net/http/partial_data.cc

   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 "net/http/partial_data.h"
   6
   7 #include "base/bind.h"
   8 #include "base/bind_helpers.h"
   9 #include "base/format_macros.h"
  10 #include "base/logging.h"
  11 #include "base/strings/string_number_conversions.h"
  12 #include "base/strings/string_util.h"
  13 #include "base/strings/stringprintf.h"
  14 #include "net/base/net_errors.h"
  15 #include "net/disk_cache/disk_cache.h"
  16 #include "net/http/http_response_headers.h"
  17 #include "net/http/http_util.h"
  18
  19 namespace net {
  20
  21 namespace {
  22
  23 // The headers that we have to process.
  24 const char kLengthHeader[] = "Content-Length";
  25 const char kRangeHeader[] = "Content-Range";
  26 const int kDataStream = 1;
  27
  28 void AddRangeHeader(int64 start, int64 end, HttpRequestHeaders* headers) {
  29   DCHECK(start >= 0 || end >= 0);
  30   std::string my_start, my_end;
  31   if (start >= 0)
  32     my_start = base::Int64ToString(start);
  33   if (end >= 0)
  34     my_end = base::Int64ToString(end);
  35
  36   headers->SetHeader(
  37       HttpRequestHeaders::kRange,
  38       base::StringPrintf("bytes=%s-%s", my_start.c_str(), my_end.c_str()));
  39 }
  40
  41 }  // namespace
  42
  43 // A core object that can be detached from the Partialdata object at destruction
  44 // so that asynchronous operations cleanup can be performed.
  45 class PartialData::Core {
  46  public:
  47   // Build a new core object. Lifetime management is automatic.
  48   static Core* CreateCore(PartialData* owner) {
  49     return new Core(owner);
  50   }
  51
  52   // Wrapper for Entry::GetAvailableRange. If this method returns ERR_IO_PENDING
  53   // PartialData::GetAvailableRangeCompleted() will be invoked on the owner
  54   // object when finished (unless Cancel() is called first).
  55   int GetAvailableRange(disk_cache::Entry* entry, int64 offset, int len,
  56                         int64* start);
  57
  58   // Cancels a pending operation. It is a mistake to call this method if there
  59   // is no operation in progress; in fact, there will be no object to do so.
  60   void Cancel();
  61
  62  private:
  63   explicit Core(PartialData* owner);
  64   ~Core();
  65
  66   // Pending io completion routine.
  67   void OnIOComplete(int result);
  68
  69   PartialData* owner_;
  70   int64 start_;
  71
  72   DISALLOW_COPY_AND_ASSIGN(Core);
  73 };
  74
  75 PartialData::Core::Core(PartialData* owner)
  76     : owner_(owner), start_(0) {
  77   DCHECK(!owner_->core_);
  78   owner_->core_ = this;
  79 }
  80
  81 PartialData::Core::~Core() {
  82   if (owner_)
  83     owner_->core_ = NULL;
  84 }
  85
  86 void PartialData::Core::Cancel() {
  87   DCHECK(owner_);
  88   owner_ = NULL;
  89 }
  90
  91 int PartialData::Core::GetAvailableRange(disk_cache::Entry* entry, int64 offset,
  92                                          int len, int64* start) {
  93   int rv = entry->GetAvailableRange(
  94       offset, len, &start_, base::Bind(&PartialData::Core::OnIOComplete,
  95                                        base::Unretained(this)));
  96   if (rv != net::ERR_IO_PENDING) {
  97     // The callback will not be invoked. Lets cleanup.
  98     *start = start_;
  99     delete this;
 100   }
 101   return rv;
 102 }
 103
 104 void PartialData::Core::OnIOComplete(int result) {
 105   if (owner_)
 106     owner_->GetAvailableRangeCompleted(result, start_);
 107   delete this;
 108 }
 109
 110 // -----------------------------------------------------------------------------
 111
 112 PartialData::PartialData()
 113     : range_present_(false),
 114       final_range_(false),
 115       sparse_entry_(true),
 116       truncated_(false),
 117       initial_validation_(false),
 118       core_(NULL) {
 119 }
 120
 121 PartialData::~PartialData() {
 122   if (core_)
 123     core_->Cancel();
 124 }
 125
 126 bool PartialData::Init(const HttpRequestHeaders& headers) {
 127   std::string range_header;
 128   if (!headers.GetHeader(HttpRequestHeaders::kRange, &range_header))
 129     return false;
 130
 131   std::vector<HttpByteRange> ranges;
 132   if (!HttpUtil::ParseRangeHeader(range_header, &ranges) || ranges.size() != 1)
 133     return false;
 134
 135   // We can handle this range request.
