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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "content/browser/download/download_resource_handler.h"
      6 
      7 #include <string>
      8 
      9 #include "base/bind.h"
     10 #include "base/logging.h"
     11 #include "base/message_loop/message_loop_proxy.h"
     12 #include "base/metrics/histogram.h"
     13 #include "base/metrics/stats_counters.h"
     14 #include "base/strings/stringprintf.h"
     15 #include "content/browser/byte_stream.h"
     16 #include "content/browser/download/download_create_info.h"
     17 #include "content/browser/download/download_interrupt_reasons_impl.h"
     18 #include "content/browser/download/download_manager_impl.h"
     19 #include "content/browser/download/download_request_handle.h"
     20 #include "content/browser/download/download_stats.h"
     21 #include "content/browser/loader/resource_dispatcher_host_impl.h"
     22 #include "content/browser/loader/resource_request_info_impl.h"
     23 #include "content/public/browser/browser_thread.h"
     24 #include "content/public/browser/download_interrupt_reasons.h"
     25 #include "content/public/browser/download_item.h"
     26 #include "content/public/browser/download_manager_delegate.h"
     27 #include "content/public/common/resource_response.h"
     28 #include "net/base/io_buffer.h"
     29 #include "net/base/net_errors.h"
     30 #include "net/http/http_response_headers.h"
     31 #include "net/http/http_status_code.h"
     32 #include "net/url_request/url_request_context.h"
     33 
     34 namespace content {
     35 namespace {
     36 
     37 void CallStartedCBOnUIThread(
     38     const DownloadUrlParameters::OnStartedCallback& started_cb,
     39     DownloadItem* item,
     40     net::Error error) {
     41   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     42 
     43   if (started_cb.is_null())
     44     return;
     45   started_cb.Run(item, error);
     46 }
     47 
     48 // Static function in order to prevent any accidental accesses to
     49 // DownloadResourceHandler members from the UI thread.
     50 static void StartOnUIThread(
     51     scoped_ptr<DownloadCreateInfo> info,
     52     scoped_ptr<ByteStreamReader> stream,
     53     const DownloadUrlParameters::OnStartedCallback& started_cb) {
     54   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     55 
     56   DownloadManager* download_manager = info->request_handle.GetDownloadManager();
     57   if (!download_manager) {
     58     // NULL in unittests or if the page closed right after starting the
     59     // download.
     60     if (!started_cb.is_null())
     61       started_cb.Run(NULL, net::ERR_ACCESS_DENIED);
     62     return;
     63   }
     64 
     65   download_manager->StartDownload(info.Pass(), stream.Pass(), started_cb);
     66 }
     67 
     68 }  // namespace
     69 
     70 const int DownloadResourceHandler::kDownloadByteStreamSize = 100 * 1024;
     71 
     72 DownloadResourceHandler::DownloadResourceHandler(
     73     uint32 id,
     74     net::URLRequest* request,
     75     const DownloadUrlParameters::OnStartedCallback& started_cb,
     76     scoped_ptr<DownloadSaveInfo> save_info)
     77     : download_id_(id),
     78       render_view_id_(0),               // Actually initialized below.
     79       content_length_(0),
     80       request_(request),
     81       started_cb_(started_cb),
     82       save_info_(save_info.Pass()),
     83       last_buffer_size_(0),
     84       bytes_read_(0),
     85       pause_count_(0),
     86       was_deferred_(false),
     87       on_response_started_called_(false) {
     88   ResourceRequestInfoImpl* info(ResourceRequestInfoImpl::ForRequest(request));
     89   global_id_ = info->GetGlobalRequestID();
     90   render_view_id_ = info->GetRouteID();
     91 
     92   RecordDownloadCount(UNTHROTTLED_COUNT);
     93 }
     94 
     95 bool DownloadResourceHandler::OnUploadProgress(int request_id,
     96                                                uint64 position,
     97                                                uint64 size) {
     98   return true;
     99 }
    100 
    101 bool DownloadResourceHandler::OnRequestRedirected(
    102     int request_id,
    103     const GURL& url,
    104     ResourceResponse* response,
    105     bool* defer) {
    106   return true;
    107 }
    108 
    109 // Send the download creation information to the download thread.
