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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     : ResourceHandler(request),
     78       download_id_(id),
     79       started_cb_(started_cb),
     80       save_info_(save_info.Pass()),
     81       last_buffer_size_(0),
     82       bytes_read_(0),
     83       pause_count_(0),
     84       was_deferred_(false),
     85       on_response_started_called_(false) {
     86   RecordDownloadCount(UNTHROTTLED_COUNT);
     87 }
     88 
     89 bool DownloadResourceHandler::OnUploadProgress(int request_id,
     90                                                uint64 position,
     91                                                uint64 size) {
     92   return true;
     93 }
     94 
     95 bool DownloadResourceHandler::OnRequestRedirected(
     96     int request_id,
     97     const GURL& url,
     98     ResourceResponse* response,
     99     bool* defer) {
    100   // We treat a download as a main frame load, and thus update the policy URL
    101   // on redirects.
    102   request()->set_first_party_for_cookies(url);
    103   return true;
    104 }
    105 
    106 // Send the download creation information to the download thread.
    107 bool DownloadResourceHandler::OnResponseStarted(
    108     int request_id,
    109     ResourceResponse* response,
    110     bool* defer) {
    111   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    112   // There can be only one (call)
    113   DCHECK(!on_response_started_called_);
    114   on_response_started_called_ = true;
    115 
    116   VLOG(20) << __FUNCTION__ << "()" << DebugString()
    117            << " request_id = " << request_id;
    118   download_start_time_ = base::TimeTicks::Now();
    119 
    120   // If it's a download, we don't want to poison the cache with it.
    121   request()->StopCaching();
    122 
    123   // Lower priority as well, so downloads don't contend for resources
    124   // with main frames.
    125   request()->SetPriority(net::IDLE);
    126 
    127   // If the content-length header is not present (or contains something other
    128   // than numbers), the incoming content_length is -1 (unknown size).
    129   // Set the content length to 0 to indicate unknown size to DownloadManager.
    130   int64 content_length =
    131       response->head.content_length > 0 ? response->head.content_length : 0;
    132 
    133   const ResourceRequestInfoImpl* request_info = GetRequestInfo();
    134 
    135   // Deleted in DownloadManager.
    136   scoped_ptr<DownloadCreateInfo> info(
    137       new DownloadCreateInfo(base::Time::Now(),
    138                              content_length,
    139                              request()->net_log(),
    140                              request_info->HasUserGesture(),
    141                              request_info->GetPageTransition(),
    142                              save_info_.Pass()));
    143 
    144   // Create the ByteStream for sending data to the download sink.
    145   scoped_ptr<ByteStreamReader> stream_reader;
    146   CreateByteStream(
    147       base::MessageLoopProxy::current(),
    148       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE),
    149       kDownloadByteStreamSize, &stream_writer_, &stream_reader);
    150   stream_writer_->RegisterCallback(
    151       base::Bind(&DownloadResourceHandler::ResumeRequest, AsWeakPtr()));
    152 
    153   info->download_id = download_id_;
    154   info->url_chain = request()->url_chain();
    155   info->referrer_url = GURL(request()->referrer());
    156   info->mime_type = response->head.mime_type;
    157   info->remote_address = request()->GetSocketAddress().host();
    158   request()->GetResponseHeaderByName("content-disposition",
    159                                      &info->content_disposition);
    160   RecordDownloadMimeType(info->mime_type);
    161   RecordDownloadContentDisposition(info->content_disposition);
    162 
    163   info->request_handle =
    164       DownloadRequestHandle(AsWeakPtr(), request_info->GetChildID(),
    165                             request_info->GetRouteID(),
    166                             request_info->GetRequestID());
    167 
    168   // Get the last modified time and etag.
    169   const net::HttpResponseHeaders* headers = request()->response_headers();
    170   if (headers) {
    171     if (headers->HasStrongValidators()) {
    172       // If we don't have strong validators as per RFC 2616 section 13.3.3, then
    173       // we neither store nor use them for range requests.