 136   byte_range_ = ranges[0];
 137   if (!byte_range_.IsValid())
 138     return false;
 139
 140   resource_size_ = 0;
 141   current_range_start_ = byte_range_.first_byte_position();
 142
 143   DVLOG(1) << "Range start: " << current_range_start_ << " end: " <<
 144                byte_range_.last_byte_position();
 145   return true;
 146 }
 147
 148 void PartialData::SetHeaders(const HttpRequestHeaders& headers) {
 149   DCHECK(extra_headers_.IsEmpty());
 150   extra_headers_.CopyFrom(headers);
 151 }
 152
 153 void PartialData::RestoreHeaders(HttpRequestHeaders* headers) const {
 154   DCHECK(current_range_start_ >= 0 || byte_range_.IsSuffixByteRange());
 155   int64 end = byte_range_.IsSuffixByteRange() ?
 156               byte_range_.suffix_length() : byte_range_.last_byte_position();
 157
 158   headers->CopyFrom(extra_headers_);
 159   if (!truncated_ && byte_range_.IsValid())
 160     AddRangeHeader(current_range_start_, end, headers);
 161 }
 162
 163 int PartialData::ShouldValidateCache(disk_cache::Entry* entry,
 164                                      const CompletionCallback& callback) {
 165   DCHECK_GE(current_range_start_, 0);
 166
 167   // Scan the disk cache for the first cached portion within this range.
 168   int len = GetNextRangeLen();
 169   if (!len)
 170     return 0;
 171
 172   DVLOG(3) << "ShouldValidateCache len: " << len;
 173
 174   if (sparse_entry_) {
 175     DCHECK(callback_.is_null());
 176     Core* core = Core::CreateCore(this);
 177     cached_min_len_ = core->GetAvailableRange(entry, current_range_start_, len,
 178                                               &cached_start_);
 179
 180     if (cached_min_len_ == ERR_IO_PENDING) {
 181       callback_ = callback;
 182       return ERR_IO_PENDING;
 183     }
 184   } else if (!truncated_) {
 185     if (byte_range_.HasFirstBytePosition() &&
 186         byte_range_.first_byte_position() >= resource_size_) {
 187       // The caller should take care of this condition because we should have
 188       // failed IsRequestedRangeOK(), but it's better to be consistent here.
 189       len = 0;
 190     }
 191     cached_min_len_ = len;
 192     cached_start_ = current_range_start_;
 193   }
 194
 195   if (cached_min_len_ < 0)
 196     return cached_min_len_;
 197
 198   // Return a positive number to indicate success (versus error or finished).
 199   return 1;
 200 }
 201
 202 void PartialData::PrepareCacheValidation(disk_cache::Entry* entry,
 203                                          HttpRequestHeaders* headers) {
 204   DCHECK_GE(current_range_start_, 0);
 205   DCHECK_GE(cached_min_len_, 0);
 206
 207   int len = GetNextRangeLen();
 208   DCHECK_NE(0, len);
 209   range_present_ = false;
 210
 211   headers->CopyFrom(extra_headers_);
 212
 213   if (!cached_min_len_) {
 214     // We don't have anything else stored.
 215     final_range_ = true;
 216     cached_start_ =
 217         byte_range_.HasLastBytePosition() ? current_range_start_  + len : 0;
 218   }
 219
 220   if (current_range_start_ == cached_start_) {
 221     // The data lives in the cache.
 222     range_present_ = true;
 223     if (len == cached_min_len_)
 224       final_range_ = true;
 225     AddRangeHeader(current_range_start_, cached_start_ + cached_min_len_ - 1,
 226                    headers);
 227   } else {
 228     // This range is not in the cache.
 229     AddRangeHeader(current_range_start_, cached_start_ - 1, headers);
 230   }
 231 }
 232
 233 bool PartialData::IsCurrentRangeCached() const {
 234   return range_present_;
 235 }
 236
 237 bool PartialData::IsLastRange() const {
 238   return final_range_;
 239 }
 240
 241 bool PartialData::UpdateFromStoredHeaders(const HttpResponseHeaders* headers,
 242                                           disk_cache::Entry* entry,
 243                                           bool truncated) {
 244   resource_size_ = 0;
 245   if (truncated) {
 246     DCHECK_EQ(headers->response_code(), 200);
 247     // We don't have the real length and the user may be trying to create a
 248     // sparse entry so let's not write to this entry.