    110 bool DownloadResourceHandler::OnResponseStarted(
    111     int request_id,
    112     ResourceResponse* response,
    113     bool* defer) {
    114   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    115   // There can be only one (call)
    116   DCHECK(!on_response_started_called_);
    117   on_response_started_called_ = true;
    118 
    119   VLOG(20) << __FUNCTION__ << "()" << DebugString()
    120            << " request_id = " << request_id;
    121   download_start_time_ = base::TimeTicks::Now();
    122 
    123   // If it's a download, we don't want to poison the cache with it.
    124   request_->StopCaching();
    125 
    126   // Lower priority as well, so downloads don't contend for resources
    127   // with main frames.
    128   request_->SetPriority(net::IDLE);
    129 
    130   std::string content_disposition;
    131   request_->GetResponseHeaderByName("content-disposition",
    132                                     &content_disposition);
    133   SetContentDisposition(content_disposition);
    134   SetContentLength(response->head.content_length);
    135 
    136   const ResourceRequestInfoImpl* request_info =
    137       ResourceRequestInfoImpl::ForRequest(request_);
    138 
    139   // Deleted in DownloadManager.
    140   scoped_ptr<DownloadCreateInfo> info(new DownloadCreateInfo(
    141       base::Time::Now(), content_length_,
    142       request_->net_log(), request_info->HasUserGesture(),
    143       request_info->GetPageTransition()));
    144 
    145   // Create the ByteStream for sending data to the download sink.
    146   scoped_ptr<ByteStreamReader> stream_reader;
    147   CreateByteStream(
    148       base::MessageLoopProxy::current(),
    149       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE),
    150       kDownloadByteStreamSize, &stream_writer_, &stream_reader);
    151   stream_writer_->RegisterCallback(
    152       base::Bind(&DownloadResourceHandler::ResumeRequest, AsWeakPtr()));
    153 
    154   info->download_id = download_id_;
    155   info->url_chain = request_->url_chain();
    156   info->referrer_url = GURL(request_->referrer());
    157   info->start_time = base::Time::Now();
    158   info->total_bytes = content_length_;
    159   info->has_user_gesture = request_info->HasUserGesture();
    160   info->content_disposition = content_disposition_;
    161   info->mime_type = response->head.mime_type;
    162   info->remote_address = request_->GetSocketAddress().host();
    163   RecordDownloadMimeType(info->mime_type);
    164   RecordDownloadContentDisposition(info->content_disposition);
    165 
    166   info->request_handle =
    167       DownloadRequestHandle(AsWeakPtr(), global_id_.child_id,
    168                             render_view_id_, global_id_.request_id);
    169 
    170   // Get the last modified time and etag.
    171   const net::HttpResponseHeaders* headers = request_->response_headers();
    172   if (headers) {
    173     std::string last_modified_hdr;
    174     if (headers->EnumerateHeader(NULL, "Last-Modified", &last_modified_hdr))
    175       info->last_modified = last_modified_hdr;
    176     if (headers->EnumerateHeader(NULL, "ETag", &etag_))
    177       info->etag = etag_;
    178 
    179     int status = headers->response_code();
    180     if (2 == status / 100  && status != net::HTTP_PARTIAL_CONTENT) {
    181       // Success & not range response; if we asked for a range, we didn't
    182       // get it--reset the file pointers to reflect that.
    183       save_info_->offset = 0;
    184       save_info_->hash_state = "";
    185     }
    186   }
    187 
    188   std::string content_type_header;
    189   if (!response->head.headers.get() ||
    190       !response->head.headers->GetMimeType(&content_type_header))
    191     content_type_header = "";
    192   info->original_mime_type = content_type_header;
    193 
    194   if (!response->head.headers.get() ||
    195       !response->head.headers->EnumerateHeader(
    196           NULL, "Accept-Ranges", &accept_ranges_)) {
    197     accept_ranges_ = "";
    198   }
    199 
    200   info->save_info = save_info_.Pass();
    201 
    202   BrowserThread::PostTask(
    203       BrowserThread::UI, FROM_HERE,
    204       base::Bind(&StartOnUIThread,
    205                  base::Passed(&info),
    206                  base::Passed(&stream_reader),
    207                  // Pass to StartOnUIThread so that variable
    208                  // access is always on IO thread but function
    209                  // is called on UI thread.