    174       if (!headers->EnumerateHeader(NULL, "Last-Modified",
    175                                     &info->last_modified))
    176         info->last_modified.clear();
    177       if (!headers->EnumerateHeader(NULL, "ETag", &info->etag))
    178         info->etag.clear();
    179     }
    180 
    181     int status = headers->response_code();
    182     if (2 == status / 100  && status != net::HTTP_PARTIAL_CONTENT) {
    183       // Success & not range response; if we asked for a range, we didn't
    184       // get it--reset the file pointers to reflect that.
    185       info->save_info->offset = 0;
    186       info->save_info->hash_state = "";
    187     }
    188 
    189     if (!headers->GetMimeType(&info->original_mime_type))
    190       info->original_mime_type.clear();
    191   }
    192 
    193   BrowserThread::PostTask(
    194       BrowserThread::UI, FROM_HERE,
    195       base::Bind(&StartOnUIThread,
    196                  base::Passed(&info),
    197                  base::Passed(&stream_reader),
    198                  // Pass to StartOnUIThread so that variable
    199                  // access is always on IO thread but function
    200                  // is called on UI thread.
    201                  started_cb_));
    202   // Guaranteed to be called in StartOnUIThread
    203   started_cb_.Reset();
    204 
    205   return true;
    206 }
    207 
    208 void DownloadResourceHandler::CallStartedCB(
    209     DownloadItem* item, net::Error error) {
    210   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    211   if (started_cb_.is_null())
    212     return;
    213   BrowserThread::PostTask(
    214       BrowserThread::UI, FROM_HERE,
    215       base::Bind(&CallStartedCBOnUIThread, started_cb_, item, error));
    216   started_cb_.Reset();
    217 }
    218 
    219 bool DownloadResourceHandler::OnWillStart(int request_id,
    220                                           const GURL& url,
    221                                           bool* defer) {
    222   return true;
    223 }
    224 
    225 // Create a new buffer, which will be handed to the download thread for file
    226 // writing and deletion.
    227 bool DownloadResourceHandler::OnWillRead(int request_id,
    228                                          scoped_refptr<net::IOBuffer>* buf,
    229                                          int* buf_size,
    230                                          int min_size) {
    231   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    232   DCHECK(buf && buf_size);
    233   DCHECK(!read_buffer_.get());
    234 
    235   *buf_size = min_size < 0 ? kReadBufSize : min_size;
    236   last_buffer_size_ = *buf_size;
    237   read_buffer_ = new net::IOBuffer(*buf_size);
    238   *buf = read_buffer_.get();
    239   return true;
    240 }
    241 
    242 // Pass the buffer to the download file writer.
    243 bool DownloadResourceHandler::OnReadCompleted(int request_id, int bytes_read,
    244                                               bool* defer) {
    245   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    246   DCHECK(read_buffer_.get());
    247 
    248   base::TimeTicks now(base::TimeTicks::Now());
    249   if (!last_read_time_.is_null()) {
    250     double seconds_since_last_read = (now - last_read_time_).InSecondsF();
    251     if (now == last_read_time_)
    252       // Use 1/10 ms as a "very small number" so that we avoid
    253       // divide-by-zero error and still record a very high potential bandwidth.
    254       seconds_since_last_read = 0.00001;
    255 
    256     double actual_bandwidth = (bytes_read)/seconds_since_last_read;
    257     double potential_bandwidth = last_buffer_size_/seconds_since_last_read;
    258     RecordBandwidth(actual_bandwidth, potential_bandwidth);
    259   }
    260   last_read_time_ = now;
    261 
    262   if (!bytes_read)
    263     return true;
    264   bytes_read_ += bytes_read;
    265   DCHECK(read_buffer_.get());
    266 
    267   // Take the data ship it down the stream.  If the stream is full, pause the
    268   // request; the stream callback will resume it.
    269   if (!stream_writer_->Write(read_buffer_, bytes_read)) {
    270     PauseRequest();
    271     *defer = was_deferred_ = true;
    272     last_stream_pause_time_ = now;
    273   }
    274 
    275   read_buffer_ = NULL;  // Drop our reference.
