }
+
+  if (header_request_)
+    client_->OnPartialDocumentLoaded();
+  else
+    client_->OnPendingRequestComplete();
+  header_request_ = false;
+
+  // The OnPendingRequestComplete could have added more requests.
+  if (!pending_requests_.empty()) {
+    DownloadPendingRequests();
+  } else {
+    // Document is not complete and we have no outstanding requests.
+    // Let's keep downloading PDF file in small chunks.
+    uint32 pos = chunk_stream_.GetFirstMissingByte();
+    std::vector<std::pair<size_t, size_t> > ranges;
+    chunk_stream_.GetMissedRanges(pos, GetRequestSize(), &ranges);
+    DCHECK(ranges.size() > 0);
+    RequestData(ranges[0].first, ranges[0].second);
+  }
+}
+
+uint32 DocumentLoader::GetRequestSize() const {
+  std::map<uint32, uint32>::const_iterator iter =
+      chunk_size_table_.lower_bound(requests_count_);
+  if (iter == chunk_size_table_.end())
+    iter--;
+  return iter->second;
+}
+
+}  // namespace chrome_pdf