    210                  started_cb_));
    211   // Guaranteed to be called in StartOnUIThread
    212   started_cb_.Reset();
    213 
    214   return true;
    215 }
    216 
    217 void DownloadResourceHandler::CallStartedCB(
    218     DownloadItem* item, net::Error error) {
    219   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    220   if (started_cb_.is_null())
    221     return;
    222   BrowserThread::PostTask(
    223       BrowserThread::UI, FROM_HERE,
    224       base::Bind(&CallStartedCBOnUIThread, started_cb_, item, error));
    225   started_cb_.Reset();
    226 }
    227 
    228 bool DownloadResourceHandler::OnWillStart(int request_id,
    229                                           const GURL& url,
    230                                           bool* defer) {
    231   return true;
    232 }
    233 
    234 // Create a new buffer, which will be handed to the download thread for file
    235 // writing and deletion.
    236 bool DownloadResourceHandler::OnWillRead(int request_id, net::IOBuffer** buf,
    237                                          int* buf_size, int min_size) {
    238   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    239   DCHECK(buf && buf_size);
    240   DCHECK(!read_buffer_.get());
    241 
    242   *buf_size = min_size < 0 ? kReadBufSize : min_size;
    243   last_buffer_size_ = *buf_size;
    244   read_buffer_ = new net::IOBuffer(*buf_size);
    245   *buf = read_buffer_.get();
    246   return true;
    247 }
    248 
    249 // Pass the buffer to the download file writer.
    250 bool DownloadResourceHandler::OnReadCompleted(int request_id, int bytes_read,
    251                                               bool* defer) {
    252   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    253   DCHECK(read_buffer_.get());
    254 
    255   base::TimeTicks now(base::TimeTicks::Now());
    256   if (!last_read_time_.is_null()) {
    257     double seconds_since_last_read = (now - last_read_time_).InSecondsF();
    258     if (now == last_read_time_)
    259       // Use 1/10 ms as a "very small number" so that we avoid
    260       // divide-by-zero error and still record a very high potential bandwidth.
    261       seconds_since_last_read = 0.00001;
    262 
    263     double actual_bandwidth = (bytes_read)/seconds_since_last_read;
    264     double potential_bandwidth = last_buffer_size_/seconds_since_last_read;
    265     RecordBandwidth(actual_bandwidth, potential_bandwidth);
    266   }
    267   last_read_time_ = now;
    268 
    269   if (!bytes_read)
    270     return true;
    271   bytes_read_ += bytes_read;
    272   DCHECK(read_buffer_.get());
    273 
    274   // Take the data ship it down the stream.  If the stream is full, pause the
    275   // request; the stream callback will resume it.
    276   if (!stream_writer_->Write(read_buffer_, bytes_read)) {
    277     PauseRequest();
    278     *defer = was_deferred_ = true;
    279     last_stream_pause_time_ = now;
    280   }
    281 
    282   read_buffer_ = NULL;  // Drop our reference.
    283 
    284   if (pause_count_ > 0)
    285     *defer = was_deferred_ = true;
    286 
    287   return true;
    288 }
    289 
    290 bool DownloadResourceHandler::OnResponseCompleted(
    291     int request_id,
    292     const net::URLRequestStatus& status,
    293     const std::string& security_info) {
    294   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    295   int response_code = status.is_success() ? request_->GetResponseCode() : 0;
    296   VLOG(20) << __FUNCTION__ << "()" << DebugString()
    297            << " request_id = " << request_id
    298            << " status.status() = " << status.status()
    299            << " status.error() = " << status.error()
    300            << " response_code = " << response_code;
    301 
    302   net::Error error_code = net::OK;
    303   if (status.status() == net::URLRequestStatus::FAILED ||
    304       // Note cancels as failures too.