    276 
    277   if (pause_count_ > 0)
    278     *defer = was_deferred_ = true;
    279 
    280   return true;
    281 }
    282 
    283 void DownloadResourceHandler::OnResponseCompleted(
    284     int request_id,
    285     const net::URLRequestStatus& status,
    286     const std::string& security_info,
    287     bool* defer) {
    288   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    289   int response_code = status.is_success() ? request()->GetResponseCode() : 0;
    290   VLOG(20) << __FUNCTION__ << "()" << DebugString()
    291            << " request_id = " << request_id
    292            << " status.status() = " << status.status()
    293            << " status.error() = " << status.error()
    294            << " response_code = " << response_code;
    295 
    296   net::Error error_code = net::OK;
    297   if (status.status() == net::URLRequestStatus::FAILED ||
    298       // Note cancels as failures too.
    299       status.status() == net::URLRequestStatus::CANCELED) {
    300     error_code = static_cast<net::Error>(status.error());  // Normal case.
    301     // Make sure that at least the fact of failure comes through.
    302     if (error_code == net::OK)
    303       error_code = net::ERR_FAILED;
    304   }
    305 
    306   // ERR_CONTENT_LENGTH_MISMATCH and ERR_INCOMPLETE_CHUNKED_ENCODING are
    307   // allowed since a number of servers in the wild close the connection too
    308   // early by mistake. Other browsers - IE9, Firefox 11.0, and Safari 5.1.4 -
    309   // treat downloads as complete in both cases, so we follow their lead.
    310   if (error_code == net::ERR_CONTENT_LENGTH_MISMATCH ||
    311       error_code == net::ERR_INCOMPLETE_CHUNKED_ENCODING) {
    312     error_code = net::OK;
    313   }
    314   DownloadInterruptReason reason =
    315       ConvertNetErrorToInterruptReason(
    316         error_code, DOWNLOAD_INTERRUPT_FROM_NETWORK);
    317 
    318   if (status.status() == net::URLRequestStatus::CANCELED &&
    319       status.error() == net::ERR_ABORTED) {
    320     // CANCELED + ERR_ABORTED == something outside of the network
    321     // stack cancelled the request.  There aren't that many things that
    322     // could do this to a download request (whose lifetime is separated from
    323     // the tab from which it came).  We map this to USER_CANCELLED as the
    324     // case we know about (system suspend because of laptop close) corresponds
    325     // to a user action.
    326     // TODO(ahendrickson) -- Find a better set of codes to use here, as
    327     // CANCELED/ERR_ABORTED can occur for reasons other than user cancel.
    328     reason = DOWNLOAD_INTERRUPT_REASON_USER_CANCELED;
    329   }
    330 
    331   if (status.is_success() &&
    332       reason == DOWNLOAD_INTERRUPT_REASON_NONE &&
    333       request()->response_headers()) {
    334     // Handle server's response codes.
    335     switch(response_code) {
    336       case -1:                          // Non-HTTP request.
    337       case net::HTTP_OK:
    338       case net::HTTP_CREATED:
    339       case net::HTTP_ACCEPTED:
    340       case net::HTTP_NON_AUTHORITATIVE_INFORMATION:
    341       case net::HTTP_RESET_CONTENT:
    342       case net::HTTP_PARTIAL_CONTENT:
    343         // Expected successful codes.
    344         break;
    345       case net::HTTP_NO_CONTENT:
    346       case net::HTTP_NOT_FOUND:
    347         reason = DOWNLOAD_INTERRUPT_REASON_SERVER_BAD_CONTENT;
    348         break;
    349       case net::HTTP_PRECONDITION_FAILED:
    350         // Failed our 'If-Unmodified-Since' or 'If-Match'; see
    351         // download_manager_impl.cc BeginDownload()
    352         reason = DOWNLOAD_INTERRUPT_REASON_SERVER_PRECONDITION;
    353         break;
    354       case net::HTTP_REQUESTED_RANGE_NOT_SATISFIABLE:
    355         // Retry by downloading from the start automatically:
    356         // If we haven't received data when we get this error, we won't.
    357         reason = DOWNLOAD_INTERRUPT_REASON_SERVER_NO_RANGE;
    358         break;
    359       default:    // All other errors.
    360         // Redirection and informational codes should have been handled earlier
    361         // in the stack.