 249     if (byte_range_.IsValid())
 250       return false;
 251
 252     if (!headers->HasStrongValidators())
 253       return false;
 254
 255     // Now we avoid resume if there is no content length, but that was not
 256     // always the case so double check here.
 257     int64 total_length = headers->GetContentLength();
 258     if (total_length <= 0)
 259       return false;
 260
 261     truncated_ = true;
 262     initial_validation_ = true;
 263     sparse_entry_ = false;
 264     int current_len = entry->GetDataSize(kDataStream);
 265     byte_range_.set_first_byte_position(current_len);
 266     resource_size_ = total_length;
 267     current_range_start_ = current_len;
 268     cached_min_len_ = current_len;
 269     cached_start_ = current_len + 1;
 270     return true;
 271   }
 272
 273   if (headers->response_code() != 206) {
 274     DCHECK(byte_range_.IsValid());
 275     sparse_entry_ = false;
 276     resource_size_ = entry->GetDataSize(kDataStream);
 277     DVLOG(2) << "UpdateFromStoredHeaders size: " << resource_size_;
 278     return true;
 279   }
 280
 281   if (!headers->HasStrongValidators())
 282     return false;
 283
 284   int64 length_value = headers->GetContentLength();
 285   if (length_value <= 0)
 286     return false;  // We must have stored the resource length.
 287
 288   resource_size_ = length_value;
 289
 290   // Make sure that this is really a sparse entry.
 291   return entry->CouldBeSparse();
 292 }
 293
 294 void PartialData::SetRangeToStartDownload() {
 295   DCHECK(truncated_);
 296   DCHECK(!sparse_entry_);
 297   current_range_start_ = 0;
 298   cached_start_ = 0;
 299   initial_validation_ = false;
 300 }
 301
 302 bool PartialData::IsRequestedRangeOK() {
 303   if (byte_range_.IsValid()) {
 304     if (!byte_range_.ComputeBounds(resource_size_))
 305       return false;
 306     if (truncated_)
 307       return true;
 308
 309     if (current_range_start_ < 0)
 310       current_range_start_ = byte_range_.first_byte_position();
 311   } else {
 312     // This is not a range request but we have partial data stored.
 313     current_range_start_ = 0;
 314     byte_range_.set_last_byte_position(resource_size_ - 1);
 315   }
 316
 317   bool rv = current_range_start_ >= 0;
 318   if (!rv)
 319     current_range_start_ = 0;
 320
 321   return rv;
 322 }
 323
 324 bool PartialData::ResponseHeadersOK(const HttpResponseHeaders* headers) {
 325   if (headers->response_code() == 304) {
 326     if (!byte_range_.IsValid() || truncated_)
 327       return true;
 328
 329     // We must have a complete range here.
 330     return byte_range_.HasFirstBytePosition() &&
 331         byte_range_.HasLastBytePosition();
 332   }
 333
 334   int64 start, end, total_length;
 335   if (!headers->GetContentRange(&start, &end, &total_length))
 336     return false;
 337   if (total_length <= 0)
 338     return false;
 339
 340   int64 content_length = headers->GetContentLength();
 341   if (content_length < 0 || content_length != end - start + 1)
 342     return false;
 343
 344   if (!resource_size_) {
 345     // First response. Update our values with the ones provided by the server.
 346     resource_size_ = total_length;
 347     if (!byte_range_.HasFirstBytePosition()) {
 348       byte_range_.set_first_byte_position(start);
 349       current_range_start_ = start;
 350     }
 351     if (!byte_range_.HasLastBytePosition())
 352       byte_range_.set_last_byte_position(end);
 353   } else if (resource_size_ != total_length) {
 354     return false;
 355   }
 356
 357   if (truncated_) {
 358     if (!byte_range_.HasLastBytePosition())
 359       byte_range_.set_last_byte_position(end);
 360   }
 361
 362   if (start != current_range_start_)
 363     return false;
 364
 365   if (byte_range_.IsValid() && end > byte_range_.last_byte_position())
 366     return false;
 367
 368   return true;
 369 }
 370
 371 // We are making multiple requests to complete the range requested by the user.
 372 // Just assume that everything is fine and say that we are returning what was
 373 // requested.