    305       status.status() == net::URLRequestStatus::CANCELED) {
    306     error_code = static_cast<net::Error>(status.error());  // Normal case.
    307     // Make sure that at least the fact of failure comes through.
    308     if (error_code == net::OK)
    309       error_code = net::ERR_FAILED;
    310   }
    311 
    312   // ERR_CONTENT_LENGTH_MISMATCH and ERR_INCOMPLETE_CHUNKED_ENCODING are
    313   // allowed since a number of servers in the wild close the connection too
    314   // early by mistake. Other browsers - IE9, Firefox 11.0, and Safari 5.1.4 -
    315   // treat downloads as complete in both cases, so we follow their lead.
    316   if (error_code == net::ERR_CONTENT_LENGTH_MISMATCH ||
    317       error_code == net::ERR_INCOMPLETE_CHUNKED_ENCODING) {
    318     error_code = net::OK;
    319   }
    320   DownloadInterruptReason reason =
    321       ConvertNetErrorToInterruptReason(
    322         error_code, DOWNLOAD_INTERRUPT_FROM_NETWORK);
    323 
    324   if (status.status() == net::URLRequestStatus::CANCELED &&
    325       status.error() == net::ERR_ABORTED) {
    326     // CANCELED + ERR_ABORTED == something outside of the network
    327     // stack cancelled the request.  There aren't that many things that
    328     // could do this to a download request (whose lifetime is separated from
    329     // the tab from which it came).  We map this to USER_CANCELLED as the
    330     // case we know about (system suspend because of laptop close) corresponds
    331     // to a user action.
    332     // TODO(ahendrickson) -- Find a better set of codes to use here, as
    333     // CANCELED/ERR_ABORTED can occur for reasons other than user cancel.
    334     reason = DOWNLOAD_INTERRUPT_REASON_USER_CANCELED;
    335   }
    336 
    337   if (status.is_success() &&
    338       reason == DOWNLOAD_INTERRUPT_REASON_NONE &&
    339       request_->response_headers()) {
    340     // Handle server's response codes.
    341     switch(response_code) {
    342       case -1:                          // Non-HTTP request.
    343       case net::HTTP_OK:
    344       case net::HTTP_CREATED:
    345       case net::HTTP_ACCEPTED:
    346       case net::HTTP_NON_AUTHORITATIVE_INFORMATION:
    347       case net::HTTP_RESET_CONTENT:
    348       case net::HTTP_PARTIAL_CONTENT:
    349         // Expected successful codes.
    350         break;
    351       case net::HTTP_NO_CONTENT:
    352       case net::HTTP_NOT_FOUND:
    353         reason = DOWNLOAD_INTERRUPT_REASON_SERVER_BAD_CONTENT;
    354         break;
    355       case net::HTTP_PRECONDITION_FAILED:
    356         // Failed our 'If-Unmodified-Since' or 'If-Match'; see
    357         // download_manager_impl.cc BeginDownload()
    358         reason = DOWNLOAD_INTERRUPT_REASON_SERVER_PRECONDITION;
    359         break;
    360       case net::HTTP_REQUESTED_RANGE_NOT_SATISFIABLE:
    361         // Retry by downloading from the start automatically:
    362         // If we haven't received data when we get this error, we won't.
    363         reason = DOWNLOAD_INTERRUPT_REASON_SERVER_NO_RANGE;
    364         break;
    365       default:    // All other errors.
    366         // Redirection and informational codes should have been handled earlier
    367         // in the stack.
    368         DCHECK_NE(3, response_code / 100);
    369         DCHECK_NE(1, response_code / 100);
    370         reason = DOWNLOAD_INTERRUPT_REASON_SERVER_FAILED;
    371         break;
    372     }
    373   }
    374 
    375   RecordAcceptsRanges(accept_ranges_, bytes_read_, etag_);
    376   RecordNetworkBlockage(
    377       base::TimeTicks::Now() - download_start_time_, total_pause_time_);
    378 
    379   CallStartedCB(NULL, error_code);
    380 
    381   // Send the info down the stream.  Conditional is in case we get
    382   // OnResponseCompleted without OnResponseStarted.