    362         DCHECK_NE(3, response_code / 100);
    363         DCHECK_NE(1, response_code / 100);
    364         reason = DOWNLOAD_INTERRUPT_REASON_SERVER_FAILED;
    365         break;
    366     }
    367   }
    368 
    369   std::string accept_ranges;
    370   bool has_strong_validators = false;
    371   if (request()->response_headers()) {
    372     request()->response_headers()->EnumerateHeader(
    373         NULL, "Accept-Ranges", &accept_ranges);
    374     has_strong_validators =
    375         request()->response_headers()->HasStrongValidators();
    376   }
    377   RecordAcceptsRanges(accept_ranges, bytes_read_, has_strong_validators);
    378   RecordNetworkBlockage(base::TimeTicks::Now() - download_start_time_,
    379                         total_pause_time_);
    380 
    381   CallStartedCB(NULL, error_code);
    382 
    383   // Send the info down the stream.  Conditional is in case we get
    384   // OnResponseCompleted without OnResponseStarted.
    385   if (stream_writer_)
    386     stream_writer_->Close(reason);
    387 
    388   // If the error mapped to something unknown, record it so that
    389   // we can drill down.
    390   if (reason == DOWNLOAD_INTERRUPT_REASON_NETWORK_FAILED) {
    391     UMA_HISTOGRAM_CUSTOM_ENUMERATION("Download.MapErrorNetworkFailed",
    392                                      std::abs(status.error()),
    393                                      net::GetAllErrorCodesForUma());
    394   }
    395 
    396   stream_writer_.reset();  // We no longer need the stream.
    397   read_buffer_ = NULL;
    398 }
    399 
    400 void DownloadResourceHandler::OnDataDownloaded(
    401     int request_id,
    402     int bytes_downloaded) {
    403   NOTREACHED();
    404 }
    405 
    406 void DownloadResourceHandler::PauseRequest() {
    407   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    408 
    409   ++pause_count_;
    410 }
    411 
    412 void DownloadResourceHandler::ResumeRequest() {
    413   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    414   DCHECK_LT(0, pause_count_);
    415 
    416   --pause_count_;
    417 
    418   if (!was_deferred_)
    419     return;
    420   if (pause_count_ > 0)
    421     return;
    422 
    423   was_deferred_ = false;
    424   if (!last_stream_pause_time_.is_null()) {
    425     total_pause_time_ += (base::TimeTicks::Now() - last_stream_pause_time_);
    426     last_stream_pause_time_ = base::TimeTicks();
    427   }
    428 
    429   controller()->Resume();
    430 }
    431 
    432 void DownloadResourceHandler::CancelRequest() {
    433   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    434 
    435   const ResourceRequestInfo* info = GetRequestInfo();
    436   ResourceDispatcherHostImpl::Get()->CancelRequest(
    437       info->GetChildID(),
    438       info->GetRequestID(),
    439       false);
    440 }
    441 
    442 std::string DownloadResourceHandler::DebugString() const {
    443   const ResourceRequestInfo* info = GetRequestInfo();
    444   return base::StringPrintf("{"
    445                             " url_ = " "\"%s\""
    446                             " info = {"
    447                             " child_id = " "%d"
    448                             " request_id = " "%d"
    449                             " route_id = " "%d"
    450                             " }"
    451                             " }",
    452                             request() ?
    453                                 request()->url().spec().c_str() :
    454                                 "<NULL request>",
    455                             info->GetChildID(),
    456                             info->GetRequestID(),
    457                             info->GetRouteID());
    458 }
    459 
    460 DownloadResourceHandler::~DownloadResourceHandler() {
    461   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
    462 
    463   // This won't do anything if the callback was called before.
    464   // If it goes through, it will likely be because OnWillStart() returned
    465   // false somewhere in the chain of resource handlers.
    466   CallStartedCB(NULL, net::ERR_ACCESS_DENIED);
    467 
    468   // Remove output stream callback if a stream exists.
    469   if (stream_writer_)
    470     stream_writer_->RegisterCallback(base::Closure());
    471 
    472   UMA_HISTOGRAM_TIMES("SB2.DownloadDuration",
    473                       base::TimeTicks::Now() - download_start_time_);
    474 }
    475 
    476 }  // namespace content
    477