 374 void PartialData::FixResponseHeaders(HttpResponseHeaders* headers,
 375                                      bool success) {
 376   if (truncated_)
 377     return;
 378
 379   headers->RemoveHeader(kLengthHeader);
 380   headers->RemoveHeader(kRangeHeader);
 381
 382   int64 range_len, start, end;
 383   if (byte_range_.IsValid()) {
 384     if (success) {
 385       if (!sparse_entry_)
 386         headers->ReplaceStatusLine("HTTP/1.1 206 Partial Content");
 387
 388       DCHECK(byte_range_.HasFirstBytePosition());
 389       DCHECK(byte_range_.HasLastBytePosition());
 390       start = byte_range_.first_byte_position();
 391       end = byte_range_.last_byte_position();
 392       range_len = end - start + 1;
 393     } else {
 394       headers->ReplaceStatusLine(
 395           "HTTP/1.1 416 Requested Range Not Satisfiable");
 396       start = 0;
 397       end = 0;
 398       range_len = 0;
 399     }
 400
 401     headers->AddHeader(
 402         base::StringPrintf("%s: bytes %" PRId64 "-%" PRId64 "/%" PRId64,
 403                            kRangeHeader, start, end, resource_size_));
 404   } else {
 405     // TODO(rvargas): Is it safe to change the protocol version?
 406     headers->ReplaceStatusLine("HTTP/1.1 200 OK");
 407     DCHECK_NE(resource_size_, 0);
 408     range_len = resource_size_;
 409   }
 410
 411   headers->AddHeader(base::StringPrintf("%s: %" PRId64, kLengthHeader,
 412                                         range_len));
 413 }
 414
 415 void PartialData::FixContentLength(HttpResponseHeaders* headers) {
 416   headers->RemoveHeader(kLengthHeader);
 417   headers->AddHeader(base::StringPrintf("%s: %" PRId64, kLengthHeader,
 418                                         resource_size_));
 419 }
 420
 421 int PartialData::CacheRead(
 422     disk_cache::Entry* entry, IOBuffer* data, int data_len,
 423     const net::CompletionCallback& callback) {
 424   int read_len = std::min(data_len, cached_min_len_);
 425   if (!read_len)
 426     return 0;
 427
 428   int rv = 0;
 429   if (sparse_entry_) {
 430     rv = entry->ReadSparseData(current_range_start_, data, read_len,
 431                                callback);
 432   } else {
 433     if (current_range_start_ > kint32max)
 434       return ERR_INVALID_ARGUMENT;
 435
 436     rv = entry->ReadData(kDataStream, static_cast<int>(current_range_start_),
 437                          data, read_len, callback);
 438   }
 439   return rv;
 440 }
 441
 442 int PartialData::CacheWrite(
 443     disk_cache::Entry* entry, IOBuffer* data, int data_len,
 444     const net::CompletionCallback& callback) {
 445   DVLOG(3) << "To write: " << data_len;
 446   if (sparse_entry_) {
 447     return entry->WriteSparseData(
 448         current_range_start_, data, data_len, callback);
 449   } else  {
 450     if (current_range_start_ > kint32max)
 451       return ERR_INVALID_ARGUMENT;
 452
 453     return entry->WriteData(kDataStream, static_cast<int>(current_range_start_),
 454                             data, data_len, callback, true);
 455   }
 456 }
 457
 458 void PartialData::OnCacheReadCompleted(int result) {
 459   DVLOG(3) << "Read: " << result;
 460   if (result > 0) {
 461     current_range_start_ += result;
 462     cached_min_len_ -= result;
 463     DCHECK_GE(cached_min_len_, 0);
 464   }
 465 }
 466
 467 void PartialData::OnNetworkReadCompleted(int result) {
 468   if (result > 0)
 469     current_range_start_ += result;
 470 }
 471
 472 int PartialData::GetNextRangeLen() {
 473   int64 range_len =
 474       byte_range_.HasLastBytePosition() ?
 475       byte_range_.last_byte_position() - current_range_start_ + 1 :
 476       kint32max;
 477   if (range_len > kint32max)
 478     range_len = kint32max;
 479   return static_cast<int32>(range_len);
 480 }
 481
 482 void PartialData::GetAvailableRangeCompleted(int result, int64 start) {
 483   DCHECK(!callback_.is_null());
 484   DCHECK_NE(ERR_IO_PENDING, result);
 485
 486   cached_start_ = start;
 487   cached_min_len_ = result;
 488   if (result >= 0)
 489     result = 1;  // Return success, go ahead and validate the entry.
 490
 491   CompletionCallback cb = callback_;
 492   callback_.Reset();
 493   cb.Run(result);
 494 }
 495
 496 }  // namespace net