    383   if (stream_writer_)
    384     stream_writer_->Close(reason);
    385 
    386   // If the error mapped to something unknown, record it so that
    387   // we can drill down.
    388   if (reason == DOWNLOAD_INTERRUPT_REASON_NETWORK_FAILED) {
    389     UMA_HISTOGRAM_CUSTOM_ENUMERATION("Download.MapErrorNetworkFailed",
    390                                      std::abs(status.error()),
    391                                      net::GetAllErrorCodesForUma());
    392   }
    393 
    394   stream_writer_.reset();  // We no longer need the stream.
    395   read_buffer_ = NULL;
    396 
    397   return true;
    398 }
    399 
    400 void DownloadResourceHandler::OnDataDownloaded(
    401     int request_id,
    402     int bytes_downloaded) {
    403   NOTREACHED();
    404 }
    405 
    406 // If the content-length header is not present (or contains something other
    407 // than numbers), the incoming content_length is -1 (unknown size).
    408 // Set the content length to 0 to indicate unknown size to DownloadManager.
    409 void DownloadResourceHandler::SetContentLength(const int64& content_length) {
    410   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    411   content_length_ = 0;
    412   if (content_length > 0)
    413     content_length_ = content_length;
    414 }
    415 
    416 void DownloadResourceHandler::SetContentDisposition(
    417     const std::string& content_disposition) {
    418   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    419   content_disposition_ = content_disposition;
    420 }
    421 
    422 void DownloadResourceHandler::PauseRequest() {
    423   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    424 
    425   ++pause_count_;
    426 }
    427 
    428 void DownloadResourceHandler::ResumeRequest() {
    429   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    430   DCHECK_LT(0, pause_count_);
    431 
    432   --pause_count_;
    433 
    434   if (!was_deferred_)
    435     return;
    436   if (pause_count_ > 0)
    437     return;
    438 
    439   was_deferred_ = false;
    440   if (!last_stream_pause_time_.is_null()) {
    441     total_pause_time_ += (base::TimeTicks::Now() - last_stream_pause_time_);
    442     last_stream_pause_time_ = base::TimeTicks();
    443   }
    444 
    445   controller()->Resume();
    446 }
    447 
    448 void DownloadResourceHandler::CancelRequest() {
    449   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    450 
    451   ResourceDispatcherHostImpl::Get()->CancelRequest(
    452       global_id_.child_id,
    453       global_id_.request_id,
    454       false);
    455 }
    456 
    457 std::string DownloadResourceHandler::DebugString() const {
    458   return base::StringPrintf("{"
    459                             " url_ = " "\"%s\""
    460                             " global_id_ = {"
    461                             " child_id = " "%d"
    462                             " request_id = " "%d"
    463                             " }"
    464                             " render_view_id_ = " "%d"
    465                             " }",
    466                             request_ ?
    467                                 request_->url().spec().c_str() :
    468                                 "<NULL request>",
    469                             global_id_.child_id,
    470                             global_id_.request_id,
    471                             render_view_id_);
    472 }
    473 
    474 DownloadResourceHandler::~DownloadResourceHandler() {
    475   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    476 
    477   // This won't do anything if the callback was called before.
    478   // If it goes through, it will likely be because OnWillStart() returned
    479   // false somewhere in the chain of resource handlers.
    480   CallStartedCB(NULL, net::ERR_ACCESS_DENIED);
    481 
    482   // Remove output stream callback if a stream exists.
    483   if (stream_writer_)
    484     stream_writer_->RegisterCallback(base::Closure());
    485 
    486   UMA_HISTOGRAM_TIMES("SB2.DownloadDuration",
    487                       base::TimeTicks::Now() - download_start_time_);
    488 }
    489 
    490 }  // namespace content
    491